Are there sex differences in neuropsychological functions among patients with schizophrenia?

OBJECTIVE: Studies of sex differences in neuropsychological performance in schizophrenia report inconsistent results, due in part to methodological artifacts. The study presented here was specifically designed to examine sex differences in neuropsychological performance. It was hypothesized that schizophrenic women would exhibit fewer neuropsychological deficits than schizophrenic men and that their performance would be more similar to that of normal women than schizophrenic men's performance would be to that of normal men. METHOD: Thirty-one outpatients with DSM-III-R-defined schizophrenia were systematically sampled from an extensive service network serving a large urban catchment area for seriously mentally ill persons. Twenty-seven normal comparison subjects were matched within sex on the basis of age, parental socioeconomic status, ethnicity, and handedness. An extensive neuropsychological test battery was administered, and multivariate analysis of variance was used to test for the effects of sex and group and sex-by-group interactions. RESULTS: Male patients were significantly impaired across all functions in comparison with normal male subjects and on tests of attention, verbal memory, and executive functions in comparison with female patients. Female patients performed significantly worse than female normal comparison subjects only on tests of attention, executive functions, visual memory, and motor functions. CONCLUSIONS: The findings suggest that women with schizophrenia may be less vulnerable to particular cognitive deficits, especially those involving verbal processing, than schizophrenic men.     

Quality of life: theory and methodology in rehabilitation

Validity studies of neuropsychological tests have typically examined individuals with neurological disorders. The present study was designed to investigate the construct validity of neuropsychological measures in patients with schizophrenia. We used Wechsler Adult Intelligence Scale Revised (WAIS-R) factor scores that were generated from the population of interest as marker variables in the present analysis. The current study included 39 patients with schizophrenia who were evaluated with a battery of neuropsychological tests assessing attention, memory, and abstract reasoning abilities. Pearson correlations indicated significant relationships between (a) WAIS-R Verbal Comprehension factor and tests of sustained attention, verbal memory and remote memory; (b) WAIS-R Perceptual Organization factor and tests of visual memory and abstraction and problem solving; and (c) WAIS-R Freedom From Distractibility factor and neuropsychological measures of attention and concentration. These results provide support for the construct validity of the neuropsychological tests in patients with schizophrenia, and indicate that these tests evaluate essentially the same constructs in patients with schizophrenia as they do for patients with structural neurological disorders.     

Further evidence for a deficit in switching attention in schizophrenia.

In this study, sustained, selective, divided, and switching attention, and reloading of working memory were investigated in schizophrenia by using a newly developed Visual Attention Battery (VAB). Twenty-four outpatients with schizophrenia and 24 control participants were studied using the VAB. Performance on VAB components was correlated with performance of standard tests. Patients with schizophrenia were significantly impaired on VAB tasks that required switching of attention and reloading of working memory but had normal performance on tasks involving sustained attention or attention to multiple stimulus features. Switching attention and reloading of working memory were highly correlated with Trails (B–A) score for patients. The decline in performance on the switching-attention task in patients with schizophrenia met criteria for a differential deficit in switching attention. Future research should examine the neurophysiological basis of the switching deficit and its sensitivity and specificity to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related practice effects across longitudinal neuropsychological assessments in older people with schizophrenia.

