Audiovestibular findings in patients with deafness caused by a mitochondrial susceptibility mutation and precipitated by an inherited nuclear mutation or aminoglycosides
I. Braverman, L. Jaber, H. Levi, C. Adelman, K. S. Arons, N. Fischel-Ghodsian, M. Shohat and J. Elidan
Department of Otolaryngology-Head and Neck Surgery, Hadassah University Hospital, Jerusalem, Israel.
OBJECTIVE: To characterize the audiological and vestibular changes
associated with a mitochondrial DNA mutation in an Arab-Israeli family and
in other families with mitochondrial predisposition to
aminoglycoside-induced hearing loss. DESIGN: Evaluation of audiological
(pure tone thresholds, speech reception thresholds, speech discrimination,
tympanometry, acoustic reflex thresholds, tone decay, and auditory
brain-stem evoked response recording) and vestibular (complete history,
physical examination, and 2-channel electronystagmography) systems. In 5
patients, structural evaluation of the inner ear was done by magnetic
resonance imaging. PATIENTS: Fifteen members of an Arab-Israeli family, and
1 Chinese woman with the same mitochondrial DNA mutation who experienced
hearing loss after short-term exposure to streptomycin. RESULTS: Most of
the patients had a profound hearing loss due to cochlear involvement. The
hearing loss usually was not accompanied by notable peripheral vestibular
dysfunction. In the patient with severe hearing loss after exposure to
aminoglycoside, the vestibular function was completely normal. CONCLUSIONS:
In most of the Arab-Israeli patients with congenital deafness, the
vestibular system function was normal, in contrast to the frequency of
vestibular abnormality among deaf children, which was described in the
literature. This may be related to genetic predisposition to
aminoglycoside-induced deafness.
