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Syllogistic reasoning and cognitive ageing.

Gilinsky and Judd (1994) demonstrated that age-related impairment in syllogistic reasoning was in part due to reduced working-memory capacity. A total of 30 older (average age 66 years) and 34 younger persons (average age 24 years) were tested on syllogisms of various types as well as on other measures. Syllogistic reasoning was significantly correlated with education, processing speed, word span, and word fluency. Correlations with visuo-spatial processing and random letter generation were just short of significance. Syllogistic reasoning performance declined with age, although the deficit was no longer statistically significant following control for age-related differences in information-processing speed. On the other hand the inclusion of word fluency as an additional covariate boosted the apparent age effect, returning it to statistical significance. Thus it is possible that cognitive processes outside of working memory might underpin at least part of the apparent age deficit. This possibility is evaluated in the light of neuropsychological evidence implicating the prefrontal cortex in both the processing of syllogisms and more generally in cognitive ageing.

Adult↗

Cognitive deficits in children with gelastic seizures and hypothalamic hamartoma.

OBJECTIVE: To characterize the cognitive deficits in children with gelastic seizures and hypothalamic hamartoma and investigate the relationship of seizure severity to cognitive abilities. METHODS: Eight children with gelastic seizures and hypothalamic hamartoma completed a neuropsychological battery of standardized and age-normed tests, including the Woodcock-Johnson Psycho-Educational Battery-Revised: Tests of Cognitive Ability, Peabody Picture Vocabulary Test-III, and initial-letter word fluency measure. RESULTS: All children displayed cognitive deficits, ranging from mild to severe. Gelastic/complex partial seizure severity was correlated with broad cognitive ability standard scores (r = -0.79; r2 = 0.63; (F[1,6] = 10.28; p = 0.018]. Frequency of gelastic/complex partial seizures was also correlated with broad cognitive ability standard scores (r = -0.72; r2 = 0.52; F[1,6] = 6.44; p = 0.044). Significant intracognitive standard score differences were found, with relative weaknesses in long-term retrieval (mean = 64.1; SD = 13.3) and processing speed (mean = 67.7; SD = 21.6) and a relative strength in visual processing (mean = 97.6; SD = 12.8). Performance in visual processing differed from performance in long-term retrieval (p = 0.009) and processing speed (p = 0.029). CONCLUSION: These findings are consistent with cognitive functions and affective/emotional states associated with conduction pathways of the hypothalamus involving cortical association areas and amygdala and hippocampal formation. These abnormalities can account for the prominent deficit found in integrating information in the processing of memories.

Child↗

Better quality of life with neuropsychological improvement on HAART.

BACKGROUND: Successful highly active antiretroviral therapy (HAART) regimens have resulted in substantial improvements in the systemic health of HIV infected persons and increased survival times. Despite increased systemic health, the prevalence of minor HIV-associated cognitive impairment appears to be rising with increased longevity, and it remains to be seen what functional outcomes will result from these improvements. Cognitive impairment can dramatically impact functional ability and day-to-day productivity. We assessed the relationship of quality of life (QOL) and neuropsychological functioning with successful HAART treatment. METHODS: In a prospective longitudinal study, subjects were evaluated before instituting HAART (naïve) or before changing HAART regimens because current therapy failed to maintain suppression of plasma viral load (treatment failure). Subjects underwent detailed neuropsychological and neurological examinations, as well as psychological evaluation sensitive to possible confounds. Re-evaluation was performed six months after institution of the new HAART regimen and/or if plasma viral load indicated treatment failure. At each evaluation, subjects underwent ultrasensitive HIV RNA quantitative evaluation in both plasma and cerebrospinal fluid. RESULTS: HAART successes performed better than failures on measures exploring speed of mental processing (p < .02). HAART failure was significantly associated with increased self-reports of physical health complaints (p < .01) and substance abuse (p < .01). An interesting trend emerged, in which HAART failures endorsed greater levels of psychological and cognitive complaints (p = .06). Analysis between neuropsychological measures and QOL scores revealed significant correlation between QOL Total and processing speed (p < .05), as well as flexibility (p < .05). CONCLUSION: Our study investigated the relationship between HIV-associated neurocognitive impairment and quality of life. HAART failures experienced slower psychomotor processing, and had increased self-reports of physical health complaints and substance abuse. Contrariwise, HAART successes experienced improved mental processing, demonstrating the impact of successful treatment on functioning. With increasing life expectancy for those who are HIV seropositive, it is important to measure cognitive functioning in relation to the actual QOL these individuals report. The study results have implications for the optimal management of HIV-infected persons. Specific support or intervention may be beneficial for those who have failed HAART in order to decrease substance abuse and increase overall physical health.

