The neuropsychological test battery from the Uniform Data Set (UDS) of the Alzheimer’s Disease Centers (ADC) program of the National Institute on Aging (NIA) consists of brief measures of attention, processing speed, executive function, episodic memory and language. This paper describes development of the battery and preliminary data from the initial UDS evaluation of 3,268 clinically cognitively normal men and women collected over the first 24 months of utilization. The subjects represent a sample of community-dwelling, individuals who volunteer for studies of cognitive aging. Subjects were considered “clinically cognitively normal” based on clinical assessment, including the Clinical Dementia Rating scale and the Functional Assessment Questionnaire. The results demonstrate performance on tests sensitive to cognitive aging and to the early stages of Alzheimer disease (AD) in a relatively well-educated sample. Regression models investigating the impact of age, education, and gender on test scores indicate that these variables will need to be incorporated in subsequent normative studies. Future plans include: 1) determining the psychometric properties of the battery; 2) establishing normative data, including norms for different ethnic minority groups; and 3) conducting longitudinal studies on cognitively normal subjects, individuals with mild cognitive impairment, and individuals with AD and other forms of dementia.
The neuropsychological battery from the National Alzheimer’s Disease Coordinating Center (NACC) is designed to provide a sensitive assessment of mild cognitive disorders for multicenter investigations. Comprised of eight common neuropsychological tests (12 measures), the battery assesses cognitive domains affected early in the course of Alzheimer’s disease (AD). We examined the factor structure of the battery across levels of cognition (normal, mild cognitive impairment (MCI), dementia) based on Clinical Dementia Rating (CDR) scores to determine cognitive domains tapped by the battery. Using data pooled from 29 NIA funded Alzheimer’s Disease Centers, exploratory factor analysis was used to derive a general model using half of the sample; four factors representing memory, attention, executive function, and language were identified. Confirmatory factor analysis (CFA) was used on the second half of the sample to evaluate invariance between groups and within groups over one year. Factorial invariance testing included systematic addition of constraints and comparisons of nested models. The general CFA model had a good fit. As constraints were added, model fit deteriorated slightly. Comparisons within groups demonstrated stability over one year. In a range of cognition from normal to dementia, factor structures and factor loadings will vary little. Further work is needed to determine if domains become more or less distinct in severely cognitively compromised individuals.
Factor Analysis; invariance; neuropsychological tests; dementia; Alzheimer’s disease
Current methods for statistical analysis of neuropsychological test data in schizophrenia are inherently insufficient for revealing valid cognitive impairment profiles. While neuropsychological tests aim to selectively sample discrete cognitive domains, test performance often requires several cognitive operations or “attributes.” Conventional statistical approaches assign each neuropsychological score of interest to a single attribute or “domain” (e.g., attention, executive, etc.), and scores are calculated for each. This can yield misleading information about underlying cognitive impairments. We report findings applying a new method for examining neuropsychological test data in schizophrenia, based on finite partially ordered sets (posets) as classification models.
A total of 220 schizophrenia outpatients were administered the Positive and Negative Symptom Scale (PANSS) and a neuropsychological test battery. Selected tests were submitted to cognitive attribute analysis a priori by two neuropsychologists. Applying Bayesian classification methods (posets), each patient was classified with respect to proficiency on the underlying attributes, based upon his or her individual test performance pattern.
Twelve cognitive “classes” are described in the sample. Resulting classification models provided detailed “diagnoses” into “attribute-based” profiles of cognitive strength/weakness, mimicking expert clinician judgment. Classification was efficient, requiring few measures to achieve accurate classification. Attributes were associated with PANSS factors in the expected manner (only the negative and cognition factors were associated with the attributes), and a double dissociation was observed in which divergent thinking was selectively associated with negative symptoms, possibly reflecting a manifestation of Kraepelin's hypothesis regarding the impact of volitional disturbances on thought.
