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1.  Computerized Cognitive Training in Cognitively Healthy Older Adults: A Systematic Review and Meta-Analysis of Effect Modifiers 
PLoS Medicine  2014;11(11):e1001756.
Michael Valenzuela and colleagues systematically review and meta-analyze the evidence that computerized cognitive training improves cognitive skills in older adults with normal cognition.
Please see later in the article for the Editors' Summary
Background
New effective interventions to attenuate age-related cognitive decline are a global priority. Computerized cognitive training (CCT) is believed to be safe and can be inexpensive, but neither its efficacy in enhancing cognitive performance in healthy older adults nor the impact of design factors on such efficacy has been systematically analyzed. Our aim therefore was to quantitatively assess whether CCT programs can enhance cognition in healthy older adults, discriminate responsive from nonresponsive cognitive domains, and identify the most salient design factors.
Methods and Findings
We systematically searched Medline, Embase, and PsycINFO for relevant studies from the databases' inception to 9 July 2014. Eligible studies were randomized controlled trials investigating the effects of ≥4 h of CCT on performance in neuropsychological tests in older adults without dementia or other cognitive impairment. Fifty-two studies encompassing 4,885 participants were eligible. Intervention designs varied considerably, but after removal of one outlier, heterogeneity across studies was small (I2 = 29.92%). There was no systematic evidence of publication bias. The overall effect size (Hedges' g, random effects model) for CCT versus control was small and statistically significant, g = 0.22 (95% CI 0.15 to 0.29). Small to moderate effect sizes were found for nonverbal memory, g = 0.24 (95% CI 0.09 to 0.38); verbal memory, g = 0.08 (95% CI 0.01 to 0.15); working memory (WM), g = 0.22 (95% CI 0.09 to 0.35); processing speed, g = 0.31 (95% CI 0.11 to 0.50); and visuospatial skills, g = 0.30 (95% CI 0.07 to 0.54). No significant effects were found for executive functions and attention. Moderator analyses revealed that home-based administration was ineffective compared to group-based training, and that more than three training sessions per week was ineffective versus three or fewer. There was no evidence for the effectiveness of WM training, and only weak evidence for sessions less than 30 min. These results are limited to healthy older adults, and do not address the durability of training effects.
Conclusions
CCT is modestly effective at improving cognitive performance in healthy older adults, but efficacy varies across cognitive domains and is largely determined by design choices. Unsupervised at-home training and training more than three times per week are specifically ineffective. Further research is required to enhance efficacy of the intervention.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
As we get older, we notice many bodily changes. Our hair goes grey, we develop new aches and pains, and getting out of bed in the morning takes longer than it did when we were young. Our brain may also show signs of aging. It may take us longer to learn new information, we may lose our keys more frequently, and we may forget people's names. Cognitive decline—developing worsened thinking, language, memory, understanding, and judgment—can be a normal part of aging, but it can also be an early sign of dementia, a group of brain disorders characterized by a severe, irreversible decline in cognitive functions. We know that age-related physical decline can be attenuated by keeping physically active; similarly, engaging in activities that stimulate the brain throughout life is thought to enhance cognition in later life and reduce the risk of age-related cognitive decline and dementia. Thus, having an active social life and doing challenging activities that stimulate both the brain and the body may help to stave off cognitive decline.
Why Was This Study Done?
“Brain training” may be another way of keeping mentally fit. The sale of computerized cognitive training (CCT) packages, which provide standardized, cognitively challenging tasks designed to “exercise” various cognitive functions, is a lucrative and expanding business. But does CCT work? Given the rising global incidence of dementia, effective interventions that attenuate age-related cognitive decline are urgently needed. However, the impact of CCT on cognitive performance in older adults is unclear, and little is known about what makes a good CCT package. In this systematic review and meta-analysis, the researchers assess whether CCT programs improve cognitive test performance in cognitively healthy older adults and identify the aspects of cognition (cognitive domains) that are responsive to CCT, and the CCT design features that are most important in improving cognitive performance. A systematic review uses pre-defined criteria to identify all the research on a given topic; meta-analysis uses statistical methods to combine the results of several studies.
What Did the Researchers Do and Find?
The researchers identified 51 trials that investigated the effects of more than four hours of CCT on nearly 5,000 cognitively healthy older adults by measuring several cognitive functions before and after CCT. Meta-analysis of these studies indicated that the overall effect size for CCT (compared to control individuals who did not participate in CCT) was small but statistically significant. An effect size quantifies the difference between two groups; a statistically significant result is a result that is unlikely to have occurred by chance. So, the meta-analysis suggests that CCT slightly increased overall cognitive function. Notably, CCT also had small to moderate significant effects on individual cognitive functions. For example, some CCT slightly improved nonverbal memory (the ability to remember visual images) and working memory (the ability to remember recent events; short-term memory). However, CCT had no significant effect on executive functions (cognitive processes involved in planning and judgment) or attention (selective concentration on one aspect of the environment). The design of CCT used in the different studies varied considerably, and “moderator” analyses revealed that home-based CCT was not effective, whereas center-based CCT was effective, and that training sessions undertaken more than three times a week were not effective. There was also some weak evidence suggesting that CCT sessions lasting less than 30 minutes may be ineffective. Finally, there was no evidence for the effectiveness of working memory training by itself (for example, programs that ask individuals to recall series of letters).
What Do These Findings Mean?
These findings suggest that CCT produces small improvements in cognitive performance in cognitively healthy older adults but that the efficacy of CCT varies across cognitive domains and is largely determined by design aspects of CCT. The most important result was that “do-it-yourself” CCT at home did not produce improvements. Rather, the small improvements seen were in individuals supervised by a trainer in a center and undergoing sessions 1–3 times a week. Because only cognitively healthy older adults were enrolled in the studies considered in this systematic review and meta-analysis, these findings do not necessarily apply to cognitively impaired individuals. Moreover, because all the included studies measured cognitive function immediately after CCT, these findings provide no information about the durability of the effects of CCT or about how the effects of CCT on cognitive function translate into real-life outcomes for individuals such as independence and the long-term risk of dementia. The researchers call, therefore, for additional research into CCT, an intervention that might help to attenuate age-related cognitive decline and improve the quality of life for older individuals.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001756.
This study is further discussed in a PLOS Medicine Perspective by Druin Burch
The US National Institute on Aging provides information for patients and carers about age-related forgetfulness, about memory and cognitive health, and about dementia (in English and Spanish)
The UK National Health Service Choices website also provides information about dementia and about memory loss
MedlinePlus provides links to additional resources about memory, mild cognitive impairment, and dementia (in English and Spanish)
doi:10.1371/journal.pmed.1001756
PMCID: PMC4236015  PMID: 25405755
2.  Liver fibrosis is associated with cognitive impairment in HIV-positive patients 
Journal of the International AIDS Society  2014;17(4Suppl 3):19722.
