Logarithmic Time Scale Recording of AEP in Patients with Central Lesion

Abstract

Auditory brainstem responses (ABR), middle latency responses (MLR) and slow vertex responses (SVR) were recorded in patients with central lesion. The responses were assessed using logarithmic time scales. The recording to acoustic stimuli was carried out on the vertex-ipsilateral mastoid. The stimuli sound was click and the averaging numbers were 500 times and analysis time was 500msec. Pass-band of the filter was 2-200H. The results were as follow;
1) Two patients with acoustic tumors showed aprolongation of I-V interpeak latency (IPL) on ABR.
2) Another patient with acoustic tumor showed nowave II to VI on ABR and decreased amplitude of each component of MLR and SVR.
3) Another patient with acoustic tumor and pons bleeding showed no ABR and MLR.
4) A patient with bleeding of the pons showed aprolongation of III-V IPL on ABR.
5) A Patient with midbrain bleeding showed a prolongation of I-V IPL on ABR and absence of Pa-Na-Pb component of MLR.
6) The patients of cortical lesions showed various kinds of abnormality of MLR.
7) All of the patients showed a normal P2 of SVR.