Using posets for extracting more precise cognitive information from neuropsychological data may reveal more valid cognitive endophenotypes, while dramatically reducing the amount of testing required.
schizophrenia; neurocognitive deficits; neuropsychological test domains; neuropsychological test data reduction; clustering techniques; Bayesian methods
Studies have found that executive functioning is affected early in the pathophysiological processes associated with Alzheimer’s disease and vascular dementia. There also exists a range of functioning on executive tasks during normal aging. Although qualitative data are commonly utilized in clinical practice for evaluating subtle changes in cognitive functioning and diagnostic discernment, it is not clear whether error responses used in clinical practice are also evident as normative behavior.
As part of an extensive battery of neuropsychological tests, executive functioning measures (i.e., Trail Making-B, Similarities and Verbal Fluency tests) were administered via standardized administration prescript. Regression analyses were used to determine associations between vascular aging indices and qualitative performance measures. Descriptive statistics are included for 1907 cognitively normal individuals.
Results suggest that while qualitative errors do occur, they are relatively infrequent within a presumably cognitively normal sample. Error commission rates on executive functioning tests are significantly associated with both age and education.
Provided is a baseline profile of errors committed on tests of executive function across a range of age and educational levels. The normative datasets are included, stratified by age and educational achievement, for which to compare qualitative test performance of clinical and research populations.
The traditional consensus diagnosis (ConsDx) of normal cognition, mild cognitive impairment (MCI), and dementia relies on the reconciliation of an informant-based report of cognitive and functional impairment by a physician (PhyDx), and a neuropsychological diagnosis (NPDx). As this procedure may be labor-intensive and influenced by the philosophy and biases of a clinician, the diagnostic algorithm (AlgDx) was developed to identify individuals as cognitively normal, with MCI or dementia.
The AlgDx combines the PhyDx with the NPDx, using a computational algorithm that provides cognitive diagnoses, as defined by the National Alzheimer Coordinating Center/Uniform Data Set (NACC/UDS) nomenclature. Reliability of the AlgDx was assessed in 532 community-dwelling elderly subjects by its concordance with the ConsDx, and association with two biomarkers, medial temporal atrophy (MTA) scores of brain MRI scans, and ApoE-ε4 genotype.
A high degree of concordance was observed between ConsDx and AlgDx with a weighted Cohen’s kappa of 0.84. Concordance of the AlgDx to the same ConsDx categories ranged from 85% to 92%. Excellent discriminative validity was observed as AlgDx, MTA scores, and APOE-ε4 allele frequencies distinguished amnestic MCI and dementia subjects from normal subjects.
The AlgDx of normal cognition, MCI, and dementia is a valid alternative that reduces time, effort and biases associated with the ConsDx. The inherent reliability of a fixed algorithm, together with its efficiency and avoidance of individual bias, suggests the AlgDx may be used in longitudinal, multi-site clinical trials and population studies of MCI and dementia.
Diagnosis; Algorithmic Diagnosis; Mild Cognitive Impairment; Dementia; Longitudinal Studies
The aim of this study was to identify the best subset of neuropsychological tests for prediction of several different aspects of functioning in a large (n = 236) sample of older people with schizophrenia. While the validity of abbreviated assessment methods has been examined before, there has never been a comparative study of the prediction of different elements of cognitive impairment, real-world outcomes, and performance-based measures of functional capacity. Scores on 10 different tests from a neuropsychological assessment battery were used to predict global neuropsychological (NP) performance (indexed with averaged scores or calculated general deficit scores), performance-based indices of everyday-living skills and social competence, and case-manager ratings of real-world functioning. Forward entry stepwise regression analyses were used to identify the best predictors for each of the outcomes measures. Then, the analyses were adjusted for estimated premorbid IQ, which reduced the magnitude, but not the structure, of the correlations. Substantial amounts (over 70%) of the variance in overall NP performance were accounted for by a limited number of NP tests. Considerable variance in measures of functional capacity was also accounted for by a limited number of tests. Different tests constituted the best predictor set for each outcome measure. A substantial proportion of the variance in several different NP and functional outcomes can be accounted for by a small number of NP tests that can be completed in a few minutes, although there is considerable unexplained variance. However, the abbreviated assessments that best predict different outcomes vary across outcomes. Future studies should determine whether responses to pharmacological and remediation treatments can be captured with brief assessments as well.
