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PubMed1991

Developmental change in speed of processing during childhood and adolescence.

Throughout childhood and adolescence, there are consistent age differences in speed of processing. Here 72 published studies yielded 1,826 pairs of response times (RTs) in which each pair consisted of adults' mean RT for a condition and the corresponding mean RT for a younger group. The primary results were that (a) children's and adolescents' RTs increase linearly as a function of adult RTs in corresponding conditions and (b) the amount of increase becomes smaller with age in a manner that is well described by an exponential function. These results are consistent with the view that age differences in processing speed reflect some general (i.e., nontask specific) component that changes rapidly during childhood and more slowly during adolescence. Possible candidates for the general component are discussed.

Adolescent↗

PubMed2003

Individual differences in rCBF correlates of syntactic processing in sentence comprehension: effects of working memory and speed of processing.

Positron emission tomography (PET) was used to determine the effect of working memory and speed of sentence processing 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). Two groups of nine subjects differing in working memory and matched for speed of sentence processing both showed increases in rCBF in lateral posteroinferior frontal lobe bilaterally. The subjects were reclassified to form two groups of eight subjects who were matched for working memory but who differed in speed of sentence processing. Fast-performing subjects activated lateral posteroinferior frontal lobe bilaterally and slow-performing subjects showed activation of left superior temporal lobe. The results indicate that rCBF responses to syntactic comprehension tasks vary as a function of speed of sentence processing but not as a function of working memory.

Adult↗

PubMedDate not supplied

Cognitive slowing and working memory difficulties in chronic fatigue syndrome.

OBJECTIVE: Patients with chronic fatigue syndrome (CFS) commonly report problems with attention, memory, learning, and speed of cognitive processing. This study attempted to evaluate these complaints using objective test criteria. METHOD: A test battery composed of six tests assessing these cognitive functions was given on two consecutive days. Twenty CFS patients were compared with 20 healthy control subjects and 14 patients with a history of major depression or dysthymia matched by age, intelligence, education level, and sex. RESULTS: Compared with control subjects, CFS patients consistently scored lower on tests in which motor and cognitive processing speeds were a critical factor, eg, reaction-time tasks. They also had more difficulty on working-memory tests in which rapid cognitive processing speed is also an important factor. The effort made on the first day of testing did not result in a decline in cognitive function on the following day. CFS patients did not qualify as having affective disorder by several different diagnostic criteria. Nonetheless, CFS patients' test performances did not differ from patients with a history of major depression or dysthymia. CONCLUSIONS: It is concluded that, although CFS and major depression and dysthymia have distinct clinical features, these disorders have slowed motor and cognitive processing speed in common.

Adult↗

PubMed1991

Naming speed deficits in reading disability: multiple measures of a singular process.

Speed of word identification is important in the theories of reading proposed by La Berge and Samuels (1974) and Perfetti (1985), and is substantially correlated with reading skill. However, there is controversy about whether disabled readers have a speed deficit that is restricted to the identification of printed words, or if instead, they have a more general speed deficit in retrieving names of even single digits. To investigate this issue, poor and average readers (N = 43) in grade 2 were assessed on several indices of speed of digit and letter naming, using both continuous-list and discrete-trial methodologies. MANCOVA indicated clear effects of reader group on discrete-trial latencies, as well as an interaction between reader group and the speed with which to-be-named items were presented. A series of hierarchical regression analyses explored the amount of shared variance between various measures of digit naming speed and five indices of reading skill. Latency for word identification shares considerable variance with latency for digit naming, and, in general, accounts for the shared variance of naming speed and several other measures of reading skill. Naming speed contributed variance in reading skill. Naming speed contributed variance in reading skill independently of measures of phonological awareness.

Attention↗

PubMed2006

Obstructive sleep apnea-hypopnea and neurocognitive functioning in the Sleep Heart Health Study.

