Neuro-otologic abnormalities in myelopathy associated with human T-cell lymphotropic virus type 1

Auditory testing (pure tone audiometry, auditory brain stem response), and vestibular tests (eye tracking test, optokinetic pattern test, and caloric test) were performed to define neuro-otologic abnormalities in myelopathy associated with human T-cell lymphotropic virus type 1. Of the eight patients tested, seven showed sensorineural hearing loss and one showed mixed hearing loss on pure tone audiometry. The auditory brain stem responses of five patients showed increases of the I-III and I-V interpeak latencies. Two patients showed fast superimposed saccadic movements on the smooth pursuit test, and one other patient showed canal paresis on the caloric test. These findings suggest both the presence of neuro-otologic abnormality and involvement of the brain stem in myelopathy associated with human T-cell lymphotropic virus type 1.