Objective: The relationship between aging and practice effects on longitudinal neuropsychological assessments was investigated in middle-aged and older people with schizophrenia and healthy controls. Method: Older people with schizophrenia (n = 107; M age = 56.1) and age-comparable nonpsychiatric controls (n = 107; M age = 57.7) were scheduled to receive annual assessments on a comprehensive battery of neuropsychological tests for an average of 2.5 years (range 11 months to 4 years). Mixed-model analyses were used to separately examine the effects of practice and age on test performance. Results: Number of prior assessments (practice) was associated with significant performance improvement across assessments, whereas older age was associated with significant decline in performance. The groups did not differ significantly in extent of age-related cognitive decline, but a three-way interaction among group, age, and practice was found, such that greater age-related decline in practice effects were found for older people with schizophrenia relative to nonpsychiatric participants. Conclusions: This study did not find any evidence of neurodegenerative age-related decline in neuropsychological abilities in middle-aged and older people with schizophrenia, but older age was associated with diminished ability to benefit from repeated exposure to cognitive tasks in people with schizophrenia. Cognitive impairment in schizophrenia may combine with cognitive decline associated with normal aging to reduce practice effects in older patients. These findings have important implications for the design of studies examining the longitudinal trajectory of cognitive functioning across the life span of people with schizophrenia, as well as clinical trials that attempt to demonstrate cognitive enhancement in these individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological functioning among the nonpsychotic relatives of schizophrenic patients: A 4-year follow-up study.

In a prior study of 54 relatives of patients with schizophrenia and 72 control participants, 3 neuropsychological functions met the criteria for risk indicators of the schizophrenia genotype: executive functioning, memory, and auditory attention. In an assessment of the stability of these findings, the sample was reexamined 4 years after the initial assessment. Three test scores were found to differ between groups (Immediate Verbal Memory, Delayed Verbal Memory, and Dichotic Listening Digits Detected) or to show a significant Group?×?Gender interaction (immediate and delayed verbal and visual memories). None of the test scores showed Group?×?Time interactions, suggesting that the discriminating power of the tests was stable over time. Evidence for deficits in working memory and rule learning on the object alternation test was also found. These results support the idea that neuropsychological dysfunction among relatives of patients with schizophrenia is a stable trait caused by the familial predisposition to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A review of neuropsychological differences between paranoid and nonparanoid schizophrenia patients

This review examines the literature on neuropsychological differences between paranoid and nonparanoid schizophrenia subjects. Thirty-two studies related to intellectual functioning, attention, memory, language, visual-spatial, and motor functions are discussed. Subjects with paranoid schizophrenia did not demonstrate higher intellectual functioning than those with nonparanoid schizophrenia, and both groups performed similarly on tests of verbal ability and visual-spatial functions. Several studies suggest that the paranoid subtype is associated with higher performance on tests of executive functions, attention, memory, and motor skills. However, the findings are inconsistent. Methodological issues in the literature are examined, including varying degrees of participants' chronicity and severity of illness among studies, criteria for diagnostic group membership, medication effects, reliability and validity of the neuropsychological measures, and statistical power.     

Hypertension and neuropsychological performance in men: Interactive effects of age.

Potentially interactive effects of hypertension and age on the performance of neuropsychological and information processing tests were examined in 123 untreated hypertensive and 50 normotensive men. After covarying education, average alcohol consumption, trait anxiety, and depression scores, results indicated an interaction of age and hypertension. Young hypertensive men (23–40 years) scored significantly worse than young normotensive men on tests of attention/executive function and working memory; middle-aged hypertensive (41–56 years) and normotensive participants were not distinguished by any measures. Hypertensive men performed significantly more poorly than normotensive men on tests of manual dexterity. Results suggest that neuropsychological sequelae of hypertension are more pronounced in young than in middle-aged hypertensive individuals and are independent of various demographic, psychosocial, and alcohol-related factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in neuropsychological functioning over 10 years following adolescent substance abuse treatment.

