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PubMed2006

Norwegian norms and factor-structure of phonemic and semantic word list generation.

Word list generation (WLG) tasks are used world wide as measures of executive function, although the tests are sensitive also to deficits in other cognitive functions. Norms derived from English-speaking samples are often used in Norway, even though the consequences of language differences are not yet been assessed. The reliability of WLG testing in Norway is increased by the norms presented in the first part of the study. The validity of WLG tests as measures of executive function is addressed in the second part, by performing a factor-analysis of neuropsychological performance in a mixed psychiatric sample. Education contributed most to performance. There were no sex-differences in overall performance. Factor analysis indicated that phonemic WLG is a more specific measure of executive function than semantic WLG. Semantic WLG correlated higher with basal processing speed, thus being more sensitive to aging. In conclusion the clinical neuropsychologist is advised to control for reduction in basal processing speed before interpreting WLG scores as specific deficits in executive function. The Norwegian norms correspond well with most comparable studies in other languages, thus failing to show any language specific effects.

Adolescent↗

PubMed1993

Prenatal alcohol exposure and infant information processing ability.

403 black, inner-city infants born to women recruited prenatally on the basis of their alcohol consumption during pregnancy were assessed on a battery focusing on information processing and complexity of play. Prenatal alcohol exposure was not related to visual recognition memory or cross-modal transfer of information but was associated with longer fixation duration, a measure indicative of slower, less efficient information processing; lower scores on elicited play; and longer periods of toy exploration, possibly also due to slower cognitive processing. The effects on processing speed and elicited play were dose-dependent and not attributable to maternal depression, parental intellectual stimulation, other prenatal drug exposure, or postpartum maternal drinking. The processing speed deficit is consistent with deficits in older children prenatally exposed to alcohol; the present study is the first to identify slower cognitive processing in infancy and in tasks not dependent on motoric proficiency.

Adolescent↗

PubMed1992

Visual expectation and dimensions of infant information processing.

Visual expectation was assessed in 103 black 6.5-month-olds using Haith, Hazan, and Goodman's paradigm and related to performance on standard developmental assessments and tests of information processing skill. As expected, percent anticipations was higher and RT lower than in 3.0-month-olds previously tested. Split-half and left-right correlations for the RT measures were moderate and similar to those previously reported, as was split-half reliability for percent anticipations. The 2 RT measures were related to fixation duration on both visual recognition memory (VRM) and cross-modal transfer, suggesting moderate cross-task and cross-age consistency in processing speed. Percent anticipations and baseline RT each contributed independently to the prediction of VRM novelty preference. Data from a factor analysis suggested 3 dimensions of cognitive function: processing speed, developmental level, and memory/attention. These findings suggest that the visual expectation paradigm provides a reliable new approach for assessing cognitive processing efficiency and attention during infancy.

Black or African American↗

PubMed2006

What do semi-illiterate adults know about 2-digit Arabic numbers?

Brazilian semi-illiterates (n=19) with 1 to 4 years of academic training compared 2-digit Arabic numbers. Like competent readers, semi-illiterates responded faster and more accurately when the larger number also had the larger unit digit (unit-decade compatibility). Even semi-illiterates with minimal academic training were sensitive to the unit-decade compatibility on number comparison. Probably semi-illiterates derive their ability to automatically activate unit-decade segmentation directly from the oral/verbal number representation. Interestingly, processing speed had an effect on two-digit number comparison. Faster participants showed a smaller or even inverted unit-decade compatibility. Processing speed reflects increased automatization of number segmentation and better selection of the decade-digits for comparison, what eliminates the semantic interference of units. In line with previous research, our data suggest that unit-decade segmentation plays a pervasive role in Arabic number comparison.

Adolescent↗

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↗

PubMed2004

Rapid adaptation to foreign-accented English.

This study explored the perceptual benefits of brief exposure to non-native speech. Native English listeners were exposed to English sentences produced by non-native speakers. Perceptual processing speed was tracked by measuring reaction times to visual probe words following each sentence. Three experiments using Spanish- and Chinese-accented speech indicate that processing speed is initially slower for accented speech than for native speech but that this deficit diminishes within one minute of exposure. Control conditions rule out explanations for the adaptation effect based on practice with the task and general strategies for dealing with difficult speech. Further results suggest that adaptation can occur within as few as two to four sentence-length utterances. The findings emphasize the flexibility of human speech processing and require models of spoken word recognition that can rapidly accommodate significant acoustic-phonetic deviations from native language speech patterns.

Adaptation, Psychological↗

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↗

PubMed2006

Attentional processes discriminate between patients with mild Alzheimer's disease and cognitively healthy elderly.

BACKGROUND: It is generally accepted that Alzheimer's disease (AD) is mainly characterized by memory disorders. Although recent studies also point to an important role of attention deficits early in the disease, this notion has not yet emerged in clinical practice. Our aim was to assess whether attention, quantified by reaction times, can discriminate between patients with mild AD and controls and therefore contribute to clinical diagnosis. METHODS: In a cross-sectional study, 33 patients with mild AD were matched with cognitively healthy elderly controls for age, gender, educational level and depressive mood. Selective attention (SA), alternating attention (AA) and error-rates were measured by a modified reaction time test. RESULTS: Significant differences between both groups were found for all measures. Logistic regression showed that SA (corrected for individual processing speed) and error-rates could correctly classify subjects with an overall hit ratio of 81%. When attention measures were not corrected for individual processing speed, the overall hit ratio improved to 97%. CONCLUSION: SA and AA deteriorate in patients with mild AD and these measures can be used to discriminate between patients and matched controls, independently of depressive mood.

