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PubMed2000

Does migraine headache affect cognitive function in the elderly? Report from the Maastricht Aging Study (MAAS).

The aim of this study was to examine two aspects of cognitive functioning-information processing speed and memory-in both young/middle-aged and older subjects with and without migraine, using data from a large population-based sample. We found that, although age had a large effect on processing speed and memory, migraine did not influence cognitive performance. In addition, there was no significant interaction between age and migraine on processing speed and memory. Our results suggest that, in the general population, migraine does not seriously affect cognitive functioning in young/middle-aged or older adults.

Adult↗

PubMed2003

Long-term memory deficits in schizophrenia: primary or secondary dysfunction?

Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance.

Adult↗

PubMed2001

Determinants of Benton Facial Recognition Test performance in normal adults.

Clinical investigations have found that lesions of the right cerebral hemisphere can disrupt face perception. Much less is known about the determinants of facial discrimination in healthy adults, although age-related differences in many cognitive abilities have been shown to correlate with simple processing speed and variation in regional brain volumes. In this study, 174 healthy adults between the ages of 20 and 92 were asked to match pictures of unfamiliar faces. After their performance was regressed on age, sex, education, and perceptual comparison speed, adding terms for frontal lobe volume, nonfrontal volume, and ventricle-to-brain ratio (VBR) derived from magnetic resonance imaging improved the model and accounted for 35% of the variance in facial discrimination. VBR and processing speed alone accounted for nearly 34% of the variance. These findings suggest that both normal atrophic brain changes and decreases in processing speed contribute to individual differences in facial discrimination.

Adult↗

PubMed1991

Speed of processing within semantic memory following severe closed head injury.

This study investigated the effects of severe closed head injury (CHI) on the speed of information processing within semantic categories. The question of whether subjects were able to benefit from priming was also investigated. Survivors of severe CHI who were less than 1 year postinjury and survivors who were greater than 1 year postinjury were compared with neurologically normal matched controls utilizing a category judgement task. The results demonstrated slower processing within semantic memory for both groups of CHI patients compared to normal controls. Furthermore, individuals with CHI were able to benefit from priming to the same relative degree as control subjects. Overall, the results suggested semantic organization remains intact after severe CHI, but accessing semantic information is slowed.

Adult↗

PubMed2026

Ultra-high-field 7T MRI reveals neural abnormalities of attention networks in relation to cognitive impairment in hypertension.

Hypertension is a significant risk factor for cognitive impairment (CI), yet the corresponding neural network abnormalities remain underexplored. In this study, we examined the associations among global and domain-specific cognitive dysfunction, neuroimaging measures, and blood pressure in a subgroup of hypertensive patients with CI (N = 41) from a randomized controlled trial who underwent ultra-high-field 7 T MRI. Structural atrophy related to CI was localized to regions overlapping the attention networks. Both whole-brain and within-network dysfunction of the attention networks were associated with worse global cognitive performance. Notably, hyperconnectivity within key attention network hubs, including the right anterior insula and posterior intraparietal sulcus, was associated with declined processing speed in hypertensive patients, mediating the association between pulse pressure and processing speed. These findings provide new insights into the neural pathophysiology of hypertension-related CI and suggest potential network-based targets for intervention.

Magnetic Resonance Imaging↗

PubMed1997

Issues concerning relative speed of processing hypotheses, schizophrenic performance deficits, and prefrontal function: comment on Schooler et al. (1997)

The authors have found the data presented in the C. Schooler, E. Neumann, L. J. Caplan, and B. R. Roberts (1997) article to be interesting and of potential value in constraining the further development of detailed theoretical models of Stroop performance. However, the authors have found that the relative speed of processing account of stimulus onset asynchrony (SOA) effects given by Schooler et al. in Experiment 1 fails to address several important and vexing issues faced by such accounts, which have been highlighted by existing formal models. The authors also have expressed concerns about Schooler et al.'s, interpretation of the reduction in Stroop interference observed among individuals with schizophrenia in Experiment 2. Whereas the authors have acknowledged that it is plausible to relate this to a dysfunction of prefrontal cortex, they have pointed to equally plausible alternative explanations, which are not addressed by the experiment or in the discussion in the Schooler et al. article.

Attention↗

PubMed2004

The effects of aging in the medial geniculate nucleus: a comparison with the inferior colliculus and auditory cortex.