BACKGROUND AND PURPOSE: Obstructive sleep apnea-hypopnea (OSAH) is associated with sleep fragmentation and nocturnal hypoxemia. In clinical samples, patients with OSAH frequently are found to have deficits in neuropsychological function. However, the nature and severity of these abnormalities in non-clinical populations is less well defined. PATIENTS AND METHODS: One hundred and forty-one participants from the Tucson, AZ and New York, NY field centers of the Sleep Heart Health Study completed a battery of neuropsychological tests for 9-40 months (mean=24 months, SD=7 months) after an unattended home polysomnogram. Sixty-seven participants had OSAH (AHI>10) and 74 did not have OSAH (control (CTL), apnea-hypopnea index (AHI)<5). In addition to the individual tests, composite variables representing attention, executive function, MotorSpeed and processing speed were constructed from the neuropsychological test battery. RESULTS: There were no significant differences in any individual neuropsychological test or composite variable between the OSAH and CTL groups. However, when time spent with O(2) saturations less than 85% was dichotomized into those participants in the top quartile of the distribution and those in the lower three quartiles, motor speed was significantly impaired in those who were more hypoxemic. In addition, poorer motor speed (model adjusted R(2)=0.242, P<0.001) and processing speed performance (model adjusted R(2)=0.122, P<0.001) were associated with more severe oxygen desaturation even after controlling for degree of daytime sleepiness, age, gender and educational level. CONCLUSIONS: Mild to moderate OSAH has little impact on the selected measures of attention, executive function, motor speed and processing speed. However, hypoxemia adversely affects both motor and processing speed. These results suggest that in middle-aged to elderly adults the neuropsychological effects of clinically unrecognized mild to moderate OSAH are neither global nor large.

Brain↗

PubMedDate not supplied

Early neurocognitive function of patients after off-pump coronary artery bypass surgery.

DESIGN: This was a prospective, descriptive study. SETTING: The study took place in cardiovascular units at a large urban metropolitan, midwestern tertiary care hospital. SAMPLE: Fifty-four patients undergoing off-pump coronary artery bypass surgery were included. OUTCOME MEASURES: Outcome measures were neurocognition preoperatively at baseline (within 72 hours of surgery) and postoperatively (at least 72 hours after surgery but before discharge). RESULTS: In neurocognitive tests of cognition (memory, language, and attention) there was an improvement in the cognitive composite from the preoperative baseline to the postoperative follow-up (P < .001). However, in tests of motor function (motor speed and information processing speed) there was a decline in the motor composite (P = .006). CONCLUSIONS: After off-pump coronary artery bypass surgery, patients had an overall improvement in tests of memory, language, and attention (cognitive composite), but a decline in tests of motor speed and information processing speed (motor composite).

Attention↗

PubMedDate not supplied

Do different components of working memory underlie different subgroups of reading disabilities?

The purpose of this study was to determine the components of working memory (WM) that underlie less skilled readers' comprehension and word recognition difficulties. Performance of 3 less skilled reading subgroups---children with reading disabilities (RD) in both word recognition and comprehension; children with comprehension deficits only; and children with low verbal IQ, word recognition, and comprehension (poor readers)--was compared to that of skilled readers on WM, short-term memory (STM), processing speed, executive, and phonological processing measures. Ability group comparisons showed that (a) skilled readers outperformed all less skilled readers on measures of WM, updating, and processing speed; (b) children with comprehension deficits only outperformed children with RD on measures of WM, STM, phonological processing, and processing speed; and (c) children with RD outperformed poor readers on WM and phonological processing measures. A hierarchical regression analysis showed that (a) subgroup differences on WM tasks among less skilled readers were moderated by a storage system not specific to phonological skills, and (b) STM and updating contributed significant variance to WM beyond what was contributed by reading group classification. The latter finding suggested that some differences in storage and executive processing emerged between skilled and less skilled readers that were not specific to reading.

Aptitude↗

PubMed1998

The role of speed of processing, inhibitory mechanisms, and presentation order in trail-making test performance.

The roles of speed of processing, inhibition, and presentation order in the Trail Making Test (TMT) performance were examined. One-hundred ten undergraduates performed the TMT (1/2 received order Part A-Part B, 1/2 received order Part B-Part A) and also completed computerized tests of inhibitory functioning and speed of processing. Neither speed of processing nor inhibitory functioning affected TMT performance. However, order of presentation significantly affected TMT performance. Presentation order is an important variable to consider in TMT performance.