Introduction
The aim of our study was to investigate the potential relationship between liver fibrosis (LF) and cognitive performance in HIV+ patients.
Materials and Methods
We performed a cross-sectional cohort study by consecutively enrolling HIV+ patients during routine outpatient visits at two clinical centres in Italy. Subjects with decompensated liver disease were excluded. All subjects underwent a comprehensive neuropsychological battery exploring memory, attention, psychomotor speed and language; cognitive impairment was defined as at least two abnormal [1.5 SD below the mean for appropriate norms] cognitive domains. LF was explored by calculating FIB4 index; in a subgroup of patients, LF was also assessed by transient elastography. Factors associated with cognitive impairment were investigated by logistic regression models.
Results
A total of 413 patients [77% males, median age 46 (IQR 39–52), 17% with past AIDS-defining events, 19% past IDU, 3% with diabetes, 94% on cART, 90% with HIV RNA <50 copies/mL, 18% co-infected with HCV] were enrolled. Seventeen patients (4%) had FIB4 >3.25 and 14/129 (3%) had liver stiffness >14KPa. Forty-seven patients (11%) were diagnosed with cognitive impairment. At multivariate analyses patients with FIB4 >1.45 showed a higher risk of cognitive impairment in comparison with those with lower values (OR 2.19, 95% CI 1.02–4.72; p=0.044) after adjusting for education (OR 0.79, 95% CI 0.71–0.88; p<0.001), past IDU (OR 1.69, 95% CI 0.67–4.23; p=0.264), diabetes (OR 2.35, 95% CI 0.62–8.86; p=0.207), HIV RNA <50 copies/mL (OR 0.47, 95% CI 0.19–1.14; p=0.095) and HCV co-infection (OR 0.88, 95% CI 0.33–2.39; p=0.807). Analyzing any single cognitive domain, a higher risk of abnormal psychomotor speed was associated with fibroscan score >14KPa in comparison with fibroscan score <7KPa (OR 285.07; 95% CI 2.42–33574.06; p=0.020) after adjusting for education (OR 0.54, 95% CI 0.31–0.92; p=0.024), age (for 10 years increase) (OR 2.03, 95% CI 0.55–7.53; p=0.288), past IDU (OR 4.43, 95% CI 0.35–7.57; p=0.526), HIV RNA <50 copies/mL (OR 0.01, 95% CI 0.00–0.18; p=0.003), HIV history (for 1 year increase) (OR 0.96, 95% CI 0.83–1.12; p=0.641), CD4 cells count at nadir (OR 1.10, 95% CI 0.56–2.16; p=0.779), and HCV co-infection (OR 0.06; 95% CI 0.00–1.93; p=0.113).
Conclusions
In HIV-infected patients higher LF, estimated through non-invasive methods, is associated to a higher risk of cognitive impairment.
doi:10.7448/IAS.17.4.19722
PMCID: PMC4225249  PMID: 25397468
3.  Immunological Responses and Long-Term Treatment Interruption after Human Immunodeficiency Virus Type 1 (HIV-1) Lipopeptide Immunization of HIV-1-Infected Patients: the LIPTHERA Study▿  
We studied the time course of immunological and virological markers after highly active antiretroviral therapy (HAART) interruption in chronically human immunodeficiency virus type 1 (HIV-1)-infected patients immunized with an HIV lipopeptide preparation. In a prospective open pilot study, 24 HIV-1-infected HAART-treated patients with undetectable plasma viral loads (pVLs) and CD4+ T-cell counts above 350/mm3 were immunized at weeks 0, 3, and 6 with a candidate vaccine consisting of six HIV lipopeptides. At week 24, patients with pVLs of <1.7 log10 copies/ml were invited to stop taking HAART. Antiretroviral therapy was resumed if the pVL rose above 4.47 log10 copies/ml and/or if the CD4+ cell count fell below 250/mm3. Immunological and virologic parameters were studied before and after HAART interruption. The median baseline and nadir CD4+ cell counts were 482 (interquartile range [IQR], 195 to 826) and 313 (IQR, 1 to 481)/mm3, respectively. New specific CD8+ cell responses to HIV-1 epitopes were detected after immunization in 13 (57%) of 23 assessable patients. Twenty-one patients were evaluated 96 weeks after HAART interruption. The median time to pVL rebound was 4 weeks (IQR, 2 to 6), and the median peak pVL was 4.26 (IQR, 3 to 5) log10 copies/ml. Thirteen of these 21 patients resumed HAART a median of 60 weeks after immunization (IQR, 9.2 to 68.4 weeks), when the median pVL was 4.8 (IQR, 2.9 to 5.7) log10 copies/ml and the median CD4+ cell count was 551 (IQR, 156 to 778)/mm3. Eight patients were still off therapy at 96 weeks, with a median pVL of 4 (IQR, 1.7 to 4.6) log10 copies/ml and a median CD4+ cell count of 412 (IQR, 299 to 832)/mm3. No clinical disease progression had occurred. Despite the lack of a control arm, these findings warrant a randomized study of therapeutic vaccination with HIV lipopeptides followed by long-term HAART interruption in AIDS-free chronically infected patients.
doi:10.1128/CVI.00165-07
PMCID: PMC2268255  PMID: 18184824
4.  Regional areas and widths of the midsagittal corpus callosum among HIV-infected patients on stable antiretroviral therapies 
Journal of neurovirology  2011;17(4):368-379.
Recent reports suggest that a growing number of human immunodeficiency virus (HIV)-infected persons show signs of persistent cognitive impairment even in the context of combination antiretroviral therapies (cART). The basis for this finding remains poorly understood as there are only a limited number of studies examining the relationship between CNS injury, measures of disease severity, and cognitive function in the setting of stable disease. This study examined the effects of HIV infection on cerebral white matter using quantitative morphometry of the midsagittal corpus callosum (CC) in 216 chronically infected participants from the multisite HIV Neuroimaging Consortium study currently receiving cART and 139 controls. All participants underwent MRI assessment, and HIV-infected subjects also underwent measures of cognitive function and disease severity. The midsagittal slice of the CC was quantified using two semi-automated procedures. Group comparisons were accomplished using ANOVA, and the relationship between CC morphometry and clinical covariates (current CD4, nadir CD4, plasma and CSF HIV RNA, duration of HIV infection, age, and ADC stage) was assessed using linear regression models. HIV-infected patients showed significant reductions in both the area and linear widths for several regions of the CC. Significant relationships were found with ADC stage and nadir CD4 cell count, but no other clinical variables. Despite effective treatment, significant and possibly irreversible structural loss of the white matter persists in the setting of chronic HIV disease. A history of advanced immune suppression is a strong predictor of this complication and suggests that antiretroviral intervention at earlier stages of infection may be warranted.
doi:10.1007/s13365-011-0033-6
PMCID: PMC4309645  PMID: 21556960
HIV; Corpus callosum; Nadir CD4; White matter; CART
5.  Cannabis use and neurocognitive functioning in a non-clinical sample of users 
Addictive behaviors  2014;39(5):994-999.
