Diagnostic value of electroencephalography and brainstem auditory evoked potentials in dizziness

Abstract

Electroencephalogram (EEG) and brainstem auditory evoked potentials (BAEP) were recorded from 142 dizzy patients. The results were compared with those obtained by other neurological examinations of the same patients. Thirty-three percent (N = 44) of the patients had an abnormal EEG: 21% (28) showed focal abnormality, 12% (16) irritative feature, and 10% (13) generalized disturbance. There were no differences in the distribution of abnormal EEGs in different diagnostic categories of dizziness, but irritative findings were not found in the cases of peripheral vestibular or psychogenic disturbances. EEG findings in 3 patients suggested temporal epilepsy, correlating with the clinical picture. BAEPs were abnormal in 18% (N = 21) of the recordings. There were 3 cases of MS and 5 ischaemic lesions in the vertebro-basilar region. Twelve of the 13 other patients with abnormal BAEP showed evidence of CNS pathology with other methods. EEG anormalities were mostly non-specific; however, the irritative findings suggested cerebral pathology, such as epilepsy. An abnormal BAEP offers reliable evidence for brainstem lesion and is thus a useful examination in dizziness.