Adult↗

PubMed2005

The E-hook of tubulin interacts with kinesin's head to increase processivity and speed.

Kinesins are dimeric motor proteins that move processively along microtubules. It has been proposed that the processivity of conventional kinesins is increased by electrostatic interactions between the positively charged neck of the motor and the negatively charged C-terminus of tubulin (E-hook). In this report we challenge this anchoring hypothesis by studying the motility of a fast fungal kinesin from Neurospora crassa (NcKin). NcKin is highly processive despite lacking the positive charges in the neck. We present a detailed analysis of how proteolytic removal of the E-hook affects truncated monomeric and dimeric constructs of NcKin. Upon digestion we observe a strong reduction of the processivity and speed of dimeric motor constructs. Monomeric motors with truncated or no neck display the same reduction of microtubule gliding speed as dimeric constructs, suggesting that the E-hook interacts with the head only. The E-hook has no effect on the strongly bound states of NcKin as microtubule digestion does not alter the stall forces produced by single dimeric motors, suggesting that the E-hook affects the interaction site of the kinesin.ADP-head and the microtubule. In fact, kinetic and binding experiments indicate that removal of the E-hook shifts the binding equilibrium of the weakly attached kinesin.ADP-head toward a more strongly bound state, which may explain reduced processivity and speed on digested microtubules.

Adenosine Diphosphate↗

PubMedDate not supplied

The role of speed of processing, rapid naming, and phonological awareness in reading achievement.

This study investigated the role of speed of processing, rapid naming, and phonological awareness in reading achievement. Measures of response time in motor, visual, lexical, grammatical, and phonological tasks were administered to 279 children in third grade. Measures of rapid object naming, phonological awareness, and reading achievement were given in second and fourth grades. Reading group comparisons indicated that poor readers were proportionally slower than good readers across response time measures and on the rapid object naming task. These results suggest that some poor readers have a general deficit in speed of processing and that their problems in rapid object naming are in part a reflection of this deficit. Hierarchical regression analyses further showed that when considered along with IQ and phonological awareness, speed of processing explained unique variance in reading achievement. This finding suggests that a speed of processing deficit may be an "extraphonological" factor in some reading disabilities.

Child↗

PubMed2006

Neurocognitive and symptom correlates of daily problem-solving skills in schizophrenia.

Functional outcome for individuals with schizophrenia has been associated with cognitive impairment. Deficits in attention, memory, speed of information processing and problem-solving skills affect independent functioning, vocational performance, and interpersonal functioning. This study investigated the relationship between neurocognitive functioning, clinical symptoms and daily problem-solving skills in seriously and persistently ill persons. Thirty-eight inpatients and outpatients were administered a neurocognitive battery for attention, working memory, processing speed, perceptual organization, and executive functioning; and semi-structured clinical interviews using the BPRS and SANS. Estimates of daily problem-solving skills were obtained using the relevant factor subscale from the Independent Living Scales (ILS-PB). Daily problem-solving skills were significantly correlated with negative symptoms, processing speed, verbal memory, and working memory scores. A regression model using an enter method suggests that working memory and negative symptoms are significant predictors of daily problem-solving skills and account for 73.2% of the variance. Further analyses demonstrate that daily problem-solving skills and negative symptoms were significantly different for inpatients and outpatients and significantly correlated with community status. The findings suggest the ILS-PB has utility as a proxy measure for assessing real-world functioning in schizophrenia.

Activities of Daily Living↗

PubMedDate not supplied

Transfer of a speed of processing intervention to near and far cognitive functions.

