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1.  Reliability of ultrasound measurement of automatic activity of the abdominal muscle in participants with and without chronic low back pain 
Ultrasound (US) imaging has been considered as a non-invasive technique to measure thickness and estimate relative abdominal muscle activity. Although some studies have assessed the reliability of US imaging, no study has assessed the reliability of US measurement of automatic activity of abdominal muscles in positions with different levels of stability in participants with chronic low back pain (cLBP). The purpose of this study was to investigate within-day and between-days reliability of US thickness measurements of automatic activity of the abdominal muscles in asymptomatic participants and within-day reliability in those with cLBP.
A total of 20 participants (10 with cLBP, 10 healthy) participated in the study. The reliability of US thickness measurements at supine lying and sitting positions (sitting on a chair, sitting on a gym ball with both feet on the ground or lifting one foot off the floor) were assessed. We evaluated within-day reliability in all participants and between-days reliability in asymptomatic participants.
We found high ICC scores (0.85-0.95) and also small SEM and MDC scores in both groups. The reliability of the measurements was comparable between participants with and without LBP in each position but the SEMs and MDCs was slightly higher in patient group compared with healthy group. It indicates high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all positions.
US imaging can be used as a reliable method for assessment of automatic activity of abdominal muscles in positions with low levels of stability in participants with and without LBP.
PMCID: PMC4029582  PMID: 24479859
Ultrasound; Reliability; Abdominal muscles; Low back pain
Platelet Rich Plasma (PRP) is an emerging non‐surgical intervention used for the treatment of tendon and ligament pathology. Despite the growing popularity of PRP in musculoskeletal medicine, there is a paucity of research that describes appropriate rehabilitation procedures following this intervention.
Case Description:
This case report presents the rehabilitation strategy used following a PRP injection for a patient with a partially torn distal triceps tendon who previously failed physical therapy interventions.
The patient returned to light weight training and coaching activity after completing 15 visits over a 3 month period. One month after discharge, the patient reported pain‐free activities of daily living and a return to previously performed gym activities.
PRP presents a viable treatment option for individuals who are recalcitrant to conservative interventions yet elect to avoid more invasive surgical measures. Despite the growing popularity of PRP, a paucity of evidence exists to guide physical therapists in the rehabilitation process of these patients. The rehabilitation strategies used in a patient who had a PRP injection for a partial triceps tendon tear are outlined. Although this case report highlights a successful rehabilitation outcome, future research regarding the concomitant effects of PRP injection and rehabilitation for tendon pathology are needed.
Level of Evidence:
4‐Case Report
PMCID: PMC3679635  PMID: 23772345
Growth factor; platelet; stem cell
3.  Exercise compliance and the gym ball: a case study 
Manipulation and exercise are recommended by chiropractors for treatment and prevention of low back problems. Many patients stop their exercise program with improvement in their symptoms. The success of exercises for the prevention of low back pain is dependent on several factors, one being continued compliance to the program. Only a small percentage of the general population do regular exercise; therefore, it is essential that patients recognize the importance of regular exercise in reducing the recurrence of their low back pain. This case study shows how the use of a gym ball appears to have improved compliance and reduced the incidence of low back pain for one patient with a history of re-occurring low back pain and a poor record of exercise compliance. The question must be asked, is this an case incident or is use of the gym ball an appropriate treatment for low back pain?
PMCID: PMC2505090
exercise; gymball; low back pain
4.  Exercise referral for drug users aged 40 and over: results of a pilot study in the UK 
BMJ Open  2013;3(5):e002619.
To test whether older drug users (aged 40 and over) could be recruited to an exercise referral (ER) scheme, to evaluate the feasibility and acceptability and measure the impact of participation on health.
Observational pilot.
Liverpool, UK.
(1) 12 men and 5 women recruited to ER. (2) 7 specialist gym instructors.
Outcome measures
Logistic feasibility and acceptability of ER and associated research, rate of recruitment, level of participation over 8 weeks and changes in health.
22 gym inductions were arranged (recruitment time: 5 weeks), 17 inductions were completed and 14 participants began exercising. Attendance at the gym fluctuated with people missing weeks then re-engaging; in week 8, seven participants were in contact with the project and five of these attended the gym. Illness and caring responsibilities affected participation. Participants and gym instructors found the intervention and associated research processes acceptable. In general, participants enjoyed exercising and felt fitter, but would have welcomed more support and the offer of a wider range of activities. Non-significant reductions in blood pressure and heart rate and improvements in metabolic equivalents (METs; a measure of fitness) and general well-being were observed for eight participants who completed baseline and follow-up assessments. The number of weeks of gym attendance was significantly associated with a positive change in METs.
It is feasible to recruit older drug users into a gym-based ER scheme, but multiple health and social challenges affect their ability to participate regularly. The observed changes in health measures, particularly the association between improvements in METs and attendance, suggest further investigation of ER for older drug users is worthwhile. Measures to improve the intervention and its evaluation include: better screening, refined inclusion/exclusion criteria, broader monitoring of physical activity levels, closer tailored support, more flexible exercise options and the use of incentives.
PMCID: PMC3664354  PMID: 23793695
Public health; Health services administration & management; Mental health
5.  Internet-Delivered Interpersonal Psychotherapy Versus Internet-Delivered Cognitive Behavioral Therapy for Adults With Depressive Symptoms: Randomized Controlled Noninferiority Trial 
Face-to-face cognitive behavioral therapy (CBT) and interpersonal psychotherapy (IPT) are both effective treatments for depressive disorders, but access is limited. Online CBT interventions have demonstrated efficacy in decreasing depressive symptoms and can facilitate the dissemination of therapies among the public. However, the efficacy of Internet-delivered IPT is as yet unknown.
This study examines whether IPT is effective, noninferior to, and as feasible as CBT when delivered online to spontaneous visitors of an online therapy website.
An automated, 3-arm, fully self-guided, online noninferiority trial compared 2 new treatments (IPT: n=620; CBT: n=610) to an active control treatment (MoodGYM: n=613) over a 4-week period in the general population. Outcomes were assessed using online self-report questionnaires, the Center for Epidemiological Studies Depression scale (CES-D) and the Client Satisfaction Questionnaire (CSQ-8) completed immediately following treatment (posttest) and at 6-month follow-up.
Completers analyses showed a significant reduction in depressive symptoms at posttest and follow-up for both CBT and IPT, and were noninferior to MoodGYM. Within-group effect sizes were medium to large for all groups. There were no differences in clinical significant change between the programs. Reliable change was shown at posttest and follow-up for all programs, with consistently higher rates for CBT. Participants allocated to IPT showed significantly lower treatment satisfaction compared to CBT and MoodGYM. There was a dropout rate of 1294/1843 (70%) at posttest, highest for MoodGYM. Intention-to-treat analyses confirmed these findings.
Despite a high dropout rate and lower satisfaction scores, this study suggests that Internet-delivered self-guided IPT is effective in reducing depressive symptoms, and may be noninferior to MoodGYM. The completion rates of IPT and CBT were higher than MoodGYM, indicating some progress in refining Internet-based self-help. Internet-delivered treatment options available for people suffering from depression now include IPT.