Aged↗

PubMed2005

Applying a psychoeducational perspective to ADHD.

This article examines whether various cognitive abilities are associated with symptoms of ADHD. Cognitive ability is conceptualized using Cattell-Horn-Carroll (CHC) theory as measured using the Woodcock-Johnson Tests of Cognitive Ability (3rd ed.). This article also examines whether test session behavior mediates the association between cognitive ability and ADHD. Participants are children ages 6 to 12 with (n= 33) and without (n= 19) ADHD. Results show that inattentive symptoms of ADHD are significantly related to the CHC ability of processing speed above and beyond the effect of test session behavior. Symptoms of ADHD (both inattention and hyperactivity/impulsivity) are also significantly associated with visual spatial processing, but this is completely mediated by test session behavior. It is concluded that inattentive symptoms of ADHD are associated with slower processing speed and that this relationship is not explained by test session behavior.

Achievement↗

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↗

PubMedDate not supplied

Basal ganglia volumes following CO poisoning: A prospective longitudinal study.

Carbon monoxide (CO) poisoning may result in focal and diffuse neuropathological changes, including basal ganglia lesions. The effect of CO poisoning on basal ganglia volumes over time is unclear. We assessed basal ganglia volumes longitudinally following CO poisoning. We prospectively enrolled 73 CO poisoned patients who underwent brain MR imaging on day 1 (baseline), 2 weeks, and 6 months post-CO poisoning. Basal ganglia volumes were obtained. One patient had bilateral globus pallidus lesions at two weeks and 6 months. Of the CO-poisoned patients 28% had volume reduction in at least one basal ganglia structure by 6 months, of which 21% had putamen, 15% had caudate, 15% had globus pallidus, and 16% had total basal ganglia volume reduction. Putamen volumes were significantly smaller from baseline to six months (p = 0.02). Verbal memory and mental processing speed correlated with smaller putamen and globus pallidus volumes. Carbon monoxide poisoning results in basal ganglia volume reduction 6 months post CO poisoning. Slow mental processing speed and impaired memory correlated with smaller putamen and globus pallidus volumes. Clinicians need to be aware of basal ganglia neuropathologic changes in the absence of observable lesions following CO poisoning.

Adolescent↗

PubMed2005

Correction of MR image distortions induced by metallic objects using a 3D cubic B-spline basis set: application to stereotactic surgical planning.

Metallic implants in MRI cause spin-echo (SE) images to be distorted in the slice and frequency-encoding directions. Chang and Fitzpatrick (IEEE Trans Med Imaging 1992;11:319-329) proposed a distortion correction method (termed the CF method) based on the magnitude images from two SE acquisitions that differ only in the polarity of the frequency-encoding and slice-selection gradients. In the present study we solved some problems with the CF method, primarily by modeling the field inhomogeneities as a single 3D displacement field built by 3D cubic B-splines. The 3D displacement field was applied in the actual distortion direction in the slice/frequency-encoding plane. To account for patient head motion, a 3D rigid body motion correction was also incorporated in the model. Experiments on a phantom containing an aneurysm clip showed that the knot spacing between the B-splines is a very important factor in both the final image quality and the processing speed. Depending on the knot spacing and the image volume size, the number of unknowns range from a few thousands to over 100,000, leading to processing times ranging from minutes to days. Optimal knot spacing, a means of increasing the processing speed, and other parameters are investigated and discussed.

Algorithms↗

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↗

PubMed2005

A neuropsychological investigation into violence and mental illness.

Previous research has reported cognitive impairment in patients with schizophrenia and antisocial personality disorder (APD), the two psychiatric illnesses most implicated in violent behaviour. Previous studies have focused on either group exclusively, and have been criticized for procedural inadequacies and sample heterogeneity. The authors investigated and compared neuropsychological profiles of individuals with APD and violent and nonviolent individuals with schizophrenia in a single investigation. The study involved four groups of subjects: (i) individuals with a history of serious violence and a diagnosis of APD, (ii) individuals with a history of violence and schizophrenia, (iii) individuals with schizophrenia without a history of violent behaviour and (iv) healthy control subjects. All study groups were compared on a neuropsychological battery designed to assess general intellectual function, executive function, attention, and processing speed. Cognitive deficits were more widespread among individuals with schizophrenia regardless of history of violence, compared with those with APD. Significant impairment in patients with APD was limited to processing speed. Violent individuals with schizophrenia demonstrated poorer performance than their nonviolent schizophrenia peers on a measure of executive function. Different cognitive impairments are manifested by individuals with APD and schizophrenia with violent behaviours, suggesting differences in underlying pathology. Furthermore, cognitive impairment appears to be more a feature of schizophrenia than of violent behaviour, although there is evidence that a combination of schizophrenia and violent behaviour is associated with greater cognitive deficits.

Adolescent↗