Sacculo-collic pathway dysfunction accompanying auditory neuropathy.
CONCLUSIONS
In a patient with bilateral auditory neuropathy (AN), the vestibular-evoked myogenic potential (VEMP) was probably absent because of a neuropathy involving the inferior vestibular nerve and/or its end organ, the saccule. Our result can therefore be interpreted as a concomitant unilateral sacculo-collic neuropathy. We suggest the use of more precise terms to characterize AN patients with involvement of different parts of the inner ear and its innervations. We encourage detailed vestibular assessment in patients with AN in order to assess the co-existence of any symptomatic or asymptomatic vestibular disorder. Information such as that provided in this report will be valuable for clinicians caring for this group of patients.


OBJECTIVE
AN is a disorder characterized by the absence or severe impairment of auditory brainstem responses in the presence of normal cochlear outer hair cell function as revealed by otoacoustic emissions (OAEs) and/or electrocochleography (ECoG). A variety of processes and etiologies are thought to be involved in its pathophysiology. In most literature reports the auditory profile of patients with AN is discussed. However, the extent of vestibular involvement, especially that involving the saccule, is not known. We performed vestibular tests to assess the status of the saccule in a patient with AN.


METHODS
One patient with AN was studied. The patient was a right-handed 21-year-old female with chief complaints of hearing loss and speech perception difficulty.


RESULTS
The auditory test results were consistent with the diagnosis of AN, i.e. absent auditory brainstem responses, moderate hearing loss, an inappropriately profound speech discrimination score and the presence of OAEs and measurable cochlear microphonics on ECoG. On neurological examination, gait and balance tests were normal. Ice-water caloric testing induced a sensation of dizziness in both ears. Short tone-burst VEMPs showed no response on left-ear stimulation and a biphasic response with normal latency and amplitude on right-ear stimulation.
Sheykholeslami
Kianoush
K
Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. kianoush48@yahoo.com
Schmerber
Sébastien
S
Habiby Kermany
Mohammad
M
Kaga
Kimitaka
K
D000328:Adult; D001300:Audiometry, Evoked Response; D001301:Audiometry, Pure-Tone; D001308:Auditory Perceptual Disorders / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D003056:Cochlear Nerve; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006310:Hearing Aids; D006311:Hearing Disorders / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D046089:Hearing Loss, Mixed Conductive-Sensorineural / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D012444:Saccule and Utricle / Q000503:physiopathology; D013063:Speech Discrimination Tests; D013067:Speech Perception; D014057:Tomography, X-Ray Computed; D014722:Vestibule, Labyrinth / Q000503:physiopathology*; D000160:Vestibulocochlear Nerve Diseases / Q000150:complications*