Recent advances in the technology of recording magnetic fields associated with electric current flow in biological tissues have provided a means of examining action currents that is more direct and possibly more accurate than conventional electrical recording. Magnetic recordings are relatively insensitive to muscle movement, and, because the recording probes are not directly connected to the tissue, distortions of the data due to changes in the electrochemical interface between the probes and the tissue are eliminated. In vivo magnetic recordings of action currents of rat common peroneal nerve and extensor digitorum longus (EDL) muscle were obtained by a new magnetic probe and amplifier system that operates within the physiological temperature range. The magnetically recorded waveforms were compared with those obtained simultaneously by conventional, extracellular recording techniques. We used the amplitude of EDL twitch force (an index of stimulus strength) generated in response to graded stimulation of the common peroneal nerve to enable us to compare the amplitudes of magnetically recorded nerve and muscle compound action currents (NCACs and MCACs, respectively) with the amplitudes of electrically recorded nerve compound action potentials (NCAPs). High, positive correlations to stimulus strength were found for NCACs (r = 0.998), MCACs (r = 0.974), and NCAPs (r = 0.998). We also computed the correlations of EDL single motor unit twitch force with magnetically recorded single motor unit compound action currents (SMUCACs) and electrically recorded single motor unit compound action potentials (SMUCAPs) obtained with both a ring electrode and a straight wire serving as a point electrode. Only the SMUCACs had a relatively strong positive correlation (r = 0.768) with EDL twitch force. Correlations for ring and wire electrode- recorded SMUCAPs were 0.565 and -0.366, respectively. This study adds a relatively direct examination of action currents to the characterization of the normal biophysical properties of peripheral nerve, muscle, and muscle single motor units.
Objective: To assess the effects of a computer-based patient record system on human cognition. Computer-based patient record systems can be considered "cognitive artifacts," which shape the way in which health care workers obtain, organize, and reason with knowledge.
Design: Study 1 compared physicians' organization of clinical information in paper-based and computer-based patient records in a diabetes clinic. Study 2 extended the first study to include analysis of doctor–patient–computer interactions, which were recorded on video in their entirety. In Study 3, physicians' interactions with computer-based records were followed through interviews and automatic logging of cases entered in the computer-based patient record.
Results: Results indicate that exposure to the computer-based patient record was associated with changes in physicians' information gathering and reasoning strategies. Differences were found in the content and organization of information, with paper records having a narrative structure, while the computer-based records were organized into discrete items of information. The differences in knowledge organization had an effect on data gathering strategies, where the nature of doctor-patient dialogue was influenced by the structure of the computer-based patient record system.
Conclusion: Technology has a profound influence in shaping cognitive behavior, and the potential effects of cognition on technology design needs to be explored.
Non-penetrating surface electrode recording techniques are typically associated with field potential recordings, while extracellular recordings from single neurons are made using penetrating metal wire or microfabricated microelectrode arrays. Here, we report on single- and multi-unit neuronal recordings made using non-penetrating electrodes placed on the epineural surface of the dorsal root ganglia (DRG). Across four experiments in anesthetized cats, approximately 40% of the electrodes recorded single- and multi-unit spiking activity with spike-rates that covaried significantly with hindlimb movement. In two intraoperative experiments in humans, compound activity was recorded from the DRG surface in response to peripheral stimulation of the common peroneal nerve. This approach may have advantages over penetrating electrode arrays in terms of clinical acceptability and recording longevity.
Ensuring the accuracy of patient identification and the linkage of records with the appropriate patient owner is the first level of quality control of data in a clinical database system.
Without a unique patient identifier, the fact that patient identity may be recorded at different places and times means that multiple identities may be associated with a given patient and new records associated with any of these identities. Even when a unique patient identifier is utilized, errors introduced in the data handling process can result in the same problems. The outcome is that the retrieval request for a given record may fail, or an erroneously identified record may be retrieved.
We have studied each of the ways this fundamental problem occurs and propose a solution based on record linkage techniques to detect errors of this type. Specifically, we propose a patient identification scheme for the situation where no unique health identifier is available and detail a method to find patient records with erroneous identifiers.
Although duplicate records are a potential patient safety hazard, the actual clinical harm associated with these records has never been studied. We hypothesized that duplicate records will be associated with missed abnormal laboratory results.
