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PubMedDate not supplied

Two-year decline in vision but not hearing is associated with memory decline in very old adults in a population-based sample.

BACKGROUND: Recent cross-sectional research in cognitive aging has demonstrated a robust association between visual acuity, auditory thresholds and cognitive performance in old age. However, the nature of the association is still unclear, particularly with respect to whether sensory and cognitive function are causally related. OBJECTIVE: This study aimed to determine whether marked declines in performance on screening measures of either visual acuity or auditory thresholds have an effect on cognitive decline over 2 years. METHODS: The sample from the Australian Longitudinal Study of Ageing (n = 2,087) were assessed in 1992 and 1994 on measures of sensory and cognitive function as part of a larger clinical assessment. A quasi-experimental design involving comparison of extreme groups using repeated measures MANCOVA with age as a covariate was used. RESULTS: Group performance on measures of hearing, memory, verbal ability and processing speed declined significantly. Decline in visual acuity had a significant effect on memory decline, but not on decline in verbal ability or processing speed. Decline in hearing was not associated with decline in any cognitive domain. CONCLUSION: The common association between visual acuity, auditory thresholds and cognitive function observed in cross-sectional studies appears to be disassociated in longitudinal studies.

Aged↗

PubMedDate not supplied

Cross-cultural similarities in the predictors of reading acquisition.

Measures of Chinese character/English word recognition, phonological awareness, speeded naming, visual-spatial skill, and processing speed were administered to 190 kindergarten students in Hong Kong and 128 kindergarten and grade 1 students in the United States. Across groups, the strongest predictor of reading itself was phonological awareness; visual processing did not predict reading. For both groups, speed of processing strongly predicted speeded naming, visual processing, and phonological awareness. Despite diversities of culture, language, and orthography to be learned, models of early reading development were remarkably similar across cultures and first and second language orthographies.

Child↗

PubMed1997

Serial neuropsychological assessment and magnetic resonance imaging analysis in multiple sclerosis.

OBJECTIVE: To assess the correlation between cognitive dysfunction and disease burden in multiple sclerosis (MS) during a 1-year period. DESIGN: The Brief, Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis was performed at entrance and 1 year. Patients underwent at least 20 proton density (range, 20-24) and T2-weighted axial magnetic resonance imaging (MRI) brain scans except for stable patients who were scanned monthly. Magnetic resonance imaging was evaluated using computer-automated, 3-dimensional volumetric analysis. SETTING: A research clinic of a university hospital. PATIENTS: Forty-four patients with MS of the following disease categories: relapsing-remitting (14), relapsing-remitting progressive (12), chronic progressive (13), and stable (5). MAIN OUTCOME MEASURES: The relationships between scores on the Brief, Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis and 2 MRI measures (total lesion volume and brain to intracranial cavity volume ratio) were assessed using linear regression. These MRI measures were also compared with cognitive status at 1 year using analysis of variance. RESULTS: Overall, there was no decline in mean cognitive test performance during 1 year. Significant correlations were found between baseline neuropsychological test scores of nonverbal memory, information-processing speed, and attention and both MRI measures. Patients with chronic progressive MS demonstrated the strongest correlations. At 1 year, change in information-processing speed and attention correlated with change in total lesion volume. The mean increase in total lesion volume was 5.7 mL for 4 patients whose cognitive status worsened compared with 0.4 mL for 19 patients who improved and 0.5 mL for 21 patients who remained stable. CONCLUSIONS: During a 1-year period mean cognitive performance did not worsen. Automated volumetric MRI measures of total lesion volume and brain to intracranial cavity volume ratio correlated with neuropsychological performance, especially in patients with chronic progressive MS. Worsening MRI lesion burden correlated with cognitive decline.

Adult↗

PubMedDate not supplied

Formulation of enterosoluble microparticles for an acid labile protein.

