We examined two-wave longitudinal changes in two indicators of neurocognitive speed (i.e., mean rate, intraindividual variability) using one simple and three complex reaction time tasks. Participants included idiopathic Parkinson’s disease (PD) patients, with and without incipient dementia, and normal controls. At baseline, there were 45 patients (26 men, 19 women) with idiopathic PD who ranged from 65 to 84 years (M = 71.3, SD = 4.5) and 47 matched controls (27 men, 20 women) who ranged from 65 to 84 years (M = 71.4, SD = 4.9). The 18-month longitudinal sample comprised of 74 returning participants (43 controls, 31 PD patients) who had no cognitive impairment or dementia at both waves. Ten of the 31 PD patients returning for Time 3 had dementia or cognitive impairment. These constituted the PD with incipient dementia (PDID) group. Repeated measures analyses of variance showed that the PD and PDID groups were slower over time on the RT tasks whereas the controls improved their performance over time on all tasks. Inconsistency distinguished the two clinical groups (i.e., the PDID group but not the PD group became more inconsistent over time). Changes in neurocognitive speed and inconsistency may be valid clinical markers of PDID.
Parkinson’s disease; Aging; Intraindividual Variability; Speed; Longitudinal Study; Reaction Time
Major depressive disorder (MDD), cognitive symptoms, and mild cognitive deficits commonly occur in HIV-infected individuals, despite highly active antiretroviral therapies. In this study, we compared neuropsychological performance and cognitive symptoms of 191 HIV-infected participants. Results indicated that participants with a formal diagnosis of current MDD performed significantly worse than participants without MDD in all seven neuropsychological domains evaluated, with the largest effect sizes in information processing speed, learning, and memory. In addition, a brief assessment of cognitive symptoms, derived from a comprehensive neuromedical interview, correlated significantly with neurocognitive functioning. Participants with MDD reported more cognitive symptoms and showed greater neurocognitive deficits than participants without MDD. These findings indicate that HIV-infected adults with MDD have more cognitive symptoms and worse neuropsychological performance than HIV-infected individuals without MDD. The results of this study have important implications for the diagnosis of HIV-associated neurocognitive disorders (HAND).
Depression; Cognition; Cognitive complaints; Neuropsychological tests; Acquired immunodeficiency syndrome; Mood disorders
Measures of brain and hippocampal volume in 40 healthy young (aged 18–30 years) and 36 healthy elderly (aged 60–83 years) subjects were compared with composite cognitive function scores in three conceptual domains: memory ability, processing speed, and general fluid intelligence. Through a series of general linear models testing the relationship between these brain measures and cognitive performance scores, a significant positive relationship between hippocampal volume and fluid intelligence ability was found in elderly subjects but not in young. No relationship between the other cognitive domains and brain or hippocampal volume was found. The findings suggest a role of hippocampal atrophy in the decline in fluid intelligence in the elderly.
Aging; Hippocampus; Brain atrophy; Cognitive decline; Fluid intelligence; Memory
This study examined the validity of the Spanish and English Neuropsychological Assessment Scales (SENAS) in comparison with clinical diagnosis of normal cognition versus cognitive impairment, not demented (CIND) versus demented in elderly Hispanics and Whites. Relationships between SENAS scales and diagnosis were essentially the same in Hispanics and Whites. Verbal memory measures were most strongly related, with more than 35% of the variance in these measures accounted for by diagnosis independent of effects of education, age, gender, and language. Diagnosis accounted for more than 10% of the variance (19% on average) in 11 of the 17 measures examined in this study. Logistic regressions showed that verbal memory was important both for distinguishing normal from CIND and CIND from demented. Object naming improved discrimination of CIND from demented beyond that of verbal memory alone. These results provide evidence of equivalent validity across Hispanics and Whites.