BACKGROUND: Evidence establishing the potential for modification of cognitive functioning in later adulthood has begun to accumulate. OBJECTIVE: The primary goal of the current study was to evaluate, among older adults, the extent to which standardized speed of processing training transfers to similar and dissimilar speeded cognitive measures as well as to other domains of cognitive functioning. METHODS: Ninety-seven older adults (mean age 73.71 years) were administered a battery of cognitive tests assessing intelligence, memory, attention, verbal fluency, visual-perceptual ability, speed of processing, and functional abilities. Forty-four of the participants received ten 1-hour sessions of speed of processing training. The remainder of participants were in a no-contact control group. Approximately 6 weeks after the pretraining assessment, all participants repeated the same battery of tests. RESULTS: The results revealed training effects for some speed of processing measures, including performance of instrumental activities of daily living, but no transfer to other domains of cognitive functioning. CONCLUSION: Speed of processing training may enhance the speed at which older adults can perform instrumental activities of daily living.

Activities of Daily Living↗

PubMed1997

Profiles of cognitive functioning in chronic spinal cord injury and the role of moderating variables.

A traumatic spinal cord injury (SCI) is accompanied by a documented moderate to severe head injury in significant numbers of SCI patients. In a previous study (Dowler et al., 1995), cognitive deficits were found in 41% of the SCI individuals who were studied with a chronic injury from a traumatic event. The present study investigated whether clinically useful subtypes of normal and impaired cognition could be identified in a chronic (M = 17 years postinjury) SCI sample using a cluster analysis of neuropsychological test performance. A battery of 16 neuropsychological tests was administered to 91 SCI patients and 75 control participants. Composite scores, reflecting performance in different cognitive domains, were derived from a factor analysis of the battery, and these scores were then used in the cluster analysis. A six-cluster solution generated the most distinct and clinically relevant SCI group profiles. Two of the cognitive profiles were characterized by normal functioning in all cognitive domains, but they were distinguished by differences in performance levels. The remaining four SCI groups (60% of the sample) showed clinically significant deficits in one or more cognitive domains, with different groups showing moderate attention and processing speed deficits, mild deficits in processing speed, executive processing difficulties, or moderate memory impairments. Though age and premorbid intellectual ability were strong predictors of the cognitive profiles of some SCI groups, when these factors were controlled, the findings suggested that the patterns of cognitive impairment were likely due to a potential concomitant head injury.

Adult↗

PubMed1999

The relationships among pulmonary function, aerobic fitness, and cognitive functioning in older COPD patients.

STUDY OBJECTIVES: To study the predictive relationships among age, pulmonary function, aerobic fitness, and cognition in people with COPD. DESIGN: Observational study conducted during baseline testing with COPD patients who volunteered to participate in an exercise intervention. PARTICIPANTS: Older adults (age, 56 to 80 years) with COPD. MEASUREMENTS AND RESULTS: Age, depression, education level, aerobic fitness, blood oxygen saturation levels, and pulmonary function were assessed. Participants were randomly assigned to take cognitive tests of (1) fluid intelligence, (2) processing speed and working memory span, or (3) processing speed and inhibition. After controlling for education and depression (F(2,57) = 7.43; r(2) = 0. 21), performance on the 6-min walk (F(1,56) = 15.27; r(2) = 0.17) and age (F(1,55) = 7.52; r(2) = 0.08) were significant predictors of fluid intelligence. On the speed-of-processing task, performance on the 6-min walk (F(1,30) = 8.17; r(2) = 0.20), maximum voluntary ventilation (F(1,29) = 5.81; r(2) = 0.16), and age (F(1,28) = 5.26; r(2) = 0.10) were significant predictors. FVC was a significant predictor (F(1,25) = 6.37; r(2) = 0.18) of working memory span. The ability to inhibit a response was not significantly predicted by any of the variables assessed. CONCLUSIONS: In an older COPD sample, age, aerobic fitness, and pulmonary function are predictive of cognitive performance on various tasks. In particular, age and aerobic fitness are predictive of speed of processing, which is a cognitive variable that may itself underlie performance on a majority of cognitive tasks.

Adult↗

PubMed2004

Neuropsychological functioning in methadone maintenance patients versus abstinent heroin abusers.

