Sacculo-collic pathway dysfunction accompanying auditory neuropathy

Abstract

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.

Vestibular dysfunction in a Japanese patient with a mutation in the gene OPA1

“…It has been reported that VEMPs are less affected than horizontal semicircular canal function during caloric testing in bilateral vestibulopathy [21]. We found only two reports with results of both caloric testing and VEMP analysis in auditory neuropathy patients with causes other than an OPA1 mutation [20,22], and these revealed normal caloric responses and abnormal VEMPs in all patients (n = 4) with auditory neuropathy. We revealed a different profile in a patient with auditory neuropathy due to an OPA1 mutation.…”

“…The VEMP consists of myogenic potentials obtained as a response to tone-burst stimuli and is used to test the saccule and inferior vestibular nerve of the vestibular system. The caloric test, on the other hand, is used to evaluate the function of the lateral semicircular canals and the superior vestibular nerve [20]. In the right ear, there was no response in the caloric test but fare VEMPs.…”

Vestibular test findings in individuals with auditory neuropathy: review

“…This correlates with reports of normal functioning in patients with auditory neuropathy on saccade, gaze and optokinetic tests. 5,[7][8][9] A subsequent case study by Sheykholeslami et al revealed no involvement of the superior vestibular nerve and its end organ, the semicircular canal, in a patient with isolated auditory neuropathy. 9 Caloric stimulation elicited a normal response in the patient, with normal functioning on other central and peripheral ENG tests.…”

“…5,[7][8][9] A subsequent case study by Sheykholeslami et al revealed no involvement of the superior vestibular nerve and its end organ, the semicircular canal, in a patient with isolated auditory neuropathy. 9 Caloric stimulation elicited a normal response in the patient, with normal functioning on other central and peripheral ENG tests. This indicates that there is also a range of variability in terms of the vestibular system status of auditory neuropathy patients who do not present with peripheral neuropathy.…”

Vestibular nerve functions in children with auditory neuropathy

“…In one study, a case of abnormal VEMP test was reported despite the normal ENG and caloric tests [15]. VEMP was used for this and another auditory neuropathy case reported by the same author and the test yielded no wave on one side in this case, as well [16]. The clinical picture and etiology of auditory neuropathy is discussed in the literature usually in relation to the auditory system.…”