Gentamicin ototoxicity: clinical features and the effect on the human vestibulo-ocular reflex.
CONCLUSIONS
Gentamicin ototoxicity presents with gait imbalance and oscillopsia, but only rarely with hearing loss and vertigo. Sinusoidal rotational stimuli with high accelerations such as the bedside head-thrust test or rotational step changes in velocity are useful to diagnose bilateral vestibulopathy.


OBJECTIVE
To describe the salient clinical features and vestibular testing results in gentamicin ototoxicity.


METHODS
A retrospective review of the quantitative vestibular function testing results for patients presenting to the UCLA Neurotology Clinic with gentamicin ototoxicity over the past 10 years (n=35).


RESULTS
All patients presented with imbalance and 33 out of 35 had oscillopsia. Three patients reported a noticeable change in hearing and five reported vertigo. Of the 35 patients, 15 were in renal failure at the time of gentamicin administration. Patients with pre-existing peripheral neuropathy compensated poorly. Sinusoidal rotational testing demonstrated profoundly decreased gain and increased phase lead over the entire frequency range, with a subset of patients having relatively preserved gain at the intermediate frequencies (0.8-1.6 Hz) and low acceleration (<30 degrees/s). There was little or no response to high acceleration step changes in velocity. The time constant measured both by sinusoidal and step responses was ultra-low. All patients tested had a positive head-thrust test bilaterally.
Ishiyama
Gail
G
Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095, USA. gishiyama@mednet.ucla.edu
Ishiyama
Akira
A
Kerber
Kevin
K
Baloh
Robert W
RW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D005260:Female; D005839:Gentamicins / Q000009:adverse effects*; D019416:Head Movements / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic; D004856:Postural Balance; D012027:Reflex, Vestibulo-Ocular / Q000187:drug effects*; D012189:Retrospective Studies; D012438:Saccades; D012678:Sensation Disorders / Q000139:chemically induced; D014717:Vertigo; D014725:Vestibular Nerve / Q000503:physiopathology
D000900:Anti-Bacterial Agents; D005839:Gentamicins