Schizophrenia; Disability; Neuropsychological assessment; Functional capacity; Abbreviated assessments
We present neuropsychological data from an 81-year-old individual who was followed over a six-year period, initially as a healthy control participant. She performed above age-adjusted cutoff scores for impairment on most neuropsychological tests, including learning and memory measures, until the final assessment when she received a diagnosis of probable Alzheimer's disease (AD). Despite generally normal scores on individual cognitive tests, her cognitive profile revealed increasingly large cognitive discrepancies when contrasting verbal versus visuospatial tasks, and complex versus basic-level tasks. The present case provides intriguing evidence that cognitive-discrepancy measures could improve our ability to detect subtle changes in cognition at the earliest, preclinical stages of AD.
Alzheimer's disease; Neuropsychology; Cognition; Discrepancy; Preclinical
Design: Retrospective cohort analysis.
Methods: 100 patients with idiopathic Parkinson's disease were given a neuropsychological test battery investigating attention, memory, and visuospatial and executive functions. Test performance was compared against normative data, and linear regression determined significant predictors of cognitive impairment from a set of demographic and disease course variables.
Results: Frontal-type cognitive dysfunction was widespread in patients with advanced Parkinson's disease. Attention and memory were mildly to moderately impaired, whereas visuospatial function showed only subtle impairment. Older age and tremor at onset were significant predictors of poor cognitive performance.
Conclusions: The observed cognitive impairment in patients with advanced Parkinson's disease is more than expected for normal aging. Although in apparent contrast with most previous research, reporting a greater risk of cognitive dysfunction in Parkinson's disease patients with predominant akinesia/rigidity, tremor at onset may be a marker for more widespread brain pathology that contributes to an increased risk of cognitive impairment.
This study compared individuals whose clinical diagnosis of Alzheimer’s disease (AD) matched or did not match neuropathologic results at autopsy on clinical and functional outcomes (cognitive impairment, functional status and neuropsychiatric symptoms). The study also assessed the extent of potentially inappropriate medication use (using potentially unnecessary medications or potentially inappropriate prescribing) among misdiagnosed patients.
Longitudinal data from the National Alzheimer’s Coordinating Center Uniform Data Set (NACC-UDS, 2005–2010) and corresponding NACC neuropathological data were utilized to compare 88 misdiagnosed and 438 accurately diagnosed patients.
Following adjustment of sociodemographic characteristics, the misdiagnosed were found to have less severe cognitive and functional impairment. However, after statistical adjustment for sociodemographics, dementia severity level, time since onset of cognitive decline and probable AD diagnosis at baseline, the groups significantly differed on only one outcome: the misdiagnosed were less likely to be depressed/dysphoric. Among the misdiagnosed, 18.18% were treated with potentially inappropriate medication. An additional analysis noted this rate could be as high as 67.10%.
Findings highlight the importance of making an accurate AD diagnosis to help reduce unnecessary treatment and increase appropriate therapy. Additional research is needed to demonstrate the link between potentially inappropriate treatment and adverse health outcomes in misdiagnosed AD patients.
Alzheimer disease; Diagnosis; Misdiagnosis; Autopsy; Neuropathology
There are few detailed data on cognition in patients undergoing dialysis. We evaluated the frequency of and risk factors for poor cognitive performance using detailed neurocognitive testing.
In this cross-sectional cohort study, 314 hemodialysis patients from 6 Boston-area hemodialysis units underwent detailed cognitive assessment. The neuropsychological battery assessed a broad range of functions, with established age-, sex-, and education-matched normative scores. Principal component analysis was used to derive composite scores for memory and executive function domains. Risk factors for each domain were evaluated using linear regression adjusting for age, sex, race, and education status. Analyses were repeated in those with Mini-Mental State Examination (MMSE) score ≥24.
Compared with population norms, patients on dialysis had significantly poorer executive function but not memory performance, a finding that persisted in the subgroup with MMSE score ≥24. In adjusted analyses, vascular risk factors and vascular disease were associated with lower executive function (p < 0.01).