A common problem among the elderly is a difficulty in discriminating speech. One factor that may contribute to this is deterioration in the ability to process the dynamic components of speech such as formant transitions. The frequency-modulated (FM) sweep is a useful stimulus for investigating the neural basis of temporal processing speed since it has features in common with formant transitions. Previously, we showed that when cells in the auditory cortex of aged animals were presented with FM sweeps, they exhibited a decrease in temporal processing speed when compared to cells recorded from young animals. However, this was not the case for cells in the inferior colliculus (IC) where neural responses did not appear to be affected by aging. One question that remains is how the auditory thalamus is affected by aging: Is it similar to that of the auditory cortex or of the IC. To this end, single units were recorded from the ventral division of the medial geniculate nucleus (MGNv) of young and aged anaesthetized rats in response to FM sweeps. Results showed that there were no age-related differences in speed or direction selectivity of FM sweep responses in the MGNv. When compared with units recorded from the IC and AI, the responses of MGNv neurons were similar to those of the IC. This suggests that temporal processing speed is affected by aging in the cortex, but not in the auditory thalamus or midbrain.

Acoustic Stimulation↗

PubMed2002

Neurocognitive correlates of the COMT Val(158)Met polymorphism in chronic schizophrenia.

BACKGROUND: Neurocognitive deficits are recognized as a cardinal feature of schizophrenia, but the determinants of these deficits remain unknown. Recent reports have suggested that a functional polymorphism, Val(158)Met in exon III of the catechol-O-methyltransferase gene, shares approximately 4% variance with performance on the Wisconsin Card Sorting Test. These findings led to suggestions that the catechol-O-methyltransferase polymorphism may exert its effects by modulating prefrontal dopamine function, but few other neurocognitive measures have been examined, leaving open questions about phenotypic specificity. METHODS: We examined the effects of the catechol-O-methyltransferase Val(158)Met polymorphism in 58 individuals with chronic schizophrenia who completed a battery of 15 neurocognitive tests, which were reduced to four reliable neurocognitive domain scores. We examined the effects of genotype on these four domains and on global neurocognitive ability. RESULTS: The Met allele was associated with better performance in the Processing Speed and Attention domain, but not with other domain scores measuring executive and visuoperceptual functions, declarative verbal learning and memory, simple motor ability, or global neurocognitive function. Genotype shared approximately 11% of variance with Processing Speed and Attention scores, and approximately 2% of variance with Wisconsin Card Sorting Test scores. CONCLUSIONS: The findings provide independent support for the hypothesis that the catechol-O-methyltransferase Val(158)Met polymorphism influences neurocognitive function in schizophrenia, and suggest that the functional effects may be expressed on measures of Processing Speed and Attention. This information may prompt reconsideration of the "prefrontal dopamine" hypothesis and invites examination of a broader range of effects in efforts to refine the neurocognitive phenotype that is most relevant to variation in catechol-O-methyltransferase expression.

Adult↗

PubMed1996

Aging, cognitive resources, and declarative learning.

A battery of cognitive tasks designed to assess information-processing speed, working memory capability, and declarative learning was administered to a cross-sectional sample of 477 adults ranging in age from 17 to 86 years. Results showed significant age-related decrements in all three constructs. A variety of structural equation models was fit to the results. The preferred model on empirical and conceptual grounds was one that showed (a) working memory capability as the most important mediator of age effects in declarative learning; (b) working memory capability as the mediator for the effects of general processing speed on declarative learning; and (c) differentiation among verbal, numeric, and spatial processing speed and between verbal and spatial working memory capability.

Adolescent↗

PubMed2003

Age-related slowing of digit symbol substitution revisited: what do longitudinal age changes reflect?

A previous investigation reported that cross-sectional age differences in Digit Symbol Substitution (DSS) test performance reflect declines in perceptual processing speed. Support for the tenability of the processing speed hypothesis requires examining whether longitudinal age-related change in DSS performance is largely mediated by changes in speed. The present study used data from the Victoria Longitudinal Study to examine patterns and predictors of longitudinal change in DSS for 512 older adults (M(age) = 68.37 years, SD = 7.43). On the basis of multilevel modeling, baseline DSS performance was poorer for older participants and men, with longitudinal declines more pronounced with increasing age and decreasing speed. In contrast to the present cross-sectional findings, statistical control of change trajectories in perceptual speed using the same data did not substantially attenuate age changes. These discrepancies suggest different sources of variance may underlie cross-sectional age differences and longitudinal age changes for DSS.

Aged↗

PubMed2006

WAIS-III and WMS-III performance in chronic Lyme disease.

There is controversy regarding the nature and degree of intellectual and memory deficits in chronic Lyme disease. In this study, 81 participants with rigorously diagnosed chronic Lyme disease were administered the newest revisions of the Wechsler Adult Intelligence Scale (WAIS-III) and Wechsler Memory Scale (WMS-III), and compared to 39 nonpatients. On the WAIS-III, Lyme disease participants had poorer Full Scale and Performance IQ's. At the subtest level, differences were restricted to Information and the Processing Speed subtests. On the WMS-III, Lyme disease participants performed more poorly on Auditory Immediate, Immediate, Auditory Delayed, Auditory Recognition Delayed, and General Memory indices. Among WMS-III subtests, however, differences were restricted to Logical Memory (immediate and delayed) and Family Pictures (delayed only), a Visual Memory subtest. Discriminant analyses suggest deficits in chronic Lyme are best characterized as a combination of memory difficulty and diminished processing speed. Deficits were modest, between one-third and two-thirds of a standard deviation, consistent with earlier studies. Depression severity had a weak relationship to processing speed, but little other association to test performance. Deficits in chronic Lyme disease are consistent with a subtle neuropathological process affecting multiple performance tasks, although further work is needed to definitively rule out nonspecific illness effects.