PURPOSE: A microencapsulation method that preserves the activity of an acid labile protein was developed. METHODS: Solvent evaporation technique that employed ICH class 2 and 3 solvents methanol and acetone, respectively to dissolve pH-sensitive Eudragit polymers was investigated. Total protein released and lactase activities were measured using the USP method A for enteric cores and optimized with respect to process parameters. RESULTS: The percentage yields and entrapment efficiencies were directly proportional to solid content. The mean percentage yield and entrapment efficiency of selected sample was 84 +/- 0.9% and 88 +/- 0.7%, respectively. The residual specific activity of lactase in the selected sample was 89% +/- 0.8 with a net activity loss of 2 +/- 0.28% and 4 +/- 0.52% under ambient and stressed storage, respectively. Dibutyl sebacate levels, lower processing temperatures and lower processing speeds were influential in modulating enzyme activity. The most important formulation factor affecting lactase stability was Eudragit type, followed in decreasing order by processing temperature, processing speed, and solid percentage. CONCLUSIONS: Reliable control of lactase release was achieved by microencapsulating the enzyme with pH-sensitive Eudragit L and S enteric polymers using either acetone- or methanol-based solvent but lactase activity was preserved only in acetone-based formulations.

Acetone↗

PubMed1989

Differential cognitive effects of terfenadine and chlorpheniramine.

The H1-histamine antagonist, terfenadine, has been proposed to have reduced cognitive side effects. In the present study, the relative cognitive effects of terfenadine, 60 mg, chlorpheniramine maleate, 8 mg, and placebo were tested with a double-blind, randomized, three-period crossover design in 24 healthy adult subjects. The dependent variable was latency of the P3-evoked potential. The P3 is a cognitively evoked electroencephalographic response that is an objective and sensitive measure of sustained attention and cerebral processing speed. Disease and drug states that adversely affect the central nervous system can slow P3 latency. For example, the centrally active anticholinergic scopolamine slows cognitive processing speed and prolongs P3 latency. P3 latency (millisecond) means (+/- mean standard error) were pretreatment, 310 (+/- 1.7; placebo, 313 (+/- 3); terfenadine, 320 (+/- 3); and chlorpheniramine, 333 (+/- 3). The findings suggest that terfenadine may be particularly advantageous in patients who require alertness and intact cognitive abilities.

Adult↗

PubMed2001

A reevaluation of the common factor theory of shared variance among age, sensory function, and cognitive function in older adults.

The common cause hypothesis of the relationship among age, sensory measures, and cognitive measures in very old adults was reevaluated. Both sensory function and processing speed were evaluated as mediators of the relationship between age and cognitive function. Cognitive function was a latent variable that comprised 3 factors including memory, speed, and verbal ability. The sample was population based and comprised very old adults (n = 894; mean age = 77.7, SD = 5.6 years) from the Australian Longitudinal Study of Ageing. The results showed that there was common variance in the cognitive factor shared by age, speed, vision, and hearing but that specific effects of age on cognition remained. Furthermore, speed did not fully mediate the effect of age or sensory function on cognition. Some age differences in cognitive performance are not explained by the same processes that explain age differences in sensory function and processing speed.

Aged↗

PubMed2003

The effects of adjunctive topiramate on cognitive function in patients with epilepsy.

