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At least 703 records · Page 39Linked to original sources
PubMed2005

Cerebral hemodynamic changes in response to an executive function task in children with attention-deficit hyperactivity disorder measured by near-infrared spectroscopy.

The aim of the present study was to evaluate the hemodynamic changes in both prefrontal regions induced by a cognitive task in children with a developmental attention-deficit disorder in comparison to normal controls using near-infrared spectroscopy (NIRS). A total of 11 boys with a mean age of 10.4 (+/-1.2) years that met the DSM-IV criteria for attention-deficit hyperactivity disorder (ADHD) participated in the study and were compared with 9 healthy age- and sex-matched controls. Using a trail-making test designed for the task of connecting numbers from 1-90 in four sets, changes in oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin, tissue oxygenation index (TOI), and cerebral blood volume (CBV) were measured by near-infrared spectroscopy. During the first test set, designed as a short-attention task, the children with ADHD showed significant increases in O2Hb and CBV, whereas the controls showed no significant changes. During the 4 task cycles in which extended attention was demanded, both groups showed increases in O2Hb and CBV, but only the controls showed an additional increase in HHb in the left prefrontal region. In the ADHD group only, TOI showed an increase mainly on the left side. NIRS is a sensitive tool for measuring differences in hemodynamic changes between boys with ADHD and normal controls. Overall, the normal controls showed lateralized oxygen consumption in the left prefrontal cortex during an extended-attention task, whereas the boys with ADHD showed an imbalance between oxygenated and deoxygenated hemoglobin during the short- and extended-attention tasks.

Age Factors↗
PubMed2005

Impairment of executive function but not memory in first-degree relatives of patients with bipolar I disorder and in euthymic patients with unipolar depression.

OBJECTIVE: The authors' goal was to characterize cognitive flexibility and verbal learning in relatives of patients with bipolar disorder and in euthymic patients with recurrent major depression. METHOD: The intradimensional/extradimensional shift task and California Verbal Learning Test were administered to 27 first-degree relatives of probands with bipolar I disorder, 15 euthymic outpatients with recurrent unipolar depression, and 47 healthy comparison subjects. RESULTS: The relatives of patients with bipolar I disorder and the euthymic patients with unipolar depression were more likely to fail the intradimensional/extradimensional shift task than the healthy comparison subjects. The impairments at the extradimensional shift stage were pronounced. Verbal learning, delayed recall, and recognition were unimpaired in all groups. CONCLUSIONS: Attentional set shifting may represent an endophenotype in mood disorder, related to underlying vulnerability rather than the actual disease phenotype.

Adolescent↗
PubMed2005

Executive function and cognitive subprocesses in first-episode, drug-naive schizophrenia: an analysis of N-back performance.

OBJECTIVE: This study investigated changes in the cognitive architecture of N-back performance in schizophrenia. METHOD: N-back performance of 12 patients with first-episode, drug-naive schizophrenia and matched healthy comparison subjects was studied in a reaction-time decomposition paradigm. RESULTS: Imposition of a working memory load led to a significant drop in response accuracy in patients. Reaction-time decomposition suggested slowing of visuomotor and choice reaction processing as well as an inability of parallel processing directed by working memory. DISCUSSION: Although N-back tasks validly access working memory function as a neurocognitive trait in the illness, several additional subprocesses and the ability for cognitive parallel processing are altered and require further study in schizophrenia.

Adult↗
PubMed2001

Executive function deficits in non-retarded autistic children.

The purpose of this study was to examine differences between Taiwanese children with autism and their typically developing peers on the Wisconsin Card Sorting Test (WCST). Twenty-six children with autism of normal IQ were included, and matched for chronological age with 52 controls. The WCST scores of the typically developing children were significantly higher for categories completed and percent conceptual level than in the autism group. Scores on perseverative responses, perseverative errors, the number of trials to complete the first category and non-perseverative errors were significantly higher in the autism group. The implications of these findings are discussed.

Attention↗
PubMed2005

Executive functions in children with communication impairments, in relation to autistic symptomatology. 1: Generativity.

