Longitudinal Study Of Cognition Research Articles

50 Remote Assessment has Minimal Effect on Test-Retest Reliability Among Older Adults with Essential Tremor

Objective:The COVID-19 pandemic increased utilization of remote assessment to allow clinicians and researchers to continue valuable work while maintaining quarantine guidelines. With guidelines relaxing, researchers have returned to in-person assessment. Information is needed regarding the effect of remote assessments on test-retest reliability. COGNET, a longitudinal study of cognition in participants with essential tremor, transitioned from in-person to remote assessments during the pandemic, and has now returned to in-person assessment. The current study investigates the extent to which remote assessment affected test-retest reliability across a range of neuropsychological assessments administered in COGNET.Participants and Methods:Participants included 27 older adults enrolled in COGNET (mean age=75.0 (9.1), education=16.2 (2.6), 67% female, and 100% white). Memory tests included: California Verbal Learning Test II, Logical Memory subtest of the Wechsler Memory Scales - Revised, and Verbal Paired? Associates. Executive function tests included: Digit Span Backwards and the Delis-Kaplan Executive Function System subtests of Verbal Fluency, Sorting, and Color-Word. Attention tests included Oral Symbol Digit Modalities Test and Digit Span Forward. Language was assessed with the Boston Naming Test. Intraclass correlation coefficients (ICCs) were calculated to examine test-retest reliability of InPerson to In-Person visits (P-P), and combination visits (e.g., In-Person to Remote (PR), and Remote to In-Person (R-P)). Following Koo & Li (2016), ICCs were interpreted as: >.90 excellent, .75-.90 good, .50-.74 moderate, and <.50 poor reliability. The Feldt approach was used to compare ICCs from P-P visits against ICCs calculated for combination visits (P-R or R-P), with the test statistic compared to an F distribution.Results:ICCs for person-to-person assessment ranged from .51 to .89. Memory test ICCs ranged from moderate to good (.51 to .80). Executive function test ICCs ranged from moderate to good (.55 to .89). The attention domain had moderate ICCs (.67 - .68). Language ICC was moderate (.70). ICCs for person-to-remote assessment ranged from .42 to .89. Memory tests ranged from moderate to good ICCs (.59 to .83). Executive function tests ranged from poor to good ICCs (.42 to .89). Attention ICCs were moderate to good (.55 to .79). The Language ICC was moderate (.72). ICCs for remote-to-person ranged from .48 to 86. Memory ICCs ranged from moderate to good (.59 to .86). Executive function ICCs ranged from poor to good (.48 to .83). Attention ICCs were moderate to good (.56 to .79). The Language ICC was good (.78). The only test for which an ICC from a combination visit was significantly lower than a person to person visit was Digit Span Backwards.Conclusions:Test-retest reliability was moderate or better for all P-P assessments, consistent with the known psychometrics of these tests. Only one test of executive function showed lower reliability when remote assessment was introduced. From a broad standpoint, current results suggest that remote administration of neuropsychological tests can be used as a reliable substitute for in-person assessment for many measures, and suggest that caution be used when interpreting any change in Digit Span Backwards across person and remote assessments.

Effects of risperidone/paliperidone versus placebo on cognitive functioning over the first 6 months of treatment for psychotic disorder: secondary analysis of a triple-blind randomised clinical trial

The drivers of cognitive change following first-episode psychosis remain poorly understood. Evidence regarding the role of antipsychotic medication is primarily based on naturalistic studies or clinical trials without a placebo arm, making it difficult to disentangle illness from medication effects. A secondary analysis of a randomised, triple-blind, placebo-controlled trial, where antipsychotic-naive patients with first-episode psychotic disorder were allocated to receive risperidone/paliperidone or matched placebo plus intensive psychosocial therapy for 6 months was conducted. A healthy control group was also recruited. A cognitive battery was administered at baseline and 6 months. Intention-to-treat analysis involved 76 patients (antipsychotic medication group: 37; 18.6Mage [2.9] years; 21 women; placebo group: 39; 18.3Mage [2.7]; 22 women); and 42 healthy controls (19.2Mage [3.0] years; 28 women). Cognitive performance predominantly remained stable (working memory, verbal fluency) or improved (attention, processing speed, cognitive control), with no group-by-time interaction evident. However, a significant group-by-time interaction was observed for immediate recall (p = 0.023), verbal learning (p = 0.024) and delayed recall (p = 0.005). The medication group declined whereas the placebo group improved on each measure (immediate recall: p = 0.024; ηp2 = 0.062; verbal learning: p = 0.015; ηp2 = 0.072 both medium effects; delayed recall: p = 0.001; ηp2 = 0.123 large effect). The rate of change for the placebo and healthy control groups was similar. Per protocol analysis (placebo n = 16, medication n = 11) produced similar findings. Risperidone/paliperidone may worsen verbal learning and memory in the early months of psychosis treatment. Replication of this finding and examination of various antipsychotic agents are needed in confirmatory trials. Antipsychotic effects should be considered in longitudinal studies of cognition in psychosis.Trial registration: Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au/; ACTRN12607000608460).