Adult↗

Cognitive function in adults with type 2 diabetes and major depression.

The aim of this study was to identify characteristics of neuropsychological functioning among type 2 diabetic adults with and without major depression. Twenty type 2 diabetics with major depression, 20 non-depressed type 2 diabetics and 34 controls without diabetes or depression were compared. A mixed effects repeated measures analysis of covariance indicated significant differences in overall cognitive functioning between diagnostic groups, specifically depressed diabetics demonstrated greater cognitive dysfunction than controls. Further comparisons indicated that depressed diabetics performed significantly worse than non-depressed diabetics in attention/information processing speed. Relative to controls, depressed diabetics performed significantly worse in attention/information processing speed and executive functioning, while there was a trend for non-depressed diabetics to perform worse in executive functioning. These findings suggest that depression negatively impacts cognitive performance among adults with type 2 diabetes, which may have implications for neural circuitry underlying cognitive and mood changes in diabetic patients.

Adult↗

Examining the locus of age effects on complex span tasks.

To investigate the locus of age effects on complex span tasks, the authors evaluated the contributions of working memory functions and processing speed. Age differences were found in measures of storage capacity, language processing speed, and lower level speed. Statistically controlling for each of these in hierarchical regressions substantially reduced, but did not eliminate, the complex span age effect. Accounting for lower level speed and storage, however, removed essentially the entire age effect, suggesting that both functions play important and independent roles. Additional evidence for the role of storage capacity was the absence of complex span age differences with span size calibrated to individual word span performance. Explanations for age differences based on inhibition and concurrent task performamce were not supported.

Adolescent↗

Memory and speed: their role in the relation of infant information processing to later IQ.

This study examined the extent to which memory and processing speed accounted for relations we had found earlier between infant information processing and childhood IQ. The measures of speed and memory were obtained when the children were 11 years of age using paper-and-pencil tasks and an extensive battery of computer-administered tasks. The relations of 7 months visual recognition memory and 1 year cross-modal transfer to 11 year IQ were both substantially reduced with statistical control of factors derived from these measures. These results suggest that speed and memory underlie some of the infant-childhood continuities in cognition. Path and structural equation modeling indicated that the significant pathways from 7 month visual recognition memory to 11 year IQ were both direct and indirect, the indirect paths going through memory and speed.

Age Factors↗

Effects of age and speed of processing on rCBF correlates of syntactic processing in sentence comprehension.

Positron emission tomography (PET) was used to determine the effect of age on regional cerebral blood flow (rCBF) during syntactic processing in sentence comprehension. PET activity associated with making plausibility judgments about syntactically more complex subject object (SO) sentences (e.g., The juice that the child spilled stained the rug) was compared to that associated with making judgments about synonymous syntactically simpler object subject (OS) sentences (e.g., The child spilled the juice that stained the rug). In the first study, 13 elderly (70-80-year-old) subjects showed increased rCBF in the left inferior parietal lobe. This result contrasted with previous studies, which have shown activation in Broca's area in this task in young subjects. Elderly subjects were noted to have longer reaction times than young subjects previously tested. A second study found that young subjects whose reaction times were as long as those of the elderly subjects tested in Experiment 1 activated left superior parietal, and not left inferior frontal, structures. A third experiment found that elderly subjects with reaction times as fast as previously tested young subjects activated left inferior frontal structures. The results suggest that the speed of syntactic processing, but not age per se is related to the neural location where one aspect of syntactic processing is carried out.

