Performance intensity functions in cochlear and eighth nerve disorders

In this report, performance intensity functions for monosyllabic materials (PI-PB) were obtained on two groups of subject: 20 patients with eighth nerve pathology and 15 individuals with Meniere's disease. The subjects with retrocochlear involvement exhibited marked deterioration in word recognition as the speech intensity was increased beyond the level required for a maximum discrimination score. Such a dramatic breakdown, referred to as the "rollover effect," was not seen to occur among the subjects with cochlear disorders. Hence, the PI-PB function appears to be a valuable tool for use in the special test battery.