SEARCH · PubMed Health

Results for “processing speed”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources

PubMed1992

Category knowledge in Alzheimer's disease: normal organization and a general retrieval deficit.

Three hypotheses that could account for deficits in the retrieval of category information in Alzheimer's disease (AD) were evaluated: abnormal organization, class- or category-specific vulnerability, and limitation by general factors, such as decreased processing speed. Relative to 18 elderly control subjects, 18 patients with AD produced fewer items in a category fluency task and had longer reaction times in a category decision task. The pattern of performance across categories on both tasks was normal in the AD group: The same categories elicited the most (or fastest) responses in both the control group and the AD group. AD patients showed normal performance in ranking of category exemplars by typicality. There was no evidence for differential accessibility by category or by class of information (animate vs. inanimate). The authors conclude that a general factor or factors limit(s) retrievability equally across all categories.

Aged↗

PubMed1994

Memory knowledge and memory monitoring in adulthood.

Age differences in 2 specific processing dimensions of metamemory, namely memory knowledge and memory monitoring, were examined. Young and old Ss recalled lists of words paired with letter, rhyme, and meaning cues over 2 trials. On both trials, Ss made predictions of recall likelihood on presentation of each word-cue pair. No age differences in initial predictions (i.e., prior memory knowledge) were apparent, whereas age-based performance differences were observed. On Trial 2, both young and old Ss significantly revised their predictions; however, old adults monitored only global discrepancies between previous expectation and performance. Young adults raised and lowered expectations across cue types in accordance with their previous performance. Age differences in processing speed accounted for some but not all of the memory-monitoring differences.

Adolescent↗

PubMed2002

Individual differences in latent neuropsychological abilities at addictions treatment entry.

The latent structure of neuropsychological abilities and risk factors for impairment were examined in 197 persons entering addictions treatment. Confirmatory factor analysis yielded 4 factors: Executive, Memory, Verbal, and Processing Speed. The measurement model was consistent with evidence that neuropsychological test performance is factorially complex and supported by multiple brain regions. Path analyses showed that risk factors explained 34%-57% of the true variance in abilities. Age, education, and medical status had the most generalized and robust associations with abilities. Drug use disorder diagnoses, childhood behavior problems, familial alcoholism, and psychopathology were also significantly related to specific latent abilities. Knowledge of neuropsychological impairment may be clinically useful, and selected risk factors may help treatment providers decide which clients should receive formal neuropsychological assessment.

Adult↗

PubMed2000

The cognitive correlates of white matter abnormalities in normal aging: a quantitative review.

Cerebral white matter of asymptomatic people frequently exhibits circumscribed areas of hyperintensity on magnetic resonance (MR) images and hypodensity on computed tomography scans. However, behavioral implications of this phenomenon remain unclear. In this meta-analysis, the authors examine cumulative evidence regarding the cognitive sequelae of white matter abnormalities in adults without dementia. The influence of potential moderator variables, such as neuroimaging technique, location of the lesions, rating scale, and demographic characteristics of the sample on the association between the burden of white matter hyperintensities and cognitive performance was also examined. Results indicate that white matter abnormalities observed on MR images are associated with attenuated performance on tasks of processing speed, immediate and delayed memory, executive functions, and indices of global cognitive functioning. There was no significant link between the white matter hyperintensities and psychometric indices of intelligence or fine motor performance.

Adult↗

PubMed2001

The frequency of reliable component difference scores for the Wechsler Intelligence Scale for Children--Third edition in two samples.

The cumulative percentage frequencies are presented for differences among reliable component analysis (RCA) scores for the verbal comprehension, perceptual organization, freedom from distractibility, and processing speed constructs assessed by the Wechsler Intelligence Scale for Children--Third edition (WISC-III) for the standardization sample and a learning disabled sample. Using RCA scores to form differences has several advantages over traditional equally weighted scores for the WISC-III. J. C. Caruso and N. Cliff (2000) presented tables to assess the statistical significance of differences among the RCA scores for the WISC-III. It is important, however, to use a dual approach in interpreting difference scores; both the statistical significance of a difference and the frequency with which it occurred in a relevant comparison group should be determined. This article contains the information necessary for practitioners to use the recommended dual approach to interpreting RCA difference scores for the WISC-III.

Adolescent↗

PubMed2004

Effects of subclinical depression and aging on generative reasoning about linear orders: same or different processing limitations?

The performance of older adults and depressed people on linear order reasoning is hypothesized to be best explained by different theoretical models. Whereas depressed younger adults are found to be impaired in generative inference making, older adults are well capable of making such inferences but exhibit problems with working memory (Experiments 1 and 2). Restriction of the available study time impairs reasoning by nondepressed control participants and. as such, proves to be a good model of older adults' but not depressed participants' limitations (Experiment 3). These results are replicated comparing depressed and older participants with a control group in the same study, providing increased power and linking the results to additional control measures of processing speed and working memory (Experiment 4).