Objective
With the recent debates over marijuana legalization and increases in use, it is critical to examine its role in cognition. While many studies generally support the adverse acute effects of cannabis on neurocognition, the non-acute effects remain less clear. The current study used a cross-sectional design to examine relationships between recent and past cannabis use on neurocognitive functioning in a non-clinical adult sample.
Method
One hundred and fifty-eight participants were recruited through fliers distributed around local college campuses and the community. All participants completed the Brief Drug Use History Form, the Structured Clinical Interview for DSM-IV Disorders, and neurocognitive assessment, and underwent urine toxicology screening. Participants consisted of recent users (n = 68), past users (n = 41), and non-users (n = 49).
Results
Recent users demonstrated significantly (p < .05) worse performance than non-users across cognitive domains of attention/working memory (M = 42.4, SD = 16.1 vs. M = 50.5, SD = 10.2), information processing speed (M = 44.3, SD = 7.3 vs. M = 52.1, SD = 11.0), and executive functioning (M = 43.6, SD = 13.4 vs. M = 48.6, SD = 7.2). There were no statistically significant differences between recent users and past users on neurocognitive performance. Frequency of cannabis use in the last 4 weeks was negatively associated with global neurocognitive performance and all individual cognitive domains. Similarly, amount of daily cannabis use was negatively associated with global neurocognitive performance and individual cognitive domains.
Conclusions
Our results support the widespread adverse effects of cannabis use on neurocognitive functioning. Although some of these adverse effects appear to attenuate with abstinence, past users' neurocognitive functioning was consistently lower than non-users.
doi:10.1016/j.addbeh.2014.01.019
PMCID: PMC4032061  PMID: 24556155
Cannabis; Cognition; Premorbid IQ; Abstinence; Past use; Abuse
6.  Magnitude and Complexity of Rectal Mucosa HIV-1-Specific CD8+ T-Cell Responses during Chronic Infection Reflect Clinical Status 
PLoS ONE  2008;3(10):e3577.
Background
The intestinal mucosa displays robust virus replication and pronounced CD4+ T-cell loss during acute human immunodeficiency virus type 1 (HIV-1) infection. The ability of HIV-specific CD8+ T-cells to modulate disease course has prompted intensive study, yet the significance of virus-specific CD8+ T-cells in mucosal sites remains unclear.
Methods and Findings
We evaluated five distinct effector functions of HIVgag-specific CD8+ T-cells in rectal mucosa and blood, individually and in combination, in relationship to clinical status and antiretroviral therapy (ART). In subjects not on ART, the percentage of rectal Gag-specific CD8+ T-cells capable of 3, 4 or 5 simultaneous effector functions was significantly related to blood CD4 count and inversely related to plasma viral load (PVL) (p<0.05). Polyfunctional rectal CD8+ T-cells expressed higher levels of MIP-1β and CD107a on a per cell basis than mono- or bifunctional cells. The production of TNFα, IFN-γ, and CD107a by Gag-specific rectal CD8+ T-cells each correlated inversely (p<0.05) with PVL, and MIP-1β expression revealed a similar trend. CD107a and IFN-γ production were positively related to blood CD4 count (p<0.05), with MIP-1β showing a similar trend. IL-2 production by rectal CD8+ T-cells was highly variable and generally low, and showed no relationship to viral load or blood CD4 count.
Conclusions
The polyfunctionality of rectal Gag-specific CD8+ T-cells appears to be related to blood CD4 count and inversely related to PVL. The extent to which these associations reflect causality remains to be determined; nevertheless, our data suggest a potentially important role for mucosal T-cells in limiting virus replication during chronic infection.
doi:10.1371/journal.pone.0003577
PMCID: PMC2570490  PMID: 18974782
7.  Impairment of cognitive functioning during Sunitinib or Sorafenib treatment in cancer patients: a cross sectional study 
BMC Cancer  2014;14:219.
Background
Impairment of cognitive functioning has been reported in several studies in patients treated with chemotherapy. So far, no studies have been published on the effects of the vascular endothelial growth factor receptor (VEGFR) inhibitors on cognitive functioning. We investigated the objective and subjective cognitive function of patients during treatment with VEGFR tyrosine kinase inhibitors (VEGFR TKI).
Methods
Three groups of participants, matched on age, sex and education, were enrolled; 1. metastatic renal cell cancer (mRCC) or GIST patients treated with sunitinib or sorafenib (VEGFR TKI patients n = 30); 2. patients with mRCC not receiving systemic treatment (patient controls n = 20); 3. healthy controls (n = 30). Sixteen neuropsychological tests examining the main cognitive domains (intelligence, memory, attention and concentration, executive functions and abstract reasoning) were administered by a neuropsychologist. Four questionnaires were used to assess subjective cognitive complaints, mood, fatigue and psychological wellbeing.
Results
No significant differences in mean age, sex distribution, education level or IQ were found between the three groups. Both patient groups performed significantly worse on the cognitive domains Learning & Memory and Executive Functions (Response Generation and Problem Solving) compared to healthy controls. However only the VEGFR TKI patients showed impairments on the Executive subdomain Response Generation. Effect sizes of cognitive dysfunction in patients using VEGFR TKI were larger on the domains Learning & Memory and Executive Functions, compared to patient controls. Both patients groups performed on the domain Attention & Concentration the same as the healthy controls. Longer duration of treatment on VEGFR TKI was associated with a worse score on Working Memory tasks.
Conclusions
Our data suggest that treatment with VEGFR TKI has a negative impact on cognitive functioning, specifically on Learning & Memory, and Executive Functioning. We propose that patients who are treated with VEGFR TKI are monitored and informed for possible signs or symptoms associated with cognitive impairment.
Trial registration
ClinicalTrials.gov Identifier: NCT01246843.
doi:10.1186/1471-2407-14-219
PMCID: PMC3987809  PMID: 24661373
Cognitive function; Sunitinib; Sorafenib; VEGFR TKI; Memory and Learning; Executive functioning
8.  Dissociations among daytime sleepiness, nighttime sleep, and cognitive status in Parkinson’s disease 
Parkinsonism & related disorders  2013;19(9):806-811.
Background
Daytime and nighttime sleep disturbances and cognitive impairment occur frequently in Parkinson’s disease (PD), but little is known about the interdependence of these non-motor complications. Thus, we examined the relationships among excessive daytime sleepiness, nighttime sleep quality and cognitive impairment in PD, including severity and specific cognitive deficits.