Adult↗

PubMed1999

Improvement in specific aspects of neurocognitive performance in children after renal transplantation.

BACKGROUND: Chronic renal failure in childhood is considered to affect neurocognitive function adversely, and kidney transplantation may ameliorate the deficits. However, previous studies have suffered from the use of poorly matched control groups, comparison of transplant with uncorrected uremia, lack of standardization of dialysis, and insufficiently sensitive neuropsychological tests. METHODS: We studied nine medically stable children and adolescents age 14.2 +/- 3.5 years with end-stage renal disease prior to and again one year after successful renal transplant. At baseline, the Wechsler Intelligence Scale for Children-III (WISC-III) or the Wechsler Adult Intelligence Scale-Revised (WAIS-R) was performed. Repeatable tests used before and after transplant included the Paced Auditory Serial Addition Test (PASAT) or the Children's Paced Auditory Serial Addition Test (CHIPASAT), the Stroop Color-Word Naming Test, the Buschke Selective Reminding Test, the Meier Visual Discrimination Test, the Grooved Pegboard Test, the WISC-III or the WAIS-R Coding subtests and the Trailmaking Test. Computer-based measures of mental processing speed, reaction time, and discrimination sensitivity included the Cognitive Abilities Test (CAT) and the Connors Continuous Performance Test (CPT). Formal kinetic modeling of dialysis delivery ensured adequate renal replacement therapy. Transplant function was good on stable doses of immunosuppressives, without recent rejections at the time of testing. RESULTS: Within-subject comparison showed statistically significant improvement in mental processing speed by CAT, reaction time and discrimination sensitivity by CPT, and working memory by PASAT/CHIPASAT after renal transplant. Other measures were unchanged. CONCLUSION: Mental processing speed and sustained attention improved in children after renal transplantation in a carefully controlled prospective cross-over study.

Adolescent↗

PubMed2003

Whole-brain N-acetylaspartate level and cognitive performance in HIV infection.

BACKGROUND AND PURPOSE: In the brain of HIV-infected patients, proton MR spectroscopic studies are typically used to examine small volumes of tissue with single-voxel methods. Since brain disease is diffuse in patients with HIV, such studies preclude assessment of the true extent of the metabolic burden. To assess this extent, the relationship between global neuronal integrity, reflected by the whole-brain N-acetylaspartate (WBNAA) concentration, was correlated with neuropsychological function and the AIDS dementia complex (ADC) stage score. METHODS: WBNAA levels were compared between 15 HIV-infected patients (seven symptomatic, eight asymptomatic) and 13 age- and sex-matched healthy subjects. The patients' WBNAA level was correlated with cognitive performance, as measured with a battery of eight tests (NPZ-8), including the ADC stage score and four total-memory, mood, motor, and processing speed subtests. RESULTS: WBNAA levels were significantly different between patients and healthy subjects (mean +/- sigma, 11.82 +/- 1.40 and 12.91 +/- 1.03 mmol/L, respectively; P =.032) after we adjusted for age and sex effects. Intermediate negative correlations were found between the WBNAA level, the processing speed subtest score (r = -0.50, P =.03), and the ADC stage score (r = -0.44, P =.05). CONCLUSION: The WBNAA concentration complements brain atrophy data with information about the quality of the remaining neuronal and axonal tissue in patients with HIV infection. In HIV-infected patients, its correlation with processing speed and the ADC score indicates that the latter reflects pathologic deficits, which are extensive throughout the brain.

AIDS Dementia Complex↗

PubMed2006

Central executive system impairment in traumatic brain injury.

The aim of the present study was to identify cognitive functions affected by traumatic brain injury (TBI) and to verify the mechanism underlying cognitive impairment. More precisely, cognitive deficits following TBI can be considered as a consequence of (a) a speed processing deficit, that is a general slowing of perceptual, motor and cognitive subroutines; (b) an impairment of the Central Executive System of working memory (CES).Thirty-seven patients were submitted to a neuropsychological battery, aimed to evaluate different cognitive functions. Results showed severe deficits in speed processing, divided attention,working memory, executive functions and long term memory. Regression analyses, performed to test the two hypotheses, showed that the working memory deficit hypothesis is able to explain divided attention, executive functions and long term memory deficits more than speed processing hypothesis.

