title: Dichotic listening performance in subtypes of developmental dyslexia and a left temporal lobe brain tumor contrast group.
abstract: This study examined dichotic listening performance in three subtypes of developmental dyslexia and in children with left temporal lobe brain tumors (clinical contrast group). Each child was administered a free-recall CV syllable dichotic paradigm (30 pairs). Analysis of variance and Tukey-HSD pairwise follow-up comparison indicated that the dichotic listening performance of the left temporal lobe brain tumor contrast group (strong LEA/right ear suppression) was significantly different from those of the visual-spatial/dyseidetic (strong REA/left ear depression) and mixed (moderate REA/bilateral ear suppression) dyslexic subtypes. The language disorder/dysphonetic dyslexic subtype demonstrated a REA with right ear depression. Closer inspection of the individual performances of the language disorder/dysphonetic dyslexic subtype revealed a bimodal distribution with 12 subjects demonstrating a strong LEA/right ear suppression and 8 subjects exhibiting a strong REA/left ear depression. These results lend support for the contention that the dyslexic population is heterogeneous in nature with each subgroup exhibiting (1) a distinct neuropsychological test profile and reading pattern and (2) a pattern of performance on the dichotic listening task which is consistent with what would be expected based upon the pattern of dysfunction exhibited on neuropsychological evaluation.
authors.affiliation: Department of Neurology, Medical College of Georgia 30912.
authors.forename: M
authors.initials: M
authors.lastname: Cohen
authors.forename: G
authors.initials: G
authors.lastname: Hynd
authors.forename: K
authors.initials: K
authors.lastname: Hugdahl
mesh_terms: D000293:Adolescent; D001921:Brain / Q000503:physiopathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D004007:Dichotic Listening Tests; D004410:Dyslexia / Q000175:diagnosis* / Q000503:physiopathology; D004828:Epilepsies, Partial / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D007806:Language Disorders / Q000175:diagnosis; D007807:Language Tests; D008297:Male; D009483:Neuropsychological Tests; D000091402:Prohibitins; D013702:Temporal Lobe / Q000503:physiopathology*