The Journal of International Advanced Otology
Original Article

Audiological and Vestibular Findings in Subjects with MELAS Syndrome

1.

Department of Otolaryngology, Head & Neck Surgery and Audiology, Aalborg University Hospital, Aalborg, Denmark;Department of Clinical Medicine, Aalborg University School of Medicine, Denmark

2.

Aalborg University School of Health Science, Denmark

3.

Department of Clinical Medicine, Aalborg University School of Medicine, Denmark;Department of Clinical Genetics, Aalborg University Hospital, Denmark

4.

Department of Clinical Medicine, Aalborg University School of Medicine, Denmark;Research and Knowledge Center in Sensory Genetics, Aalborg University Hospital, Denmark

J Int Adv Otol 2019; 15: 296-303
DOI: 10.5152/iao.2019.5913
Read: 119 Downloads: 36 Published: 03 September 2019

Abstract

 

OBJECTIVES: The mitochondrial DNA (mtDNA) point mutation m.3243A>G is known to express the following two syndromes among others: maternally inherited diabetes and deafness (MIDD) and mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Sensorineural hearing loss (SNHL) is the most frequent symptom in individuals harboring the m.3243A>G mutation. However, dysfunction of the vestibular organs has been scarcely examined. Therefore, the present study aimed to study the impact of the m.3243A>G mutation on the inner ear.

 

MATERIALS and METHODS: A total of 8 subjects harboring the blood-verified m.3243A>G mutation underwent thorough audiological and vestibular examinations, including tone and speech audiometry, video head impulse test (vHIT), ocular and cervical vestibular-evoked myogenic potential (oVEMP and cVEMP), and full otoneurological examination. The subjects also answered a Dizziness Handicap Inventory (DHI) questionnaire.

 

RESULTS: SNHL was identified in all the 8 subjects, with a mean pure-tone average-4 (PTA-4) of 59 dB. Speech discrimination score (n=7) ranged from 24% to 100% (mean 74%), and vHIT (n=42) detected pathology in nine lateral semicircular canals (SCCs), five posterior SCCs, and one anterior SCC, whereas three measurements were inconclusive. All oVEMPs (n=14 ears) were absent, nine cVEMPs were absent, and two were inconclusive. Based on the DHI scores, 6 subjects reported none to mild dizziness, 1 reported moderate, and 1 reported severe dizziness.

 

CONCLUSION: Our study population had pathological findings from every audiological and vestibular end organs. The results indicated that the pathological findings originated from within the end organs themselves and not within the superior and inferior vestibular or cochlear nerve.

 

Cite this article as: Hougaard DD, Hestoy DH, Højland AT, Gaihede M, Petersen MB. Audiological and Vestibular Findings in Subjects with MELAS Syndrome. J Int Adv Otol 2019; 15(2): 296-303.

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ISSN1308-7649 EISSN 2148-3817