Methods
Ninety-three PD patients underwent clinical and neuropsychological evaluations including the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI). Patients were classified as having normal cognition (PD-NC), mild cognitive impairment (PD-MCI), or dementia (PDD) using recently proposed Movement Disorder Society PD-MCI and PDD criteria. Relationships between the sleep and cognitive measures and PD cognitive groups were examined.
Results
The PD cohort included PD-NC (n=28), PD-MCI (n=40), and PDD (n=25) patients. ESS scores, as a measure of daytime sleepiness, were significantly worse (p=0.005) in cognitively impaired PD patients, particularly PDD patients. ESS scores correlated significantly with Mini-Mental State Examination scores and also with cognitive domain scores for attention/working memory, executive function, memory, and visuospatial function. In contrast, PSQI scores, as a measure of nighttime sleep quality, neither differed among cognitive groups nor correlated with any cognitive measures.
Conclusions
Daytime sleepiness in PD, but not nighttime sleep problems, is associated with cognitive impairment in PD, especially in the setting of dementia, and attention/working memory, executive function, memory, and visuospatial deficits. The presence of nighttime sleep problems is pervasive across the PD cognitive spectrum, from normal cognition to dementia, and is not independently associated with cognitive impairment or deficits in cognitive domains.
doi:10.1016/j.parkreldis.2013.05.006
PMCID: PMC3729741  PMID: 23735187
Dementia; Excessive daytime sleepiness; Executive function; MCI (mild cognitive impairment); Parkinson’s disease; Sleep disorders
9.  Impact of smoking on cognitive decline in early old age: the Whitehall II cohort study 
Archives of General Psychiatry  2012;69(6):627-635.
Context
Smoking is a possible risk factor for dementia although its impact may have been underestimated in elderly populations due to the shorter lifespan of smokers.
Objective
To examine the association between smoking history and cognitive decline in the transition from midlife to old age.
Design, Setting, and Participants
Data are from 5099 men and 2137 women in the Whitehall II study, mean age 56 years (range=44–69 years) at the first cognitive assessment (1997–1999), repeated over 2002–2004 and 2007–2009.
Main Outcome Measures
The cognitive test battery was composed of tests of memory, vocabulary, executive function (composed of one reasoning and two fluency tests), and a global cognitive score summarising performance across all five tests. Smoking status was assessed over the entire study period. Linear mixed models were used to assess the association between smoking history and 10-year cognitive decline, expressed as z-scores.
Results
In men, 10-year cognitive decline in all tests except vocabulary among never smokers ranged from a quarter to a third of the baseline standard deviation. Faster cognitive decline was observed among current smokers compared to never smokers in men [mean difference in 10-year decline in global cognition=−0.09 (95%CI:−0.15;−0.03) and executive function=−0.11 (−0.17;−0.05)]. Recent ex-smokers had greater decline in executive function (−0.08 (−0.14;−0.02)) while the decline in long-term ex-smokers was similar to that among never smokers. In analyses that additionally took drop-out and death into account, these differences were 1.2 to 1.5 times larger. In women, cognitive decline did not vary as a function of smoking status.
Conclusions
Compared to never smokers, middle-aged male smokers experienced faster cognitive decline in global cognition and executive function. In ex-smokers with at least 10-year cessation there were no adverse effects on cognitive decline.
doi:10.1001/archgenpsychiatry.2011.2016
PMCID: PMC3675806  PMID: 22309970
Adult; Aged; Cognition Disorders; etiology; physiopathology; Cohort Studies; Female; Great Britain; Humans; Male; Middle Aged; Neuropsychological Tests; Smoking; adverse effects; Time Factors
10.  Plasma HIV Viral Rebound following Protocol-Indicated Cessation of ART Commenced in Primary and Chronic HIV Infection 
PLoS ONE  2012;7(8):e43754.
Objectives
The magnitude of HIV viral rebound following ART cessation has consequences for clinical outcome and onward transmission. We compared plasma viral load (pVL) rebound after stopping ART initiated in primary (PHI) and chronic HIV infection (CHI).
Design
Two populations with protocol-indicated ART cessation from SPARTAC (PHI, n = 182) and SMART (CHI, n = 1450) trials.
Methods
Time for pVL to reach pre-ART levels after stopping ART was assessed in PHI using survival analysis. Differences in pVL between PHI and CHI populations 4 weeks after stopping ART were examined using linear and logistic regression. Differences in pVL slopes up to 48 weeks were examined using linear mixed models and viral burden was estimated through a time-averaged area-under-pVL curve. CHI participants were categorised by nadir CD4 at ART stop.
Results
Of 171 PHI participants, 71 (41.5%) rebounded to pre-ART pVL levels, at a median of 50 (95% CI 48–51) weeks after stopping ART. Four weeks after stopping treatment, although the proportion with pVL≥400 copies/ml was similar (78% PHI versus 79% CHI), levels were 0.45 (95% CI 0.26–0.64) log10 copies/ml lower for PHI versus CHI, and remained lower up to 48 weeks. Lower CD4 nadir in CHI was associated with higher pVL after ART stop. Rebound for CHI participants with CD4 nadir >500 cells/mm3 was comparable to that experienced by PHI participants.
Conclusions
Stopping ART initiated in PHI and CHI was associated with viral rebound to levels conferring increased transmission risk, although the level of rebound was significantly lower and sustained in PHI compared to CHI.
doi:10.1371/journal.pone.0043754
PMCID: PMC3432055  PMID: 22952756
11.  Cognitive Function Predicts 24-Month Weight Loss Success Following Bariatric Surgery 
Background
Clinically significant cognitive impairment, particularly in attention/executive and memory function, is found in many patients undergoing bariatric surgery. These difficulties have previously been linked to decreased weight loss 12 months post-surgery, but more protracted examination of this relationship has not yet been conducted.
Objectives
The current study prospectively examined the independent contribution of cognitive function to weight loss 24 months following bariatric surgery. Given the rapid rate of cognitive improvement observed following surgery, postoperative cognitive function (i.e., cognition 12 weeks following surgery, controlling for baseline cognition) was expected to predict lower body mass index (BMI) and higher percent total weight loss (%WL) at 24-month follow-up.
Setting
Data were collected by three sites of the Longitudinal Assessment of Bariatric Surgery (LABS) parent project.
Methods
Fifty-seven individuals enrolled in the LABS project undergoing bariatric surgery completed cognitive evaluation at baseline, 12 weeks, and 24 months. %WL and BMI were calculated for 24-month postoperative follow-up.
Results
Better cognitive function 12 weeks following surgery predicted higher %WL and lower BMI at 24 months, and specific domains of attention/executive and memory function were robustly related to decreased BMI and greater %WL at 24 months.