Neuropsychological assessment; Ethnic groups; Cognitive impairment; Dementia; Early diagnosis; Cognition
A growing body of literature has documented evidence for emotion labeling (EL) deficits after traumatic brain injury (TBI); however, long-term effects of TBI on EL abilities, particularly among young children, are unclear. We investigated EL abilities and socio-emotional outcomes in 32 children with moderate–severe TBI, 23 with complicated-mild TBI, and 82 children with orthopedic injuries (OI), shortly after injury and at 18 months post-injury. All children were between 3:0 and 6:11 years of age at the time of injury. Repeated measures analyses indicated that all groups showed improved EL performance between acute and 18-month assessments, but that the moderate–severe TBI group improved at a slower rate than the OI group, so that the two groups showed significantly different performance at 18 months. Emotion labeling ability did not significantly contribute to the prediction of socio-emotional outcomes after controlling for pre-injury functioning. These results provide preliminary evidence of emerging EL deficits after early childhood TBI that are related to injury severity but that do not predict social and behavioral outcomes.
Head injury; Emotion; Longitudinal studies; Social adjustment; Pediatric; Chronic brain injury
Episodic memory tasks are one of the most sensitive tools to discriminate Alzheimer’s disease (AD). This study aimed to validate a shorter version verbal memory test that will efficiently assess Chinese elderly with memory complaints. One hundred and eighty-five elderly with normal cognition (NC) and 217 AD patients were evaluated. Each participant received the Chinese Version Verbal Learning Test (CVVLT) consisting of 9 two-character nouns with 4 learning trials, 2 delayed recalls in 30 seconds and 10 minutes, and a word recognition test. In the NC elderly, age and sex had significant effects on recall scores in CVVLT, while education level showed an inverse correlation with 3 different patterns of errors made during the learning, recall, and recognition trials. AD patients had lower scores across all recall tests. In those with lower educational level, NC elderly had higher perseveration errors than AD patients. The cutoff value between the AD and NC groups in the 10-minute recall was 4/5 for those aged >75 years and 5/6 for those aged <75 years. This study has good validity in discriminating AD participants and the data here can help in diagnosing AD and mild cognitive impairment using the CVVLT.
Chinese Verbal Learning Test; education; memory; dementia; cutoff value; validation
Existing evidence suggests that psychosocial stress is associated with cognitive impairment in older adults. Perceived discrimination is a persistent stressor in African Americans that has been associated with several adverse mental and physical health outcomes. To our knowledge, the association of discrimination with cognition in older African Americans has not been examined. In a cohort of 407 older African Americans without dementia (mean age = 72.9; SD = 6.4), we found that a higher level of perceived discrimination was related to poorer cognitive test performance, particularly episodic memory (estimate = −0.03; SE = .013; p < .05) and perceptual speed tests (estimate = −0.04; SE = .015; p < .05). The associations were unchanged after adjusting for demographics and vascular risk factors, but were attenuated after adjustment for depressive symptoms (Episodic memory estimate = −0.02; SE = 0.01; Perceptual speed estimate = −0.03; SE = 0.02; both p’s = .06). The association between discrimination and several cognitive domains was modified by level of neuroticism. The results suggest that perceived discrimination may be associated with poorer cognitive function, but does not appear to be independent of depressive symptoms.
African American; Cognitive function; Epidemiology; Psychological stress; Depressive symptoms; Cohort study
Theory of mind (ToM) involves thinking about mental states and intentions to understand what other people know and to predict how they will act. We studied ToM in children with traumatic brain injury (TBI) and age- and gender-matched children with orthopedic injuries (OI), using a new three-frame Jack and Jill cartoon task that measures intentional thinking separate from contingent task demands. In the key ToM trials, which required intentional thinking, Jack switched a black ball from one hat to another of a different color, but Jill did not witness the switch; in the otherwise identical non-ToM trials, the switch was witnessed. Overall accuracy was higher in children with OI than in those with TBI. Children with severe TBI showed a larger decline in accuracy on ToM trials, suggesting a specific deficit in ToM among children with severe TBI. Accuracy was significantly higher on trials following errors than on trials following correct responses, suggesting that all groups monitored performance and responded to errors with increased vigilance. TBI is associated with poorer intentional processing in school-age children and adolescents relative to peers with OI; furthermore, children with TBI are challenged specifically by intentional demands, especially when their injury is severe.