Long-term psychological consequences of stroke (OX-CHRONIC): A longitudinal study of cognition in relation to mood and fatigue after stroke: Protocol.

BackgroundThe long-term psychological consequences of stroke and how cognitive problems change over time after the first-year following stroke remain unclear. Particularly, trajectories of domain-specific and domain-general cognitive functions and how cognition interacts with mood, fatigue and quality of life are not well described.AimsTo determine the prevalence, trajectories and wider impact of domain-specific cognitive impairment in long-term stroke survivors, in relation to mood, fatigue and quality of life.MethodsParticipants who previously took part in the Oxford Cognitive Screening study, completed the 6-month follow-up with cognitive, mood, fatigue and quality of life assessments and agreed to be contacted for future research will be recruited into OX-CHRONIC. The eligible cohort is between 2- and 9-years post-stroke. Cognition will be assessed with a detailed neuropsychological battery, alongside questionnaire measures of mood, fatigue, activities of daily life and quality of life measures at two timepoints, 1 year apart. Additionally, medical records will be accessed to extract further clinical information about the stroke and patients may opt-in to wear an activity monitor for 1 week to provide fine-grained measures of sleep and activity. The study protocol and study materials were approved by the national ethics committee (REC Ref: 19/SC/0520).Planned outputsOX-CHRONIC will provide detailed data on the evolving cognitive profiles of stroke survivors over several years post-stroke. Estimates of long-term prevalence as well as the effect of changes in cognitive profiles on mood, fatigue and quality of life will be examined. This study is funded by a Priority Programme Grant from the Stroke Association (SA PPA 18/100032).

A longitudinal study of cognition, functional outcome and quality of life in bipolar disorder and major depression

Objective Cognitive impairments are known to be a frequent cause of disability in bipolar disorder (BD) and major depression (MDD). Yet there is no consensus regarding the particular cognitive functions whose impairments can lead to disability in each domain of functioning. The aim of this study was to perform a longitudinal evaluation of working memory, inhibition, cognitive flexibility and attention in BD and MDD, investigate the relationship of these cognitive functions to disability and quality of life, and evaluate the impact of variables related to cognitive reserve (education and daily cognitive stimulation) on cognitive performance. Method 31 participants (MDD = 12; BD = 19) were evaluated at baseline and after an average time of 2 years. Results the BD group showed improvements in attention while patients with MDD improved on measures of attention and working memory. In BD working memory performance was associated with the cognition and mobility domains of functioning, and with physical and environmental quality of life. In MDD, cognitive flexibility was related to social relationships and environmental quality of life. Conclusion working memory and cognitive flexibility may be an interesting target for interventions aiming to improve everyday functioning and quality of life in BD and MDD.

An Observational, Longitudinal Study of Cognition in Medical Cannabis Patients over the Course of 12 Months of Treatment: Preliminary Results

AbstractObjective:Cannabis use has increased dramatically across the country; however, few studies have assessed the long-term impact of medical cannabis (MC) use on cognition. Studies examining recreational cannabis users generally report cognitive decrements, particularly in those with adolescent onset. As MC patients differ from recreational consumers in motives for use, product selection, and age of onset, we assessed cognitive and clinical measures in well-characterized MC patients over 1 year. Based on previous findings, we hypothesized MC patients would not show decrements and might instead demonstrate improvements in executive function over time.Method:As part of an ongoing study, MC patients completed a baseline visit prior to initiating MC and evaluations following 3, 6, and 12 months of treatment. At each visit, patients completed a neurocognitive battery assessing executive function, verbal learning/memory, and clinical scales assessing mood, anxiety, and sleep. Exposure to delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) was also quantified.Results:Relative to baseline, MC patients demonstrated significant improvements on measures of executive function and clinical state over the course of 12 months; verbal learning/memory performance generally remained stable. Improved cognitive performance was not correlated with MC use; however, clinical improvement was associated with higher CBD use. Analyses suggest cognitive improvements were associated with clinical improvement.Conclusions:Study results extend previous pilot findings, indicating that MC patients may exhibit enhanced rather than impaired executive function over time. Future studies should examine distinctions between recreational and MC use to identify potential mechanisms related to cognitive changes and the role of clinical improvement.