Conclusions
Results demonstrate that cognitive performance shortly after bariatric surgery predicts greater long-term %WL and lower BMI 24 months following bariatric surgery. Further work is needed to clarify the degree to which this relationship is mediated by adherence to postoperative guidelines.
doi:10.1016/j.soard.2013.04.011
PMCID: PMC3788845  PMID: 23816443
memory; cognition; executive function; adherence
12.  MRI predictors of cognitive change in a diverse and carefully characterized elderly population 
Neurobiology of aging  2010;33(1):83-95.e2.
Background
Trajectories of cognitive decline among elderly individuals are heterogeneous, and markers that have high reliability for predicting cognitive trajectories across a broad spectrum of the elderly population have yet to be identified.
Method
This study examined the utility of a variety of MRI-based brain measures, obtained at baseline, as predictors of subsequent declines in domain-specific measures of cognitive function in a cohort of 307 community-dwelling elderly individuals with varying degrees of cognitive impairment who were diverse across a number of relevant demographic variables and were evaluated yearly. Psychometrically matched measures of cognition were used to assess episodic memory, semantic memory, and executive function. Relationships between baseline MRI measures, including the volumes of the brain, hippocampus, and white matter hyperintensities (WMH), and cognitive trajectories were assessed in mixed effects regression models that modeled MRI effects on cognitive performance at baseline and rate of change as well as inter-individual variability in cognitive baseline and rate of change.
Results
Greater baseline brain volume predicted slower subsequent rate of decline in episodic memory and smaller WMH volume predicted slower subsequent rate of decline in executive function and semantic memory. Baseline hippocampal volume, while strongly related to baseline cognitive function, was not predictive of subsequent change in any of the cognitive domains.
Conclusions
Baseline measures of brain structure and tissue pathology predicted rate of cognitive decline in a diverse and carefully-characterized cohort, suggesting that they may provide summary measures of pre-existing neuropathological damage or the capacity of the brain to compensate for the impact of subsequent neuropathology on cognition. Conventional MRI measures may have utility for predicting cognitive outcomes in highly heterogeneous elderly populations.
doi:10.1016/j.neurobiolaging.2010.01.021
PMCID: PMC2909327  PMID: 20359776
13.  X4 viruses are frequently archived in patients with long-term HIV infection but do not seem to influence the “inflamm-aging” process 
BMC Infectious Diseases  2013;13:220.
Background
Co-receptor tropism (CRT) in patients with a long history of HIV-1 infection and antiretroviral treatment has been rarely investigated to date. The aim of this study was to determine the prevalence of X4 and R5 strains in patients with a >15-year follow-up and to investigate the demographical, viral, immunological, clinical and therapeutic determinants of CRT in this population. The possible influence of CRT on the inflammation state related to chronic HIV infection was also examined.
Methods
A total of 118 HIV-1 infected patients with an initial HIV-1-positive test before 1997, and still on follow-up, were enrolled and consecutively submitted to blood sampling. Of these, 111 were on antiretroviral therapy and 89/111 (80.2%) had a plasma viral load (pVL) <25 copies/ml at testing. HIV-1 DNA was extracted and amplified from PBMCs for env gp120 sequencing. CRT was assigned by using geno2pheno and isolates were classified as X4 (FPR ≤20%) or R5 (FPR >20%). Level of serological inflammation biomarkers including IL-6, hsPCR, and D-dimers were measured.
Results
An X4 virus was evidenced in HIV-1 proviral DNA of 50 patients (42%) while the remaining 68 patients were classified as R5. The median follow-up was 19 years (range 15–25). No association was observed between CRT and sex, age, nationality, subtype, HIV risk factor, HBV/HCV co-infection, baseline CD4+ cell count and pVL, overall duration of antiretroviral therapy, past exposure to mono-or dual therapies, and duration of NNRTI or PI-based therapy. The presence of an X4 strain was associated with CD4 nadir (p = 0.005), CD4 absolute count over time (p < 0.001), and cumulative positive (copy/years) viremia (p <0.001) during the whole patient history. No differences were found between R5 and X4 patients regarding inflammation marker levels including Il-6, hsPCR and D-dimers.
Conclusions
An archived X4 virus was demonstrated in 42% of patients with a >15-year-history of HIV infection. This presence was clearly associated with a greater exposure to positive viremia and a poorer CD4 trend over time compared to R5, independent of type and duration of antiretroviral treatment. CRT does not seem to influence the inflammation rate of patients aging with HIV.
doi:10.1186/1471-2334-13-220
PMCID: PMC3661370  PMID: 23678991
HIV proviral DNA; Co-receptor tropism; CXCR4; CCR5; Geno2pheno; Aging; Inflammation markers
14.  The Montreal Cognitive Assessment (MoCA) - A Sensitive Screening Instrument for Detecting Cognitive Impairment in Chronic Hemodialysis Patients 
PLoS ONE  2014;9(10):e106700.
Background
Chronic kidney disease (CKD) patients undergoing hemodialysis (HD) therapy have an increased risk of developing cognitive impairment and dementia, which are known relevant factors in disease prognosis and therapeutic success, but still lack adequate screening in clinical routine. We evaluated the Montreal Cognitive Assessment (MoCA) for suitability in assessing cognitive performance in HD patients in comparison to the commonly used Mini-Mental State Examination (MMSE) and a detailed neuropsychological test battery, used as gold standard.
Methods
43 HD patients and 42 healthy controls with an average age of 58 years, were assessed with the MoCA, the MMSE and a detailed neuropsychological test battery, covering the domains of memory, attention, language, visuospatial and executive functions. Composite scores were created for comparison of cognitive domains and test results were analyzed using Spearman's correlation and linear regression. Cognitive dysfunction was defined using z-score values and predictive values were calculated. Sensitivity and specificity of the MoCA were determined using receiver operating characteristic (ROC) analysis.
Results
HD patients performed worse in all cognitive domains, especially in memory recall and executive functions. The MoCA correlated well with the detailed test battery and identified patients with cognitive impairment with a sensitivity of 76.7% and specificity of 78.6% for a cut-off value of ≤24 out of 30 points. In the detailed assessment executive functions accounted significantly for performance in the MoCA. The MMSE only discriminated weakly between groups.