Intentionality; Childhood head injury; Glasgow Coma Scale; Social cognition; Social problem solving; Error monitoring
Visual perceptual problems are common in Parkinson's disease (PD) and often affect activities of daily living (ADLs). PD patients with non-tremor symptoms at disease onset (i.e., rigidity, bradykinesia, gait disturbance or postural instability) have more diffuse neurobiological abnormalities and report worse non-motor symptoms and functional changes than patients whose initial symptom is tremor, but the relation of motor symptom subtype to perceptual deficits remains unstudied. We assessed visual ADLs with the Visual Activities Questionnaire in 25 non-demented patients with PD, 13 with tremor as the initial symptom and 12 with an initial symptom other than tremor, as well as in 23 healthy control participants (NC). As expected, the non-tremor patients, but not the tremor patients, reported more impairment in visual ADLs than the NC group, including in light/dark adaptation, acuity/spatial vision, depth perception, peripheral vision and visual processing speed. Non-tremor patients were significantly worse than tremor patients overall and on light/dark adaptation and depth perception. Environmental enhancements especially targeted to patients with the non-tremor PD subtype may help to ameliorate their functional disability.
Parkinsonism; Tremor; PD subtype; Activities of daily living; Neuropsychology; Quality of life
In healthy individuals and those with insomnia, poor sleep quality is associated with decrements in performance on tests of cognition, especially executive function. Sleep disturbances and cognitive deficits are both prevalent in Parkinson’s disease (PD). Sleep problems occur in over 75% of patients, with sleep fragmentation and decreased sleep efficiency being the most common sleep complaints, but their relation to cognition is unknown. We examined the association between sleep quality and cognition in PD. In 35 non-demented individuals with PD and 18 normal control adults (NC), sleep was measured using 24-hr wrist actigraphy over 7 days. Cognitive domains tested included attention and executive function, memory and psychomotor function. In both groups, poor sleep was associated with worse performance on tests of attention/executive function but not memory or psychomotor function. In the PD group, attention/executive function was predicted by sleep efficiency, whereas memory and psychomotor function were not predicted by sleep quality. Psychomotor and memory function were predicted by motor symptom severity. This study is the first to demonstrate that sleep quality in PD is significantly correlated with cognition and that it differentially impacts attention and executive function, thereby furthering our understanding of the link between sleep and cognition.
Parkinson’s disease; Sleep; Cognition; Executive function; Actigraphy; Memory
Cognitive reserve (CR) has been proposed as a latent variable that can account for the frequent discrepancy between an individual’s underlying level of brain pathology and their observed clinical outcome. A possible behavioral manifestation of CR is best strategy choice. Older adults have been shown to choose sub-optimal strategies for performing various tasks. The present study attempted to investigate whether greater levels of CR could predict greater strategy selection, particularly in older adults. A computational estimation task was administered to 20 healthy young adults (mean age = 24.7 ± 3.6; 20–31 years) and 18 healthy older adults (68.2 ± 4.5; 62–77 years) wherein participants needed to estimate the product of two two-digit numbers by using one of two strategies. The results revealed an effect of age group on strategy choice and supported the hypothesis that CR is associated with increased strategy selection abilities.
Aging; Cognitive reserve; Compensation; Strategy selection; Strategy adaptivity; Computational estimation
Given the importance of identifying dementia prodromes for future treatment efforts, we examined two methods of diagnosing mild cognitive impairment (MCI) and determined whether empirically-derived MCI subtypes of these diagnostic methods were consistent with one another as well as with conventional MCI subtypes (i.e., amnestic, non-amnestic, single-domain, multi-domain). Participants were diagnosed with MCI using either conventional Petersen/Winblad criteria (n = 134; >1.5 SDs below normal on one test within a cognitive domain) or comprehensive neuropsychological criteria developed by Jak et al. (2009) (n = 80; >1 SD below normal on two tests within a domain), and the resulting samples were examined via hierarchical cluster and discriminant function analyses. Results showed that neuropsychological profiles varied depending on the criteria used to define MCI. Both criteria revealed an Amnestic subtype, consistent with prodromal Alzheimer’s disease (AD), and a Mixed subtype that may capture individuals in advanced stages of MCI. The comprehensive criteria uniquely yielded Dysexecutive and Visuospatial subtypes, whereas the conventional criteria produced a subtype that performed within normal limits, suggesting its susceptibility to false positive diagnostic errors. Whether these empirically-derived MCI subtypes correspond to dissociable neuropathologic substrates and represent reliable prodromes of dementia will require additional follow-up.
