Central auditory deficits and temporal-lobe lesions.

The capacity of auditory pathways from the weak ear (ear with the suppressed score in a dichotic listening test) to transmit speech information to the cortical processing areas was examined on 10 patients with unilateral temporal-lobe lesions. Three lines of evidence were developed to suggest that auditory pathways from the weak ear and speech information presented to the weak ear are not completely suppressed during dichotic stimulation. Speech in the weak ear frequently interacts with competing speech information in the strong ear causing contrasting articulatory features from the two ears to be blended into a single response. Two models of unilateral central auditory deficits are discussed: ipsilateral-suppression and transmission-line.