There is a high frequency of poor cognitive performance in hemodialysis patients, primarily affecting executive function. Risk factors for worse executive function include vascular risk factors as well as vascular disease. Normal performance on the MMSE does not preclude impaired cognitive function, because individuals with MMSE score ≥24 also have a high frequency of poor cognitive performance.
There is no consensus as to whether mesial temporal lobe epilepsy (MTLE) leads to executive function deficits. In this study, we adopted an extensive neuropsychological test battery and assessed different executive functions in chronic, unilateral MTLE. Performance of MTLE patients was compared with that of healthy peers and with normative data. Several MTLE patients had scores below cut-off or below the 10th percentile of normative data. Scores of the whole patient group were overall in the average range of normative data. Relative to controls, MTLE patients performed poorly in tests of working memory, cognitive flexibility, categorical verbal fluency, set-shifting, categorization, and planning. These findings raise an important methodological issue as they suggest that executive function deficits in chronic MTLE may be individually variable and that their assessment should include different tests. Deficits in chronic MTLE are not limited to temporal lobe functions, such as memory, but may extend to extra temporal cognitive domains, such as executive functions.
To develop an informant-based instrument that would provide a valid estimate of premorbid cognitive abilities in low-educated populations.
A questionnaire was drafted by focusing on the premorbid period with a 10-year time frame. The initial pool of items was submitted to classical test theory and a factorial analysis. The resulting instrument, named the Premorbid Cognitive Abilities Scale (PCAS), is composed of questions addressing educational attainment, major lifetime occupation, reading abilities, reading habits, writing abilities, calculation abilities, use of widely available technology, and the ability to search for specific information. The validation sample was composed of 132 older Brazilian adults from the following three demographically matched groups: normal cognitive aging (n = 72), mild cognitive impairment (n = 33), and mild dementia (n = 27). The scores of a reading test and a neuropsychological battery were adopted as construct criteria. Post-mortem inter-informant reliability was tested in a sub-study with two relatives from each deceased individual.
All items presented good discriminative power, with corrected item-total correlation varying from 0.35 to 0.74. The summed score of the instrument presented high correlation coefficients with global cognitive function (r = 0.73) and reading skills (r = 0.82). Cronbach's alpha was 0.90, showing optimal internal consistency without redundancy. The scores did not decrease across the progressive levels of cognitive impairment, suggesting that the goal of evaluating the premorbid state was achieved. The intraclass correlation coefficient was 0.96, indicating excellent inter-informant reliability.
The instrument developed in this study has shown good properties and can be used as a valid estimate of premorbid cognitive abilities in low-educated populations. The applicability of the PCAS, both as an estimate of premorbid intelligence and cognitive reserve, is discussed.
While neuropsychological deficits have been reported in healthy individuals who use street cannabis, data in patients with multiple sclerosis (MS) are lacking. Given that MS is associated with cognitive deterioration, the aim of this study was to determine the neuropsychological effects of cannabis use in this population.
Two groups, each of 25 patients with MS (cannabis users and nonusers), were administered the Minimal Assessment of Cognitive Function in MS battery of neuropsychological tests, the Hospital Anxiety and Depression Scale (HADS), and the Structured Clinical Interview for the DSM-IV Axis I Disorders (SCID-I). Group-matching and regression analysis were used to control for the effects of age, sex, education, premorbid intelligence, disability, and disease course and duration on cognitive function.
Cannabis users performed significantly more poorly than nonusers on measures of information processing speed, working memory, executive functions, and visuospatial perception. They were also twice as likely as nonusers to be classified as globally cognitively impaired. There were no between-group differences on the HADS measures of depression and anxiety or lifetime SCID-I psychiatric diagnoses.
This cross-sectional study provides empirical evidence that prolonged use of inhaled or ingested street cannabis in patients with MS is associated with poorer performance on cognitive domains commonly affected in this population. Whatever subjective benefits patients may derive from using street cannabis (e.g., pain and spasticity relief) should be weighed against the associated cognitive side effects.
