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Biomedical subjects

M B Denckla

Publications and source records attributed to M B Denckla.

At least 73 records · Page 4Linked to original sources
PubMed1987

Regional cerebral blood flow in severe developmental dyslexia.

Regional cerebral blood flow was measured under three task conditions in 14 men with severe developmental dyslexia and their control subjects using a xenon 133 inhalation technique. No group differences in overall level or in pattern of gray matter flow were seen under relatively undemanding cognitive conditions. Despite minimal group differences in performance, the dyslexic group showed an increased hemispheric asymmetry (left greater than right) on a semantic classification task and a reduced anteroposterior difference on a line orientation task relative to controls. The exaggerated asymmetry suggests the possibility of less efficient information processing or inadequate bihemispheric integration. The reduced anteroposterior gradient may reflect a deficit in the ability of frontal systems to respond adequately to cognitive demands.

Adult↗
PubMed1986

Magnetic resonance imaging of brain anatomy in severe developmental dyslexia.

The brain anatomy of ten men (aged 18 to 28 years) with persistent, severe developmental dyslexia was examined with magnetic resonance imaging to explore the possibility of visualizing pathology not seen in previous computed tomographic scan studies. Nine of the ten examinations were clinically normal. One showed a focal finding thought to be incidental to dyslexia. The volume of the temporal lobes was judged to be symmetrical in nine of ten examinations, a finding supportive of previous computed tomographic scan and neuropathologic reports of unusual symmetries of posterior brain regions. Thus, despite its sensitivity, magnetic resonance imaging failed to identify a common focal pathology. The choice of imaging planes (particularly coronal) and lack of bone artifact may, however, prove useful for studying macroscopic asymmetries in dyslexia.

Adolescent↗
PubMed1986

Gilles de la Tourette syndrome: etiologic considerations.

The prevalence of Gilles de la Tourette syndrome is 28/100,000 in subjects of among the school age population. Familial cases have been described, although it is not an hereditary disease. This indicates that non genetic factors are critical. The fact that Gilles de la Tourette syndrome is frequently associated with migraine, sleep disturbances, attentional or compulsive deficits, does not orient towards a specific cause. An environmental factor has never been demonstrated. Epidemiological studies should be developed in the future, and more systematic anatomical and biochemical researches should be undertaken.

Animals↗
PubMed1985

Motor proficiency in dyslexic children with and without attentional disorders.

Motor proficiency, in terms of speed, rhythm and absence of overflow, has previously been shown to distinguish nonlearning disabled hyperactive boys from matched controls. Accepted screening methods for selecting children with dyslexia do not include assessments of hyperactivity or other attentional deficits. Dyslexic children selected in this customary manner were compared with an otherwise matched group that had been screened for attentional disorders, on a series of repetitive and alternating movements of the fingers, hands, and feet. The screened dyslexic group performed more rapidly on five of six movements and had fewer qualitative signs of dysrhythmia or overflow.

Attention Deficit Disorder with Hyperactivity↗
PubMed1984

Development of motor co-ordination by normal left-handed children.

Ninety-six normal left-handed children were tested for motor co-ordination on a series of timed repetitive tasks, alternating left and right hands, feet and fingers. Preferred hand advantage could be demonstrated to the same degree for the left hand of these children as it had been for the preferred right hand in previously studied groups of the same age (Denckla 1973, 1974). The only test (finger to thumb successive opposition) that failed to show a preferred hand advantage in left-handers also had failed to show such an advantage among right-handers. This same test was performed more rapidly by left-handed girls than boys, as it had been by right-handed girls. However, left-foot superiority appeared to be less well established among left-handers than superiority of the right foot among right-handers, and at a later age. Left-handed children were less likely than their right-handed counterparts to choose their preferred hand when trying out a new task. Writing posture, i.e. whether inverted or straight, could not be established unambiguously for the left-handed children up to the age of 10, and often differed for writing and printing.

Child↗
PubMed1984

Computerized tomography and neuropsychological test measures in adolescents with obsessive-compulsive disorder.

The authors administered CAT scans and neuropsychological tests to 16 adolescents with obsessive-compulsive disorder (mean age +/- SD = 13.7 +/- 1.6 years) and 16 matched controls. The patients had a mean ventricular-brain ratio (VBR) significantly higher than the controls' and showed spatial-perceptual deficits similar to those found in patients with frontal lobe lesions. Memory, reaction time, and decision time did not differ significantly from controls'. Neurodevelopmental examination of seven patients yielded a high frequency of age-inappropriate synkinesias and left hemibody signs. These results suggest CNS dysfunctioning in children with obsessive-compulsive disorder, with possible right cerebral involvement. However, the patients' neuropsychological test deficits and VBRs were not correlated.

Adolescent↗
PubMed1983

Evidence for differential hemispheric function in children with hemiplegic cerebral palsy.

Eight children with right infantile hemiplegia and eight with left infantile hemiplegia were compared with each other and with 13 sibling controls on a test of manual dexterity, an extended neurological examination and a battery of neuropsychological tests. Right-hemiplegic children performed significantly less well than left-hemiplegic children and the controls on measures of syntactical awareness and the repetition of semantically coherent materials, despite similar verbal IQs. Both hemiplegic groups tended to perform less well than the controls, although not significantly so, on the short-term memory task, repetition of digits, and on a task of confrontation naming. There was also a strong correlation between left-hand impairment and poor arithmetical computation skill in both hemiplegic groups, which conforms with present views as to right-lateralization of certain mathematical functions. The results as a whole support the premise that there is innate hemispheric organization for some language tasks.

Adolescent↗
PubMed1980

Dyslexia: regional differences in brain electrical activity by topographic mapping.

Electroencephalographic (EEG) and evoked potential data were recorded during behavioral testing from 8 dyslexic and 10 normal boys aged 9 to 11 years. Topographic mapping of their brain electrical activity revealed four discrete regions of difference between the two groups involving both hemispheres, left more than right. Aberrant dyslexic physiology was not restricted to a single locus but was found in much of the cortical region ordinarily involved in reading and speech. Prominent group differences were observed in the bifrontal area in addition to the more expected left temporal and left posterior quadrant regions. Although activation tests produced more prominent group difference, dyslexics differed from normal subjects at rest as well. EEG alpha activity was increased for the dyslexics, suggesting relative cortical inactivity in that group.

Alpha Rhythm↗
PubMed1980

Dyslexia: automated diagnosis by computerized classification of brain electrical activity.

We describe a method for the diagnosis of dyslexia based upon a study of electroencephalographic and evoked potential data recorded from 13 normal and 11 dyslexic boys. Measurements were made from topographic maps of brain electrical activity recorded during resting and activated testing conditions. Using a statistically based technique, we developed rules for classification that successfully diagnosed 80 to 90% of subjects not used in the initial rule development. The nature of the most useful measurements suggests that aberrant neurophysiology in dyslexia involves both hemispheres and is present at rest as well as during complex testing. The method has promise for future diagnosis and research.

Alpha Rhythm↗
PubMed1978

Anomalies of motor development in hyperactive boys.

Forty-eight boys who scored high on rating scales for the "hyperactive syndrome" but who went without traditional neurological signs of learning disabilities were compared with 50 control boys on coordination tests. Discriminant function scores for speed, rhythm, and overflow correctly classified 89% of the boys as those with "hyperactive" versus "normal" behavioral histories. Thus, neurological examination of "hyperactive" boys does reveal developmentally immature coordination.

Child↗