Adult↗

The California Verbal Learning Test-Children's Version: relation to factor indices of the Wechsler Intelligence Scale for Children-Third Edition.

The California Verbal Learning Test-Children's Version (CVLT-C) provides clinicians with a method of assessing various aspects of children's verbal memory and has been found to be sensitive to memory deficits resulting from a variety of neurological conditions. Intuitively, the CVLT-C would be expected to be highly related to a child's verbal cognitive abilities; however, with only a few exceptions, the relationship of this test to various domains of cognitive function has not been broadly studied empirically. To examine this issue, we evaluated the amount of unique variance in CVLT-C scores that could be predicted by the Verbal Comprehension, Perceptual Organization, Freedom from Distractibility, and Processing Speed indices of the Wechsler Intelligence Scale for Children, Third Edition (WISC-III) beyond that accounted for by age and gender in a sample of 62 children referred to an outpatient psychiatry clinic for neuropsychological evaluation. While the Processing Speed Index predicted a significant amount of variance for both short and long delay free and cued recall, the Verbal Comprehension Index was a poor predictor of CVLT-C performance on all outcome variables, accounting for only 1.5 to 4.5% additional variance above age and gender. These findings indicate that while the CVLT-C may be relatively independent of influences of verbal intelligence and abstract verbal reasoning, general speed and efficiency of processing play an important role in successful encoding for later retrieval on the CVLT-C.

Adolescent↗

Corpus callosum atrophy is associated with mental slowing and executive deficits in subjects with age-related white matter hyperintensities: the LADIS Study.

BACKGROUND: Previous research has indicated that corpus callosum atrophy is associated with global cognitive decline in neurodegenerative diseases, but few studies have investigated specific cognitive functions. OBJECTIVE: To investigate the role of regional corpus callosum atrophy in mental speed, attention and executive functions in subjects with age-related white matter hyperintensities (WMH). METHODS: In the Leukoaraiosis and Disability Study, 567 subjects with age-related WMH were examined with a detailed neuropsychological assessment and quantitative magnetic resonance imaging. The relationships of the total corpus callosum area and its subregions with cognitive performance were analysed using multiple linear regression, controlling for volume of WMH and other confounding factors. RESULTS: Atrophy of the total corpus callosum area was associated with poor performance in tests assessing speed of mental processing--namely, trail making A and Stroop test parts I and II. Anterior, but not posterior, corpus callosum atrophy was associated with deficits of attention and executive functions as reflected by the symbol digit modalities and digit cancellation tests, as well as by the subtraction scores in the trail making and Stroop tests. Furthermore, semantic verbal fluency was related to the total corpus callosum area and the isthmus subregion. CONCLUSIONS: Corpus callosum atrophy seems to contribute to cognitive decline independently of age, education, coexisting WMH and stroke. Anterior corpus callosum atrophy is related to the frontal-lobe-mediated executive functions and attention, whereas overall corpus callosum atrophy is associated with the slowing of processing speed.

Aged↗

Temporal segmentation of response speed in depression: neuro-electrophysiological approaches.

1. Depressive psychomotor retardation, as observed by delayed reaction times (RT), may be related to a slowing in information processing speed. 2. Two separate studies compared indices of information processing speed in depressed patients and non-clinical controls by segmenting behavioral RT with brain event-related potentials (ERPs) and electromyographic (EMG) responses. 3. In Study I, slower behavioral RTs in depression were concomitant with slower central processing times (CPT) but not motor execution times (MET). 4. In Study II, P165, a putative early cognitive ERP related to 'stimulus evaluation time', was found to be slower but within normal range in depressed patients.

Acoustic Stimulation↗

High-speed memory scanning in Parkinson's disease: adverse effects of levodopa.