Conclusions
The MoCA represents a suitable cognitive screening tool for hemodialysis patients, demonstrating good sensitivity and specificity levels, and covering executive functions, which appear to play an important role in cognitive performance of HD patients.
doi:10.1371/journal.pone.0106700
PMCID: PMC4209968  PMID: 25347578
15.  VASCULAR RISK FACTORS AND COGNITIVE DECLINE IN A POPULATION SAMPLE 
We examined several vascular factors in relation to rates of decline in five cognitive domains in a population-based cohort. In an age-stratified random sample (N=1982) aged 65+ years, we assessed at baseline the cognitive domains of attention, executive function, memory, language, and visuospatial function, and also vascular, inflammatory, and metabolic indices. Random effects models generated slopes of cognitive decline over the next four years; linear models identified vascular factors associated with these slopes, adjusting for demographics, baseline cognition, and potential interactions. Several vascular risk factors (history of stroke, diabetes, central obesity, C-Reactive Protein), although associated with lower baseline cognitive performance, did not predict rate of subsequent decline. APOE*4 genotype was associated with accelerated decline in language, memory, and executive functions. Homocysteine elevation was associated with faster decline in executive function. Hypertension (history or systolic blood pressure >140 mm) was associated with slower decline in memory. Baseline alcohol consumption was associated with slower decline in attention, language, and memory. Different indices of vascular risk are associated with low performance and with rates of decline in different cognitive domains. Cardiovascular mechanisms explain at least some of the variance in cognitive decline. Selective survival may also play a role.
doi:10.1097/WAD.0000000000000004
PMCID: PMC3945071  PMID: 24126216
16.  APOE modifies the association between Aβ load and cognition in cognitively normal older adults 
Neurology  2012;78(4):232-240.
Objective:
To determine the relationship between β-amyloid (Aβ) load as measured by [11C]–Pittsburgh compound B (PiB) PET and cognitive function in cognitively normal older adults.
Methods:
We studied 408 cognitively normal older adults who participated in the population-based Mayo Clinic Study of Aging (MCSA) from January 2009 through March 2011. The participants underwent PiB PET and neuropsychometric testing within 6 months. The association between PiB retention and cognitive function was measured by partial correlation and an interaction with APOE status was tested using linear regression after adjusting for age, sex, and education.
Results:
Higher PiB retention was associated with cognitive performance (Spearman partial r = −0.18; p < 0.01), specifically the memory, language, attention/executive, and visual-spatial processing domains in the whole group of participants. The association between PiB retention and cognition was modified by the APOE status on linear regression analysis even after controlling for the differences in the distribution of PiB values among APOE ϵ4 carriers and noncarriers (p = 0.02). Cognitive performance was associated with the Aβ deposition in the frontal, temporal, and parietal lobe association cortices in APOE ϵ4 carriers on SPM analysis (p < 0.001).
Conclusion:
There is a modest association between PiB retention and cognitive function in cognitively normal older adults and this relationship between Aβ load and cognitive function is modified by APOE status. Whereas Aβ load is associated with greater cognitive impairment in APOE ϵ4 carriers, the cognitive function in APOE ϵ4 noncarriers is influenced less by the Aβ load, suggesting that APOE isoforms modulate the harmful effects of Aβ on cognitive function. Neurology® 2012;78:232–240
doi:10.1212/WNL.0b013e31824365ab
PMCID: PMC3280056  PMID: 22189452
17.  PERFORMANCE OF A COMPUTER-BASED ASSESSMENT OF COGNITIVE FUNCTION MEASURES IN TWO COHORTS OF SENIORS 
International journal of geriatric psychiatry  2013;28(12):10.1002/gps.3949.
Background
Computer-administered assessment of cognitive function is being increasingly incorporated in clinical trials, however its performance in these settings has not been systematically evaluated.
Design
The Seniors Health and Activity Research Program (SHARP) pilot trial (N=73) developed a computer-based tool for assessing memory performance and executive functioning. The Lifestyle Interventions and Independence for Seniors (LIFE) investigators incorporated this battery in a full scale multicenter clinical trial (N=1635). We describe relationships that test scores have with those from interviewer-administered cognitive function tests and risk factors for cognitive deficits and describe performance measures (completeness, intra-class correlations).
Results
Computer-based assessments of cognitive function had consistent relationships across the pilot and full scale trial cohorts with interviewer-administered assessments of cognitive function, age, and a measure of physical function. In the LIFE cohort, their external validity was further demonstrated by associations with other risk factors for cognitive dysfunction: education, hypertension, diabetes, and physical function. Acceptable levels of data completeness (>83%) were achieved on all computer-based measures, however rates of missing data were higher among older participants (odds ratio=1.06 for each additional year; p<0.001) and those who reported no current computer use (odds ratio=2.71; p<0.001). Intra-class correlations among clinics were at least as low (ICC≤0.013) as for interviewer measures (ICC≤0.023), reflecting good standardization. All cognitive measures loaded onto the first principal component (global cognitive function), which accounted for 40% of the overall variance.
Conclusion
Our results support the use of computer-based tools for assessing cognitive function in multicenter clinical trials of older individuals.
doi:10.1002/gps.3949
PMCID: PMC3775886  PMID: 23589390
Cognitive function; Clinical trial; Performance measures
18.  Cardiovascular Disease and Cognitive Function in Maintenance Hemodialysis Patients 
Background
Cardiovascular disease (CVD) and cognitive impairment are common in dialysis patients. Given the proposed role of microvascular disease on cognitive function, particularly cognitive domains that incorporate executive functions, we hypothesized that prevalent systemic CVD would be associated with worse cognitive performance in hemodialysis patients.
Design
Cross-sectional cohort
Setting and Participants
200 maintenance hemodialysis patients without prior stroke from 5 Boston-area hemodialysis units
Predictor
CVD, defined by history of coronary disease or peripheral vascular disease
Outcome
Performance on a detailed neurocognitive battery. Primary analyses quantified cognitive performance using principal components analysis to reduce cognitive tests to a processing speed/executive function domain and a memory domain. Multivariable linear regression models adjusted for age, sex, education, race and other clinical and demographic characteristics.
Results
Mean (SD) age of participants was 62 (18) years and 75 (38%) had CVD. Individuals with CVD were older, more likely to be men, diabetic, and current or former smokers. In adjusted models, individuals with CVD performed 0.50 standard deviations worse (p<0.001) on tests assessing processing speed/executive function, while there was no difference in performance on tests of memory. Similar results were seen when assessing individual tests, with performance on the block design, digit symbol coding and Trail Making Tests A and B significantly associated with CVD in age, sex, education and race-adjusted analyses and approaching toward significance in fully adjusted models.
Limitations
CVD ascertainment dependent on patient recall and dialysis unit documentation. No brain imaging.
Conclusions
The presence of CVD is associated with worse cognitive performance on tests of processing speed and executive functioning in hemodialysis patients and identifies a high risk population for greater difficulty with complex tasks.
doi:10.1053/j.ajkd.2011.03.034
PMCID: PMC3199371  PMID: 21778003
19.  A 35-Year Longitudinal Assessment of Cognition and Midlife Depression Symptoms: The Vietnam Era Twin Study of Aging 
Objective
To determine whether early adult cognitive ability is a risk factor for depressive symptoms in midlife and how genetic and environmental influences explain the association; to examine cross-sectional relationships between depressive symptoms and specific cognitive abilities at midlife.