Adolescent↗

PubMed2004

Executive functioning, memory, and learning in phenylketonuria.

The executive deficit hypothesis of treated phenylketonuria (PKU) suggests that dopaminergic depletion in the lateral prefrontal cortex leads to selective executive impairment. This was examined by comparing adults with PKU on a lifelong diet with a matched healthy control group. Those with PKU were impaired on selective and sustained attention, working memory (Self-Ordered Pointing), and letter fluency. However, they failed to show differential sensitivity to increased cognitive load on the attentional and working memory tasks, and they did not differ significantly on the remaining executive tasks (rule finding, inhibition, and multitasking). Nor did they differ significantly on recall or recognition memory. Overall, the findings provided little support for the executive deficit hypothesis. A possible explanation in terms of slowed information processing speed is explored.

Adolescent↗

PubMed2005

Anoxic versus traumatic brain injury: amount of tissue loss, not etiology, alters cognitive and emotional function.

Research in neuropsychology suggests that the etiology of a neurologic injury determines the neuropathological and neuropsychological changes. This study compared neuropsychological outcome in subjects who had traumatic brain injury (TBI) with subjects who had anoxic brain injury (ABI), who were matched for age, gender, and ventricle-to-brain ratio. There were no group differences for morphologic or neuropsychological measures. Both groups exhibited impaired memory, attention, and executive function, as well as slowed mental processing speed. Intelligence correlated with whole brain volume, and measures of memory correlated with hippocampal atrophy. There was no unique contribution of hippocampal atrophy on neuropsychological outcome between the groups. In the absence of localized lesions, the amount of neural tissue loss, rather than etiology, may be the critical factor in neuropsychological outcome.

Adult↗

PubMed2006

Neuropsychological functioning in posttraumatic stress disorder and alcohol abuse.

Studies have shown differences in neuropsychological functioning between groups with posttraumatic stress disorder (PTSD) and control participants. Because individuals with PTSD often have a history of comorbid alcohol abuse, the extent to which an alcohol confound is responsible for these differences remains a concern. The current study compares neuropsychological testing scores in 4 groups of veterans with and without PTSD (PTSD+ and PTSD-, respectively) and with and without a history of alcohol abuse (ETOH+ and ETOH-, respectively): n for PTSD+/ETOH- = 30, n for PTSD+/ETOH- = 37, n for PTSD-/ETOH+ = 30, and n for PTSD-/ETOH- = 31. Results showed that PTSD, when alcohol, educational level, vocabulary, and depression are controlled for, was associated with decreased verbal memory, attention, and processing speed performance. Alcohol abuse history was associated with decreased visual memory performance. By controlling for alcohol and depression, the authors can more conclusively demonstrate that verbal memory and attention differences are associated with PTSD.

Adult↗

PubMed2007

Serum uric acid and cognitive function in community-dwelling older adults.

Among possible markers of age-related cognitive decline, uric acid (UA) is controversial because it has antioxidant properties but is increased in diseases that often lead to cognitive impairment. In this study of 96 elderly adults, participants with mildly elevated (but normal) serum UA were 2.7 to 5.9 times more likely to score in the lowest quartile of the sample on measures of processing speed, verbal memory, and working memory. Even after controlling for age, sex, race, education, diabetes, hypertension, smoking, and alcohol abuse, the multivariate-adjusted odds of poor verbal memory and working memory remained significant (ps < .05). Despite its antioxidant properties, these findings suggest that even mild elevations of UA might increase the risk of cognitive decline among older adults.

Aged↗

PubMed2000

Confirmatory factor analyses of the WAIS-III standardization data.

Confirmatory factor analyses with the standardization data of the Wechsler Adult Intelligence Scale-Third Edition (Wechsler, 1997a) compared 6 models with 1 to 4 factors for 11- and 13-subtest versions of the test. Three factors usually fit the data better than 2 factors, but 2-factor models were more parsimonious. A 2-factor model with a Verbal Comprehension factor (Vocabulary, Similarities, Information, and Comprehension) was as good as and sometimes better than the 2-factor model defined by the traditional separation of Verbal and Performance subtests. For 3-factor models, alternative specifications of processing speed subtests on either the Perceptual Organization or Freedom From Distractibility factor were comparable, and specifying a 4th factor for Digit Symbol and Symbol Search had little advantage in comparison with 3-factor models with correlated errors for the 2 subtests.

Adolescent↗

PubMed2003

The joint WAIS-III and WMS-III factor structure: development and cross-validation of a six-factor model of cognitive functioning.

During the standardization of the Wechsler Adult Intelligence Scale (3rd ed.; WAIS-III) and the Wechsler Memory Scale (3rd ed.; WMS-III) the participants in the normative study completed both scales. This "co-norming" methodology set the stage for full integration of the 2 tests and the development of an expanded structure of cognitive functioning. Until now, however, the WAIS-III and WMS-III had not been examined together in a factor analytic study. This article presents a series of confirmatory factor analyses to determine the joint WAIS-III and WMS-III factor structure. Using a structural equation modeling approach, a 6-factor model that included verbal, perceptual, processing speed, working memory, auditory memory, and visual memory constructs provided the best model fit to the data. Allowing select subtests to load simultaneously on 2 factors improved model fit and indicated that some subtests are multifaceted. The results were then replicated in a large cross-validation sample (N = 858).