Physical Activity as a Predictor of Cognitive Decline in an Elderly Essential Tremor Cohort: A Prospective, Longitudinal Study.

Background: Essential tremor (ET), one of the most common neurological diseases, is associated with cognitive impairment. Surprisingly, predictors of cognitive decline in ET remain largely unidentified, as longitudinal studies are rare. In the general population, however, lower physical activity has been linked to cognitive decline.Objectives: To determine whether baseline physical activity level is a predictor of cognitive decline in ET.Methods: One hundred and twenty-seven ET cases (78.1 ± 9.5 years, range = 55–95), enrolled in a prospective, longitudinal study of cognition. At baseline, each completed the Physical Activity Scale for the Elderly (PASE), a validated, self-rated assessment of physical activity. Cases underwent an extensive battery of motor-free neuropsychological testing at baseline, 1.5 years, and 3 years, which incorporated assessments of cognitive subdomains. Generalized estimating equations (GEEs) were used to assess the predictive utility of baseline physical activity for cognitive change.Results: Mean follow-up was 2.9 ± 0.4 years (range = 1.3–3.5). In cross-sectional analyses using baseline data, lower physical activity was associated with lower overall cognitive function as well as lower cognitive scores in numerous cognitive domains (memory, language, executive function, visuospatial function and attention, all p < 0.05). In adjusted GEE models, lower baseline physical activity level significantly predicted overall cognitive decline over time (p=0.047), and declines in the subdomains of memory (p = 0.001) and executive function (p = 0.03).Conclusions: We identified reduced physical activity as a predictor of greater cognitive decline in ET. The identification of risk factors often assists clinicians in determining which patients are at higher risk of cognitive decline over time. Interventional studies, to determine whether increasing physical activity could modify the risk of developing cognitive decline in ET, may be warranted.

“I Felt like My Practice Was Catching up with My Beliefs:” A Longitudinal Cognitive Study of Seven Early Career Literacy Teachers and Their Praxis

ABSTRACT Using a qualitative approach, this article reports findings of a longitudinal study of seven successful elementary educators from the inception of their final preservice field experience through the first seven years of their independent teaching. The research centers the development of teachers’ literacy-related instructional practices over the course of their early teaching careers, as well as the factors that influenced and impacted their instructional choices. Through repeated surveys and a culminating reflective interview, the researchers examined patterns of literacy beliefs and practices reported by these teachers over time, as well as the extent to which they internalized and used those beliefs and practices. The authors share what impacted teachers’ perceptions and practice of reading instruction throughout the formative stages of their teaching careers and suggest implications for teacher preparation programs in attending to pre- and early-career teachers’ praxis.

Are latent variable models preferable to composite score approaches when assessing risk factors of change? Evaluation of type-I error and statistical power in longitudinal cognitive studies.

As with many health constructs, cognition is difficult to measure accurately; it is assessed by multiple psychometric tests. Two approaches are commonly adopted to address this multivariate aspect in longitudinal analyses: the composite score approach summarizes the tests into a single outcome and subsequently analyzes its change; the multivariate approach relates the tests to the underlying cognitive level and simultaneously analyzes its change. We compared the quality of inference of these approaches in a simulation study based on three combinations of tests inspired by two population-based cohorts. In the absence of missing data and with relatively Gaussian psychometric tests, the composite score approach provided similar type-I error rates and statistical power as the multivariate latent process approach. In the more plausible scenario with departures from normality, transformations of each constituent test or of the composite score were required to avoid excess type-I error rates. When missing tests were more likely in cognitively impaired subjects, inference with the composite was not correct. In conclusion, composite scores can be used to assess risk factors for cognitive change provided they are correctly normalized, constituent tests are reliable and the amount of uninformative missing tests remains small. Otherwise, latent variable models are recommended.

