ABR results in patients with posterior fossa tumors and normal pure-tone hearing.

Sixteen patients with confirmed mass lesions of the posterior fossa and normal hearing sensitivity for pure tones were studied. Patients' main symptoms, auditory brain-stem response (ABR), and lesion size were analyzed. All patients manifested neurologic and/or otoneurologic symptoms or complained of hearing difficulty disproportionate to their pure-tone findings. Interestingly, the patients in this select group were younger (mean = 34 years) than the typical patient with a posterior fossa tumor. ABR results were abnormal in 15 of the patients, although several indices--including absolute and interwave latencies, interaural latency difference, and wave presence/absence--were employed to achieve this sensitivity. Lesion size varied considerably and failed to correlate with ABR or pure-tone results.