High-speed memory scanning as assessed by the Sternberg paradigm was studied in 12 nondemented patients with fluctuating Parkinson's disease and 13 age-matched healthy controls. Patients were first assessed before taking their morning dose of levodopa ("off") and again after that dose had produced full clinical effect ("on") after that dose had produced full clinical effect ("on"). Although motor components of the measured choice reaction time were slower in patients when off than in control subjects, memory scanning speed was not different. After levodopa (on), patients' motor time normalized, but cognitive processing speed became significantly slower when compared with previous performance in the off condition and with controls. Contrary to previous concepts of bradyphrenia in patients with Parkinson's disease, these results indicate that dopaminergic stimulation can reduce cognitive processing speed.

Frontal Lobe↗

Slowed information processing in multiple sclerosis.

Sixteen patients with a definitive diagnosis of multiple sclerosis (MS) and an equal number of matched controls were administered tests of memory and information processing speed. Results indicated a significant long-term verbal memory impairment in patients with MS, with spared short-term memory and memory scanning. Speed of information processing was evaluated with the Paced Auditory Serial Addition Test. The results for the two highest rates of presentation revealed significantly impaired processing in the MS group. Performance at the higher rates and retrieval of information from long-term memory were significantly correlated. These results suggest that slowed information processing is a deficit that contributes to long-term memory impairment in patients with MS.

Adult↗

Do severity and duration of depressive symptoms predict cognitive decline in older persons? Results of the Longitudinal Aging Study Amsterdam.

BACKGROUND AND AIMS: Some prospective studies show that depression is a risk factor for cognitive decline. So far, the explanation for the background of this association has remained unclear. The present study investigated 1) whether depression is etiologically linked to cognitive decline; 2) whether depression and cognitive decline may be the consequence of the same underlying subcortical pathology, or 3) whether depression is a reaction to global cognitive deterioration. METHODS: A cohort of 133 depressed and 144 non-depressed older persons was followed at eight successive observations over 3 years. All subjects were participants in the Longitudinal Aging Study Amsterdam (LASA). Depression symptoms were measured by means of the CES-D at eight successive waves. Cognitive function (memory function, information processing speed, global cognitive functioning) was assessed at baseline and at the last CES-D measurement. RESULTS: The severity and duration of depressive symptoms were not associated with subsequent decline in memory functioning or global cognitive decline. There was an association between both chronic mild depression and chronic depression, and decline in speed of information processing. CONCLUSIONS: These results support the hypothesis that, in older persons, chronic depression as well as cognitive decline may be the consequence of the same underlying subcortical pathology.

Aged↗

Cognitive correlates of 1H MRS measures in the healthy elderly brain.

Ageing is associated with cognitive decline, with some studies indicating that this decline can be mostly accounted for by slowing of information processing speed. Whilst it is likely that this is associated with age-related changes in fronto-subcortical neuronal circuits, such changes are not visible on routine neuroimaging. We examined the integrity of this brain region using proton magnetic resonance spectroscopy (1H MRS) and hypothesised that functional changes measured by 1H MRS would be associated with cognitive performance. Fifty-nine healthy elderly subjects (age 58-85 years) underwent single-voxel 1H MRS in frontal white matter and occipito-parietal gray matter, and a comprehensive neuropsychological battery. The results showed a significant correlation between frontal white matter NAA/H2O and a composite measure of neuropsychological performance representing speed of information processing, attentional function and visual memory, controlling for age and sex. This research highlights the importance of the relationship between regional brain changes and cognitive function in the ageing brain, and suggests that MRS may be a sensitive marker of subclinical change in cognition.

Aged↗

Serum lipid fatty acids and temporal processing acuity in children with oral clefts.