Mild Traumatic Brain Injury: Longitudinal Study of Cognition, Functional Status, and Post-Traumatic Symptoms.

More than 75% of traumatic brain injuries (TBIs) seeking medical attention are mild, and outcome in that group is heterogeneous. Until sensitive and valid biomarkers are identified, methods are needed to classify mild TBI into more homogeneous subgroups. Four hundred twenty-one adults with mild TBI were divided into groups based on Glasgow Coma Scale (GCS) 13-15 without computed tomography (CT) abnormalities, GCS 15 with CT abnormalities, and GCS 13-14 with CT abnormalities, and were compared with 120 trauma controls on 1-month and 1-year outcomes. At 1 month post-injury, almost all neuropsychological variables differed significantly among the groups. Compared with trauma controls, the GCS 13-15 CT normal group showed no significant differences on any neuropsychological measure or Glasgow Outcome Scale (GOS). The GCS 15 CT abnormal group performed significantly worse on only a measure of episodic memory and learning (Selective Reminding Recall [SRCL]) and GOS, and the GCS 13-14 CT abnormal group performed significantly worse on most neuropsychological measures and GOS. At 1 year post-injury, except for an isolated difficulty on SRCL in the GCS 13-14 CT abnormal group, no differences were observed on any neuropsychological measures nor on GOS. Mean percent of total post-traumatic symptoms endorsed as new or worse and percent endorsing three or more symptoms differed significantly (p < 0.001), with each TBI subgroup reporting significantly more symptoms than the trauma controls at both 1 month and 1 year. In conclusion, this subgrouping improves granularity within mild TBI. While most neuropsychological and functional differences abate by 1 year, reporting three or more post-traumatic symptoms remain for about half of individuals.

Pattern and Rate of Cognitive Decline in Cerebral Small Vessel Disease: A Prospective Study.

ObjectivesCognitive impairment, predominantly affecting processing speed and executive function, is an important consequence of cerebral small vessel disease (SVD). To date, few longitudinal studies of cognition in SVD have been conducted. We determined the pattern and rate of cognitive decline in SVD and used the results to determine sample size calculations for clinical trials of interventions reducing cognitive decline.Methods121 patients with MRI confirmed lacunar stroke and leukoaraiosis were enrolled into the prospective St George’s Cognition And Neuroimaging in Stroke (SCANS) study. Patients attended one baseline and three annual cognitive assessments providing 36 month follow-up data. Neuropsychological assessment comprised a battery of tests assessing working memory, long-term (episodic) memory, processing speed and executive function. We calculated annualized change in cognition for the 98 patients who completed at least two time-points.ResultsTask performance was heterogeneous, but significant cognitive decline was found for the executive function index (p<0.007). Working memory and processing speed decreased numerically, but not significantly. The executive function composite score would require the smallest samples sizes for a treatment trial with an aim of halting decline, but this would still require over 2,000 patients per arm to detect a 30% difference with power of 0.8 over a three year follow-up.ConclusionsThe pattern of cognitive decline seen in SVD over three years is consistent with the pattern of impairments at baseline. Rates of decline were slow and sample sizes would need to be large for clinical trials aimed at halting decline beyond initial diagnosis using cognitive scores as an outcome measure. This emphasizes the importance of more sensitive surrogate markers in this disease.

Longitudinal study of cognition in Niemann-Pick disease type C

Marc C. Patterson, Eugen Mengel, Frits A. Wijburg, Marie T. Vanier, Barbara Schwierin, Audrey Muller, Harir Drevon, Merce Pineda, Mayo Clinic, Rochester, MN, USA, Villa Metabolica, University of Mainz, Mainz, Germany, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands, INSERM Unit 820, Lyon, France, Actelion Pharmaceuticals Ltd, Allschwil, Switzerland, Numerus Ltd, Sandhurst, UK, Hospital Sant Joan de Deu, Barcelona, Spain

The cognitive side of essential tremor: what are the therapeutic implications?

