[ERA-findings by "cortical hearing disorder" (author's transl)].

Since about the last 2 years the late potential's component N1 (90--110 ms) as well as the early acoustically evoked potentials, appearing in a latency range of 1--8 ms and consisting of the nerve action potential (Pot. I) and the brain-stem potentials (Pot. II-V), were registered at some hearing impaired patients. This procedure enabled us to diagnose a "cortical hearing defect" at five patients: a) three children at an age of 2--3 years; they all have a slight cerebral damage, a hearing impairment and no speech-development; b) a 15 year old girl with a hearing impairment which is on the right side more severe than on the left side, as consequence of an encephalitis; and c) a 50 year old man suffering on both sides from a loss of temporal brain's substance and from a total deafness after an insult of both arteriae meningeae mediae. At all these patients the ERA-findings result in an almost normal behaviour of the bioelectrical transfer of the acoustic stimuli in the region of the brain-stem, whereas the late potential's component N1 showed a pathologic distortion. The ERA-results together with the anammesis make a "cortical hearing disorder" probable at these five patients. The audiograms and the ERA-characteristic lines are shown and discussed.