Normal planum temporale asymmetry in dyslexics with a magnocellular pathway deficit.
Developmental dyslexia has been associated with both abnormal hemispheric symmetry of the planum temporale (PT) and a deficit in the magnocellular visual pathway. We examined the relationship between these two abnormalities. Using sagittal magnetic resonance images and three methods, we measured the PT in dyslexic subjects with a documented magnocellular deficit and controls. Dyslexic subjects did not deviate from normal leftward PT asymmetry, but both groups became less left-lateralized with methods that excluded sulcul tissue. Results suggest that dyslexic subjects with a magnocellular deficit do not always have abnormal symmetry of the PT. PT symmetry may instead be related to a different subtype of dyslexia. In addition, PT asymmetry in any subject group depends on the measurement method.
Best
M
M
Department of Clinical and Health Psychology, MCP Hahnemann University, Philadelphia, PA 19103, USA.
Demb
J B
JB
D000328:Adult; D001306:Auditory Pathways / Q000473:pathology*; D004410:Dyslexia / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012016:Reference Values; D013702:Temporal Lobe / Q000473:pathology*; D014795:Visual Pathways / Q000473:pathology*