Trial Registration
International Standard Randomized Controlled Trial Number (ISRCTN): 69603913; (Archived by WebCite at
PMCID: PMC3668608  PMID: 23669884
interpersonal relations; cognitive behavior therapy; depressive disorder; Internet; randomized controlled trial
6.  Rate of injury and subjective benefits of gravitational wellness weightlifting 
A preliminary study using the “gravitational wellness” weightlifting technique demonstrated this to be a unique technique for loading the musculoskeletal system with extremely high loads over short arcs. This leads to rapid weekly strength gains using 30-minute weekly training sessions. This study was designed to further assess the benefit–risk ratio of the gravitational wellness weightlifting technique.
This descriptive/retrospective study examined musculoskeletal and well-being outcomes as well as injuries reported by consecutive participants at one gravitational wellness gym.
Materials and methods
All adults presenting for training at the Atlanta, Georgia, gravitational wellness system facility over a 6-month period were invited to participate. Data were obtained by telephone interview concerning the presenting complaint/objective of training, subjective outcome, weights lifted, and injuries incurred during training.
Of the 77 participants contacted via telephone, 92% agreed to participate (male, n=40; female, n=31). The participants ranged in age from 18 years to 69 years, with a mean age of 48.6 years. Of these, 42 (59%) presented to the gym with the objective of improving a defined musculoskeletal issue. The modal of these was chronic low-back pain. The subjects realized improvement on a 5-point Likert scale of 4.2/5 for their presenting complaint, and improved by 4.27/5 in their overall subjective health. There were no injuries.
This study of consecutive participants at a gravitational wellness gym found that by lifting large weights over short arcs 3 0 minutes per week, participants significantly increased their strength, reduced their musculoskeletal pain, improve their subjective well-being, and reported a low rate of injury.
PMCID: PMC4168877  PMID: 25246813
gravitational wellness system; rate of injuries; weight training; descriptive study
7.  Fitness-Related Activities and Medical Claims Related to Hospital Admissions — South Africa, 2006 
Preventing Chronic Disease  2009;6(4):A120.
We report on the effect of an incentive-based wellness program on medical claims and hospital admissions among members of a major health insurer. The focus of this investigation was specifically on fitness-related activities in this insured population.
Adult members of South Africa's largest private health insurer (n = 948,974) were grouped, a priori, on the basis of documented participation in fitness-related activities, including gym visits, into inactive (80%, equivalent to ≤3 gym visits/y), low active (7.0%, 4-23 gym visits/y), moderate active (5.2%, 24-48 gym visits/y), and high active (7.4%, >48 gym visits/y) groups. We compared medical claims data related to hospital admissions between groups after adjustment for age, sex, medical plan, and chronic illness benefits.
Hospitalization costs per member were lower in each activity group compared with the inactive group. This same pattern was demonstrated for admissions rates. There was good agreement between level of participation in fitness-related activities and in other wellness program offerings; 90% of people only nominally engaged in the wellness program also were low active or inactive, whereas 84% of those in the high active group also had the highest overall participation in the wellness program.
Participation in fitness-related activities within an incentive-based health insurance wellness program was associated with lower health care costs. However, involvement in fitness-related activities was generally low, and further research is required to identify and address barriers to participation in such programs.
PMCID: PMC2774634  PMID: 19754996
8.  Differential diagnosis of a patient referred to physical therapy with neck pain: a case study of a patient with an atypical presentation of angina 
Background and purpose:
A 64-year-old man with acute onset neck pain was referred to physical therapy by a neurosurgeon. The purpose of this case study is to examine the process of differential diagnosis in a patient with neck pain and to discuss common diagnostic errors that can occur in the outpatient setting.
Case description:
The patient had an 8-week history of neck pain, which was worse when running and lifting objects. He presented with imaging of the cervical spine demonstrating degenerative changes. During the examination, several differential diagnoses were considered. A thorough physical examination of the cervical spine and upper quarter failed to reproduce his symptoms. At that time, the physical therapist was suspicious that the origin of the patient’s neck pain was non-mechanical in nature. Additional testing during the examination included having the patient exercise briefly on gym equipment; this reproduced his symptoms. After additional positional and postural changes did not alleviate the symptoms, he stopped exercising, and his pain ceased.
The patient was referred back to his primary care physician who ordered cardiovascular testing including an electrocardiogram and echocardiogram. These tests revealed significant cardiac abnormalities including multi-vessel blockage of the coronary arteries and evidence of infarction. He underwent a coronary artery bypass graft 4 days later.
To make an appropriate differential diagnosis, physical therapists must use a patient-centered model of clinical reasoning and meta-cognition and have an awareness of diagnostic errors such that they can be avoided. The goal of the physical therapy examination, including differential diagnosis, is to efficiently classify the patient for treatment or to direct patients to the proper healthcare provider, thereby minimizing and preventing mortality and morbidity.
PMCID: PMC3500134  PMID: 24179330
Cervical spine; Differential diagnosis; Neck pain; Cardiovascular; Angina pectoris
9.  Post-operative guidelines following hip arthroscopy 
Rehabilitation following hip arthroscopy can vary significantly. Existing programs have been developed as a collaborative effort between physicians and rehabilitation specialists. The evolution of protocol advancement has relied upon feedback from patients, therapists and observable outcomes. Although reports of the first femoroacetabular impingement (FAI) surgeries were reported in the 1930’s, it was not until recently that more structured, physiologically based guidelines have been developed and executed. Four phases have been developed in this guideline based on functional and healing milestones achieved which allow the patient to progress to the next level of activity. The goal of Phase I, the protective phase, is to progressively regain 75% of full range of motion (ROM) and normalize gait while respecting the healing process. The primary goal of Phase II is for the patient to gain function and independence in daily activities without discomfort. Rehabilitation goals include uncompensated step up/down on an 8 inch box, as well as, adequate pelvic control during low demand exercises. Phase III goals strive to accomplish pain free, non-compensated recreational activities and higher demand work functions. Manual muscle testing (MMT) grading of 5/5 should be achieved for all hip girdle musculature and an ability to dynamically control body weight in space. Phase IV requires the patient be independent with home and gym programs and be asymptomatic and pain free following workouts. Return to running may be commenced at the 12 week mark, but the proceeding requirements must be achieved. Athletes undergoing the procedure may have an accelerated timetable, based on the underlying pathology. Recognizing the patient’s pre-operative health status and post-operative physical demands will direct both the program design and the program timetable.