Previously, Anderson, Ramo, Cummins, and Brown (2010) described six distinct patterns of alcohol and other drug (AOD) use during the decade following adolescents' treatment for alcohol and other substance use disorders (A/SUD). This time period represents a phase of significant neurodevelopment, and the influence of substance use on the brain is a concern. In the present study, we examined patterns of neuropsychological function over these 10 years in relation to the AOD trajectories identified for youth as they transition into their twenties. Participants were part of a longitudinal research project following adolescents with and without A/SUD who received neuropsychological examinations at baseline and up to 7 times thereafter spanning 10 years (N = 213; 46% female at baseline). Neuropsychological trajectories were significantly related to substance involvement patterns over time on measures of verbal learning and memory (ps = .011 to p = .0002), and verbal attention/working memory (p = .020), with heavier use patterns generally followed by poorer cognition. Heavy use of alcohol alone was independently associated with poorer verbal memory over time. Furthermore, substance withdrawal symptoms during each follow-up time point were related to poorer verbal learning and memory scores (ps     

Neuropsychology of Adults With Attention-Deficit/Hyperactivity Disorder: A Meta-Analytic Review.

A comprehensive, empirically based review of the published studies addressing neuropsychological performance in adults diagnosed with attention-deficit/hyperactivity disorder (ADHD) was conducted to identify patterns of performance deficits. Findings from 33 published studies were submitted to a meta-analytic procedure producing sample-size-weighted mean effect sizes across test measures. Results suggest that neuropsychological deficits are expressed in adults with ADHD across multiple domains of functioning, with notable impairments in attention, behavioral inhibition, and memory, whereas normal performance is noted in simple reaction time. Theoretical and developmental considerations are discussed, including the role of behavioral inhibition and working memory impairment. Future directions for research based on these findings are highlighted, including further exploration of specific impairments and an emphasis on particular tests and testing conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word and tone working memory deficits in schizophrenia

BACKGROUND: Verbal memory deficits have been reported in many studies of patients with schizophrenia. We evaluated the specificity of these deficits by comparing patients and control subjects on several verbal and nonverbal auditory memory tests. METHODS: Performance of stable, medicated outpatients with DSM-III-R diagnoses of schizophrenia (N = 38) was compared with that of healthy subjects (N = 39) on a word list immediate recall task, tone delayed discrimination tasks, and word and tone serial position tasks. Before memory testing, patients were divided into 2 groups based on their ability to perform normally on a screening test requiring pitch discrimination and sustained attention. RESULTS: The nonverbal tests were more difficult for control subjects than the verbal tests. Despite this, patients who performed normally on the screening test of perception and attention performed normally on both nonverbal tests but had highly significant deficits on both verbal tests (P<.001 and P = .02). Patients who performed poorly on the screening test had highly significant performance deficits on all the memory tests. CONCLUSIONS: One subgroup of patients with schizophrenia has a selective deficit in verbal memory despite normal motivation, attention, and general perceptual function. Another group has deficits in multiple aspects of cognitive function suggestive of failure in early stages of information processing.     

Highly active antiretroviral treatment in HIV infection: benefits for neuropsychological function

OBJECTIVES: To determine whether highly active antiretroviral therapy (HAART) is associated with reduced HIV-associated neuropsychological impairment. DESIGN: Cross-sectional analysis in a natural history study of adaptation to HIV/AIDS. METHOD: A sample of 130 homo-/bisexual men with HIV/AIDS (mean age, 41 years; 42% non-white) were evaluated with a neuropsychological battery assessing attention, concentration, psychomotor speed, learning, memory and executive function. Subjects taking HAART were compared with those not taking HAART on demographics, CD4 cell count, viral load, scores on individual neuropsychological tests and proportion with neuropsychological impairment. RESULTS: Sixty-nine (53%) subjects were taking HAART, and 48 (37%) were neuropsychologically impaired. Subjects taking HAART had lower mean CD4 cell counts than those not taking HAART (254 versus 342 x 10(6)/l; P < 0.05), although they were more likely to have undetectable viral load (42 versus 20%; P < 0.01) and were less likely to be neuropsychologically impaired (22 versus 54%; P < 0.0001). Subjects taking HAART performed significantly better on tests of attention, concentration, learning, memory, and psychomotor speed. After excluding subjects with potential non-HIV confounders of neuropsychological function, those without neuropsychological impairment had significantly lower mean viral load levels and were more likely to have undetectable viral load than those with impairment. CONCLUSION: These preliminary findings suggest that HAART benefits neuropsychological function through the reduction of viral load.     