The aim of this research was to assess similarity in cognitive factor structures underlying neuropsychological test performance of elders belonging to three clinical groups: Alzheimer’s disease (AD), Mild Cognitive Impairment (MCI), and normal elderly. We administered a battery of neuropsychological tests to 214 elderly participants in the groups. First, the underlying cognitive structure of a Combined-Set of AD, MCI, and Control subjects was determined by Principal Components Analysis (PCA), including quantitative relationships (loadings) between the test measures and the factors. The PCA resolved 17 neuropsychological test measures into 6 interpretable factors, accounting for 78% of the variance. This cognitive structure was compared with separate cognitive structures from an AD-Set, an MCI-Set, and a Control-Set (different individuals in each set) in additional PCA using Procrustes factor rotation. Analysis of congruence coefficients between each set and the Combined-Set by a bootstrapping statistical procedure supported the factor invariance hypothesis. These close similarities across groups in their underlying neuropsychological dimensions support the use of a common metric system (the factor structure of a Combined-Set) for measuring neuropsychological factors in all these elderly individuals.
Neuropsychological tests; Principal Components Analysis (PCA); cognitive structures; cognitive dimensions; common metric; Procrustes factor rotation; Alzheimer’s disease; Mild Cognitive Impairment; elderly controls; congruence coefficients
Although subtle cognitive injury as revealed by neuropsychological testing occurs in a substantial number of patients following carotid endarterectomy (CEA), there is controversy about whether this finding is a result of the surgery or the anesthesia.
To examine the changes in neuropsychological test performance in patients following CEA vs a control group of patients older than 60 years following spine surgery, so as to determine whether neuropsychological dysfunction after CEA is a result of surgery or anesthesia.
Patients undergoing CEA (n=80) and lumbar spine surgery (n=25) were assessed with a battery of neuropsychological tests preoperatively and on postoperative days 1 and 30. The neuropsychological performance of patients in the control group was used to normalize performance for patients in the CEA group, by calculating z scores using the mean and SD of the change scores in the control group. Significant cognitive dysfunction was defined as performance that exceeded 2 SDs above the mean performance of patients in the control group.
Postoperative days 1 and 30 total deficit scores were significantly worse in the CEA group compared with the controls. When individual test results were examined, the CEA group performed significantly worse than the controls on the Rey Complex Figure test and Halstead-Reitan Trails B on day 1, and on the Rey Complex Figure on day 30. Overall, cognitive dysfunction was seen in 22 patients (28%) in the CEA group on day 1 and in 11 (23%) of 48 patients on day 30.
Subtle cognitive decline following CEA occurs and persists for at least several weeks after surgery. This decline was absent in a control group.
To determine whether quality of life (QOL) ratings are reduced in mild cognitive impairment (MCI) and analyze correlations between QOL ratings and cognitive, neuropsychiatric and functional indices in MCI.
Easton Center for Alzheimer’s Disease Research at UCLA.
205 individuals who met criteria for normal cognition (NC; n=97) or MCI (n=108). The MCI group included amnestic (AMN; n=72) and non-amnestic (NON; n=36) MCI.
QOL was assessed using subject and informant ratings on the Quality of Life-Alzheimer’s Disease (QOL-AD) scale. Cognitive performance was assessed with the National Alzheimer’s Disease Coordinating Center Uniform Data Set neuropsychological battery. Neuropsychiatric symptoms were assessed with the Geriatric Depression Scale (GDS) and the Neuropsychiatric Inventory (NPI). Functional abilities were assessed with the Functional Activities Questionnaire (FAQ).
The NC group had significantly higher QOL-AD scores than the MCI group on both subject and informant assessments. Individual item analyses indicated that the largest group differences were seen on the mood and memory items. Similar QOL-AD scores were seen in the AMN and NON MCI subgroups. Multiple regression analyses within the MCI group indicated that QOL-AD ratings were not correlated with neuropsychological performance. Subject QOL-AD ratings were inversely correlated with GDS scores and informant QOL-AD ratings were inversely correlated with GDS, NPI, and FAQ scores.
Significant declines in QOL are seen in MCI and are associated with neuropsychiatric symptoms and functional decline. Interventions targeting mood symptoms and/or instrumental activities of daily living may improve QOL in MCI.
quality of life; mild cognitive impairment; cognitive; neuropsychiatric; functional
To recommend a set of neuropsychological and physical exercise tests for researchers to assess cognition and physical fitness in clinical trials with older patients with dementia; to create consensus, decrease heterogeneity, and improve research quality.
