Vestibular Evoked Myogenic Potential among Dizzy Patients

Click-evoked myogenic potential of cervical muscle to intense clicks shows a characteristic short-latency positivity-negativity, and it is thought to be due to vestibulo-collic reflex. In this study, in order to evaluate the origin, myogenic potential and caloric response were compared among 4 dizzy patients.In the first two case (right delayed endolymphatic hydrops and right acoustic tumor), the myogenic potential to the click of affected ear was normal, while caloric testing revealed a high CP % (71% and 53%). In the remaining two cases (right Meniere's disease and left acoustic tumor), myogenic response was abnormal compared with low CP % (21% and 29%).These discrepancies between myogenic potential and caloric response suggest that click-evoked short-latency myogenic potential may be dependent on lateral semicircular canal function.