Previous research has found that people with autism generate few novel responses in ideational fluency tasks, and it has been suggested this deficit is a specific correlate of stereotyped/repetitive behavior. We assessed generativity in children with pragmatic language impairment (PLI) who showed communicative abnormalities resembling those seen in autism. We compared four groups: high-functioning autism; PLI; specific language impairment; and control. Generativity was measured using two fluency tasks previously shown to be sensitive to autistic disorder. Correlational analysis revealed a significant relationship between the percentage of correct responses on the fluency tasks and measures of communicative abnormality. It is often assumed that pragmatic difficulties are caused by limitations of social cognition. This study suggests that difficulties in generating relevant ideas can be another cause of autistic-like communicative abnormalities.

Autistic Disorder↗
PubMed2004

Executive functioning in preschoolers: reducing the inhibitory demands of the dimensional change card sort task.

To investigate the role of inhibitory control in preschoolers' ability to switch sets, 3 conditions of the Dimensional Change Card Sort task ( Zelazo, Reznick, & Pinon, 1995) were tested. In Condition B (novel response options, standard stimuli) action inhibition was reduced, but the need for attentional inhibition was maintained. In Condition C (novel stimuli, standard response options) demands on both action and attentional inhibition were reduced. Performance in these was compared to that in the standard condition (A). Rule complexity was comparable across conditions. All 21 children who passed preswitch (average age 37 months) were tested on all postswitch conditions, order counterbalanced. Although reducing demands on action inhibition (Condition B) did not significantly improve performance, when demands on both action and attentional inhibition were reduced (Condition C) almost all children (95%) successfully switched sets (even children only 2 1/2 years old). Inadequate inhibition (of attention alone or both attention and action) appears sufficient to account for virtually all errors by preschoolers on this card sorting task.

Attention↗
PubMed2002

Improved executive functioning following repetitive transcranial magnetic stimulation.

The cognitive effects of active and sham repetitive transcranial magnetic stimulation (rTMS) were examined in 19 middle-aged and elderly patients with refractory depression. Patients received either active (n = 9) or sham (n = 10) rTMS targeted at the anterior portion of the left middle frontal gyrus. Patients in the active rTMS group improved significantly on a test of cognitive flexibility and conceptual tracking (Trail Making Test-B).

Aged↗
PubMed2004

Performance of university students on random number generation at different rates to evaluate executive functions.

OBJECTIVE: To evaluate the performance of adult young subjects in a Random Number Generation (RNG) task by controlling the response speed (RS). METHOD: Sixty-nine university students of both sexes took part in the experiment (25.05 +/- 6.71 year-old). Participants were alloted into 3 groups which differed in RS rates to generate numbers: 1, 2 and 4 seconds to generate each number. A digital metronomer was used to control RS. Participants were asked to generate 100 numbers. The responses were measured through Evans's RNG Index. RESULTS: There were statistically significant differences among the groups [F (3, 68) = 7.120; p <.05]. Differences were localized between 1 and 2 seconds (p = 0.004) and between 1 and 4 seconds (p = 0.006). No differences were observed between 2 and 4 seconds (p = 0.985). CONCLUSION: The present results suggest that the response speed in production of random numbers influences the performance of the Random Numbers Generation task.

Adolescent↗
PubMed1992

Use of a verbal fluency measure in understanding and evaluating ADHD as an executive function disorder.

A primary characteristic of Attention Deficit Hyperactivity Disorder (ADHD) is an inability to establish and maintain sustained attention, which is speculated to reflect frontal lobe involvement. The Knight Verbal Fluency measure was administered to 19 ADHD inpatient boys and to a cohort group of 7 children who were matched for mean age, psychiatric diagnosis (depression), treatment facility, and examiner but were without the diagnosis of ADHD. Analysis indicated that ADHD children performed significantly lower than expected and lower than the similar non-ADHD children. These findings lend support to the hypothesis that frontal lobe dysfunction is involved in attentional process disorders and suggests the potential clinical usefulness in the diagnostic screening of ADHD children of a simply administered measure amenable to interpretation of frontal lobe function.

Adolescent↗