title: Handedness and language cerebral lateralization.
abstract: Repetitive transcranial magnetic stimulation (rTMS) induces lateralized speech arrest consistent with cerebral dominance for language. Studies of language cerebral dominance in differently handed healthy subjects have been limited. Using a focal magnetic coil, we examined the degree of consistency between handedness as evaluated by the Stanley Coren Score and hemispheric dominance for language as determined by rTMS in 25 right- and 25 left-handed medical students. They were categorized according to the score into 24 strongly right-handed, 1 moderately right-handed, 19 strongly left-handed, 3 moderately left-handed and 3 ambidextrous (equally-handed). In the strongly right-handed subjects, left-sided language cerebral dominance was recorded in 87.5% of the subjects, and bilateral cerebral representation in 8.2%, and right-sided language cerebral dominance in 4.2%. In the strongly left-handed subjects, 73.7% had left-side language cerebral dominance, 15.8% had bilateral cerebral representation and 10.5% had right-side cerebral language dominance. In mixed handed subjects (moderately right, left and ambidextrous), bilateral cerebral representation was observed in 57% and left-side cerebral language dominance in 43%. There were 27 subjects who developed speech arrest at 140% of motor threshold, the others developed speech arrest at lower intensities. Speech lateralized to the left-side cerebral dominance in strongly right- and left-handed subjects, but bilateral cerebral representation was frequent in mixed handedness and right-sided cerebral dominance rarely occurred.
authors.affiliation: Department of Neurology, The University Hospital, Assiut, Egypt. Emankhedr99@yahoo.com
authors.forename: Eman M
authors.initials: EM
authors.lastname: Khedr
authors.forename: Enas
authors.initials: E
authors.lastname: Hamed
authors.forename: Anwar
authors.initials: A
authors.lastname: Said
authors.forename: Jamal
authors.initials: J
authors.lastname: Basahi
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology*; D004558:Electric Stimulation; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008280:Magnetics; D008297:Male; D013060:Speech / Q000502:physiology*