PMCID: PMC3535124  PMID: 22361976
Femoroacetabular impingement; Hip arthroscopy; Rehabilitation guidelines; Return to sport
10.  Complex exercise rehabilitation program for women of the II period of age with metabolic syndrome 
The purpose of this study was to develop a complex exercise program integrating Eastern and Western complex exercise rehabilitation programs in order to examine the effects of it on the human body with the subjects for women of the II period of mature age with metabolic syndrome. The subjects of this study are 60 II period of mature aged women with metabolic syndrome living in G City, and the experimental group conducted Taekwon-aerobic exercise, European rehabilitation gymnastics, gym ball exercise, and elastic band exercise while the control group performed European rehabilitation gymnastics, gym ball exercise, and elastic band exercise which is the rehabilitation program being presently conducted in Russia, for 90 min per day for three weeks. Two-way ANOVA with repeated measures was utilized to verify pre and post-intergroup difference, and the significant level was set as P< 0.05. Whereas body weight, % fat, WHR, SBP, DBP and blood glucose were significant decreased, muscle weight and pulse wave velocity were significant increased after complex exercise rehabilitation programs Both Eastern and Western complex exercise rehabilitation programs showed positive effects on the body of the II period of mature aged women with metabolic syndrome, and if various exercise programs are conducted, it will be more effective in improving II period of mature aged women’s metabolic syndrome afterwards.
PMCID: PMC3836512  PMID: 24278877
Physical rehabilitation; Women of mature age; Metabolic syndrome
11.  Biomechanical Characteristics and Determinants of Instep Soccer Kick 
Good kicking technique is an important aspect of a soccer player. Therefore, understanding the biomechanics of soccer kicking is particularly important for guiding and monitoring the training process. The purpose of this review was to examine latest research findings on biomechanics of soccer kick performance and identify weaknesses of present research which deserve further attention in the future. Being a multiarticular movement, soccer kick is characterised by a proximal-to-distal motion of the lower limb segments of the kicking leg. Angular velocity is maximized first by the thigh, then by the shank and finally by the foot. This is accomplished by segmental and joint movements in multiple planes. During backswing, the thigh decelerates mainly due to a motion-dependent moment from the shank and, to a lesser extent, by activation of hip muscles. In turn, forward acceleration of the shank is accomplished through knee extensor moment as well as a motion-dependent moment from the thigh. The final speed, path and spin of the ball largely depend on the quality of foot-ball contact. Powerful kicks are achieved through a high foot velocity and coefficient of restitution. Preliminary data indicate that accurate kicks are achieved through slower kicking motion and ball speed values.
Key pointsSoccer kick is achieved through segmental and joint rotations in multiple planes and via the proximal-to-distal sequence of segmental angular velocities until ball impact. The quality of ball - foot impact and the mechanical behavior of the foot are also important determinants of the final speed, path and spin of the ball.Ball speed values during the maximum instep kick range from 18 to 35 msec-1 depending on various factors, such as skill level, age, approach angle and limb dominance.The main bulk of biomechanics research examined the biomechanics of powerful kicks, mostly under laboratory conditions. A powerful kick is characterized by the achievement of maximal ball speed. However, maximal ball speed does not guarantee a successful kick: in each case, the ball must reach the target. As already explained, when the player is instructed to hit the ball accurately, joint and segment velocities are lower as opposed to a fast and powerful kick performance. It is therefore apparent that future research should focus on biomechanics of fast but accurate kicking.
PMCID: PMC3786235  PMID: 24149324
Soccer; biomechanics; kicking; football; sports; technique analysis
12.  Gym exercising patterns, lifestyle and high-risk sexual behaviour in men who have sex with men and in heterosexual men 
BMJ Open  2014;4(11):e005205.
Lifestyle may be associated with risk behaviours. This study compares gym exercise and sexual risk behaviour between men who have sex with men (MSM) and heterosexual men. The research was based on the assumption that men who become muscular and physically attractive increase their number of sex partners and consequently their risk of HIV or other sexually transmitted infections (STIs).
Five gyms in central Tel Aviv, Israel.
In 2012, a sample of 182 (48%) MSM and 197 (52%) heterosexual men who train in gyms completed anonymous questionnaires regarding their training, health and sexual behaviours.
Participants in this cross-sectional study who exercised more than the median number of anaerobic training hours were defined as performing intensive anaerobic training (IAT), and those who had performed more than one act of unprotected anal/vaginal intercourse in the preceding 6 months with a partner whose HIV status was unknown were defined as high risk.
MSM showed a stronger desire to become muscular than heterosexual men, were more likely to perform IAT, and used protein powders or anabolic steroids. They reported that improving their body shape and increasing their self-confidence were their main reasons for training, whereas heterosexual men indicated weight loss and health improvement as the main reasons for training. MSM engaged in riskier sexual behaviour than heterosexual men. Of all the high-risk men, 61.9% (N=70) performed IAT, while 38.1% (N=43) performed moderate anaerobic training (p<0.01). The association between IAT and sexual risk was stronger in MSM than in heterosexual men (p<0.01 vs p=0.05, respectively). The interaction between MSM and IAT in high-risk participants was multiplicative.
MSM practised more IAT than heterosexual men, and their interaction between IAT and sexual risk was multiplicative. The MSM community could benefit from a holistic approach to sexual health and its association with body image and IAT. The gym MSM culture demonstrates how internal dynamics and social norms are possible factors driving MSM to high-risk behaviour for HIV/STI.
Study registration
The study was approved by the Wolfson Hospital Review Board, Holon, Israel (WOMC-0058-09).
PMCID: PMC4244394  PMID: 25421336
Gay men; Gym; Sexual risk; Israel
13.  Defining GERD. 
"It is not the death of GERD that I seek, but that it turns from its evil ways and follows the path of righteousness." The reflux world is fully aware of what GERD is and what GERD does. What the world does not know, however, is the answer to the most important yet least asked question surrounding GERD's raison-d'etre: Why is GERD here and why do we have it? What GERD is: abnormal gastric reflux into the esophagus that causes any type of mischief. What GERD does: causes discomfort and/or pain with or without destroying the mucosa; causes stricture or stenosis, preventing food from being swallowed; sets the stage for the development of esophageal adenocarcinoma; invades the surrounding lands to harass the peaceful oropharyngeal, laryngeal and broncho-pulmonary territories; reminds us that we are not only human, but that we are dust and ashes. Why GERD is here: We propose three separate and distinct etiologies of GERD, and we offer the following three hypotheses to explain why, after 1.5 million years of standing erect, we have evolved into a species (specifically Homosapiens sapiens) that is destined to live with the scourge of GERD. Hypothesis 1: congenital. The antireflux barrier, comprising the smooth-muscled lower esophageal sphincter, the skeletal-muscled right crural diaphragm and the phreno-esophageal ligament does not completely develop due to a developmental anomaly or incomplete gestation. Hypothesis 2: acute trauma: The antireflux barrier in adults suffering acute traumatic injury to the abdomen or chest is permanently disrupted by unexpected forces, such as motor vehicle accidents (with steering wheel crush impact), blows to the abdomen (from activities such as boxing, etc.), heavy lifting or moving (e.g., pianos, refrigerators) or stress positions (e.g., hand stands on parallel gym bars). The trauma creates a hiatal hernia that renders the antireflux mechanism useless and incapable of preventing GERD. Hypothesis 3: chronic trauma: The antireflux barrier in children and adults is gradually weakened over time as a result of chronic straining to defecate and straining in an unphysiologic position, both of which stem from our modern day habits of eating a low-fiber diet and living on the high-seated toilet. We suggest that the chronic traumatic hiatal hernia is (a) the cause of more than 90 percent of the GERD that stalks the Western world; (b) is a direct result of abandoning the popular and worldwide practice of squatting to socialize, eat and defecate; and (c) is our just reward for adopting the "civilized" high sitting position on chairs and modern toilets.