Methods
Design
35-year longitudinal and cross-sectional twin study of cognitive aging.
Setting
Large multicenter study in the United States.
Participants
1237 male twins ages 51 to 60.
Measurements
At age 20 and midlife, participants completed the same version of a general cognitive ability test (Armed Forces Qualification Test [AFQT]). Midlife testing included an extensive neurocognitive protocol assessing processing speed, verbal memory, visual-spatial memory, working memory, executive function, and visual-spatial ability. Participants completed the Center for Epidemiologic Studies Depression Scale prior to cognitive testing and provided health and lifestyle information during a medical history interview.
Results
Lower age 20 AFQT scores predicted higher levels of depressive symptoms at age 55 (r=−.16, p<.001). In bivariate twin modeling, 77% of the correlation between early cognitive ability and midlife depressive symptoms was due to shared genetic influences. Controlling for current age, age 20 AFQT, and non-independence of observations, depressive symptoms were associated with worse midlife AFQT scores and poorer performance in all cognitive domains except verbal memory
Conclusion
Results suggest that low cognitive ability is a risk factor for depressive symptoms; this association is partly due to shared genetic influences. Cross-sectional analyses indicate that the association between depressive symptoms and performance is not linked to specific cognitive domains.
doi:10.1097/JGP.0b013e3181ef79f1
PMCID: PMC3101375  PMID: 21606899
20.  CD4 nadir is a predictor of HIV neurocognitive impairment in the era of combination antiretroviral therapy 
AIDS (London, England)  2011;25(14):10.1097/QAD.0b013e32834a40cd.
Objective
Despite immune recovery in individuals on combination antiretroviral therapy (CART), the frequency of HIV-associated neurocognitive disorders (HANDs) remains high. Immune recovery is typically achieved after initiation of ART from the nadir, or the lowest historical CD4. The present study evaluated the probability of neuropsychological impairment (NPI) and HAND as a function of CD4 nadir in an HIV-positive cohort.
Methods
One thousand five hundred and twenty-five HIV-positive participants enrolled in CNS HIV Antiretroviral Therapy Effects Research, a multisite, observational study that completed comprehensive neurobehavioral and neuromedical evaluations, including a neurocognitive test battery covering seven cognitive domains. Among impaired individuals, HAND was diagnosed if NPI could not be attributed to comorbidities. CD4 nadir was obtained by self-report or observation. Potential modifiers of the relationship between CD4 nadir and HAND, including demographic and HIV disease characteristics, were assessed in univariate and multivariate analyses.
Results
The median CD4 nadir (cells/μl) was 172, and 52% had NPI. Among impaired participants, 603 (75%) had HAND. Higher CD4 nadirs were associated with lower odds of NPI such that for every 5-unit increase in square-root CD4 nadir, the odds of NPI were reduced by 10%. In 589 virally suppressed participants on ART, higher CD4 nadir was associated with lower odds of NPI after adjusting for demographic and clinical factors.
Conclusion
As the risk of NPI was lowest in patients whose CD4 cell count was never allowed to fall to low levels before CART initiation, our findings suggest that initiation of CART as early as possible might reduce the risk of developing HAND, the most common source of NPI among HIV-infected individuals.
doi:10.1097/QAD.0b013e32834a40cd
PMCID: PMC3867631  PMID: 21750419
CD4 nadir; combination antiretroviral therapy; HIV-associated; neurocognitive disorders; neurocognitive impairment
21.  Temporal increase in HIV-1 non-R5 tropism frequency among antiretroviral-naive patients from northern Poland 
Journal of the International AIDS Society  2014;17(4Suppl 3):19687.
Introduction
Sequencing of the third hypervariable loop allows to identify genotype-based HIV tropism. R5-tropic viruses associated with early stages of infection are preferentially transmitted, while non-R5 HIV-1 tropism has been associated with severe immunodeficiency and lower lymphocyte CD4 nadir and may reflect delayed HIV diagnosis. In this study, we investigate the changes in tropism frequency from 2007 to 2013.
Materials and Methods
Study included 194 patients with confirmed HIV infection linked to care in 2007–2013. Baseline plasma samples from treatment naive patients were used for HIV-1 genotypic tropism assessment based on triplicate V3 loop sequencing. Non-R5 tropism prediction thresholds were assigned using a false positive rate (FPR) of 10% and 5.75% FPR and associated with clinical and laboratory data (age, gender, date of HIV diagnosis, route of transmission, CDC clinical category at diagnosis, pretreatment HIV viral load, baseline and nadir lymphocyte CD4 counts). For statistics, chi-square and Mann–Whitney U tests were used, time trends were examined using logistic regression (R statistical platform, v. 3.1.0) for binary variables and linear regression for continuous ones.
Results
Overall non-R5 tropism frequency for the 5.75% FPR was 15.5% and 27.8% for 10% FPR. Frequency of the non-R5 tropism predicted using 5.75% FPR increased significantly from 2007 (0%) to 2013 (25%) [OR: 1.44 (95% CI 1.14–1.86), p=0.003, rough slope +3.89%/year] (Figure 1a). With 10% FPR, the frequency changed from 7% (2007) to 33% (2013) [OR: 1.17 (95% CI 0.99–1.39), p=0.054, rough slope +3.0%/year] (Figure 1b). Baseline lymphocyte CD4 count and nadir, as well as pretreatment HIV-1 viral loads were stable over time of observation (r=0.014, p=0.84; r=0.13, p=0.085; r=0.016, p=0.83 for CD4 baseline, nadir and HIV load, respectively). Frequency of AIDS at HIV diagnosis increased from 21.4% in 2007 to 38.0% in 2013, however trend over time was insignificant [OR: 1.1 (95% CI 0.95–1.31), p=0.19]. Temporal trends for HIV transmission route, gender, non-B variant frequencies also were not significant.
Conclusions
R5 tropism predominates among the treatment naive individuals but increase in the frequency of non-R5 tropic variants may limit clinical efficacy of the coreceptor inhibitors. Increased prevalence of non-R5 HIV-1 may be related to late care entry and higher number of AIDS diagnoses in the recent years.
doi:10.7448/IAS.17.4.19687
PMCID: PMC4225429  PMID: 25397437
22.  Longitudinal comparison of HIV-1 plasma viral load and cellular proviral load 
Journal of the International AIDS Society  2014;17(4Suppl 3):19669.
