Cochlear dysfunction in hyperuricemia: otoacoustic emission analysis.
OBJECTIVE
The objective of this study is to provide evidence that primary hyperuricemia is associated with cochlear dysfunction as other metabolic diseases that interfere with cell metabolism.


METHODS
Cochlear function was evaluated in 25 subjects with asymptomatic hyperuricemia using routine diagnostic audiometry along with transient evoked and distortion product otoacoustic emissions (TEOAE and DPOAE, respectively). To support the notion that vascular compromise was a significant underlying factor for such cochlear dysfunction, we assessed vascular anatomical and functional states through measuring the common carotid artery intima-media thickness and flow velocity of the basal intracranial vessels.


RESULTS
Compared with control subjects, reduced response levels of TEOAEs (P < .01) and amplitudes of DPOAEs (P < .001) were detected at higher frequencies. The reduced DPOAE levels at 5 kHz and TEOAEs at 4 kHz correlated significantly with uric acid (P < .05; P < .01), patients' age (P < .06; P < .05), duration since diagnosis of hyperuricemia (P < .05; P < .001), common carotid artery intima-media thickness (P < .05), mean flow velocities of middle cerebral arteries (P < .05), and vertebral arteries (P < .01). Multivariate analysis showed that the abnormalities at higher frequencies were significantly correlated with the duration and degree of hyperuricemia.


CONCLUSIONS
These data suggest that subclinical changes in cochlear function are associated with hyperuricemia. They support the usefulness of otoacoustic emissions in early detection of cochlear dysfunction. It is possible that hyperuricemia could be accompanied by increased stiffness and/or compromise of blood supply of the outer hair cells, which will impair their electromotile response.
Hamed
Sherifa A
SA
Department of Neurology, Assiut University Hospital, Assiut, Egypt. hamed_sherifa@yahoo.com
El-Attar
Amal M
AM
D000161:Acoustic Stimulation; D000328:Adult; D001300:Audiometry, Evoked Response; D001301:Audiometry, Pure-Tone / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D003051:Cochlea / Q000503:physiopathology*; D004534:Egypt; D005072:Evoked Potentials, Auditory; D006785:Hospitals, University; D006801:Humans; D033461:Hyperuricemia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D017585:Ultrasonography, Doppler, Transcranial