Low frequency perceptive hearing loss in a patient with a brainstem tumor.

This paper reports a case of brainstem tumor with low frequency perceptive hearing loss. A 10-year-old girl had complained of headache, vomiting, dizziness and tinnitus of the right ear for 2 months and was admitted to Tokyo Medical College Hospital. Clinical examinations revealed a glioma in the lower brainstem which caused hydrocephalus, perceptive deafness with low frequency hearing loss, abnormal ABR consisting of only waves I-III, gaze nystagmus in all directions and abnormal patterns in both eyetracking and optokinetic nystagmus tests. MRI showed a tumor, probably a glioma, in the lower brainstem.She was treated with a V-P shunt operation to decrease cerebrospinal pressure followed by irradiation to lessen the tumor size. She showed noticeable improvement, and her hearing recovered to within the normal range with ABRs of I-IV waves.Low frequency perceptive hearing loss due to brainstem lesions is discussed with reference to our own 48 patients plus 14 described in the literature. Approximately one fourth of patients with hearing impairment due to a brain stem lesion have low frequency hearing loss. Ventro-lateral lesions of the pons and the medulla oblongata may be responsible for this type of deafness.