Several studies have reported on neuropsychological status as an important contributing variable in drug abuse rehabilitation outcomes. However, few studies have dealt with cognitive impairment in methadone maintenance patients (MMP), despite the fact that methadone is the most frequently used opioid substitution treatment in European countries. The objective of the present study is to contrast the neuropsychological performance of MMP with that of abstinent heroin abusers (AHA). Participants were matched with respect to age, education, pre-morbid IQ, employment status and lifetime drug abuse, and they underwent a set of tests aimed at assessing visuo-spatial attention, processing speed and executive functions. Although processing speed and attention deficits have previously been the focus of studies with MMP, executive functions have not received a similar degree of attention. The purpose of comparing matched MMP and AHA is two-fold: firstly, to test the differential effects of current opioid consumption and past opioid abuse on cognitive-executive performance and secondly, to assess the potential consequences of opioid-related neuropsychological deficits. Results showed a significantly slower performance by MMP on processing speed, visuo-spatial attention, and cognitive flexibility tests (Five Digit Test (FDT) parts 1 and 3; Oral Trails (OT) parts 1, 2; Interference 2-1), and less accuracy in working memory and analogical reasoning tests extracted from the Wechsler Adult Intelligence Scale (WAIS III). Effect sizes for significant comparisons ranged from 0.67 to 1. These results seem to suggest that methadone consumption by itself induces significant cognitive impairments that could compromise drug-treatment outcomes in MMP.

Adult↗

PubMed1995

Sentence comprehension in multiple sclerosis.

INTRODUCTION: Explanations of sentence processing difficulty in aphasia have implicated slowed information processing speed. We tested this hypothesis by evaluating sentence comprehension in multiple sclerosis (MS), and relating comprehension performance to measures of information processing speed. MATERIAL & METHODS: Twenty right-handed, high school-educated, non-demented, native English speakers with clinically definite MS and 16 age- and education-matched control subjects were examined on 3 different sentence comprehension measures that stress grammatical appreciation. Performance was related to quantitative assessments of mental information processing speed. RESULTS: Group-wide analyses demonstrated a trend toward sentence comprehension difficulty in MS. Analyses of individual patient profiles identified a subgroup of MS patients who were consistently impaired to a significant extent across all sentence comprehension tasks. Their sentence comprehension difficulty was associated with selectively compromised mental information processing speed. CONCLUSION: Sentence comprehension difficulty in MS is associated with slowed information processing speed. This finding supports the claim that information processing speed contributes to sentence processing.

Adult↗

PubMed2000

Depression, psychomotor retardation, negative symptoms, and memory in schizophrenia.

OBJECTIVE: The purpose of this study was to examine the relations between depression, psychomotor retardation, and negative symptoms in schizophrenia as well as the specific contribution of each of these factors to memory impairment. BACKGROUND: It has been suggested that depression overlaps with negative symptomatology in schizophrenia. The relation between psychomotor retardation and negative symptomatology has been unclear. METHOD: The Hamilton Depression Rating Scale, The Positive and Negative Symptom Scale for Schizophrenia, and Scale for the Assessment of Negative Symptoms were used to assess depressive and negative symptomatology in a sample of patients with schizophrenia. Verbal memory performance was assessed by a free recall test. Two indices of processing speed were measured. Correlations among variables were computed. RESULTS: Depression score was correlated with the avolition item from the Scale for the Assessment of Negative Symptoms and with both measures of processing speed. Negative symptomatology was unrelated to processing speed. Memory performance was correlated with depression score, slowing of processing speed, and avolition. Its correlation with depression score and processing speed remained significant when the other factors were partialled out. CONCLUSIONS: Memory performance in schizophrenia may be affected by lack of motivation, psychomotor retardation, and depression. It is suggested that negative symptoms could be split between a volitional component linked to depression and cognitive efficiency and an emotional component unrelated to them.

Adult↗

PubMed2005

Affective integration speeds trait processing.

We investigated whether affective integration increases the speed of processing of personality trait knowledge. The fan effect was compared between cases where trait knowledge is stored with the affective value and cases where it is not stored with the affective value. 18 college students first memorized a set of traits about fictitious individuals and then made recognition judgments. In the 2 x 2 factorial repeated-measures design, the number of traits learned about a fictitious individual and whether those traits were integrated by a shared affective value were manipulated. The significant interaction showed that knowledge of personality trait with affective integration was processed quickly even if the particular person's memory had rich connections with traits.

Adolescent↗