Mild cognitive impairment; Amnestic MCI; Non-amnestic MCI; Dementia; Cluster analysis; Neuropsychology
Neuropsychologists are often asked to answer questions about the effects of cognitive deficits on everyday functioning. This study examined the relationship between and the cognitive correlates of self-report, performance-based, and direct observation measures commonly used as proxy measures for everyday functioning. Participants were 88 community-dwelling, cognitively healthy older adults (age 50–86 years). Participants completed standardized neuropsychological tests and questionnaires, and performed eight activities of daily living (e.g., water plants, fill a medication dispenser) while under direct observation in a campus apartment. All proxy measures of everyday function were sensitive to the effects of healthy cognitive aging. After controlling for age, cognitive predictors explained a unique amount of the variance for only the performance-based behavioral simulation measure (i.e., Revised Observed Tasks of Daily Living). The self-report instrumental activities of daily living (IADL) and the performance-based everyday problem-solving test (i.e., EPT) did not correlate with each other; however, both were unique predictors of the direct observation measure. These findings suggest that neuropsychologists must be cautious in making predictions about the quality of everyday activity completion in cognitively healthy older adults from specific cognitive functions. The findings further suggest that a self-report of IADLs and the performance-based EPT may be useful measures for assessing everyday functional status in cognitively healthy older adults.
Activities of daily living; Cognitive correlates; Functional status; Aging; Instrumental activities of daily living; Everyday functioning
Neuropsychological disturbances have been reported in association with use of the recreational drug “ecstasy,” or 3,4-methylenedioxymethamphetamine (MDMA), but findings have been inconsistent. We performed comprehensive neuropsychological testing examining seven ability domains in 21 MDMA users (MDMA+) and 21 matched control participants (MDMA−). Among MDMA+ participants, median [interquartile range] lifetime MDMA use was 186 [111, 516] doses, with 120 [35–365] days of abstinence. There were no significant group differences in neuropsychological performance, with the exception of the motor speed/dexterity domain in which 43% of MDMA+ were impaired compared with 5% of MDMA− participants (p = .004). Motor impairment differences were not explained by use of other substances and were unrelated to length of abstinence or lifetime number of MDMA doses. Findings provide limited evidence for neuropsychological differences between MDMA+ and MDMA− participants with the exception of motor impairments observed in the MDMA+ group. However, replication of this finding in a larger sample is warranted.
Ecstasy; N-Methyl-3; 4-methylenedioxyamphetamine; Neurocognitive; Neurotoxicity; Stimulant; Hallucinogen
Sensorimotor inhibition, or the ability to filter out excessive or irrelevant information, theoretically supports a variety of higher-level cognitive functions. Impaired inhibition may be associated with increased impulsive and risky behavior in everyday life. Individuals infected with HIV frequently show impairment on tests of neurocognitive function, but sensorimotor inhibition in this population has not been studied and may be a contributor to the profile of HIV-associated Neurocognitive Disorders (HAND). 37 HIV-infected individuals (15 with HAND) and 48 non-infected comparison subjects were assessed for prepulse inhibition (PPI), an eyeblink startle paradigm measuring sensorimotor gating. Although HIV status alone was not associated with PPI deficits, HIV-positive participants meeting criteria for HAND showed impaired PPI compared to cognitively intact HIV-positive subjects. In HIV-positive subjects, PPI was correlated with working memory but was not associated with antiretroviral therapy or illness factors. In conclusion, sensorimotor disinhibition in HIV accompanies deficits in higher-order cognitive functions, though the causal direction of this relationship requires investigation. Subsequent research on the role of sensorimotor gating on decision-making and risk behaviors in HIV may be indicated.