PMCID: PMC2579007  PMID: 10780568
14.  The Clinical Effectiveness of Web-Based Cognitive Behavioral Therapy With Face-to-Face Therapist Support for Depressed Primary Care Patients: Randomized Controlled Trial 
Most patients with mild to moderate depression receive treatment in primary care, but despite guideline recommendations, structured psychological interventions are infrequently delivered. Research supports the effectiveness of Internet-based treatment for depression; however, few trials have studied the effect of the MoodGYM program plus therapist support. The use of such interventions could improve the delivery of treatment in primary care.
To evaluate the effectiveness and acceptability of a guided Web-based intervention for mild to moderate depression, which could be suitable for implementation in general practice.
Participants (N=106) aged between 18 and 65 years were recruited from primary care and randomly allocated to a treatment condition comprising 6 weeks of therapist-assisted Web-based cognitive behavioral therapy (CBT), or to a 6-week delayed treatment condition. The intervention included the Norwegian version of the MoodGYM program, brief face-to-face support from a psychologist, and reminder emails. The primary outcome measure, depression symptoms, was measured by the Beck Depression Inventory-II (BDI-II). Secondary outcome measures included the Beck Anxiety Inventory (BAI), the Hospital Anxiety and Depression Scale (HADS), the Satisfaction with Life Scale (SWLS), and the EuroQol Group 5-Dimension Self-Report Questionnaire (EQ-5D). All outcomes were based on self-report and were assessed at baseline, postintervention, and at 6-month follow-up.
Postintervention measures were completed by 37 (71%) and 47 (87%) of the 52 participants in the intervention and 54 participants in the delayed treatment group, respectively. Linear mixed-models analyses revealed a significant difference in time trends between the groups for the BDI-II, (P=.002), for HADS depression and anxiety subscales (P<.001 and P=.001, respectively), and for the SWLS (P<.001). No differential group effects were found for the BAI and the EQ-5D. In comparison to the control group, significantly more participants in the intervention group experienced recovery from depression as measured by the BDI-II. Of the 52 participants in the treatment program, 31 (60%) adhered to the program, and overall treatment satisfaction was high. The reduction of depression and anxiety symptoms was largely maintained at 6-month follow-up, and positive gains in life satisfaction were partly maintained.
The intervention combining MoodGYM and brief therapist support can be an effective treatment of depression in a sample of primary care patients. The intervention alleviates depressive symptoms and has a significant positive effect on anxiety symptoms and satisfaction with life. Moderate rates of nonadherence and predominately positive evaluations of the treatment also indicate the acceptability of the intervention. The intervention could potentially be used in a stepped-care approach, but remains to be tested in regular primary health care.
Trial Registration
Australian New Zealand Clinical Trials Registry: ACTRN12610000257066; (Archived by WebCite at
PMCID: PMC3742404  PMID: 23916965
cognitive therapy; therapy; computer-assisted; Internet; mental health; depression; randomized controlled trial; primary health care
15.  A 2-year prospective longitudinal study on low back pain in primary school children 
European Spine Journal  2002;11(5):459-464.
There is increasing evidence that non-specific low back pain (LBP) is common among children and adolescents, but there are few longitudinal studies on this subject. This is a longitudinal prospective study aimed at finding factors associated with the prediction of low back pain in schoolchildren aged 9–12 years, which is a younger age group than has previously been studied. This study was performed on school children in the city of Antwerp, Belgium. A total of 287 children filled out a questionnaire and were examined at the beginning of the study (T1) and 2 years later (T2). The questionnaire asked about back pain, general health, health perceptions, quality of life perceptions, sports, leisure, daily life, school life (weight of satchel...) and some issues related to parents (smoking, LBP). The questionnaire reliability was tested. Logistic regression was used to analyse the data. No predictors for LBP in children could be identified. Using logistic regression techniques, we analysed the children who reported no lifetime episode of LBP at both T1 and T2, the children who did report a lifetime episode at both T1 and T2 and also those who reported a history of LBP at T2 only (New LBP). At T2 there were 51 children (17.8%) reporting suffering at least one lifetime episode of LBP who had not reported such an episode at T1. Only one parameter showed a statistical difference: New LBP was observed significantly more frequently in children who do not walk to school (P<0.0001). An interesting point of this study is that a number of children who had reported a history of LBP at T1 did not do so at T2. It may be that LBP in children is so benign and its natural history so favourable that the memory of the episode fades away. It is extremely interesting to note that among the few significant variables, those related to general well-being and self-perception of health, are prominent. It appears, therefore, that psychological factors play a role in the experience of LBP in a similar way to what has been reported in adults. Poor self-perception of health (health belief) could be a factor behind the reporting of LBP. Some variables linked to consequences of LBP (absence from school or from gym and visit to a doctor) play a significant role in reporting LBP, which suggests that those "health care" factors may reinforce a feeling of disease severity.
PMCID: PMC3611315  PMID: 12384754
Low back pain Children
16.  Norwegian General Practitioners’ Perspectives on Implementation of a Guided Web-Based Cognitive Behavioral Therapy for Depression: A Qualitative Study 
Previous research suggests that Internet-based cognitive behavioral therapy (ICBT) has a positive effect on symptoms of depression. ICBT appears to be more effective with therapist support, but it is unclear what this support should comprise. General practitioners (GPs) have positive attitudes toward ICBT. However, ICBT is rarely used in regular care in general practice. More research is warranted to integrate the potential of ICBT as part of regular care.
The aim of this study was to explore aspects perceived by GPs to affect the implementation of guided ICBT in daily practice. Understanding their perspectives may contribute to improving the treatment of depression in the context of general practice.
A training package (3-day course) introducing a Norwegian translation of the ICBT program MoodGYM was developed and presented to GPs in Norway. Following training, GPs were asked to include guided ICBT in their regular care of patients with symptoms of depression by providing brief, face-to-face follow-up consultations between modules. We interviewed 11 GPs who had taken the course. Our interview guide comprised open questions that encouraged GPs to frame their responses using examples from their experiences when implementing ICBT. Thematic analysis was chosen to explore patterns across the data.
