Language lateralisation and early right ear deafness: was Wernicke right?

The effects of early right ear deafness on lateralisation of auditory langu age functions are not fully known. A 36 year old right handed man, with a h istory of perinatal right ear deafness and undergoing evaluation for surgic al treatment of seizures that began at age 10 years was studied. Language l ateralisation testing by intracarotid sodium amobarbital injection showed r eceptive and expressive language functions to be strongly lateralised to th e left hemisphere. Results with intracarotid sodium amobarbital injection f urther suggested that transmission of auditory input to the patient's left hemisphere was partially dependent on ipsilateral left ear pathways. Cortic al language mapping through implanted subdural electrodes localised auditor y language functions to traditional left posterior perisylvian language are as. These results suggest that early right ear deafness does not impede lef t hemisphere lateralisation and localisation of auditory language functions . Moreover, transmission of auditory information to the patient's left hemi sphere seems to be accomplished, in part, by recruitment of ipsilateral lef t ear pathways.