Crystallized verbal skills in schizophrenia: Relationship to neurocognition, symptoms, and functional status.

Objective: To study the relationship of superior (i.e., ≥ 90th percentile), average (11th?89th percentile) or extremely low (i.e., ≤ 10th percentile) crystallized verbal skills to neurocognitive profiles, symptoms and everyday life function in schizophrenia. Method: Crystallized verbal skill was derived from Vocabulary subtest scores from the Wechsler Adult Intelligence Scale (WAIS). Out of a sample of 165 stable outpatients with schizophrenia we identified 25 participants with superior crystallized verbal skill, 104 participants with average verbal skill, and 36 participants with extremely low crystallized verbal skill. Each participant was administered measures of attention, working memory, verbal learning and memory, problem-solving and processing speed, as well as symptom and performance-based adaptive life skill assessments. Results: The magnitude of neuropsychological impairment across the three groups was different, after adjusting for group differences in education and duration of illness. Working memory, and verbal learning and memory skills were different across all three groups, while processing speed differentiated the extremely low verbal skill group from the other two groups and problem-solving differentiated the very low verbal skill group from the superior verbal skill group. There were no group differences in sustained attention. Capacity measures of everyday life skills were different across each of the three groups. Conclusion: Crystallized verbal skill in schizophrenia is related to the magnitude of impairment in neurocognitive function and performance-based skills in everyday life function. Patterns of neuropsychological impairment were similar across different levels of crystallized verbal skill. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The life of Maurice Virenque (1888-1946). From "Gueules Cassées" to cervicofacial facelift

Neuroimaging and neuropsychological studies have consistently implicated dorsolateral prefrontal cortex as abnormal in schizophrenia. However, other areas of frontal cortex have received far less attention. In particular, few studies have examined orbital frontal regions with other than olfactory tests. In the present study we wished to assess the functional capability of orbital frontal cortex using a test developed by Bechara et al. (1994) that assesses a subject's capacity to acquire a preference through reward and punishment, using a gambling task that involved gains and losses of play money. Thirty normal subjects and 12 patients with schizophrenia (three undifferentiated, eight paranoid, one schizoaffective) comprised the sample in the present study. We found that patients with schizophrenia exhibited a pattern of findings similar to that of normals and dissimilar to that of patients with known orbital frontal damage. In our study, both normal subjects and schizophrenic patients chose most frequently from decks of cards in which there were frequent rewards and infrequent penalties, as might be expected on the basis of operant conditioning literature. We also found that performance on this task was not correlated with tests of working memory or long-term memory, suggesting that the development of a preference may occur implicitly. Our findings also argue against a general deficit in schizophrenia, as performance on the gambling task appeared relatively uncompromised.     

Immune function and neuropsychological performance in HIV-1-infected homosexual men

This study explores the relationship of immune dysfunction to the neuropsychological performance of individuals infected with HIV-1. Fifty-five HIV-positive homosexual men and 37 negative homosexual controls were evaluated using neuropsychological measures, physical exams, and measures of immune functioning. There were no significant differences favoring HIV-negative subjects over HIV-positive subjects. HIV-positive subjects, in fact, performed slightly better on attention and memory procedures. The HIV-positive subjects were then stratified according to the Centers for Disease Control symptom groupings (Group II, asymptomatic, n = 19; Group III, lymphadenopathy, n = 17; and Group IVA or C-2, symptomatic, non-AIDS, (n = 19). There were no significant neuropsychological differences among the three CDC groups. The HIV-positive subjects were also stratified on two measures of immune functioning: absolute CD4 counts (< 200, 201-400, > 400) and beta 2-microglobulin (beta 2M) (> or = 5.0, 3.0-5.0, < 3.0). Individuals with greater immune compromise, as measured by beta 2M, were more impaired on measures of attention and memory and had greater overall neuropsychological impairment (p < 0.05). Furthermore, 57% of the subjects who were abnormal on beta 2M were also impaired on measures of attention and memory, whereas only 14% of those with normal beta 2M were impaired on these same measures (p < 0.05). These results suggest that HIV-positive asymptomatics without evidence of immune compromise do not appear to be at greater risk of cognitive impairment than HIV-negative controls. However, for those HIV-positive individuals who are immune-compromised (even while asymptomatic), there is increased risk of neuropsychological impairment. These results also suggest that knowledge of serostatus and the use of the CDC classification system alone are insufficient in exploring the development of neuropsychiatric changes in HIV-1 infection.     