A retrospective, matched, cohort study of 904 events of abnormal laboratory result (HgbA1c, TSH, Vitamin B12, LDL). We compared the rates of missed laboratory results between patients with duplicate and non-duplicate records from the ambulatory clinics. Cases were matched according to test and ordering physician.
Duplicate records were associated with a higher rate of missed laboratory results (OR=1.44, 95% CI 1.1–1.9). Other factors associated with missed lab results were tests performed as screening (OR=2.22, 95% CI 1.4–3.4), and older age (OR=1.15 for every decade, 95% CI 1.01–1.2). In most cases test results were reported into the main patient record.
Duplicate records were associated with a higher risk of missing important laboratory results.
To analyse the technical quality of electronic patient records in relation to legislation and to evaluate their quality associated with the quality of consultations as rated by patients and GPs.
Cross-sectional study of electronic patient records.
Four primary healthcare (PHC) centres in Finland using three different electronic patient record systems.
Patient records of 175 PHC consultations by 50 GPs, rated as the best (n=86) and the worst (n=89) of a total of 2191 consultations.
Main outcome measures
Documentation of records compared with legislation, the general informative value of records, and its relation to the experienced quality of consultations and to the electronic system employed.
Reason for encounter was mentioned in 79% of cases and patient history in 32%. An acute problem was described moderately well or well in 84%, examination findings in 62%, medical problem or diagnosis in 90%, and treatment in 95% of cases. Medication was documented adequately in 38% of the cases where medication was documented. Concerning general informative value, 18% were assessed as poor, 62% as moderate, and 20% as good. No correspondence was found between experienced quality of consultation and general informative value in the patient records. The quality of patient records was found to change according to the electronic system employed.
Finnish patient records are inadequate documents of consultations and below the standard of that country's legislation. Developing better models of recording would guarantee a higher quality of work.
Family medicine; family practice; patient record; quality of consultation
Over the last five decades, progress in neural recording techniques has allowed the number of simultaneously recorded neurons to double approximately every 7 years, mimicking Moore’s law. Such exponential growth motivates us to ask how data analysis techniques are affected by progressively larger numbers of recorded neurons. Traditionally, neurons are analyzed independently on the basis of their tuning to stimuli or movement. Although tuning curve approaches are unaffected by growing numbers of simultaneously recorded neurons, newly developed techniques that analyze interactions between neurons become more accurate and more complex as the number of recorded neurons increases. Emerging data analysis techniques should consider both the computational costs and the potential for more accurate models associated with this exponential growth of the number of recorded neurons.
The prevalence of chronic kidney disease (CKD) at stage 3–5 is estimated at 8.5% in the UK, but the recorded rate of CKD from Quality and Outcomes Framework (QOF) registers in 2007–2008 was 2.9%. This study aimed to identify practice or patient characteristics associated with recorded rates of CKD. Demographic and QOF data for 230 general practices were combined into a database for cross-sectional analysis. Regression analyses investigated factors associated with CKD recording; deprivation, location in Leicester city or Northamptonshire, and low recording of hypertension and stroke were associated with low CKD recording.
diagnosis; kidney diseases; primary health care; renal insufficiency, chronic
To measure the prevalence of domestic violence among women attending general practice; test the association between experience of domestic violence and demographic factors; evaluate the extent of recording of domestic violence in records held by general practices; and assess acceptability to women of screening for domestic violence by general practitioners or practice nurses.
Self administered questionnaire survey. Review of medical records.
General practices in Hackney, London.
1207 women (>15 years) attending selected practices.
Main outcome measures
Prevalence of domestic violence against women. Association between demographic factors and domestic violence reported in questionnaire. Comparison of recording of domestic violence in medical records with that reported in questionnaire. Attitudes of women towards being questioned about domestic violence by general practitioners or practice nurses.
425/1035 women (41%, 95% confidence interval 38% to 44%) had ever experienced physical violence from a partner or former partner and 160/949 (17%, 14% to 19%) had experienced it within the past year. Pregnancy in the past year was associated with an increased risk of current violence (adjusted odds ratio 2.11, 1.39 to 3.19). Physical violence was recorded in the medical records of 15/90 (17%) women who reported it on the questionnaire. At least 202/1010 (20%) women objected to screening for domestic violence.
With the high prevalence of domestic violence, health professionals should maintain a high level of awareness of the possibility of domestic violence, especially affecting pregnant women, but the case for screening is not yet convincing.