We investigated the relation between a biological factor (fatty acids, FA) and a cognitive processing speed factor (temporal processing acuity, TPA) that are both suggested to relate to neuronal and cognitive functioning. Blood samples of 49 ten-year-old children with oral clefts were collected for FA analysis in serum triglycerides, cholesteryl esters, and phospholipids on the same day as they performed behavioral TPA tasks (simultaneity/nonsimultaneity judgments) in several perceptual modalities (visual, auditory, tactile, audiotactile, visuotactile, and audiovisual). This population has larger than expected variation in the relevant cognitive measures (TPA, learning ability, and intelligence). Sequential regression analyses (adjusted for age, gender, and cleft type) showed that saturated FAs were not generally associated with TPA. Monounsaturated erucic and nervonic acids were inversely related with TPA. Of the polyunsaturated fatty acids, eicosapentaenoic and docosahexaenoic acids were positively associated with TPA, whereas gamma-linolenic acid was inversely related to TPA. In summary, we found significant relations between a biological (certain FAs) and a cognitive factor (TPA).

Auditory Perception↗

Cognitive and clinical predictors of success in vocational rehabilitation in schizophrenia.

Cognitive impairments in schizophrenia appear to be associated with social problem solving, social and vocational functioning, and psychosocial skill acquisition. The present study examined the relationship of cognitive functioning, as well as clinical symptoms, to vocational outcomes among individuals with schizophrenia. One hundred and twelve participants with DSM-IV schizophrenia spectrum diagnoses underwent a comprehensive neuropsychiatric evaluation after enrolling in one of several employment programs. The neuropsychological evaluation examined verbal learning and memory, attention, speed of information processing, and executive functioning. Clinical symptoms were evaluated with the Positive and Negative Syndrome Scale (PANSS). Vocational outcomes were assessed 4 months after baseline assessment and included both measures of employment outcome (e.g., earnings) and of work performance as assessed by the Work Behavior Inventory (WBI). Negative symptoms, learning and memory performance, processing speed, and executive functioning were related to hours, weeks, and wages earned on the job. Stepwise multiple regression analyses found that among baseline clinical and cognitive predictors, only verbal learning and memory and cognitive disorganization symptoms were significant predictors of work behaviors 4 months later. Learning and memory were the only significant predictors of integrated employment at 4 months. These results suggest specific aspects of cognition may be modestly predictive of vocational outcomes.

Achievement↗

Decline in working memory associated with HIV infection. HNRC Group.

HIV infection has been associated with decline in a number of cognitive functions that are components of 'working memory'. Thus, tests of working memory that require the interaction of these components may be particularly sensitive to cognitive dysfunction that arises from HIV infection. To assess this possibility, working memory was examined in 147 HIV-seropositive (HIV+) and 38 HIV-seronegative (HIV-) males using the Reading Span Test and the Digit Span subtest from the Wechsler Memory Scale-Revised (WMS-R). Speed of information processing, a component of some working memory tasks, was assessed with a version of the Sternberg Memory Scanning task. Results indicated that symptomatic HIV+ subjects were impaired relative to HIV- control subjects on the Reading Span and Digit Span tests. Asymptomatic and mildly symptomatic HIV+ groups exhibited a trend toward impairment on these tests, and on the whole, a greater proportion of HIV+ subjects than HIV- subjects were impaired. The groups did not differ significantly in information processing speed. These results indicate that deficits in working memory are apparent in at least a subset of HIV-infected individuals. These deficits are most apparent in symptomatic HIV+ individuals, but the decline may begin during the asymptomatic phase of infection.

Adult↗

Attentional function in secondary school students receiving isoniazid prophylaxis for tuberculosis infection.

Reports have suggested that isoniazid treatment may be associated with poor concentration and subtle reduction in memory. This study examines attentional function and processing speed in a group of 25 adolescents who received isoniazid prophylaxis for at least 6 months. As adolescents often face major educational assessment milestones, such cognitive side effects may have important implications. Participants were assessed before treatment, 1 month into treatment and at least 1 week after treatment cessation. Measures included the Paced Auditory Serial Addition Test and subtests of the appropriate Wechsler scale sensitive to attention and speed of information processing. Isoniazid does not appear to cause significant adverse effects on attentional function in adolescents.

Adolescent↗