Unexplained and explained natural deaths among persons above 1 year of age in a series of medico-legal autopsies

We investigated the association of neuropsychological risk indicators in a matched sample of first-degree relatives of schizophrenic patients (n = 54) and normal controls (n = 72). We focussed on three functions previously identified in a smaller, initial sample as putative risk indicators of the schizophrenia genotype: abstraction, verbal memory and auditory attention. The expanded sample of relatives displayed significantly lower scores than controls on abstraction, verbal memory and auditory attention. The relatives demonstrated significant intercorrelations among these three functions. The significant correlations among relatives between attention and verbal memory and between attention and abstraction differed significantly from these correlations among controls. We discuss how the use of multiple risk indicators may help us better identify those relatives that carry the schizophrenia genotype.     

Correlation of auditory 'oddball' P300 with verbal memory deficits in schizophrenia

BACKGROUND: The study attempts to recruit well known 'cognitive' event related potential measures as an objective estimate of cognitive and specific memory impairment in schizophrenia. METHODS: We examined 19 schizophrenic patients and 28 healthy controls using an auditory discrimination task to elicit event related potentials, and a number of neuropsychological tests, including tests of general intellectual ability, putative frontal lobe function and verbal memory. RESULTS: The late positive deflection presumed to be associated with stimulus evaluation (P300) was of lower amplitude and had a longer latency in the patients compared with controls of similar age and sex. We found correlations between P300 amplitude and latency, and neuropsychological performance scores in patients. There were correlations between decreased P300 amplitude and lower IQ and poorer memory performance, in particular, abnormal semantic clustering, discriminability and intrusion errors. Increased P300 latency was correlated with lower pre-morbid IQ, poorer total memory scores and serial clustering, but paradoxically less relative retrieval deficit and fewer intrusion errors. CONCLUSIONS: These findings suggest that abnormal P300 is generally more likely to occur in patients with memory impairment.     

Measurement invariance of neuropsychological tests in diverse older persons.

Objective: Comparability of meaning of neuropsychological test results across ethnic, linguistic, and cultural groups is important for clinicians challenged with assessing increasing numbers of older ethnic minorities. We examined the dimensional structure of a neuropsychological test battery in linguistically and demographically diverse older adults. Method: The Spanish and English Neuropsychological Assessment Scales (SENAS), developed to provide psychometrically sound measures of cognition for multiethnic and multilingual applications, was administered to a community dwelling sample of 760 Whites, 443 African Americans, 451 English-speaking Hispanics, and 882 Spanish-speaking Hispanics. Cognitive function spanned a broad range from normal to mildly impaired to demented. Multiple group confirmatory factor analysis was used to examine equivalence of the dimensional structure for the SENAS across the groups defined by language and ethnicity. Results: Covariance among 16 SENAS tests was best explained by five cognitive dimensions corresponding to episodic memory, semantic memory/language, spatial ability, attention/working memory, and verbal fluency. Multiple Group confirmatory factor analysis supported a common dimensional structure in the diverse groups. Measures of episodic memory showed the most compelling evidence of measurement equivalence across groups. Measurement equivalence was observed for most but not all measures of semantic memory/language and spatial ability. Measures of attention/working memory defined a common dimension in the different groups, but results suggest that scores are not strictly comparable across groups. Conclusions: These results support the applicability of the SENAS for use with multiethnic and bilingual older adults, and more broadly, provide evidence of similar dimensions of cognition in the groups represented in the study. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Longitudinal deficits to attention, executive, and working memory in subtypes of mild cognitive impairment.

