AUDITORY BRAIN-STEM RESPONSES AFTER RADIOTHERAPY FOR NASOPHARYNGEAL CARCINOMA

The effect of irradiation for nasopharyngeal carcinoma on auditory bra instem responses and hearing was investigated in 19 otologically norma l patients undergoing standard fractionated megavoltage radiotherapy. Auditory brainstem responses and pure tone audiometry were performed b efore radiotherapy: and at 3 and 12 months after completion of radioth erapy. There were no significant changes in the wave I-III and III-V i nterpeak intervals, or in sensorineural hearing thresholds (bone condu ction at 4 kHz and average of bone conduction at 0.5, 1, 2 and 3 kHz), after radiotherapy. ln contrast to previous studies, we found no evok ed potential evidence of subclinical brainstem damage arising from irr adiation for nasopharyngeal carcinoma.