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Biomedical subjects

J Kershner

Publications and source records attributed to J Kershner.

9 recordsLinked to original sources
PubMed1995

The career success of an adult with a learning disability: a psychosocial study of amnesic-semantic aphasia.

B.I. is a 39-year-old, intellectually gifted (IQ = 130) man with learning disabilities who, without known cause, demonstrated symptoms of amnesic-semantic aphasia at age 13. This led to placement in a public school class for students with mild mental retardation and to his dropping out of school after repeating Grade 9. His aphasia is associated with a severe deficit in speech comprehension, poor reading and writing, spatial confusion, and episodic memory loss. We studied the remarkable behavioral and cognitive adjustments that have enabled him to lead a fulfilling life and become a highly successful business executive. Implications are discussed in the context of patterns of successful functioning and current views of the neuropsychological and neurological bases of such disorders.

Adaptation, Psychological↗
PubMed1992

Consonant-vowel lateralization in dyslexic children: deficit or compensatory development?

Two studies with the same subjects examined dyslexic children's puzzling superiority in forced left ear (LE) dichotic recall with consonant-vowel (CV) combinations. Thirty dysphonemic dyslexics were compared to 30 age-matched and 30 younger reading-matched normal readers. The children were tested in directed attention dichotic listening and in pseudoword decoding, word recognition, reading comprehension, spelling, arithmetic, and general intelligence (IQ). Failure to replicate the LE effect in the first experiment or in free-recall trials suggests its probable origin in aberrant attention/arousal rather than in deviant verbal lateralization. Experiment two replicated the superior LE effect in comparison to both control groups but also found the dyslexics poorer at the right ear (RE). Laterality coefficients confirmed that the dyslexics were more weakly lateralized. Corrections for stimulus dominance revealed that the uncorrected scores (1) concealed the extreme difficulty of the task and (2) obscured floor effects in the LE performance of the normals. Correlations suggest cautiously that CV lateralization may be associated inversely with reading comprehension and word decoding in the dyslexics and normal readers. The results provide mild support for the hypothesis that weak attentional lateralization for CVs in dyslexia may result from the precocious development of posterior right hemisphere attentional systems in compensation for presumed posterior left hemisphere lesions. No support was found for the competing hypothesis that such weak lateralization may be a component of the dyslexics' primary, correlated, or secondary deficit symptomatology.

Brain↗
PubMed1986

Sex-linked left lateralized central processor for hierarchically-structured material? Evidence from Broca's aphasia.

Based on a study with seven nonfluent aphasics, Grossman (Neuropsychologia 18, 299-308, 1980) advanced the 'central processor' claim that the mental representation of hierarchical linguistic structure is functionally equivalent to processing hierarchically-structured, nonlinguistic forms. Grossman reported that both abilities are compromised in Broca's aphasia. We attempted to replicate this effect with eight nonfluent aphasics using essentially the same task requiring the reconstruction from memory of stick designs. With the addition of controls for post-stroke interval, responding hand and gender, only the female aphasics had difficulty executing the hierarchical arrangement of visual-spatial materials. This sex difference disputes the strong form of the central processor hypothesis and supports the view that females may be more likely to possess partial noncomplementarity of specialization (dependence on the same hemisphere for selective language and spatial functions).

Adult↗
PubMed1984

Writing induces a right hemisphere linguistic advantage in dysphonetic dyslexic children: implications for attention and capacity models of laterality.

An experiment demonstrated a complete hemispheric processing reversal in 10 male, dysphonetic dyslexic children that occurred during a dichotic listening test of their verbal working memory. Requiring a written response to dichotic digits produced a right hemisphere/left ear superiority in the dysphonetic dyslexics whereas normal subjects and other dyslexics maintained a left hemisphere/right ear advantage. This reversal was unaffected by changes in task difficulty. A second experiment assessed the influence on producing the reversal of concurrent manual interference with left hemisphere verbal processing (responding orally vs. manually) and selective right hemisphere priming (Forward Writing vs. Backward Writing). The dysphonetic children reverted to a strong left hemisphere superiority when recalling the dichotic digits orally. Backward writing produced no ear advantage in either direction. The findings suggest that dysphonetic dyslexia may be related to (1) left hemisphere processing demands that exceed capacity, (2) easily activated right hemisphere processing strategies and (3) failure to coordinate linguistic processing interhemispherically. The results supported a novel hybrid conceptualization of dyslexia consisting of a synthesis of selective activation, and dual processor-limited capacity, theories.

Attention↗
PubMed1979

Megavitamins and learning disorders: a controlled double-blind experiment.

The study investigated the effectiveness of large amounts of ascorbic acid, niacinamide, calcium pantothenate, and pyridoxine when added to a low carbohydrate-high protein diet with 20 learning disabled children. After a double-blind, 6-month period of treatment, the addition of vitamins to the diet failed to produce significant improvements when compared to the diet alone on a variety of intellectual, school achievement, perceptual, and behavioral, measures. Regardless of their group assignment, 18 children showed improvements on a parent-administered behavior checklist. However, without a diet-placebo control group, these gains may have been produced by parental enthusiasm or the children's maturation rather than dietary control. The children's urinary excretion of kryptopyrrole was unrelated to whether or not they showed pre-, post-test gains and, therefore, proved to be invalid as a screening test for "vitamin dependent (on pharmacologic doses) learning disorders."

Adolescent↗