An overall belief that ICBT would benefit both the patients’ health and the GPs’ own work satisfaction prompted the GPs to take the ICBT course. ICBT motivated them to invest time and effort in improving treatment. The most important motivating aspects in MoodGYM were that a program based on cognitive behavioral therapy could add a structured agenda to their consultations and empower depressed patients. Organizational aspects, such as a lack of time and varied practice, inhibited the use of ICBT. Inadequate knowledge, recalling the program, and changing own habits were also challenging. The GPs were ambivalent about whether ICBT had a negative impact on the doctor–patient interaction in the module follow-ups. Generally, GPs made an effort to recommend MoodGYM, but the expected module follow-ups were often not provided to patients and instead the GPs returned to standard treatment.
GPs’ feedback in the present study contribute to our understanding of the challenges of changing treatment for depression. Our findings indicated that recommending ICBT could add to the GP’s toolkit. Offering training and highlighting the following aspects may increase recommendation of ICBT by GPs: (1) ICBT is theory-based and credible, (2) ICBT increases the GPs’ work satisfaction by having a tool to offer, and (3) ICBT facilitates empowerment of patients in their own health. In addition, the present study also indicated that complex aspects must be accommodated before module follow-ups can be incorporated into GPs’ treatment of depression.
PMCID: PMC4180343  PMID: 25208886
mental health; Internet; telemedicine; qualitative research; primary health care; cognitive therapy; depression
17.  Keeping Your Eyes Continuously on the Ball While Running for Catchable and Uncatchable Fly Balls 
PLoS ONE  2014;9(3):e92392.
When faced with a fly ball approaching along the sagittal plane, fielders need information for the control of their running to the interception location. This information could be available in the initial part of the ball trajectory, such that the interception location can be predicted from its initial conditions. Alternatively, such predictive information is not available, and running to the interception location involves continuous visual guidance. The latter type of control would predict that fielders keep looking at the approaching ball for most of its flight, whereas the former type of control would fit with looking at the ball during the early part of the ball's flight; keeping the eyes on the ball during the remainder of its trajectory would not be necessary when the interception location can be inferred from the first part of the ball trajectory. The present contribution studied visual tracking of approaching fly balls. Participants were equipped with a mobile eye tracker. They were confronted with tennis balls approaching from about 20 m, and projected in such a way that some balls were catchable and others were not. In all situations, participants almost exclusively tracked the ball with their gaze until just before the catch or until they indicated that a ball was uncatchable. This continuous tracking of the ball, even when running close to their maximum speeds, suggests that participants employed continuous visual control rather than running to an interception location known from looking at the early part of the ball flight.
PMCID: PMC3966785  PMID: 24670972
18.  Momentum and Kinetic Energy Before the Tackle in Rugby Union 
Understanding the physical demands of a tackle in match situations is important for safe and effective training, developing equipment and research. Physical components such as momentum and kinetic energy, and it relationship to tackle outcome is not known. The aim of this study was to compare momenta between ball-carrier and tackler, level of play (elite, university and junior) and position (forwards vs. backs), and describe the relationship between ball-carrier and tackler mass, velocity and momentum and the tackle outcome. Also, report on the ball-carrier and tackler kinetic energy before contact and the estimated magnitude of impact (energy distributed between ball-carrier and tackler upon contact). Velocity over 0.5 seconds before contact was determined using a 2-dimensional scaled version of the field generated from a computer alogorithm. Body masses of players were obtained from their player profiles. Momentum and kinetic energy were subsequently calculated for 60 tackle events. Ball-carriers were heavier than the tacklers (ball-carrier 100 ± 14 kg vs. tackler 93 ± 11 kg, d = 0.52, p = 0.0041, n = 60). Ball-carriers as forwards had a significantly higher momentum than backs (forwards 563 ± 226 Kg.m.s-1 n = 31 vs. backs 438 ± 135 Kg.m.s-1, d = 0.63, p = 0.0012, n = 29). Tacklers dominated 57% of tackles and ball-carriers dominated 43% of tackles. Despite the ball-carrier having a mass advantage before contact more frequently than the tackler, momentum advantage and tackle dominance between the ball-carrier and tackler was proportionally similar. These findings may reflect a characteristic of the modern game of rugby where efficiently heavier players (particularly forwards) are tactically predetermined to carry the ball in contact.
Key PointsFirst study to quantify momentum, kinetic energy, and magnitude of impact in rugby tackles across different levels in matches without a device attached to a player.Physical components alone, of either ball-carrier or tackler, are not good predictors of tackle dominance.The range of magnitudes of impact of injury free tackles observed in this study provides evidence for the physical tolerance of players during the tackle.
PMCID: PMC4126292  PMID: 25177182
Tackle; rugby union; contact sports; momentum; kinetic energy
19.  Effectiveness of physiotherapy exercise following total knee replacement: systematic review and meta-analysis 
Rehabilitation, with an emphasis on physiotherapy and exercise, is widely promoted after total knee replacement. However, provision of services varies in content and duration. The aim of this study is to update the review of Minns Lowe and colleagues 2007 using systematic review and meta-analysis to evaluate the effectiveness of post-discharge physiotherapy exercise in patients with primary total knee replacement.
We searched MEDLINE, Embase, PsycInfo, CINAHL and Cochrane CENTRAL to October 4th 2013 for randomised evaluations of physiotherapy exercise in adults with recent primary knee replacement.
Outcomes were: patient-reported pain and function, knee range of motion, and functional performance. Authors were contacted for missing data and outcomes. Risk of bias and heterogeneity were assessed. Data was combined using random effects meta-analysis and reported as standardised mean differences (SMD) or mean differences (MD).
Searches identified 18 randomised trials including 1,739 patients with total knee replacement. Interventions compared: physiotherapy exercise and no provision; home and outpatient provision; pool and gym-based provision; walking skills and more general physiotherapy; and general physiotherapy exercise with and without additional balance exercises or ergometer cycling.
Compared with controls receiving minimal physiotherapy, patients receiving physiotherapy exercise had improved physical function at 3–4 months, SMD −0.37 (95% CI −0.62, −0.12), and pain, SMD −0.45 (95% CI −0.85, −0.06). Benefit up to 6 months was apparent when considering only higher quality studies.
There were no differences for outpatient physiotherapy exercise compared with home-based provision in physical function or pain outcomes. There was a short-term benefit favouring home-based physiotherapy exercise for range of motion flexion.
There were no differences in outcomes when the comparator was hydrotherapy, or when additional balancing or cycling components were included. In one study, a walking skills intervention was associated with a long-term improvement in walking performance. However, for all these evaluations studies were under-powered individually and in combination.
After recent primary total knee replacement, interventions including physiotherapy and exercise show short-term improvements in physical function. However this conclusion is based on meta-analysis of a few small studies and no long-term benefits of physiotherapy exercise interventions were identified. Future research should target improvements to long-term function, pain and performance outcomes in appropriately powered trials.
Electronic supplementary material
The online version of this article (doi:10.1186/s12891-015-0469-6) contains supplementary material, which is available to authorized users.