While essential tremor (ET) has traditionally been categorized as a pure motor disease, cross-sectional and longitudinal studies of cognition in ET have demonstrated that these patients may have cognitive dysfunction. Recent epidemiological studies demonstrate an association between ET (particularly with onset after age 65) and increased risk for cognitive impairment and dementia. Although existing studies have generally conceptualized cognitive changes in ET as consistent with a 'frontosubcortical' or 'corticocerebellar' profile, results from these same studies suggest that cognitive impairment in ET may in fact be heterogeneous. Furthermore, the underlying mechanisms remain uncertain. Cognitive changes could be a byproduct of the cerebellar dysfunction of ET itself; alternately, they may be a feature of concomitant neurodegenerative diseases that have been associated in several studies with ET, including Alzheimer's disease, Parkinson's disease or progressive supranuclear palsy. While the study of cognitive dysfunction in ET has received research attention in recent years, the results of these studies have not been translated into the clinical domain and clinical practice. This review first summarizes the current literature on the potential relationships between ET and cognitive change. We then suggest areas of further clinical evaluation and treatment; these suggestions are directed at physicians caring for ET patients who may demonstrate or complain of cognitive impairment. As we discuss, clinicians should ideally screen ET patients for possible signs or symptoms of cognitive impairment in addition to assessing for psychiatric comorbidity and quality of life. These recommendations are in contrast to most current clinical practice, which does not routinely include such assessment among ET patients. To our knowledge, there have been no pharmacotherapeutic trials to date of any agent for cognitive change associated with ET. We believe that studies for this indication are now called for. Future efforts in this direction will also need to take into account the pathobiology of cognitive changes in ET, which itself is an area that is ripe for future investigations.

A Longitudinal Study of Cognition, Proton MR Spectroscopy and Synaptic and Neuronal Pathology in Aging Wild-type and AβPPswe-PS1dE9 Mice

Proton magnetic resonance spectroscopy (1H MRS) is a valuable tool in Alzheimer’s disease research, investigating the functional integrity of the brain. The present longitudinal study set out to characterize the neurochemical profile of the hippocampus, measured by single voxel 1H MRS at 7 Tesla, in the brains of AβPPSswe-PS1dE9 and wild-type mice at 8 and 12 months of age. Furthermore, we wanted to determine whether alterations in hippocampal metabolite levels coincided with behavioral changes, cognitive decline and neuropathological features, to gain a better understanding of the underlying neurodegenerative processes. Moreover, correlation analyses were performed in the 12-month-old AβPP-PS1 animals with the hippocampal amyloid-β deposition, TBS-T soluble Aβ levels and high-molecular weight Aβ aggregate levels to gain a better understanding of the possible involvement of Aβ in neurochemical and behavioral changes, cognitive decline and neuropathological features in AβPP-PS1 transgenic mice. Our results show that at 8 months of age AβPPswe-PS1dE9 mice display behavioral and cognitive changes compared to age-matched wild-type mice, as determined in the open field and the (reverse) Morris water maze. However, there were no variations in hippocampal metabolite levels at this age. AβPP-PS1 mice at 12 months of age display more severe behavioral and cognitive impairment, which coincided with alterations in hippocampal metabolite levels that suggest reduced neuronal integrity. Furthermore, correlation analyses suggest a possible role of Aβ in inflammatory processes, synaptic dysfunction and impaired neurogenesis.

A longitudinal study of cognition in asymptomatic and mildly symptomatic bipolar disorder patients

Bipolar disorder (BD) is characterized by cognitive deficits that impair patients' functioning and quality of life. Most of the earlier studies assessing changes in BD patients' cognitive functioning over time utilized a cross-sectional research design. The few longitudinal studies that were conducted tended to have methodological limitations such as very short follow-up periods, recruitment of acutely ill patients, and lack of assessment of practice effects. The current study aimed to assess changes over time in the cognitive functioning of typical BD outpatients. For this purpose, asymptomatic and mildly symptomatic BD outpatients were assessed at baseline and after two years (n=31). At baseline, the cognitive functioning of the BD patients was compared to that of gender- and age-matched healthy controls. Practice effects were estimated by re-assessing the controls one week after their first assessment. Compared to the controls, BD patients had deficits in psychomotor speed, sustained attention, and one domain of executive functioning (cognitive planning). No evidence was found of a decline in their cognitive functioning over the two year time interval. These findings support a developmental model of cognitive impairment in BD. Studies using longer follow-up periods and larger sample sizes, however, are needed before these conclusions can be stated confidently.