Adolescent↗

PubMed2004

Values for comparison of WAIS-III index scores with overall means.

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; Wechsler, 1997b) provides factor-based index scores but allows only for pairwise comparison of these scores, producing inflated Type I error rates and reducing profile interpretability. This article provides tables for simultaneous comparison to the overall mean index score, thus reducing error rates and aiding interpretation. The Working Memory Index or Processing Speed Index can also be specifically compared when an individual is believed to have a condition, such as a learning disability or traumatic brain injury, associated with the selective depression of these indexes. Tables for the infrequency of specific differences are also provided, allowing the practitioner to note how unusual an obtained difference is in the general population.

Adult↗

PubMed1998

Visual search for features and conjunctions in development.

Visual search performance was examined in three groups of children 7 to 12 years of age and in young adults. Colour and orientation feature searches and a conjunction search were conducted. Reaction time (RT) showed expected improvements in processing speed with age. Comparisons of RT's on target-present and target-absent trials were consistent with parallel search on the two feature conditions and with serial search in the conjunction condition. The RT results indicated searches for feature and conjunctions were treated similarly for children and adults. However, the youngest children missed more targets at the largest array sizes, most strikingly in conjunction search. Based on an analysis of speed/accuracy trade-offs, we suggest that low target-distractor discriminability leads to an undersampling of array elements, and is responsible for the high number of misses in the youngest children.

Adult↗

PubMed1998

The effects of frontal eye field and dorsomedial frontal cortex lesions on visually guided eye movements.

In the frontal lobe of primates, two areas play a role in visually guided eye movements: the frontal eye fields (FEF) and the medial eye fields (MEF) in dorsomedial frontal cortex. Previously, FEF lesions have revealed only mild deficits in saccadic eye movements that recovered rapidly. Deficits in eye movements after MEF ablation have not been shown. We report the effects of ablating these areas singly or in combination, using tests in which animals were trained to make saccadic eye movements to paired or multiple targets presented at various temporal asynchronies. FEF lesions produced large and long-lasting deficits on both tasks. Sequences of eye movements made to successively presented targets were also impaired. Much smaller deficits were observed after MEF lesions. Our findings indicate a major, long-lasting loss in temporal ordering and processing speed for visually guided saccadic eye movement generation after FEF lesions and a significant but smaller and shorter-lasting loss after MEF lesions.

Animals↗

PubMed1996

Neurocognitive function in chronic hemodialysis patients.

We administered a comprehensive neuropsychological test battery, including measures of intelligence, immediate and delayed memory, attention and mental processing speed, language abilities, complex problem solving, motor skills, and depression, to 16 well-dialyzed (Kt/Vurea = 1.46 +/- 0.24) patients with end-stage renal disease (ESRD) and 12 age- and education-matched medical controls. We observed no clear neuropsychological deficits in these ESRD patients who had low average intelligence and limited educational achievement, and hypothesize that previously observed apparent deficits resulted either from very low dialysis delivery or comparison with poorly-matched historical controls. There were significant deficits in language ability and intelligence in ESRD patients with higher than median scores on the Beck Depression Inventory compared with less-depressed ESRD patients. However, this effect of depression did not result in differences between dialysis and non-ESRD patient groups.

Adult↗

PubMed2006

Genetics of intelligence.

This article provides an overview of the biometric and molecular genetic studies of human psychometric intelligence. In the biometric research, special attention is given to the environmental and genetic contributions to specific and general cognitive ability differences, and how these differ from early childhood to old age. Special mention is also made of multivariate studies that examine the genetic correlation between intelligence test scores and their correlates such as processing speed, birth weight and brain size. After an overview of candidate gene associations with intelligence test scores, there is a discussion of whole-genome linkage and association studies, the first of which have only recently appeared.

Age Factors↗

PubMed2003

Is there an auditory-visual flash-lag effect?

A flash adjacent to the path of a moving object appears behind the moving object: the 'flash-lag effect'. We sought to test the flash-lag effect with a 'click' instead of a flash: a white triangle horizontally traversed the screen at a constant 12 degrees /s passing through a fixation cross in the presence of a quiet click. The subject judged whether the click occurred before or after the triangle passed through the cross. To be perceived as co-instantaneous events, the click had to be presented 127 ms after the moving triangle reached the cross (a 'click-lead' effect, providing falsification of predictive accounts of the flash-lag effect), as opposed to a standard flash-lag effect condition where a flashed triangle replaced the click and had to appear 60 ms before the moving triangle to appear aligned. With the auditory versus visual processing speed advantage considered, the neural time required to calculate a moving object's position is constant, independent of the modality of the flag.

Acoustic Stimulation↗