PMCID: PMC4333167
Systematic review; Meta-analysis; Rehabilitation; Physiotherapy; Total knee replacement; Arthroplasty; Exercise; Osteoarthritis; Outcome
20.  Patients’ Experiences of Helpfulness in Guided Internet-Based Treatment for Depression: Qualitative Study of Integrated Therapeutic Dimensions 
Quantitative research on Internet-based cognitive behavioral therapy (ICBT) has collected substantial evidence for the effectiveness of this treatment approach on health outcomes. Less is known about how patients find ICBT to be generally meaningful and helpful for treating depression.
To explore patients’ experiences of being in ICBT treatment with a focus on the treatment dimensions that they considered helpful.
Choosing a phenomenological-hermeneutical approach, 14 patients were interviewed with semistructured qualitative interviews to elicit their understanding of using ICBT. The patients took part in a clinical trial using ICBT with MoodGYM, which also featured brief consultations with a clinical psychologist. The interviews were transcribed and analyzed according to the chosen methodology and organized into significant themes.
The phenomenological-hermeneutical analysis identified 5 themes relating overall to the meaning of this mode of treatment in terms of helpfulness. Two related to treatment in general: (1) taking action to address one’s problems and (2) the value of talking to a professional. The next two themes specifically addressed guided self-help using the MoodGYM program: (3) acquiring relevant knowledge, and (4) restructuring the new knowledge acquired through ICBT. A fifth theme concerned (5) actual changes in patients’ perceptions and interactions, related to either the self-help material or the face-to-face consultations with the therapist.
Three important dimensions were made explicit: the active engagement of the patient, the guidance of the therapist, and the content of the treatment program. The findings pointed to (1) the role of MoodGYM as a source of new knowledge providing patients with a structured approach to work with their depression, (2) the patient’s role as the primary agent of change through adapting relevant knowledge from MoodGYM to their situation, and (3) the dialogue with the therapist as a trusting relationship in which to share thoughts and feelings, receive feedback and advice, and to assist the patient in making use of the MoodGYM content.
PMCID: PMC3713917  PMID: 23786763
Internet-based cognitive behavioral therapy; ICBT; guided self-help; depression; qualitative
21.  Metal-on-Metal Total Hip Resurfacing Arthroplasty 
Executive Summary
The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population.
Clinical Need
Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years.
Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries.
The Technology
Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup.
Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR.
A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada.
Review Strategy
A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety).
The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained.
Summary of Findings
Health Outcomes
The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score.
The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative Oxford hip scores, but no preoperative values were reported.
None of the reviewed studies reported procedure-related deaths. Four studies reported implant survival rates ranging from 94.4% to 99.7% for a follow-up period of 2.8 to 3.5 years. Three studies reported on the range of motion. One reported improvement in all motions including flexion, extension, abduction-adduction, and rotation, and another reported improvement in flexion. Yet another reported improvement in range of motion for flexion abduction-adduction and rotation arc. However, the author reported a decrease in the range of motion in the arc of flexion in patients with Brooker class III or IV heterotopic bone (all patients were men).
Safety of Metal-on-Metal Hip Resurfacing Arthroplasty
There is a concern about metal wear debris and its systemic distribution throughout the body. Detectable metal concentrations in the serum and urine of patients with metal hip implants have been described as early as the 1970s, and this issue is still controversial after 35 years.
Several studies have reported high concentration of cobalt and chromium in serum and/or urine of the patients with metal hip implants. Potential toxicological effects of the elevated metal ions have heightened concerns about safety of MOM bearings. This is of particular concern in young and active patients in whom life expectancy after implantation is long.
Since 1997, 15 studies, including 1 randomized clinical trial, have reported high levels of metal ions after THR with metal implants. Some of these studies have reported higher metal levels in patients with loose implants.
Adverse Biological Effects of Cobalt and Chromium
Because patients who receive a MOM hip arthroplasty are shown to be exposed to high concentrations of metallic ions, the Medical Advisory Secretariat searched the literature for reports of adverse biological effects of cobalt and chromium. Cobalt and chromium make up the major part of the metal articulations; therefore, they are a focus of concern.
Risk of Cancer
To date, only one study has examined the incidence of cancer after MOM and polyethylene on metal total hip arthroplasties. The results were compared to that of general population in Finland. The mean duration of follow-up for MOM arthroplasty was 15.7 years; for polyethylene arthroplasty, it was 12.5 years. The standardized incidence ratio for all cancers in the MOM group was 0.95 (95% CI, 0.79–1.13). In the polyethylene on metal group it was 0.76 (95% CI, 0.68–0.86). The combined standardized incidence ratio for lymphoma and leukemia in the patients who had MOM THR was 1.59 (95% CI, 0.82–2.77). It was 0.59 (95% CI, 0.29–1.05) for the patients who had polyethylene on metal THR. Patients with MOM THR had a significantly higher risk of leukemia. All patients who had leukemia were aged over than 60 years.
Cobalt Cardiotoxicity
Epidemiological Studies of Myocardiopathy of Beer Drinkers
An unusual type of myocardiopathy, characterized by pericardial effusion, elevated hemoglobin concentrations, and congestive heart failure, occurred as an epidemic affecting 48 habitual beer drinkers in Quebec City between 1965 and 1966. This epidemic was directly related the consumption of a popular beer containing cobalt sulfate. The epidemic appeared 1 month after cobalt sulfate was added to the specific brewery, and no further cases were seen a month after this specific chemical was no longer used in making this beer. A beer of the same name is made in Montreal, and the only difference at that time was that the Quebec brand of beer contained about 10 times more cobalt sulphate. Cobalt has been added to some Canadian beers since 1965 to improve the stability of the foam but it has been added in larger breweries only to draught beer. However, in small breweries, such as those in Quebec City, separate batches were not brewed for bottle and draught beer; therefore, cobalt was added to all of the beer processed in this brewery.
In March 1966, a committee was appointed under the chairmanship of the Deputy Minister of Health for Quebec that included members of the department of forensic medicine of Quebec’s Ministry of Justice, epidemiologists, members of Food and Drug Directorate of Ottawa, toxicologists, biomedical researchers, pathologists, and members of provincial police. Epidemiological studies were carried out by the Provincial Ministry of Health and the Quebec City Health Department.
The association between the development of myocardiopathy and the consumption of the particular brand of beer was proven. The mortality rate of this epidemic was 46.1% and those who survived were desperately ill, and recovered only after a struggle for their lives.
Similar cases were seen in Omaha (Nebraska). The epidemic started after a cobalt additive was used in 1 of the beers marketed in Nebraska. Sixty-four patients with the clinical diagnosis of alcoholic myocardiopathy were seen during an 18-month period (1964–1965). Thirty of these patients died. The first patient became ill within 1 month after cobalt was added to the beer, and the last patient was seen within 1 month of withdrawal of cobalt.
A similar epidemic occurred in Minneapolis, Minnesota. Between 1964 and 1967, 42 patients with acute heart failure were admitted to a hospital in Minneapolis, Minnesota. Twenty of these patients were drinking 6 to 30 bottles per day of a particular brand of beer exclusively. The other 14 patients also drank the same brand of beer, but not exclusively. The mortality rate from the acute illness was 18%, but late deaths accounted for a total mortality rate of 43%. Examination of the tissue from these patients revealed markedly abnormal changes in myofibrils (heart muscles), mitochondria, and sarcoplasmic reticulum.