PURPOSE: We investigated possible cognitive effects of topiramate (TPM) in polypharmacy on patients with intractable epilepsy. METHODS: Study 1 evaluated 22 consecutively admitted patients whose antiepileptic drugs (AEDs) on admission to the Montreal Neurological Hospital included TPM. Performance on neuropsychological tests administered on and subsequently off TPM was analyzed. Four patients also were tested before taking TPM, allowing comparisons off, then on, and then off the drug again. Measures included intellectual function, verbal and nonverbal memory, language, word and design fluency, somatosensory sensitivity, and motor skills. In Study 2, 16 patients at the Minnesota Epilepsy Group were tested first off, then on TPM with nine cognitive tasks that measured concentration, verbal fluency, language, and psychomotor speed. RESULTS: In Study 1, significant (p < or = 0.01) improvements were observed off TPM on 13 measures including verbal and nonverbal fluency and certain verbal and perceptual tasks. Notably, verbal learning and memory were unaffected; a limited effect was observed on nonverbal memory. Patients tested 3 times scored better in both tests off TPM compared with on this drug. In Study 2, declines on TPM were observed on all measures, significantly (p < or = 0.05) for tests of fluency, sustained concentration, and visual motor processing speed. CONCLUSIONS: TPM was associated with declines in fluency, attention/concentration, processing speed, language skills, and perception; working memory but not retention was affected. As the two studies used an opposite order of testing on versus off TPM, our results clearly show a performance decrement while patients are taking TPM, without respect to which condition is tested first.

Adolescent↗

PubMed1996

Does melatonin have an effect on cognitive performance?

Exogeneous melatonin causes phase shifts of circadian rhythms, reduces core body temperature, and induces drowsiness, but dispute still surrounds the hormone's effect on cognitive performance. Using a N = 1 double-blind alternating treatments design, daytime performance on four cognitive tests (logical reasoning, serial add/subtract, visual-spatial, and four-choice reaction time tasks) was measured after PO doses of placebo and 1.6 mg melatonin. Serum melatonin and core body temperature were also recorded. Performance was measured during time windows corresponding to the serum melatonin peak and the temperature trough respectively, following melatonin administration. The data showed that performance speed and accuracy measures were not affected during the serum melatonin peak, but that reaction times on all cognitive tasks increased substantially during the temperature trough. These results suggest that circulating melatonin has no direct and immediate effect on cortical information processing, and that the reduction in cognitive processing speed during body temperature trough occurs as a consequence of the hormone's hypothermic properties, causing a slowing down of cerebral processing speed.

Adult↗

PubMed2001

A comparison of the neuropsychological profiles of the DSM-IV subtypes of ADHD.

Recent research on the DSM-IV subtypes of attention-deficit/hyperactivity disorder (ADHD) has demonstrated that the subtypes differ in demographic characteristics, types of functional impairment, and profiles of comorbidity with other childhood disorders. However, little research has tested whether the subtypes differ in underlying neuropsychological deficits. This study compared the neuropsychological profiles of children without ADHD (n = 82) and children who met symptom criteria for DSM-IV Predominantly Inattentive subtype (ADHD-IA; n = 67), Predominantly Hyperactive Impulsive subtype (ADHD-HI; n = 14), and Combined subtype (ADHD-C; n = 33) in the areas of processing speed, vigilance, and inhibition. We hypothesized that children with elevations of inattention symptoms (ADHD-IA and ADHD-C) would be impaired on measures of vigilance and processing speed, whereas children with significant hyperactivity/impulsivity (ADHD-HI and ADHD-C) would be impaired on measures of inhibition. Contrary to prediction, symptoms of inattention best predicted performance on all dependent measures, and ADHD-IA and ADHD-C children had similar profiles of impairment. In contrast, children with ADHD-HI were not significantly impaired on any dependent measures once subclinical symptoms of inattention were controlled. Our results do not support distinct neuropsychological deficits in ADHD-IA and ADHD-C children, and suggest that symptoms of inattention, rather than symptoms of hyperactivity/impulsivity, are associated with neuropsychological impairment.

Adolescent↗

PubMed2000

Age-sensitive cognitive function, growth hormone and insulin-like growth factor 1 plasma levels in healthy older men.