A literature search (2005–2011) yielded 89 randomized controlled trials. To provide information on test recommendations the frequency of test use, effect size of the test outcome, study quality, and psychometric properties of tests were analyzed.
Fifty-nine neuropsychological tests (cognitive domains: global cognition, executive functioning, memory, and attention) and 10 exercise tests (physical domains: endurance capacity, muscle strength, balance, and mobility) were found.
The Severe Impairment Battery, Mini Mental State Examination, and Alzheimer Disease Assessment Scale – cognitive subscale were recommended to measure global cognition. The Verbal Fluency Test Category/Letters, Clock Drawing Test, and Trail Making Test-B were recommended to measure executive functioning. No specific memory test could be recommended. The Digit Span Forward, Digit Span Backward, and Trail Making Test-A were recommended to measure attention. As physical exercise tests, the Timed Up and Go and Six Meter Walk for mobility, the Six Minute Walk Distance for endurance capacity, and the Tinetti Balance Scale were recommended.
Dementia; Neuropsychological tests; Exercise tests; Tool use; Outcome measures; Systematic review
Many studies have investigated factors associated with the rate of decline and evolution from mild cognitive impairment to Alzheimer’s disease (AD) dementia in elderly patients. In this analysis we compared the rates of decline to dementia estimated from three common global measures of cognition: Mini Mental Status Examination (MMSE) score, Clinical Dementia Rating sum of boxes score (CDR-SB), and a neuropsychological tests composite score (CS).
A total of 2,899 subjects in the National Alzheimer’s Coordinating Center Uniform Data Set age 65+ years diagnosed with amnestic mild cognitive impairment (aMCI) were included in this analysis. Population-averaged decline to dementia rates were estimated and compared for standardized MMSE, CDR-SB, and Composite scores using Generalized Estimating Equations (GEE). Associations between rate of decline and several potential correlates of decline were also calculated and compared across measures.
The CDR-SB had the steepest estimated slope, with a decline of .49 standard deviations (SD) per year, followed by the MMSE with .22 SD/year, and finally the CS with .07 SD/year. The rate of decline of the three measures differed significantly in a global test for differences (p<.0001). Age at visit, BMI at visit, APOE ε4 allele status, and race (black vs. white) had significantly different relationships with rate of decline in a global test for difference among the three measures.
These results suggest that both the rate of decline and the effects of AD risk factors on decline to dementia can vary depending on the evaluative measure used.
neuropsychological testing; Alzheimer’s Disease; cognitive assessment; aging
To measure the association of cognition, visual perception, and motor function with driving safety in Alzheimer disease (AD).
Forty drivers with probable early AD (mean Mini-Mental State Examination score 26.5) and 115 elderly drivers without neurologic disease underwent a battery of cognitive, visual, and motor tests, and drove a standardized 35-mile route in urban and rural settings in an instrumented vehicle. A composite cognitive score (COGSTAT) was calculated for each subject based on eight neuropsychological tests. Driving safety errors were noted and classified by a driving expert based on video review.
Drivers with AD committed an average of 42.0 safety errors/drive (SD = 12.8), compared to an average of 33.2 (SD = 12.2) for drivers without AD (p < 0.0001); the most common errors were lane violations. Increased age was predictive of errors, with a mean of 2.3 more errors per drive observed for each 5-year age increment. After adjustment for age and gender, COGSTAT was a significant predictor of safety errors in subjects with AD, with a 4.1 increase in safety errors observed for a 1 SD decrease in cognitive function. Significant increases in safety errors were also found in subjects with AD with poorer scores on Benton Visual Retention Test, Complex Figure Test-Copy, Trail Making Subtest-A, and the Functional Reach Test.
Drivers with Alzheimer disease (AD) exhibit a range of performance on tests of cognition, vision, and motor skills. Since these tests provide additional predictive value of driving performance beyond diagnosis alone, clinicians may use these tests to help predict whether a patient with AD can safely operate a motor vehicle.