In Belgium, a similar epidemic was reported in 1966, in which, cobalt was used in some Belgian beers. There was a difference in mortality between the Canadian or American epidemic and this series. Only 1 of 24 patients died, 1.5 years after the diagnosis. In March 1965, at an international meeting in Brussels, a new heart disease in chronic beer drinkers was described. This disease consists of massive pericardial effusion, low cardiac output, raised venous pressure, and polycythemia in some cases. This syndrome was thought to be different from the 2 other forms of alcoholic heart disease (beriberi and a form characterized by myocardial fibrosis).
The mystery of the above epidemics as stated by investigators is that the amount of cobalt added to the beer was below the therapeutic doses used for anemia. For example, 24 pints of Quebec brand of beer in Quebec would contain 8 mg of cobalt chloride, whereas an intake of 50 to 100 mg of cobalt as an antianemic agent has been well tolerated. Thus, greater cobalt intake alone does not explain the occurrence of myocardiopathy. It seems that there are individual differences in cobalt toxicity. Other features, like subclinical alcoholic heart disease, deficient diet, and electrolyte imbalance could have been precipitating factors that made these patients susceptible to cobalt’s toxic effects.
In the Omaha epidemic, 60% of the patients had weight loss, anorexia, and occasional vomiting and diarrhea 2 to 6 months before the onset of cardiac symptoms. In the Quebec epidemic, patients lost their appetite 3 to 6 months before the diagnosis of myocardiopathy and developed nausea in the weeks before hospital admission. In the Belgium epidemic, anorexia was one of the most predominant symptoms at the time of diagnosis, and the quality and quantity of food intake was poor. Alcohol has been shown to increase the uptake of intracoronary injected cobalt by 47%. When cobalt enters the cells, calcium exits; this shifts the cobalt to calcium ratio. The increased uptake of cobalt in alcoholic patients may explain the high incidence of cardiomyopathies in beer drinkers’ epidemics.
As all of the above suggest, it may be that prior chronic exposure to alcohol and/or a nutritionally deficient diet may have a marked synergistic effect with the cardiotoxicity of cobalt.
MOM hip resurfacing arthroplasty has been shown to be an effective arthroplasty procedure as tested in younger patients.
However, evidence for effectiveness is based only on 7 case series with short duration of follow-up (2.8–3.5 years). There are no RCTs or other well-controlled studies that compare MOM hip resurfacing with THR.
Revision rates reported in the MOM studies using implants currently licensed in Canada (hybrid systems, uncemented acetabular, and cemented femoral) range from 0.3% to 3.6% for a mean follow-up ranging from 2.8 to 3.5 years.
Fracture of femoral neck is not very common; it occurs in 0.4% to 2.2% of cases (as observed in a short follow-up period).
All the studies that measured health outcomes have reported improvement in Harris Hip and SF-12 scores; 1 study reported significant reduction in pain and improvement in function, and 2 studies reported significant improvement in SF-12 scores. One study reported significant improvement in UCLA Hip scores.
Concerns remain on the potential adverse effects of metal ions. Longer-term follow-up data will help to resolve the inconsistency of findings on adverse effects, including toxicity and carcinogenicity.
Ontario-Based Economic Analysis
The device cost for MOM ranges from $4,300 to $6,000 (Cdn). Traditional hip replacement devices cost about $2,000 (Cdn). Using Ontario Case Costing Initiative data, the total estimated costs for hip resurfacing surgery including physician fees, device fees, follow-up consultation, and postsurgery rehabilitation is about $15,000 (Cdn).
Cost of Total Hip Replacement Surgery in Ontario
MOM hip arthroplasty is generally recommended for patients aged under 55 years because its bone-conserving advantage enables patients to “buy time” and hence helps THRs to last over the lifetime of the patient. In 2004/2005, 15.9% of patients who received THRs were aged 55 years and younger. It is estimated that there are from 600 to 1,000 annual MOM hip arthroplasty surgeries in Canada with an estimated 100 to 150 surgeries in Ontario. Given the increased public awareness of this device, it is forecasted that demand for MOM hip arthroplasty will steadily increase with a conservative estimate of demand rising to 1,400 cases by 2010 (Figure 10). The net budget impact over a 5-year period could be $500,000 to $4.7 million, mainly because of the increasing cost of the device.
Projected Number of Metal-on-Metal Hip Arthroplasty Surgeries in Ontario: to 2010
PMCID: PMC3379532  PMID: 23074495
22.  Perseverative responding in a violation-of-expectation task in 6.5-month-old infants 
Cognition  2003;88(3):277-316.
In the present research, 6.5-month-old infants perseverated in a violation-of-expectation task designed to examine their reasoning about width information in containment events. After watching a familiarization event in which a ball was lowered into a wide container, the infants failed to detect the violation in a test event in which the same ball was lowered into a container only half as wide as the ball (narrow-container test event). This negative result (which was replicated in another experiment) was interpreted in terms of a recent problem-solving account of infants’ perseverative errors in various means-end tasks (Aguiar, A., & Baillargeon, R. (2000). Perseveration and problem solving in infancy. In H. W. Reese (Ed.), Advances in child development and behavior (Vol. 27, pp. 135–180). San Diego, CA: Academic Press). It was assumed that the infants in the present experiments (1) did not attend to the relative widths of the ball and container in their initial analysis of the narrow-container test event, (2) categorized the event as similar to the familiarization event shown on the preceding trials, and (3) retrieved the expectation they had formed for that event (“the ball will fit into the container”), resulting in a perseverative error. This interpretation was supported by additional experiments in which different modifications were introduced that led to non-perseverative responding, indicating that 6.5-month-old infants could detect the violation in the narrow-container test event. The present findings are important for several reasons. First, they provide the first demonstration of perseverative responding in a violation-of-expectation task. Second, they make clear the breadth and usefulness of the problem-solving account mentioned above. Finally, they add to the evidence for some degree of continuity between infants’ and adults’ problem-solving abilities.
PMCID: PMC4212222  PMID: 12804814
Infant cognition; Physical reasoning; Violation-of-expectation task; Perseveration
23.  Sex Differences During Visual Scanning of Occlusion Events in Infants 
Developmental psychology  2011;48(4):1091-1105.