Objective: Mild cognitive impairment (MCI) has emerged as a classification for a prodromal phase of cognitive decline that may precede the emergence of Alzheimer's disease (AD). Recent research suggests that attention, executive, and working memory deficits may appear much earlier in the progression of AD than traditionally conceptualized, and may be more consistently associated with the later development of AD than memory processing deficits. The present study longitudinally tracked attention, executive and working memory functions in subtypes of MCI. Method: In a longitudinal study, 52 amnestic MCI (a-MCI), 29 nonamnestic MCI (na-MCI), and 25 age- and education-matched controls undertook neuropsychological assessment of visual and verbal memory, attentional processing, executive functioning, working memory capacity, and semantic language at 10 month intervals. Results: Analysis by repeated measures ANOVA indicate that the a-MCI and na-MCI groups displayed a decline in simple sustained attention (ηp2 = .054) with a significant decline on a task of divided attention (ηp2 = .053) being evident in the a-MCI group. Stable deficits were found on other measures of attention, working memory and executive function in the a-MCI and na-MCI groups. The a-MCI group displayed stable impairments to visual and verbal memory. Conclusions: The results indicate that a-MCI and na-MCI display a stable pattern of deficits to attention, working memory, and executive function. The decline in simple sustained attention in a-MCI and n-MCI groups and to divided attention in a-MCI may be early indicators of possible transition to dementia from MCI. However, further research is required to determine this. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Neuropsychological characteristics of three subgroups of Flemish delinquent adolescents.

Sixty-three adjudicated adolescents, aged 14-17 years, were followed for 2 years to examine the neuropsychological characteristics of subgroups of delinquents. Nonrecidivistic subjects (n=29) and late recidivistic subjects (n=22) differed from early recidivistic subjects (n=12) on intelligence, self-control functioning, and memory. Late recidivistic subjects, compared with not recidivistic subjects, showed a lower verbal IQ. The differences remained when controlling for the level of substance abuse. This study suggests that neuropsychological assessment may help in differentiating delinquent adolescents, although more research is needed to unravel the mediating influences of substance abuse and early neuropsychological and academic problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlation between deletion patterns of SMN and NAIP genes and the clinical features of spinal muscular atrophy in Japanese patients

OBJECTIVE: To look for preclinical markers of Alzheimer's dementia in a sample of healthy, oldest old individuals. DESIGN: Prospective, longitudinal study of individuals examined at yearly intervals with neuropsychological tests selected to be sensitive to the early detection of dementia. PARTICIPANTS: One hundred and thirty-nine community-dwelling, functionally independent, healthy individuals 65 to 106 years of age who met strict criteria for lack of dementia at entry. Incident dementia cases consisted of 16 volunteers all 80 years old or older who developed dementia of the Alzheimer's type and 31 volunteers 80 years old and older showing no evidence of dementia during a mean 2.8-year follow-up interval. MEASUREMENTS: Scores on 10 neuropsychological measures were analyzed for the initial examination when none of the volunteers showed clinical evidence of dementia and for the two subsequent yearly examinations. RESULTS: Individuals who subsequently developed dementia showed evidence of verbal memory impairment at their initial examination, which was a mean of 2.8 years before clinical evidence of dementia. The average yearly incidence rate for dementia in those 80 years of age and older was 12%. Performance of individuals who did not development dementia remained relatively stable during follow-up for up to 5 years. CONCLUSION: Alzheimer's disease has a preclinical stage in which verbal memory decline is the earliest sign. Dementia in the oldest old is distinguishable from age-related cognitive decline.