title: Audiological manifestations in mitochondrial encephalomyopathy lactic acidosis and stroke like episodes (MELAS) syndrome.
abstract: OBJECTIVE
  Reports of audiological manifestations in specific subgroups of mitochondrial disorders are limited. This study aims to describe the audiological findings in patients with MELAS syndrome and m.3243A>G mutation.
  
  
  METHODS
  Audiological evaluation was carried out in eight patients with confirmed MELAS syndrome and m.3243A>G mutation. The evaluation included a complete neurological evaluation, pure tone audiometry (n=8), otoacoustic emissions (n=8) and brainstem evoked response audiometry (n=6), magnetic resonance imaging (n=8) and muscle biospy (n=6).
  
  
  RESULTS
  Eight patients (Age range: 5-45 years; M:F-1:3) including six children and two adults underwent formal audiological evaluation. Five patients had hearing loss; of these two had "subclinical hearing loss", one had moderate and two had severe hearing loss. The abnormalities included abnormal audiometry (n=5), otoacoustic emission testing (n=7) and absent brainstem auditory evoked responses (n=1). The findings were suggestive of cochlear involvement in four and retrocochlear in one.
  
  
  CONCLUSIONS
  This study shows that hearing loss of both cochlear and retrocochlear origin occurs in patients with MELAS and may be subclinical. Early referrals for audiological evaluation is warranted to recognize the subclinical hearing loss in these patients. The therapeutic implications include early interventions in the form of hearing aids, cochlear implants and cautioning the physicians for avoidance of aminoglycosides.
authors.affiliation: Dept. of Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: vpvandana@gmail.com.
authors.forename: V P
authors.initials: VP
authors.lastname: Vandana
authors.affiliation: Dept. of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: drpsbindu@yahoo.co.in.
authors.forename: Parayil Sankaran
authors.initials: PS
authors.lastname: Bindu
authors.affiliation: Dept. of Clinical Neurosciences, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: sonamkothari86@yahoo.com.
authors.forename: Kothari
authors.initials: K
authors.lastname: Sonam
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India. Electronic address: pgovinth@gmail.com.
authors.forename: Periyasamy
authors.initials: P
authors.lastname: Govindaraj
authors.affiliation: Dept. of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: abtaly@yahoo.com.
authors.forename: Arun B
authors.initials: AB
authors.lastname: Taly
authors.affiliation: Dept. of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: gayathrin12@rediffmail.com.
authors.forename: Narayanappa
authors.initials: N
authors.lastname: Gayathri
authors.affiliation: Dept. of Clinical Neurosciences, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.
authors.forename: Shwetha
authors.initials: S
authors.lastname: Chiplunkar
authors.affiliation: Dept. of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: drgobiraj76@yahoo.com.
authors.forename: Chikkanna
authors.initials: C
authors.lastname: Govindaraju
authors.affiliation: Dept. of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: aravind.radiology@gmail.com.
authors.forename: H R
authors.initials: HR
authors.lastname: Arvinda
authors.affiliation: Dept. of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: madhu_nagappa@yahoo.co.in.
authors.forename: Madhu
authors.initials: M
authors.lastname: Nagappa
authors.affiliation: Dept. of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. Electronic address: sanjib_sinha2004@yahoo.co.in.
authors.forename: Sanjib
authors.initials: S
authors.lastname: Sinha
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India. Electronic address: thangs@ccmb.res.in.
authors.forename: Kumarasamy
authors.initials: K
authors.lastname: Thangaraj
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis / Q000209:etiology*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D017241:MELAS Syndrome / Q000150:complications*; D008297:Male; D008875:Middle Aged
keywords: Auditory neuropathy; MELAS; Sensory neural deafness; m.3243A>G