Longitudinal Study of Cognition in Patients with Niemann-Pick Disease, Type C

Longitudinal Study of Cognition in Patients with Niemann-Pick Disease, Type C

Longitudinal Studies of Cognition in First Episode Psychosis: A Systematic Review of the Literature

Although cognitive deficits are recognized as a core feature in schizophrenia, their evolution over the course of the illness is still debated. Longitudinal studies of cognition in patients after a first episode of psychosis (FEP) provide extremely useful information, in that they include an adequate and realistic baseline measure of cognitive performance, while at the same time minimizing the effect of confounding variables associated with chronicity. The aim of this systematic review was to summarize findings of studies assessing the longitudinal course of neuropsychological deficits in patients with FEP for durations of at least one year. Overall, the neuropsychological deficits that are present following a first episode of psychosis appeared to remain stable over time for periods of up to ten years, the only possible exception being verbal memory deficits, where there is some evidence of further deterioration over the long term. However, further studies are needed to confirm this conclusion, especially in the (somewhat inconsistently defined) domain of executive function. Improvements in psychopathology appear to positively influence the course of cognitive deficits, although the effects of antipsychotic medication are not as clear.

Longitudinal study of cognition in Niemann-Pick Disease, Type C

Longitudinal study of cognition in Niemann-Pick Disease, Type C

Risk Factors for Nursing Home Placement in Alzheimer's Disease: A Longitudinal Study of Cognition, ADL, Service Utilization, and Cholinesterase Inhibitor Treatment

To identify risk factors for early nursing home placement (NHP) in Alzheimer's disease (AD), focusing on the impact of longitudinal change in cognition, activities of daily living (ADL), service utilization, and cholinesterase inhibitor treatment (ChEI). In an open, 3-year, prospective, multicenter study in a routine clinical setting, 880 AD patients were treated with either donepezil, rivastigmine, or galantamine. At baseline and every 6 months, they were assessed with several rating scales including Mini-Mental State Examination, Instrumental Activities of Daily Living scale (IADL), and Physical Self-Maintenance scale. Moreover, the dose of ChEI, the amount of weekly assistance (home help service and adult day care), and the date of NHP were recorded. Cox regression models were constructed to predict the risk of NHP. During the study, 206 patients (23%) were admitted to nursing homes. Factors that precipitated institutionalization were lower cognitive and functional abilities at baseline, faster rate of decline in IADLs, female gender, solitary living, and a lower mean dose of ChEI. The men living alone and patients with a substantial increase in adult day care also demonstrated shorter time to NHP. The rate of functional but not cognitive decline was a strong risk factor for NHP. The results could be used to identify the care recipients that might risk early NHP to ensure that these individuals receive a sufficient level of assistance. Furthermore, higher doses of ChEI might postpone institutionalization in AD.

Longitudinal study of cognition among adolescent marijuana users over three weeks of abstinence

Background Cognitive deficits that persist up to a month have been detected among adult marijuana users, but decrements and their pattern of recovery are less known in adolescent users. Previously, we reported cognitive deficits among adolescent marijuana users after one month of abstinence (Medina, Hanson, Schweinsburg, Cohen-Zion, Nagel, & Tapert, 2007). In this longitudinal study, we characterized neurocognitive changes among marijuana-using adolescents across the first three weeks of abstinence. Method Participants were adolescent marijuana users with limited alcohol and other drug use ( n = 19) and demographically similar non-using controls ( n = 21) ages 15–19. Participants completed a brief neuropsychological battery on three occasions, after 3 days, 2 weeks, and 3 weeks of stopping substance use. Abstinence was ascertained by decreasing tetrahydrocannabinol metabolite values on serial urine drug screens. Verbal learning, verbal working memory, attention and vigilance, and time estimation were evaluated. Results Marijuana users demonstrated poorer verbal learning ( p < .01), verbal working memory ( p < .05), and attention accuracy ( p < .01) compared to controls. Improvements in users were seen on word list learning after 2 weeks of abstinence and on verbal working memory after 3 weeks. While attention processing speed was similar between groups, attention accuracy remained deficient in users throughout the 3-week abstinence period. Conclusions This preliminary study detected poorer verbal learning and verbal working memory among adolescent marijuana users that improved during three weeks of abstinence, while attention deficits persisted. These results implicate possible hippocampal, subcortical, and prefrontal cortex abnormalities.

106. Longitudinal study of cognition in subjects with Niemann–Pick disease, type C

106. Longitudinal study of cognition in subjects with Niemann–Pick disease, type C