Left minineglect in dyslexic adults.
We searched for a core mechanism underlying the diverse behavioural and sensorimotor deficits in dyslexic subjects. In psychophysical temporal order judgement and line motion illusion tasks, adult dyslexics processed stimuli in the left visual hemifield significantly (approximately 15 ms) more slowly than normal readers, indicating a left-sided 'minineglect'. Furthermore, abrupt stimuli captured attention in both visual hemifields less effectively in dyslexics than in normal readers. These abnormalities could reflect right parietal lobe hypofunction, a consequence of a general magnocellular deficit demonstrated previously. Based on these and previous data, we propose a causal chain which could result in several sensory and cognitive deficits observed in dyslexic subjects.
Hari
R
R
Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland. hari@neuro.hut.fi
Renvall
H
H
Tanskanen
T
T
D000328:Adult; D001288:Attention; D004410:Dyslexia / Q000209:etiology* / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009039:Motion Perception; D010296:Parietal Lobe / Q000503:physiopathology*; D010468:Perceptual Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time; D013998:Time Perception; D014794:Visual Fields