Auditory and vestibular findings in Fabry disease: a study of hemizygous males and heterozygous females

Aim: This study aimed to evaluate audiological and vestibular involvement in Fabry disease and the early effects of enzyme replacement therapy with human alpha-galactosidase A. Methods: Fourteen patients ( 10 males, 4 females) aged 14 - 57 years were studied. Each patient underwent a clinical ( history of otological and vestibular aspects, otoscopy) and instrumental ( pure tone and speech audiometry, impedance, auditory brainstem response and oto-acoustic emission recordings, vestibular caloric tests, electronystagmography during acceleratory stimulation, dynamic posturography) evaluation before starting enzyme replacement therapy. Results: Fifty per cent of patients complained of hearing symptoms ( hearing loss, tinnitus, ear fullness). Subjective hearing loss was present in six cases and in three cases it was the first reported symptom of Fabry disease. In six of the seven cases the onset and/or progression of hearing symptoms were sudden. Vertigo or dizziness was reported by four patients and in two cases was associated with hearing symptoms. Audiological evaluation showed sensorineural hearing loss in eight patients ( 5 males, 3 females). Hearing loss was unilateral in six cases and bilateral in the remaining two cases. The hearing loss (HL) ranged from 30 to 80 dB HL ( mean, 43 dB HL) and the lesion was always cochlear. Vestibular examination showed abnormalities in four patients ( bilateral weak/abolished response in three cases, side prevalence in one case), which were not related to either the audiological results or the history of vertigo/dizziness. Conclusion: Involvement of the inner ear is common in men and women with Fabry disease. We found a high incidence of cochlear hearing loss, which was typically unilateral and showed onset and/or progression by sudden episodes. Vascular or hydropic mechanisms could be hypothesized to explain audiological findings. Vestibular involvement had a lower incidence and showed a different pattern, thus suggesting that several pathophysiological mechanisms could play a role in determining inner ear damage in Fabry disease. Our preliminary results show that enzyme replacement therapy may stabilize hearing function; however, further follow-up is required.