What is already known on this topicDomestic violence is associated with a wide range of health and social problems for women and their childrenWomen experiencing violence are often not identified by health professionals in hospital settingsProfessional organisations and politicians are promoting a policy of screening for domestic violenceWhat this study addsOver a third of women attending general practices had experienced physical violence from a male partner or former partnerMost women who had experienced physical violence were not identified by general practitioners, according to data extracted from their medical recordsWomen pregnant in the previous year were at high risk for current physical violenceA substantial minority of women object to routine questioning about domestic violence
Single chamber ventricular pacing (VVI) may be associated with a group of adverse symptoms known as the pacemaker syndrome. Cough is an unusual but recognised feature of the pacemaker syndrome. A patient with a VVI permanent pacemaker experienced a disturbing cough during VVI pacing. There were no other symptoms associated with the pacemaker syndrome. The effects of short-term ventricular pacing on the cough were examined while the subject was standing and lying. After control recordings, the pulse generator was programmed to either VVI 50 beats/min or 90 beats/min and recordings made over 60 seconds. There was an interval of 60s between recordings. Overall, five recording periods at VVI of 50 beats/min and VVI of 90 beats/min were made in random order. The patient was blinded to the order of programming. The recordings were repeated with the subject lying. Cough was not found during normal sinus rhythm. During VVI pacing the patient experienced a tickling sensation in the throat associated with intermittent coughing. The number of coughs decreased during each successive recording period. The pacing cough reflex was enhanced when the patient was lying down. The mechanism of cough during VVI pacing is uncertain. The findings suggest a possible role for afferent vagal receptors from the airways.
A pilot study was conducted to ascertain the level of agreement between auscultatory findings derived from heart sound recordings by a cardiologist and the results of a computer-based heart sound analysis algorithm. Heart sound recordings were obtained from volunteer subjects previously diagnosed with hypertrophic cardiomyopathy. Twenty-second recordings were obtained at each of 4 standard auscultatory locations on the precordium in 2 postures: standing and reclining. Detailed auscultatory findings were derived by a cardiologist, who listened to the heart sound recordings and was blinded to the study design. The recordings were analyzed by an algorithm that detects heart sounds and murmurs, and derives associated timing and energy parameters. The algorithm results were compared with the auscultatory findings provided by the cardiologist and correlated with the medical histories provided by the volunteer subjects.
A high degree of concordance between the medical histories, auscultatory findings, and computer analyses was obtained. The 1st and 2nd heart sounds were detected with high sensitivity (90.7%) and positive predictivity (93.0%). Systolic murmurs were detected with a sensitivity that increased from 50% for grade 1 to 100% for grades 2–3 and 3. The signal energy in the mid-frequency range correlated well with murmur grade judgments, and also agreed well with the cardiologist's judgments of the relative loudness of murmurs in standing versus reclining postures. The computer analysis algorithm thus instantiates the objective detection and identification of apical systolic murmurs that are louder in standing than in reclining postures; such murmurs are a cardinal sign of hypertrophic obstructive cardiomyopathy.
Athletics; cardiomyopathy, hypertrophic; death, sudden, cardiac; diagnosis, computer-assisted; heart auscultation; heart murmurs; human; screening
Many behaviors of interest to neurophysiologists are difficult to study under laboratory conditions because such behaviors are often inhibited when an animal is restrained and socially isolated. Even under the best conditions, such behaviors may be sparse enough as to require long duration neural recordings or simultaneous recording of multiple neurons to gather a sufficient amount of data for analysis. We have developed a preparation for chronic, multi-electrode recordings in the auditory cortex of marmoset monkeys, small primates, as well as techniques for neurophysiological recordings when the animals are free-roaming while singly caged in the environment of the monkey colony. In this report, we describe our solutions to overcome the problems associated with chronic recordings in free-roaming animals, where three-dimensional movements present particular challenges.
implanted electrodes; multi-electrode arrays; chronic recording; free-roaming; marmoset; auditory cortex
In 1985 and then again in 1987, attendees at the American Medical Record Association (AMRA) annual meeting were surveyed to determine the extent of computer utilization in medical record departments. The results indicated that over 90 percent of respondents used a computer for at least one application. The degree of usage for the various applications is important for understanding the capabilities of medical record services, planning continuing education programs, product development and marketing strategies, and system implementation timetables. This study also sought information on the extent of computerization of the medical record. Findings indicate that over 40 percent of respondents' hospitals had at least one component of their medical records computerized.
