Diabetes is associated with dementia in older adults, but it remains unclear whether nondemented adults with type 2 diabetes show subtle abnormalities across cognition, neuroanatomy, and everyday functioning. Using the Aging, Brain Imaging, and Cognition study sample of 301 community-dwelling, middle-aged and older adults, we conducted a secondary analysis on 28 participants with and 150 participants without diabetes. We analyzed brain magnetic resonance imaging data, cognitive test performance, and informant ratings of personal and instrumental activities of daily living (PADL/IADL). Relative to controls, participants with diabetes had lower brain-to-intracranial volume ratios (69.3 ± 4.5% vs. 71.7 ± 4.6%; p < .02), and performed more poorly on measures of working memory, processing speed, fluency, and crystallized intelligence (all p <.05). Decrements in working memory and processing speed were associated with IADL limitations (p < .01). Nondemented adults with diabetes exhibit neuroanatomic and cognitive abnormalities. Their cognitive deficits correlate with everyday functional limitations.
Diabetes; Endocrine disorders; Cognition; Neuropsychological testing; MRI; Function; Behavior
HIV+ individuals have been shown to demonstrate deficits on the Iowa Gambling Task (IGT), a complex measure of “decision-making.” Little remains known about what other neurocognitive processes may account for variability in IGT performance among HIV+ samples or the role of procedural learning (PL) in IGT performance. A sample of 49 HIV+ individuals with a history of substance use disorders was examined to explore the relationship between IGT performance and three measures of PL: The Rotary Pursuit, Mirror Star Tracing, and Weather Prediction tasks. We found no statistically significant relationships between IGT performance and any of the PL tasks, despite finding significant correlations among the PL tasks. This pattern of results persisted when analyzing IGT performance in various ways (e.g., performance on earlier trial blocks or impairment classifications). Although other nondeclarative processes (e.g., somatic markers) may be important for IGT performance, these findings do not support PL as an important component neurocognitive process for the IGT. Similarly, these results suggest that differences in PL performance does not account for the decision-making deficits or variability in performances observed on the IGT among HIV+ individuals with a history of substance dependence.
HIV; Substance use disorders; Nondeclarative memory; Implicit memory; Decision-making; Basal ganglia; Orbitofrontal cortex; Executive functions
The n-back is a putative working memory task frequently used in neuroimaging research; however, literature addressing n-back use in clinical neuropsychological evaluation is sparse. We examined convergent validity of the n-back with an established measure of working memory, digit span backward. The relationship between n-back performance and scores on measures of processing speed was also examined, as was the ability of the n-back to detect potential between-groups differences in control and Parkinson's disease (PD) groups. Results revealed no correlation between n-back performance and digit span backward. N-back accuracy significantly correlated with a measure of processing speed (Trail Making Test Part A) at the 2-back load. Relative to controls, PD patients performed less accurately on the n-back and showed a trend toward slower reaction times, but did not differ on any of the neuropsychological measures. Results suggest the n-back is not a pure measure of working memory, but may be able to detect subtle differences in cognitive functioning between PD patients and controls.
Working memory; Executive function; Information processing speed; Parkinson's disease; Neuropsychology
Recent studies have shown that self-perceived health status (HS) in Parkinson's disease (PD) is associated with motor, cognitive, or mood symptoms, with the greatest association typically occurring with mood. The purpose of this study was to determine if these associations are present in nondepressed and nondemented individuals with PD by using sensitive neuropsychological measures and statistically derived factors from mood and motor scales. The best predictors of poor HS in PD participants (N = 32) without dementia or depression were mood symptoms, specific to self-reported cognitive impairment and anxiety. Bivariate correlations between HS and number of correct categories on the Wisconsin Card Sorting Test and the gait–balance factor from the Unified Parkinson's Disease Rating Scale Part III were also significant or approached significance. These findings suggest that specific mood and cognitive symptoms continue to be important factors in HS in those individuals who lack clinical levels of depression or dementia.
Parkinson's disease; Health status; Health-related quality of life; Quality of life
Memory assessment is an important component of a neuropsychological evaluation, but far fewer visual than verbal memory instruments are available. We examined the preliminary psychometric properties and clinical utility of a novel, motor-free paper and pencil visuospatial memory test, the Indiana faces in places test (IFIPT). The IFIPT and general neuropsychological performance were assessed in 36 adults with amnestic mild cognitive impairment (aMCI) and 113 older adults with no cognitive impairment at baseline, 1 week, and 1 year. The IFIPT is a visual memory test with 10 faces paired with spatial locations (three learning trials and non-cued delayed recall). Results showed that MCI participants scored lower than controls on several variables, most notably total learning (p < .001 at all three time points), delayed recall (baseline p = .03, 1 week p < .001, 1 year p < .001), and false-positive errors (range p = .03 to <0.001). The IFIPT showed similar test–retest reliability at 1-week and 1-year follow-up to other neuropsychological tests (r = 0.71–0.84 for MCI and 0.53–0.72 for controls). Diagnostic accuracy was modest for this sample (areas under the receiver operating characteristic curve between 0.64 and 0.66). Preliminary psychometric analyses support further study of the IFIPT. The measure showed evidence of clinical utility by demonstrating group differences between this sample of healthy adults and those with MCI.