Circulating levels of growth hormone (GH) change during the process of aging. Decline of cognitive functioning with aging is also well established. In this study, we investigated whether insulin-like growth factor 1 (IGF-1) and the GH response to a challenge of GH-releasing hormone and GH-releasing peptide 6 were associated with age-sensitive cognitive functions, but not with functions that do not decline with aging, in 17 healthy male subjects aged between 66 and 76 years. In addition, relations with anthropometric measures were examined. Neuropsychological performance was scored on tests of variables not sensitive to aging (general knowledge, vocabulary, basic visual perception and reading ability), and of variables sensitive to aging (visuoconstructive ability, perceptual motor and mental processing speed, and verbal long-term memory). After correcting for education, the serum GH response was significantly associated with two age-sensitive cognitive tests (measures of mental processing speed), but with none of the tests not sensitive to aging. However, the direction of the association was opposite to the relation between IGF-1 and these cognitive tests: higher levels of GH response were associated with poorer cognitive performance, whereas higher levels of IGF-1 were associated with better performance. GH response, but not IGF-1, was inversely correlated with body mass index. The results are in accordance with previous research suggesting a disruption of the relation between IGF-1 and GH secretion in older age.

Aged↗

PubMed1995

Cognitive mediation of adult age differences in language performance.

Young (M = 20 years) and old (M = 68 years) adults completed language processing tasks, measures of working memory capacity (backward span and the n-back lag task), inhibitory efficiency (Stroop interference), and processing speed (color naming). regression analyses revealed that each of the resource measures significantly predicted language performance and attenuated variance in language performance that would otherwise be attributed to age. When speed variance was entered into the equation first, the mediating influence of the inhibition and working memory measures remained significant. When speed and inhibition differences were controlled, the working memory measures could not reliably predict language performance. These results suggest that language performance differences may be fundamentally mediated by age differences in processing speed and inhibitory efficiency.

Adolescent↗

PubMed2002

Older age, traumatic brain injury, and cognitive slowing: some convergent and divergent findings.

Reaction time (RT) meta-analyses of cognitive slowing indicate that all stages of processing slow equivalently and task independently among both older adults (J. Cerella & S. Hale, 1994) and adults who have suffered a traumatic brain injury (TBI; F. R. Ferraro, 1996). However, meta-analyses using both RT and P300 latency have revealed stage-specific and task-dependent changes among older individuals (T. R. Bashore, K. R. Ridderinkhof, & M. W. van der Molen, 1998). Presented in this article are a meta-analysis of the effect of TBI on processing speed, assessed using P300 latency and RT, and a qualitative review of the literature. They suggest that TBI induces differential slowing. Similarities in the effects of older age and TBI on processing speed are discussed and suggestions for future research on TBI-induced cognitive slowing are offered.

Adult↗

PubMed1995

Neuropsychological impairments in chronic fatigue syndrome, multiple sclerosis, and depression.

To examine the degree and nature of cognitive impairments in chronic fatigue syndrome, a comprehensive neuropsychological battery was given to patients with chronic fatigue syndrome, multiple sclerosis, depressed patients, and healthy controls. The battery included tests of attention and concentration, information processing speed, verbal and visual memory, intellectual ability, and concept formation. Measures of depression and anxiety were also obtained. The chronic fatigue syndrome group did not differ from the depressed group in overall neuropsychological performance, but differed from the multiple sclerosis and control groups. The most significant impairment was in information processing speed in the chronic fatigue syndrome group. Depression and anxiety were not related to neuropsychological performance. The influence of reduced information processing on other areas of cognition is discussed.

Adult↗

PubMed2002

Cognitive functioning and quality of life in long-term adult survivors of bone marrow transplantation.