Few studies have evaluated the validity of adolescent diet recall after many decades. Between 1943 and 1970, yearly diet records were completed by parents of adolescents participating in an ongoing US study. In 2005–2006, study participants who had been 13–18 years of age when the diet records were collected were asked to complete a food frequency questionnaire regarding their adolescent diet. Food frequency questionnaires and diet records were available for 72 participants. The authors calculated Spearman correlation coefficients between food, food group, and nutrient intakes from the diet records and food frequency questionnaire and deattenuated them to account for the effects of within-person variation measured in the diet records on the association. The median deattenuated correlation for foods was 0.30, ranging from −0.53 for a beef, pork, or lamb sandwich to 0.99 for diet soda. The median deattenuated correlation for food groups was 0.31 (range: −0.48 for breads to 0.70 for hot beverages); for nutrient intakes, it was 0.25 (range: −0.08 for iron to 0.82 for vitamin B12). Some dietary factors were reasonably recalled 3–6 decades later. However, this food frequency questionnaire did not validly measure overall adolescent diet when completed by middle-aged and older adults on average 48 years after adolescence.
adolescent; diet; mental recall; nutrition assessment; questionnaires; validation studies
The development of a mobile telephone food record has the potential to ameliorate much of the burden associated with current methods of dietary assessment. When using the mobile telephone food record, respondents capture an image of their foods and beverages before and after eating. Methods of image analysis and volume estimation allow for automatic identification and volume estimation of foods. To obtain a suitable image, all foods and beverages and a fiducial marker must be included in the image.
To evaluate a defined set of skills among adolescents and adults when using the mobile telephone food record to capture images and to compare the perceptions and preferences between adults and adolescents regarding their use of the mobile telephone food record.
We recruited 135 volunteers (78 adolescents, 57 adults) to use the mobile telephone food record for one or two meals under controlled conditions. Volunteers received instruction for using the mobile telephone food record prior to their first meal, captured images of foods and beverages before and after eating, and participated in a feedback session. We used chi-square for comparisons of the set of skills, preferences, and perceptions between the adults and adolescents, and McNemar test for comparisons within the adolescents and adults.
Adults were more likely than adolescents to include all foods and beverages in the before and after images, but both age groups had difficulty including the entire fiducial marker. Compared with adolescents, significantly more adults had to capture more than one image before (38% vs 58%, P = .03) and after (25% vs 50%, P = .008) meal session 1 to obtain a suitable image. Despite being less efficient when using the mobile telephone food record, adults were more likely than adolescents to perceive remembering to capture images as easy (P < .001).
A majority of both age groups were able to follow the defined set of skills; however, adults were less efficient when using the mobile telephone food record. Additional interactive training will likely be necessary for all users to provide extra practice in capturing images before entering a free-living situation. These results will inform age-specific development of the mobile telephone food record that may translate to a more accurate method of dietary assessment.
Mobile telephone food record; dietary assessment; technology; image analysis; volume estimation
Direct recording from sequential processing stations within the brain has provided opportunity for enhancing understanding of important neural circuits, such as the corticothalamic loops underlying auditory, visual, and somatosensory processing. However, the common reliance upon microwire-based electrodes to perform such recordings often necessitates complex surgeries and increases trauma to neural tissues. This paper reports the development of titanium-based, microfabricated, microelectrode devices designed to address these limitations by allowing acute recording from the thalamic nuclei and associated cortical sites simultaneously in a minimally-invasive manner. In particular, devices were designed to simultaneously probe rat auditory cortex and auditory thalamus, with the intent of recording auditory response latencies and isolated action potentials within the separate anatomical sites. Details regarding the design, fabrication, and characterization of these devices are presented, as are preliminary results from acute in vivo recording.
Ecological or survey based methods to investigate screening uptake rates are fraught with many limitations which can be circumvented by record linkage between Census and health services datasets using variations in breast screening attendance as an exemplar. The aim of this current study is to identify the demographic, socio-economic factors associated with uptake of breast screening.
Record linkage study: combining 2001 Census data within the Northern Ireland Longitudinal Study (NILS) with data relating to validated breast screening histories from the National Breast Screening System. A cohort was identified of 37,059 women aged 48-64 at the Census who were invited for routine breast screening in the three years following the Census. All cohort attributes were as recorded on the Census form.