sensorimotor gating; AIDS dementia complex; cognition; startle; working memory; impulsivity
Previous research has identified cognitive impairment in children with sickle cell anemia (SCA, Hemoglobin SS) compared with controls, partly accounted for by overt neuropathology after clinical stroke, “covert” (“silent”) infarction, and severity of anemia. However, cognitive deficits have also been identified in children with SCA with no history of stroke and a normal T2-weighted magnetic resonance imaging (MRI) scan. Our aim was to investigate whether nocturnal hemoglobin oxygen desaturation and sleep fragmentation could be associated with cognitive impairment in children with SCA. We assessed 10 children with SCA (9 with normal MRI) using neuropsychological measures of executive function. Cognitive assessment was immediately followed by overnight polysomnography to record nocturnal hemoglobin oxygen saturation and sleep arousals. Decreases in hemoglobin oxygen saturation and/or increased sleep arousals were associated with reduced performance on cognitive assessment. Nocturnal hemoglobin oxygen desaturation and sleep fragmentation may be a contributing factor to executive dysfunction in SCA.
Anemia; Sickle cell; Intelligence; Neuropsychology; Oximetry; Sleep arousal disorders; Polysomnography
This study compared mathematical outcomes in children with predominantly moderate to severe traumatic brain injury (TBI; n =50) or orthopedic injury (OI; n=47) at 2 and 24 months post-injury. Working memory and its contribution to math outcomes at 24 months post-injury was also examined. Participants were administered an experimental cognitive addition task and standardized measures of calculation, math fluency, and applied problems; as well as experimental measures of verbal and visual-spatial working memory. Although children with TBI did not have deficits in foundational math fact retrieval, they performed more poorly than OIs on standardized measures of math. In the TBI group, performance on standardized measures was predicted by age at injury, socioeconomic status, and the duration of impaired consciousness. Children with TBI showed impairments on verbal, but not visual working memory relative to children with OI. Verbal working memory mediated group differences on math calculations and applied problems at 24 months post-injury. Children with TBI have difficulties in mathematics, but do not have deficits in math fact retrieval, a signature deficit of math disabilities. Results are discussed with reference to models of mathematical cognition and disability and the role of working memory in math learning and performance for children with TBI.
Head injury; Cognitive addition; Math fluency; Calculation; Math problem solving; Verbal working memory; Visual-spatial working memory
Children with either fetal alcohol spectrum disorder (FASD) or attention-deficit/hyperactivity disorder (ADHD) display deficits in attention and executive function (EF) and differential diagnosis of these two clinical groups may be difficult, especially when information about prenatal alcohol exposure is unavailable. The current study compared EF performance of three groups: children with heavy prenatal alcohol exposure (ALC); nonexposed children with attention-deficit/hyperactivity disorder (ADHD); and typically developing controls (CON). Both clinical groups met diagnostic criteria for ADHD. The EF tasks used were the Wisconsin Card Sorting Test (WCST), the Controlled Oral Word Association Test (COWAT), and the Trail Making Test (TMT). Results indicated different patterns of deficit; both clinical groups displayed deficits on the WCST and a relative weakness on letter versus category fluency. Only the ALC group displayed overall deficits on letter fluency and a relative weakness on TMT-B versus TMT-A. In addition, WCST performance was significantly lower than expected based on IQ in the ADHD group and significantly higher than expected in the ALC group. These results, which indicate that, although EF deficits occurred in both clinical groups, the degree and pattern of deficit differed between the ALC and ADHD groups, may improve differential diagnosis.