Mild cognitive impairment; Visual memory; Face memory; Test–retest reliability
Prospective memory is defined as the ability to “remember to remember” something at a future time despite intervening distractions and may be particularly important in remembering to take prescribed medication among people infected with HIV. Ninety-seven HIV-positive participants in a clinical trial had their adherence measured by electronic pillcaps and were administered neuropsychological screening tests and the memory for intentions screening test (MIST). Factor analysis of the MIST and other neuropsychological measures identified four factors. Two were derived from MIST subscales and accounted for approximately 50% of the variance in cognitive functioning. Only one factor was significantly correlated with adherence, and this was a MIST factor. In this preliminary study, the MIST assessed a memory function that (a) could be distinguished from traditional retrospective recall and executive functioning and (b) was correlated with antiretroviral adherence.
HIV; Neuropsychological function; Adherence; Medication compliance; Substance use
The goals of this project were threefold: to determine the nature of the memory deficit in children/adolescents with dyslexia, to utilize clinical memory measures in this endeavor, and to determine the extent to which semantic short-term memory (STM) is related to basic reading performance. Two studies were conducted using different samples, one incorporating the Wide Range Assessment of Memory and Learning and the other incorporating the California Verbal Learning Test-Children's Version. Results suggest that phonological STM is deficient in children with dyslexia, but semantic STM and visual–spatial STM are intact. Long-term memory (LTM) for both visual and verbal material also is intact. Regarding reading performance, semantic STM had small correlations with word identification and pseudoword decoding across studies despite phonological STM being moderately to strongly related to both basic reading skills. Overall, results are consistent with the phonological core deficit model of dyslexia as only phonological STM was affected in dyslexia and related to basic reading skill.
Dyslexia; Reading disabilities; Child; Adolescent; Short-term memory; Long-term memory
Deficits in learning, memory, and executive functions are common cognitive sequelae of Parkinson's disease with dementia (PDD) and Alzheimer's disease (AD); however, the pattern of deficits within these populations is distinct. Hierarchical regression was used to investigate the contribution of two measures with executive function properties (Verbal Fluency and CLOX) on list-learning performance (CVLT-II total words learned) in a sample of 25 PDD patients and 25 matched AD patients. Executive measures were predictive of list learning in the PDD group after the contribution of overall cognition and contextual verbal learning was accounted for, whereas in the AD group the addition of executive measures did not add to prediction of variance in CVLT-II learning. These findings suggest that deficits in executive functions play a vital role in learning impairments in patients with PDD; however, for AD patients, learning difficulties appear relatively independent of executive dysfunction.
Parkinson's disease with dementia; Alzheimer's disease; Executive function; List learning; Neuropsychologic tests; Comparative studies
White matter hyperintensities (WMH) can compromise cognition in older adults, but differences in sampling, WMH measurements, and cognitive assessments contribute to discrepant findings across studies. We examined linear and nonlinear effects of WMH volumes on cognition in 253 reasonably healthy adults. After adjusting for demographic characteristics and total brain volumes, WMH burden was not associated with cognition in those aged 20–59. In participants aged 60 and older, models accounted for ≥58% of the variance in performance on tests of working memory, processing speed, fluency, and fluid intelligence, and WMH volumes accounted for variance beyond that explained by age and other demographic characteristics. Larger increases in WMH burden over 5 years also were associated with steeper cognitive declines over the same interval. Results point to both age-related and age-independent effects of WMH on cognition in later life and suggest that the accumulation of WMH might partially explain normal age-related declines in cognition.
White matter hyperintensities; Aging; Cognition; Cardiovascular disease
Self-report post-concussion symptom scales have been a key method for monitoring recovery from sport-related concussion, to assist in medical management, and return-to-play decision-making. To date, however, item selection and scaling metrics for these instruments have been based solely upon clinical judgment, and no one scale has been identified as the “gold standard”. We analyzed a large set of data from existing scales obtained from three separate case–control studies in order to derive a sensitive and efficient scale for this application by eliminating items that were found to be insensitive to concussion. Baseline data from symptom checklists including a total of 27 symptom variables were collected from a total of 16,350 high school and college athletes. Follow-up data were obtained from 641 athletes who subsequently incurred a concussion. Symptom checklists were administered at baseline (preseason), immediately post-concussion, post-game, and at 1, 3, and 5 days post-injury. Effect-size analyses resulted in the retention of only 12 of the 27 variables. Receiver-operating characteristic analyses were used to confirm that the reduction in items did not reduce sensitivity or specificity. The newly derived Concussion Symptom Inventory is presented and recommended as a research and clinical tool for monitoring recovery from sport-related concussion.
Brain injury; Post-concussion; Scale
Beyond the Numbers: Expanding the Boundaries of Neuropsychology was Dr Perry's 2007 presidential address in the annual conference of the National Academy of Neuropsychology. In his address he discussed the achievements of the science of neuropsychology and highlighted some areas that exemplified the expansion of the boundaries of neuropsychology. These areas are: (i) the study of neuropsychological functioning in new or non-traditional populations, particularly seemingly healthy people and people with non-brain diseases; (ii) the interface of cognition and genetics; (iii) the use of the process approach as a means of understanding brain functioning; and (iv) a translational application to the science of neuropsychology.
Neuropsychology; Translational research; Process approach; Genetics; Deconstruction