Introduction
The goal of antiretroviral treatment (ART) in HIV-1 infection is the permanent suppression of plasma viral load (pVL) below the currently existing limit of detection of 50 copies/mL (DAIG HIV-therapy guidelines). Therefore, treatment effectiveness is based on pVL. pVL measurements however do not give any information about the viral reservoir in peripheral blood mononuclear cells (PBMCs). Therefore, the proviral DNA of HIV-1 could be a useful marker for the investigation of viral reservoirs and monitoring ART in patients showing undetectable pVL.
Materials and Methods
Seventy-seven treatment-experienced HIV-1 infected patients with pVL <50 copies/mL were randomly selected. pVL and proviral DNA load were measured using the Roche COBAS TaqMan HIV-1 v2.0 assay. Additionally, CD4+ cell count per mL and the total white blood cell (wbc) count per mL were determined for each patient. Follow-up data were collected 24 weeks after the time point of the first measurement. Proviral DNA load per mL, CD4+ cell count per mL as well as wbc count per mL were observed over time and differences were estimated using the Mann–Whitney U test. Additionally, correlations between the clinical parameters were analyzed using the two-sided Pearson correlation analysis.
Results
Out of the 77 patients, 38 show a significant increase in proviral load per mL over time (p=0,001), whereas 39 patients show a significant decrease (p=0,001). No differences became visible in the CD4+ cell count per mL comparing week 0 and week 24 data. Thirty five patients show a significant increase in wbc count per mL over time (p<0,001), while 42 patients show a significant decrease (p<0,001). A significant correlation of increasing proviral load per mL and wbc count per mL for data of the first (p<0.001) and the second measurement (p<0.001) can be detected, while there are no correlations found between proviral load per mL and CD4+ cell count per mL.
Conclusions
Our data show that the presence of viral reservoirs in other cell types and not only CD4+ cells is most probable. HIV-1 proviral DNA seems to be an interesting marker in patients with undetectable pVL and allows the assessment of replication under ART. Nevertheless, further longitudinal studies are needed to assess the usefulness and the clinical significance of this marker.
doi:10.7448/IAS.17.4.19669
PMCID: PMC4225422  PMID: 25397419
23.  Maximal brain size remains an important predictor of cognition in old age, independent of current brain pathology 
Neurobiology of Aging  2011;33(8):1758-1768.
Background
There is growing interest in the influence of early-life development on clinical manifestations of late-life diseases.
Methods
Latent variable modeling was used to investigate how maximal brain volume (measured by intracranial volume (ICV)) and current brain volumes uniquely contribute to domain-specific cognitive performance in a group of 401 cognitively and ethnically diverse older adults. Individual effects of volumetric MRI measures including ICV were examined as predictors of episodic memory, semantic memory, spatial ability and executive function.
Results
Current brain volume related to all cognitive domains; hippocampal volume was associated primarily with episodic memory; white matter hyperintensity volume was related to executive function and episodic memory. Maximal brain size as measured by ICV was related to semantic memory, executive function, and spatial ability independent of current brain volumes (ps <.01). Relationships between MRI variables and cognition did not differ substantially across groups defined by ethnicity, gender, and with minor exceptions clinical diagnosis.
Conclusions
Results suggest maximal brain development and measures of brain injury/atrophy jointly contribute to cognitive function in older people.
doi:10.1016/j.neurobiolaging.2011.03.017
PMCID: PMC3177982  PMID: 21531482
cognition; cognitive impairment; MRI; cognitive reserve
24.  Treatment effects in multiple cognitive domains in Alzheimer’s disease: a two-year cohort study 
Introduction
Despite widespread use of second-generation cholinesterase inhibitors for the symptomatic treatment of Alzheimer’s disease (AD), little is known about the long term effects of cholinergic treatment on global cognitive function and potential specific effects in different cognitive domains. The objectives of this study were to determine the association between cholinergic treatment and global cognitive function over one and two years in a cohort of patients with mild or moderate AD and identify potential differences in domain-specific cognitive outcomes within this cohort.
Methods
A cohort of patients meeting the revised National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for mild or moderate AD, including patients both on treatment with a cholinesterase inhibitor and untreated controls (treated = 65, untreated = 65), were recruited from the Cognitive Neurology Clinic at Sunnybrook Health Sciences Centre, as part of the Sunnybrook Dementia Study. Patients were followed for one to two years and underwent standardized neuropsychological assessments to evaluate global and domain-specific cognitive function. Associations between cholinesterase inhibitor use and global and domain-specific cognitive outcome measures at one and two years of follow-up were estimated using mixed model linear regression, adjusting for age, education, and baseline mini mental state examination (MMSE).
Results
At one year, treated patients showed significantly less decline in global cognitive function, and treatment and time effects across tests of executive and visuospatial function. At two years, there was a significant trend towards less decline in global cognition for treated patients. Moreover, treated patients showed significant treatment and time effects across tests of executive functioning, memory, and visuospatial function.
Conclusions
The present study offers two important contributions to knowledge of the effectiveness of cholinesterase inhibitor treatment in patients with mild-moderate AD: 1) that second-generation cholinesterase inhibitors demonstrate long-term effectiveness for reducing global cognitive decline over one to two years of follow-up, and 2) that decline in function for cognitive domains, including executive function, memory, and visuospatial skill that are primarily mediated by frontal networks and by the cholinergic system, rather than memory, may be slowed by treatment targeting the cholinergic system.
doi:10.1186/alzrt280
PMCID: PMC4255390  PMID: 25484926
25.  Gait and Cognition: A Complementary Approach to Understanding Brain Function and the Risk of Falling 
Until recently, clinicians and researchers have performed gait assessments and cognitive assessments separately when evaluating older adults. Increasing evidence from clinical practice, epidemiological studies, and clinical trials shows that gait and cognition are inter-related in older adults. Quantifiable alterations in gait among older adults are associated with falls, dementia, and disability. At the same time, emerging evidence indicates that early disturbances in cognitive processes such as attention, executive function, and working memory are associated with slower gait and gait instability during single and dual-task testing, and that these cognitive disturbances assist in the prediction of future mobility loss, falls, and progression to dementia.
This paper reviews the importance of the gait-cognition inter-relationship in aging and presents evidence that gait assessments can provide a window into the understanding of cognitive function and dysfunctions, and fall risk in older people in clinical practice. To this end, the benefits of dual-task gait assessments (e.g., walking while performing an attention-demanding task) as a marker of fall risk are summarized. Further, we also present a potential complementary approach for reducing the risk of falls by improving certain aspects of cognition through both non-pharmacological and pharmacological treatments.
Untangling the relationship between early gait disturbances and early cognitive changes may be helpful for identifying older adults at higher risk of experiencing mobility decline, falls and the progression to dementia.
doi:10.1111/j.1532-5415.2012.04209.x
PMCID: PMC3498517  PMID: 23110433
Falls; Mild Cognitive Impairment; Dual-task; Cognitive function; Gait Variability

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