The record linkage methodology enabled the records of almost 40,000 of those invited for screening to be analysed at an individual level, exceeding the largest published survey by a factor of ten. This produced a more robust analysis and demonstrated (in fully adjusted models) the lower uptake amongst non-married women and those in the lowest social class (OR 0.74; 95%CI 0.66, 0.82), factors that had not been reported earlier in the UK. In addition, with the availability of both individual and area information it was possible to show that the much lower screening uptake in urban areas is not due to differences in population composition suggesting unrecognised organisational problems.
Linkage of screening data to Census-based longitudinal studies is an efficient and powerful way to increase the evidence base on sources of variation in screening uptake within the UK.
Data linkage; Breast screening; Inequalities; Equity monitoring
The objective was to evaluate the potential use of genotype probabilities to handle records of non-genotyped animals in the context of survival analysis. To do so, the risks associated with the PrP genotype and other transmission factors in relation to clinical scrapie were estimated. Data from 4049 Romanov sheep affected by natural scrapie were analyzed using survival analysis techniques. The original data set included 1310 animals with missing genotypes; five of those had uncensored records. Different missing genotype-information patterns were simulated for uncensored and censored records. Three strategies differing in the way genotype information was handled were tested. Firstly, records with unknown genotypes were discarded (P1); secondly, those records were grouped in an unknown class (P2). Finally the probabilities of genotypes were assigned (P3). Whatever the strategy, the ranking of relative risks for the most susceptible genotypes (VRQ-VRQ, ARQ-VRQ and ARQ-ARQ) was similar even when the non-genotyped animals were not a negligible part of uncensored records. However, P3 had a more efficient way of handling missing genotype information. As compared to P1, either P2 or P3 avoided discarding the records of non-genotyped animals; however, P3 eliminated the unknown class and the risk associated with this group. Genotype probabilities were shown to be a useful technique to handle records of individuals with unknown genotype.
genotype probabilities; survival analysis; PrP genotypes;
The Canadian Medical Association (CMA) regards medical records as confidential documents, owned by the physician/institution/clinic that compiled them or had them compiled. Patients have a right to medical information contained in their records but not to the documents themselves. The first consideration of the physician is the well-being of the patient, and discretion must be used when conveying information contained in a medical record to a patient. This medical information often requires interpretation by a physician or other health care professional. Other disclosures of information contained in medical records to third parties (eg. physician-to-physician transfer for administrative purposes, lawyer, insurance adjuster) require written patient consent or a court order. CMA is opposed to legislation at any level which threatens the confidentiality of medical records.
The Canadian Medical Association (CMA) regards medical records as confidential documents, owned by the physician/institution/clinic that compiled them or had them compiled. Patients have a right to information contained in their records but not to the documents themselves. The first consideration of the physician is the well-being of the patient, and discretion must be used when conveying information contained in a medical record to a patient. This medical information often requires interpretation by a physician or other health care professional. Other disclosures of information contained in medical records to third parties (eg. physician-to-physician transfer, lawyer, insurance adjuster) require written patient consent or a court order. The CMA is opposed to legislation at any level which threatens the confidentiality of medical records.
The new perinatal death certificate proposed by the World Health Organisation was examined in relation to existing measures for recording perinatal death statistics and also with regard to new information gathered. Present procedures appear to underestimate the number of perinatal deaths by roughly 10%, though late registrations may lower this figure slightly. The use of a minimum birth weight as the criterion for inclusion in perinatal statistics removed much of the uncertainty associated with definitions of live birth and stillbirth. The new certificate led to duplication of some information already recorded through birth notification yet failed to provide information on some other factors generally considered relevant to perinatal mortality. The format proposed for recording cause of death provided a more logical presentation of events. Standardizing birth information recorded on all infants, modifying death certificates, and developing efficient record-linkage schemes would be more valuable than introducing the WHO certificate. Useful interpretation of the meaning of the characteristics of infants dying in the perinatal period awaits these timely changes.