Adolescent↗

PubMed2006

Durability and mechanism of effects of cognitive enhancement therapy.

OBJECTIVES: This study sought to determine whether previously reported effects of cognitive enhancement therapy (CET) are maintained one year after treatment. CET is a developmental, small-group approach to the remediation of neurocognitive and social-cognitive deficits among persons with schizophrenia. A mechanism of action that might explain the effects of CET was also sought. METHODS: After a study in which 121 participants with schizophrenia or schizoaffective disorder were randomly assigned to CET (N=67) or an enriched supportive therapy (EST) (N=54) for a two-year period, 106 patients who completed treatment underwent behavioral and neuropsychological assessments one year later. Data were analyzed by linear trend analysis. Mechanisms of action were explored with a mediator analytic strategy. RESULTS: Significant improvement favoring CET continued through the follow-up year on composite measures of processing speed, cognitive style, social cognition, and social adjustment. The difference between CET and EST on the neurocognition composite measure was not maintained because the stress-regulating effects of treatment appeared to lead to improved neurocognitive performance in both groups. Early improvement in processing speed was a strong (partial) mediator of long-term CET effects on social cognition and social adjustment. To a lesser extent, early improvement in neurocognition partially mediated changes in cognitive style (impoverished, disorganized, or rigid) in the CET group but had little influence on social adjustment or social cognition in the CET group. CONCLUSIONS: Most effects of the highly efficacious CET were sustained one year after treatment. Early improvement in processing speed (and perhaps other unassessed aspects of attention) seems to be the principal mediator of CET effects.

Adult↗

PubMed2005

Multivariate modeling of age and retest in longitudinal studies of cognitive abilities.

Longitudinal multivariate mixed models were used to examine the correlates of change between memory and processing speed and the contribution of age and retest to such change correlates. Various age- and occasion-mixed models were fitted to 2 longitudinal data sets of adult individuals (N>1,200). For both data sets, the results indicated that the correlation between the age slopes of memory and processing speed decreased when retest effects were included in the model. If retest effects existed in the data but were not modeled, the correlation between the age slopes was positively biased. The authors suggest that although the changes in memory and processing speed may be correlated over time, age alone does not capture such a covariation.

Age Factors↗

PubMed2005

Predictors of web navigation performance in a life span sample of adults.

The influence of age, subject matter knowledge, working memory, reading abilities, spatial abilities, and processing speed on Web navigation was assessed in a sample of 41 participants between the ages of 19 and 83 years. Each participant navigated a stand-alone tourism Web site to find answers to 12 questions. Performance was measured using time per trial, number of pages per trial, and number of revisited pages per trial. Age did not influence the number of total pages or repeat pages visited, which were predicted by domain knowledge, working memory, and processing speed. Age was associated with slower times per trial, and the effect remained significant after controlling for working memory, processing speed, and spatial abilities. Only with the addition of subject matter knowledge and World Wide Web experience was the age effect eliminated. Actual or potential applications of this research include redesigning Web sites to minimize memory demands and enhance visual segmentation. The data also suggest that age differences in Web navigation can be offset partially by taking advantage of older adults' prior experiences in the domain.

Adult↗

PubMed2006

Cognitive dysfunction in advanced heart failure and prospective cardiac assist device patients.

BACKGROUND: Extended periods of hypoperfusion in an advanced heart failure (HF) places patients at high risk for neurobehavioral compromise, which has not been studied systematically. It is also not clear how intravenous inotropic therapy and mechanical cardiac assist devices (MCAD) affect cognitive function. METHODS: This prospective cross-sectional cognitive preliminary study evaluated 252 potential heart transplant candidates assessing functions in memory, motor, and processing speed. Patients were divided into three HF groups based on severity of disease: group 1 outpatients (n = 113), group 2 in-patients requiring inotropic infusion (n = 83), and group 3 inpatients likely requiring MCAD support (n = 56). Aggregate z-scores for memory, motor, and processing speed and independent samples t tests assessed intergroup differences on 13 cognitive measures. RESULTS: A broad pattern of cognitive impairment was observed within the advanced HF group; fewer deficits were found in group 1 outpatients and more severe deficits in group 3 MCAD subjects. A difference in motor functions was observed as the earliest abnormality, with group 3 showing significant changes compared with group 1. The most dramatic changes were seen in domain mental processing speed along with specific verbal and visual memory functions, which were slower in group 3 compared with groups 1 and 2. CONCLUSIONS: Cognitive deficits are common in advanced HF and worsen with increasing severity of HF. Appropriately designed and randomized studies will be needed to demonstrate if earlier MCAD implantation is warranted to arrest cognitive dysfunction and better postimplantation adaptation.

Adult↗