Fetal alcohol syndrome; Fetal alcohol spectrum disorders; Differential diagnosis; FAS; ADHD; Neuropsychological function
Behavioral dysregulation is a common and detrimental consequence of traumatic brain injury (TBI) in children that contributes to poor academic achievement and deficits in social development. Unfortunately, behavioral dysregulation is difficult to predict from either injury severity or early neuropsychological evaluation. The uncinate fasciculus (UF) connects orbitofrontal and anterior temporal lobes, which are commonly implicated in emotional and behavioral regulation. Using probabilistic diffusion tensor tractography (DTT), we examined the relationship between the integrity of the UF 3 months post-injury and ratings of executive functions 12 months post-injury in children with moderate to severe TBI and a comparison group with orthopedic injuries. As expected, fractional anisotropy of the UF was lower in the TBI group relative to the orthopedic injury group. DTT metrics from the UF served as a biomarker and predicted ratings of emotional and behavior regulation, but not metacognition. In contrast, the Glasgow Coma Scale score was not related to either UF integrity or to executive function outcomes. Neuroanatomical biomarkers like the uncinate fasciculus may allow for early identification of behavioral problems and allow for investigation into the relationship of frontotemporal networks to brain-behavior relationships.
Diffusion tensor imaging; Executive function; Neuropsychology; Child; Anisotropy; Behavior
The purpose of this study was to investigate the effects of pediatric traumatic brain injury (TBI) on verbal and visual-spatial working memory (WM). WM tasks examined memory span through recall of the last item of a series of stimuli. Additionally, both verbal and visual-spatial tests had a dual-task condition assessing the effect of increasing demands on the central executive (CE). Inhibitory control processes in verbal WM were examined through intrusion errors. The TBI group (n = 73) performed more poorly on verbal and visual-spatial WM tasks than orthopedic-injured children (n = 30) and non-injured children (n = 40). All groups performed more poorly on the dual-task conditions, reflecting an effect of increasing CE load. This effect was not greater for the TBI group. There were no group differences in intrusion errors on the verbal WM task, suggesting that problems in WM experienced by children with TBI were not primarily due to difficulties in inhibitory control. Finally, injury-related characteristics, namely days to follow commands, accounted for significant variance in WM performance, after controlling for relevant demographic variables. Findings suggest that WM impairments in TBI are general rather than modality-specific and that severity indices measured over time are better predictors of WM performance than those taken at a single time point.
Traumatic brain injury; Pediatric; Working memory; Inhibitory control; Dual-task; Outcome
Systematic cognitive training produces long-term improvement in cognitive function and less difficulty in performing activities of daily living. We examined whether cognitive training was associated with reduced rate of incident dementia. Participants were from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (n=2,802). Incident dementia was defined using a combination of interview- and performance-based methods. Survival analysis was used to determine if ACTIVE treatment affected the rate of incident dementia during 5 years of follow-up. A total of 189 participants met criteria for incident dementia. Baseline factors predictive of incident dementia were older age, male gender, African American race, fewer years of education, relationship other than married, no alcohol use, worse MMSE< worse SF-36 physical functioning, higher depressive symptomatology, diabetes, and stroke (all p<.05). A multivariable model with significant predictors of incident dementia and training group revealed that cognitive training was not associated with a lower rate of incident dementia. Cognitive training did not affect rates of incident dementia after 5 years of follow-up. Longer follow-up or enhanced training may be needed to fully explore the preventive capacity of cognitive training in forestalling onset of dementia.
Cognitive training; Intervention; Aging; Dementia; Prevention; Cognition
Both HIV infection and high levels of early life stress (ELS) have been related to abnormalities in frontal-subcortical structures, yet the combined effects of HIV and ELS on brain structure and function have not been previously investigated. In this study we assessed 49 non-demented HIV-seropositive (HIV+) and 47 age-matched HIV-seronegative healthy control (HC) adults. Levels of ELS exposure were quantified and used to define four HIV-ELS groups: HC Low-ELS (N = 20); HC High-ELS (N = 27); HIV+ Low-ELS (N = 24); HIV+ High-ELS (N = 25). An automated segmentation tool measured volumes of brain structures known to show HIV-related or ELS-related effects; a brief neurocognitive battery was administered. A significant HIV-ELS interaction was observed for amygdala volumes, which was driven by enlargements in HIV+ High-ELS participants. The HIV+ High-ELS group also demonstrated significant reductions in psychomotor/processing speed compared with HC Low-ELS. Regression analyses in the HIV+ group revealed that amygdala enlargements were associated with higher ELS, lower nadir CD4 counts, and reduced psychomotor/processing speed. Our results suggest that HIV infection and high ELS interact to increase amygdala volume, which is associated with neurocognitive dysfunction in HIV+ patients. These findings highlight the lasting neuropathological influence of ELS and suggest that high ELS may be a significant risk factor for neurocognitive impairment in HIV-infected individuals.