OBJECTIVES--To determine the accuracy of diagnoses of schizophrenia and non-affective psychosis entered by general practitioners on a computer system. To compare recording of clinical events on computer with written records. DESIGN--Examination of case notes of all patients with a computer diagnosis of psychosis. Search of 8000 randomly selected patient records to identify patients with psychosis not recorded on computer and comparison of 141 computer and written entries for prescribing and consultation in each practice. SETTING--13 London practices on the VAMP research bank. MAIN OUTCOME MEASURES--Accuracy of record of psychosis compared with ICD 9, American Psychiatric Association diagnostic manual, and syndrome checklist criteria. RESULTS--Computer search revealed 102 patients with schizophrenia, 78 with other psychoses, and 71 with non-affective psychosis who had adequate case notes. The sensitivity and positive predictive value of the computer diagnosis of schizophrenia were 88% (95% confidence interval 62% to 98%) and 71% (48% to 88%). For all non-organic psychoses sensitivity was 91% (74% to 97%) and positive predictive value was 91% (74% to 98%). On average 95% of all known prescriptions and 74% of all consultations were recorded on computer compared with 42% and 75% in written records. CONCLUSIONS--Recording of psychotic illness on the VAMP computer is accurate and complete. Prescribing was more fully recorded on the computer than on the written records. Computer databases of well motivated general practitioners could be used for research.
OBJECTIVE--To describe the epidemiology of presenile Alzheimer's disease in Scotland from 1974 to 1988. DESIGN--Retrospective review of hospital records of patients aged less than 73 years admitted to psychiatric hospital with various diagnoses of dementia. Diagnoses were classified by National Institute for Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association Criteria and the Hachinski score. Completeness of the study sample was evaluated by scrutiny of neurology outpatient and general hospital records. SETTING--All general psychiatric hospitals in Scotland. SUBJECTS--All patients with onset of dementia aged 40-64. MAIN OUTCOME MEASURES--Probable and broad Alzheimer's disease, sex of patient, age at onset. RESULTS--5874 psychiatric hospital records, 129 neurology outpatient records, and 89 records from non-psychiatric hospitals were examined. 317 patients met criteria for probable Alzheimer's disease, 569 met criteria for broad Alzheimer's disease, and 267 met those for multi-infarct dementia. Minimal incidences per 100,000 population aged 40-64 years were 22.6 (95% confidence interval, 20.2 to 25.2) and 40.5 (38.9 to 42.3) per 100,000 for probable and broad Alzheimer's disease. In the 1981 census year the annual incidence of probable Alzheimer's disease was 1.6 (1.0 to 2.6). Women were at greater risk with incidence rates for probable Alzheimer's disease of 28.2 (24.5 to 32.4) per 100,000 compared with 16.5 (13.8 to 19.8) per 100,000 for men. The incidence per 100,000 for multi-infarct dementia was greater in men (25.1, 23.3 to 27.1) than women (13.4, 12.1 to 14.8). CONCLUSION--Female sex seems to be positively associated with development of Alzheimer's disease before age 65 years.
A study was carried out to assess the feasibility of using record linkage for drug monitoring. For two years, three types of records were collected for a total of 43 117 people: (1) details of basic attributes, such as sex and age; (2) details of prescriptions dispensed; and (3) records of hospital admissions, obstetric deliveries, and deaths. The records about each person were linked together, and analyses were performed to reveal associations between drugs and diagnoses. The study suggested that record linkage would be useful both for generating and for testing hypotheses about the adverse effects of drugs. The method would be especially valuable for detection of delayed effects (such as the induction of cancer), sudden deaths outside hospital, and effects of the fetus-all of which are difficult to study by other means. A full-scale project would need to cover a large population, and some of the practical issues that would arise are discussed.
Early human evolution is characterised by pulsed speciation and dispersal events that cannot be explained fully by global or continental paleoclimate records. We propose that the collated record of ephemeral East African Rift System (EARS) lakes could be a proxy for the regional paleoclimate conditions experienced by early hominins. Here we show that the presence of these lakes is associated with low levels of dust deposition in both West African and Mediterranean records, but is not associated with long-term global cooling and aridification of East Africa. Hominin expansion and diversification seem to be associated with climate pulses characterized by the precession-forced appearance and disappearance of deep EARS lakes. The most profound period for hominin evolution occurs at about 1.9 Ma; with the highest recorded diversity of hominin species, the appearance of Homo (sensu stricto) and major dispersal events out of East Africa into Eurasia. During this period, ephemeral deep-freshwater lakes appeared along the whole length of the EARS, fundamentally changing the local environment. The relationship between the local environment and hominin brain expansion is less clear. The major step-wise expansion in brain size around 1.9 Ma when Homo appeared was coeval with the occurrence of ephemeral deep lakes. Subsequent incremental increases in brain size are associated with dry periods with few if any lakes. Plio-Pleistocene East African climate pulses as evinced by the paleo-lake records seem, therefore, fundamental to hominin speciation, encephalisation and migration.