AD = Alzheimer disease; AVLT = Auditory Verbal Learning Test; Blocks = Block Design subtest; BVRT = Benton Visual Retention Test; CFT = Complex Figure Test; CI = confidence interval; COWA = Controlled Oral Word Association; CS = contrast sensitivity; FVA = far visual acuity; JLO = Judgment of Line Orientation; MCI = mild cognitive impairment; MMSE = Mini-Mental State Examination; NVA = near visual acuity; SFM = structure from motion; TMT = Trail-Making Test; UFOV = Useful Field of View.
Some patients with bipolar disorder (BD) demonstrate neuropsychological deficits even when stable. However, it remains unclear whether these differ qualitatively from those seen in schizophrenia (SZ).
We compared the nature and severity of cognitive deficits shown by 106 patients with SZ and 66 patients with BD to 316 healthy adults (NC). All participants completed a cognitive battery with 19 individual measures. After adjusting their test performance for age, sex, race, education, and estimated premorbid IQ, we derived regression-based T-scores for each measure and the six cognitive domains.
Both patient groups performed significantly worse than NCs on most (BD) or all (SZ) cognitive tests and domains. The resulting effect sizes ranged from 0.37 to 1.32 (mean = 0.97) across tests for SZ patients and from 0.23 to 0.87 (mean = 0.59) for BD patients. The Pearson correlation of these effect sizes was 0.71 (p < 0.001).
Patients with bipolar disorder suffer from cognitive deficits that are milder but qualitatively similar to those of patients with schizophrenia. These findings support the notion that schizophrenia and bipolar disorder show greater phenotypic similarity in terms of the nature than severity of their neuropsychological deficits.
bipolar disorder; schizophrenia; cognitive testing; neuropsychology; biomarker
Evidence links diabetes mellitus to cognitive impairment and increased risk of Alzheimer's disease (AD) and suggests that insulin therapy improves cognition. With an increasing percentage of the US elderly population at high risk for diabetes and AD, the evidence of an association between diabetes and poor cognition in non-demented elderly may have implications for diagnosis, prevention and treatment of cognitive decline including AD.
In our study, we hypothesized that diabetic elders with normal cognition would demonstrate poorer cognitive outcomes than non-diabetic elders and that diabetic elders receiving diabetes treatment would demonstrate better outcomes than those not receiving treatment.
Data were evaluated from the National Alzheimer's Coordinating Center's Uniform Data Set (UDS). The UDS consists of clinical and neuropsychological assessments of a sample of elderly research subjects recruited from thirty-one Alzheimer's Disease Centers nationwide. The UDS provides a unique opportunity to study cognition in a nationally recruited sample with structured neuropsychological tests.
We examined the impact of diabetes and diabetes treatment on cognitive measures in 3421 elderly research subjects from 2005-2007 with normal cognition. We performed linear regression analyses to compare cognitive scores between diabetic subjects and non-diabetic subjects. Diabetic subjects had lower scores than non-diabetic subjects including attention, psychomotor function and executive function, but no differences in memory or semantic memory language. There was no association between diabetes treatment and cognitive scores.
These subtle but significant cognitive deficits in diabetic subjects compared to non-diabetic subjects may contribute to difficulty with compliance with complex diabetes medication regimens. A specific role of diabetes as a risk for cognitive impairment will require longitudinal study.
Diabetes; Cognition; Alzheimer's; Elderly
To evaluate the performance of nondemented subjects 85 years and older on the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychological battery, and to assess its relationship with sociodemographic variables.
We studied 196 subjects enrolled in an Alzheimer’s Disease Research Center study who had a complete CERAD neuropsychological assessment. We used multiple regression analysis to predict performance on the neuropsychological tests from age, education, and sex. Eight representative hypothetical individuals were created (for example, an 87-year-old man, with high education). For each test, estimates of performance at the 10th, 25th, 50th, and 75th percentiles were reported for the eight representative hypothetical individuals.
Mean age was 89.2 years (SD = 3.2), mean years of education was 14.9 (SD = 3.2), and 66% of the sample were women. For 11 of the 14 neuropsychological tests, there was a significant multiple regression model using education, age, and sex as predictors. Neither the models nor the predictors used individually were significant for Delayed Recall, Savings, or correct Recognition. Among the significant results, seven had education as the strongest predictor. Lower age and higher education were associated with better performance. Women performed better than men in three of four tests with significant results for sex.