HIV; Stress; Amygdala; Neuroimaging; Cognition
Two major challenges facing researchers interested in cognitive change are that measures of change are often not very reliable, and they may reflect effects of prior test experience in addition to the factors of primary interest. One approach to dealing with these problems is to obtain multiple measures of change on parallel versions of the same tests in a measurement burst design. A total of 783 adults performed three parallel versions of cognitive tests on two occasions separated by an average of 2.6 years. Performance increased substantially across the three sessions within each occasion, and for all but vocabulary ability these within-occasion improvements were considerably larger than the between-occasion changes. Reliabilities of the changes in composite scores were low, but averages of the three changes had larger, albeit still quite modest, reliabilities. In some cognitive abilities individual differences were evident in the relation of prior test experience and the magnitude of longitudinal change. Although multiple assessments are more time consuming than traditional measurement procedures, the resulting estimates of change are more robust than those from conventional methods, and also allow the influence of practice on change to be systematically investigated.
Longitudinal; Aging; Neurocognitive; Reliable change; Measurement burst; Gains and losses
Individuals with anorexia nervosa (AN) are often characterized as possessing excessive self-control and are unusual in their ability to reduce or avoid the consumption of palatable foods. This behavior promotes potentially life-threatening weight loss and suggests disturbances in reward processing. We studied whether individuals with AN showed evidence of increased self-control by examining the tendency to delay receipt of a monetary, non-food related, reward. Underweight AN (n=36) and healthy controls (HC, n=28) completed a monetary intertemporal choice task measuring delay discounting factor. Individuals with AN reduced the value of a monetary reward over time significantly less than HC (F[1,61]=5.03, p=0.029). Secondary analyses indicated that the restricting subtype of AN, in particular, showed significantly less discounting than HC (F[1,46]=8.3, p=0.006). These findings indicate that some individuals with AN show less temporal discounting than HC, suggestive of enhanced self-control that is not limited to food consumption. This is in contrast to other psychiatric disorders, e.g. substance abuse, which are characterized by greater discounting. Though preliminary, these findings suggest that excessive self-control may contribute to pathological processes and individuals with AN may have neuropsychological characteristics that enhance their ability to delay reward and thereby may help to maintain persistent food restriction.
eating disorders; temporal discounting; neuroeconomics; self-control; delay discounting; neuropsychology
The effect of race on cognitive test performance in the evaluation of Alzheimer’s disease (AD) remains controversial. One factor that may contribute substantially to differences in cognitive test performance in diverse populations is education. The current study examined the extent to which quality of education, even after controlling for formal years of education, accounts for differences in cognitive performance between African Americans and White Non-Hispanics (WNHs). The retrospective cohort included 244 patients diagnosed with AD who self-identified as African Americans (n=51) or WNHs (n=193). The Wechsler Test of Adult Reading (WTAR) was used as an estimate of quality of education. In an analysis that controlled for traditional demographics, including age, sex, and years of formal education, African Americans scored significantly lower than WNHs on the Mini-Mental State Examination, as well as on neuropsychological tests of memory, attention, and language. However, after also adjusting for reading level, all previously observed differences were significantly attenuated. The attenuating effect remained even after controlling for disease severity, indicating that reading scores are not confounded by severity of dementia. These findings suggest that quality, and not just quantity, of education needs to be taken into account when assessing cognitive performance in African Americans with AD.