The SISI test was given to 27 normal hearing subjects, 95 patients with cochlear lesion, 15 with VIIIth nerve lesion, and 3 patients with uncertain etiology. Test scores of 60% were taken to be indicative of cochlear involvement. Only 4 such patients failed to obtain a scale of 60%. The 11 patients with Vinth nerve tumor and 1 patient with internal carotid aneurysm had SISI Score of 0%. 3 patients with Vinth nerve involvement other than tumors met the 60% criterion. These tests appearly highly useful in determining the site of the lesion.