In a sample of oldest old whose primary language is English, neuropsychological testing is influenced mainly by education and age. Cutoff scores based on younger populations and applied to the oldest old might lead to increased false-positive misclassifications.
OBJECTIVE: To determine the prevalence and correlates of neuropsychological impairment in a large cohort (n = 146) of patients with typical, sporadic (non-familial) amyotrophic lateral sclerosis. METHODS: A battery of neuropsychological tests was administered to patients with amyotrophic lateral sclerosis who were attending a monthly outpatient clinic or who were in hospital undergoing diagnostic tests. RESULTS: Comparing individual patient's scores with relevant normative data, 35.6% of the patients displayed evidence of clinically significant impairment, performing at or below the 5th percentile on at least two of the eight neuropsychological measures. Deficits were most common in the areas of problem solving, attention/mental control, continuous visual recognition memory, word generation, and verbal free recall. Impairment was most prevalent in patients with dysarthria (48.5%), but 27.4% of non-dysarthric patients were also impaired. Impaired patients had more severe or widespread symptoms of amyotrophic lateral sclerosis than non-impaired patients, and had fewer years of education. CONCLUSION: Neither the conventional wisdom that cognition is intact in nearly all patients with amyotrophic lateral sclerosis, nor more recent suggestions that cognition is often at least mildly impaired seems to be correct. A minority of patients with amyotrophic lateral sclerosis displayed evidence of significant impairment. Dysarthria, low education, and greater severity of motor symptoms were risk factors for impairment.
Controversy exists regarding whether high blood pressure (BP) is a risk factor for an accelerated decline in persons with mild cognitive impairment (MCI). The purpose of this study was to examine whether elevated BP levels are associated with a faster decline in specific cognitive domains.
Prospective longitudinal cohort.
Uniform Data Set of the NIH-NIA Alzheimer’s Disease Centers.
1385 participants with a diagnosis of MCI and measured BP values at baseline and two annual follow-up visits.
Neuropsychological test scores and Clinical Dementia Rating Sum of Boxes score.
MCI patients with two or three annual occasions of high BP values (≥140 systolic BP or ≥90 diastolic BP) had a significantly faster decline on neuropsychological measures of visuomotor sequencing, set shifting, and naming than those who were normotensive on all three occasions. Elevated systolic BP values were associated as well with a faster decline on the Clinical Dementia Rating Sum of Boxes score.
Hypertension is associated with a faster cognitive decline in persons at risk for dementia.
Mild Cognitive Impairment; Hypertension; Neuropsychology; Cerebrovascular Disease; Dementia
Polychlorinated biphenyls (PCBs) may accelerate the cognitive and motor dysfunction found in normal aging, but few studies have examined these outcomes and PCB exposure among older adults.
We evaluated neuropsychological status and low-level PCB exposure among older adults living along contaminated portions of the upper Hudson River in New York.
A total of 253 persons between 55 and 74 years of age were recruited and interviewed, and provided blood samples for congener-specific PCB analysis. Participants also underwent a neuropsychological battery consisting of 34 tests capable of detecting subtle deficits in cognition, motor function, affective state, and olfactory function.
After adjustment for potential confounders, the results indicated that an increase in serum total PCB concentration from 250 to 500 ppb (lipid basis) was associated with a 6.2% decrease in verbal learning, as measured by California Verbal Learning Test trial 1 score (p = 0.035), and with a 19.2% increase in depressive symptoms, as measured by the Beck Depression Inventory (p = 0.007).
The results suggest that exposure to PCBs may be associated with some measures of memory and learning and depression among adults 55–74 years of age whose current body burdens are similar to those of the general population. Although the results are useful in delineating the neuropsychological effects of low-level exposure to PCBs, further studies of whether older men and women are a sensitive subpopulation are needed.
adult; affective symptoms; hazardous waste; neurobehavioral manifestations; neuropsychological tests; polychlorinated biphenyls