BACKGROUND: The late neurotoxic effects of bone marrow transplantation (BMT) on cognitive functioning and quality of life (QOL) were investigated in a consecutively treated cohort of long-term adult survivors. METHODS: Progression-free patients treated with BMT or peripheral stem cell grafts for a hematologic malignancy at least 2 years before study participation were examined with a comprehensive battery of neuropsychological tests and questionnaires for QOL and mood states. The results of the neuropsychological tests were compared with healthy population norms. RESULTS: Forty patients were included, 87.5% of whom had undergone an allogeneic transplantation. All received total body irradiation up to 12 Gy (in two fractions). Assessment took place 22-82 months after BMT. Mild to moderate cognitive impairment was found in 24 patients (60%). Compared with healthy population norms, selective attention and executive function, information processing speed, verbal learning, and verbal and visual memory were most likely to be affected. The mean score for the total patient group revealed that these patients scored significantly lower on the information processing speed task compared with expected scores obtained from the normal population. The main predictors for poor neuropsychological performance were fatigue, global health, and educational level. Other correlations with moderate to severe cognitive impairment were subjective cognitive complaints, physical functioning, social functioning, overall mood states, and employment status. CONCLUSIONS: These data indicate that BMT may lead to cognitive complaints and late cognitive deficits in long-term adult survivors. Cognitive functioning should therefore be used as an outcome parameter in BMT studies.

Adolescent↗

PubMed2003

Speed of information processing after unilateral stroke.

Speed of information processing in the subacute stage after stroke was studied in 88 first ever, unilateral, ischemic stroke patients. The patient group included 42 right and 46 left hemisphere patients. Seventy-one control subjects were also examined. Four reaction time tasks with different levels of complexity were used: two visuomotor, and two semantic categorisation tasks. The results showed that stroke causes a decrease in decision making speed, but that the effect is different for right and left hemisphere patients. The right hemisphere group were slower than the control group on all reaction time tasks, and slower than the left hemisphere patients on the visuomotor tasks. The left hemisphere patients were slower than the healthy controls, only on the most complex tasks, the categorisation tasks.

Adult↗

PubMed1999

Speech-reading: cognitive predictors and displayed emotion.

The present study had three aims: to examine the effects of displayed emotion and message length on speech-reading performance, and how measures of working memory (cf. Baddeley 1986) and verbal information processing speed relate to speech-reading performance. Words and sentences with either positive or negative meaning were used in a word decoding and a sentence-based speech-reading test. A total of 48 normal-hearing subjects participated. The results revealed general effects of displayed emotion, message meaning and message length and no effect of displayed emotion vs message length. Furthermore, working memory but not verbal information processing speed nor accuracy predicted speech-reading performance. The results were discussed with respect to a model of face-processing (Bruce & Young 1986) and with respect to clinical implications.

Adult↗

PubMed1994

Analysis of adult age differences on the Raven's Advanced Progressive Matrices Test.

The purpose of this project was to examine the nature of performance, and specifically, age-related performance, on the Raven's Advanced Progressive Matrices (APM) Test (Raven, Court, & Raven, 1983). In the 1st of 2 studies, 2 tests presumed to measure each of 4 hypothesized components of the APM and 3 tests presumed to measure processing speed were presented to 165 young adults. On the basis of correlational and confirmatory analyses, 1 of the components was not included in Study 2. The 2nd study was designed to examine the influence of the 3 remaining components, processing speed, and working memory on the individual and age-related differences on the APM. Participants included 183 adults between the ages of 21 and 83. The results suggest that although all 3 components are important to performance on the APM, rule application tasks seem to hold the most promise in accounting for age-related variance on the APM.

Adult↗

PubMed2001

Inhibitory control across the life span.

Findings from previous research suggest that inhibitory control improves during early childhood and declines during late adulthood. Very few researchers, however, have examined life-span changes in this ability in single studies. Within this life-span context, we investigated 1 type of inhibitory control--the ability to inhibit aprepotent response and generate an incompatible response--in individuals ranging from 6 to 82 years of age. Examination of raw reaction time data revealed a significantly larger inhibitory control effect for children and older adults than for young adults. Using proportional and z score transformations, we demonstrated that a processing speed explanation is sufficient to account for the differences in performance between children and young adults; this explanation, however, did not adequately explain the discrepancy between young and older adults. Taken together, these findings suggest that, above and beyond differences in processing speed, inhibitory control was less efficient in older adults. Our findings are consistent with the assertion that inhibitory control develops quite early and declines at the later end of the developmental spectrum.

Adolescent↗