A growing number of sex differences in infant behavior have been reported over the last 10 years. One task on which sex differences have been observed reliably is the event-mapping task. In this task, infants view an occlusion event involving 1 or 2 objects, the occluder is removed, and then infants see 1 object sitting on the platform. When the occlusion sequence is complex (i.e., involves paths of motion that change direction when occluded), boys are more likely than girls to detect an inconsistency between a 2-object occlusion event and a 1-object display. The current research used eye-tracking technology to investigate the specific cognitive processes that underlie these sex differences. Three experiments were conducted with 2 age groups of infants with mean ages of 9 months and 4 months. Infants saw a ball–box (2-object) or ball–ball (1-object) occlusion event followed by a 1-ball display; visual scanning of the occlusion event and the 1-ball display was recorded. In the older age group, boys were more likely than girls to visually track the objects through occlusion; they were also more likely to detect an inconsistency between the ball–box event and the 1-ball display (i.e., they visually searched for the missing box). In addition, tracking of the objects through occlusion was related to infants' scanning of the 1-ball display. In the younger age group, both boys and girls failed to track the objects through occlusion and to detect an inconsistency between the ball–box event and the 1–ball display. These results suggest that infants' capacity to track objects through occlusion facilitates extraction of the structure of the initial event (i.e., the number of distinct objects involved), that infants can map onto the final display, and that sex differences in this ability emerge between 4 and 9 months. Possible explanations for how the structure of an occlusion event is extracted and mapped onto a subsequent nonocclusion display are considered.
PMCID: PMC3722862  PMID: 22148944
infants; object processing; sex differences; occlusion; eye tracking
24.  Prevention of relapsing backache 
The condition of non-specific back pain is characterized by high prevalence, non satisfactory therapeutic options and severe socioeconomic consequences. Therefore prevention seems an attractive option to downsize the problem. However, the construction of effective preventive measures is complicated by the obscure aetiology of the condition, the multidimensionality of risk and prognostic factors (bio psychosocial model!) and the variability of its natural as well as clinical course. This led to the development of a wide variety of preventive measures: e. g. exercise programs, educational measures (including back school), ergonomic modification of the work environment, mechanical supports (e. g. back belts) as well as multidisciplinary interventions. For two reasons the workplace seems to be a suitable setting for prevention. First, because a number of strong risk factors are associated with working conditions and second, because it allows addressing a large proportion of the adult population. Against this background the assessment at hand sets out to answer the following questions:
What is the amount and methodological quality of the available scientific literature on the effectiveness of back pain prevention in the workplace environment? What are effective measures for the prevention of back pain and its consequences in the workplace environment and how effective are they? Is back pain prevention in the workplace environment cost-effective? Is there a need for more research? As primary outcomes for effectiveness the assessment will focus on time lost from work and the frequency and duration of episodes with back pain. The preventive measures assessed belong to the following categories: exercise programs, educational and information measures, multidimensional interventions, back belts, lifting teams and ergonomic interventions.
The assessment is based on a systematic review of the published literature according to the methodological requirements of DAHTA. Proceedings of the electronic literature searches are documented in the appendix. In addition references of review articles were searched. Methodological quality of publications (systematic reviews, HTA reports) was assessed using the checklists developed by the German Scientific Working Group for Technology Assessment in Health Care (GSWGTAHC) or with the Jadad-Score (controlled trials) respectively. Due to the large number of relevant publications the assessment is mainly based on data reported by systematic reviews and supplemented by the results of newer trials. A separate economic assessment was not performed because of the low amount of available data. An assessment of ethical, legal and social impact was omitted due to resource constraints.
For preventive interventions based on exercise programs most of the analysed trials demonstrate some effectiveness. Due to the heterogeneity of the programs it is not possible to conclude whether positive effects are associated with a special type, duration or intensity of exercise. For purely educational measures or information strategies applied in a workplace setting the available trials were not able to demonstrate effectiveness. Back school programs, which in addition to theoretical instructions offer intensive exercising may in the short term, be successful in reducing the incidence of new episodes of back pain. Some trials in high risk groups demonstrate effectiveness of multidimensional interventions on time lost from work. These programs include education and exercise as well as cognitive behavioural interventions to change pain perception. The assessment of the benefits of back belts for the prevention of back pain is based on results of high quality efficacy as well as effectiveness trials. Their results imply for the otherwise healthy working population no protective effect of back belts on time lost from work due to back pain, on the incidence of painful episodes or on days with impairment by back pain. So far there are no data from controlled trials that demonstrate the effectiveness of "lifting teams" in nursing care to prevent back pain or its consequences. However, results from uncontrolled pilot studies indicate a potential for effectiveness. Among "ergonomic interventions" three different approaches have to be distinguished: interventions addressing changes of the workplace setting, interventions addressing the individual's behaviour and combined interventions. Studies evaluating the effectiveness of setting interventions (modification of the physical workplace environment, changes of production processes, organisational changes) yield no dependable results. This conclusion is not based on indifferent trial results but rather on the lack of methodologically sound studies. Results from studies on ergonomic interventions addressing the individual confirm the conclusions drawn for exercise and educational measures. The most marked results are found in trials that examine the effectiveness of combined interventions in high risk groups and contain a strong participatory component. Hardly any of the trials studying the effects of ergonomic interventions satisfied methodological quality criteria that are accepted standard for clinical or public health intervention studies.
There were no data allowing firm conclusions on the cost-effectiveness of interventions from any of the categories.
The significance of the results of the assessment at hand is strongly limited by the comprehensiveness of the questions addressed. Reviewing the literature on the basis of (even systematic) review articles impairs the differentiated examination of the role of target groups, program contents, application and duration, effect sizes and context factors. While the methodological quality of the review articles is quite high, the quality of individual trials (even those included in the review papers) is highly variable. While most trials examining preventive interventions addressed at individuals satisfy at least some methodological requirements many studies dealing with setting interventions do not.
In conclusion, sound scientific evidence for the effectiveness and cost-effectiveness of back pain prevention in the workplace environment is still quite scarce. Further research should include:
The development of interventions guided by the bio psychosocial model of back pain aetiology that combines individual prevention as well as measures addressing the workplace environment.The integration of results from basic ergonomic research into prevention concepts and the conduct of trials focussing outcomes with relevance to the workplace setting. The conduct of qualitative studies to identify factors that impair the effectiveness of prevention programs (e. g. motivation, compliance, people skills).The integration of cost-effectiveness evaluations into all interventional studies.
PMCID: PMC3011361  PMID: 21289963
25.  Infants’ reasoning about opaque and transparent occluders in an individuation task 
Cognition  2002;85(1):B1-10.
There has been some debate about whether infants 10 months and younger can use featural information to individuate objects. The present research tested the hypothesis that negative results obtained with younger infants reflect limitations in information processing capacities rather than the inability to individuate objects based on featural differences. Infants aged 9.5 months saw one object (i.e. a ball) or two objects (i.e. a box and a ball) emerge successively to opposite sides of an opaque occluder. Infants then saw a single ball either behind a transparent occluder or without an occluder. Only the infants who saw the ball behind the transparent occluder correctly judged that the one-ball display was inconsistent with the box–ball sequence. These results suggest that: (a) infants categorize events involving opaque and transparent occluders as the same kind of physical situation (i.e. occlusion) and (b) support the notion that infants are more likely to give evidence of object individuation when they need to reason about one kind of event (i.e. occlusion) than when they must retrieve and compare categorically distinct events (i.e. occlusion and no-occlusion).
PMCID: PMC3708599  PMID: 12086715
Object individuation; Infant cognition; Cognitive development

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