Brain Advance Access originally published online on May 30, 2008
Brain 2008 131(8):2002-2012; doi:10.1093/brain/awn104
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Speech perception ability in individuals with Friedreich ataxia
1Department of Otolaryngology, The University of Melbourne, East Melbourne 3002, Australia, 2Royal Victorian Eye & Ear Hospital and 3Murdoch Childrens Research Institute, Melbourne, Australia
Correspondence to: Assoc Prof. Gary Rance, PhD, Department of Otolaryngology, The University of Melbourne, 172 Victoria Parade, East Melbourne 3002, Australia E-mail: grance{at}unimelb.edu.au
The aim of this study was to investigate auditory pathway function and speech perception ability in individuals with Friedreich ataxia (FRDA). Ten subjects confirmed by genetic testing as being homozygous for a GAA expansion in intron 1 of the FXN gene were included. While each of the subjects demonstrated normal, or near normal sound detection, 3 of the 10 showed electrophysiological evidence of auditory pathway disorder [presenting with the auditory neuropathy/dyssynchrony (AN/AD) result pattern], and 9 of the 10 showed abnormal speech understanding when tested with levels of background noise typical of everyday listening conditions. Information transmission analyses of the speech perception findings for the three FRDA subjects with AN/AD type hearing loss when compared with those of a cohort of individuals with peripheral [sensorineural (SN)] hearing loss, showed a distinct pattern of perceptual disruption. Where the listeners with SN loss confused sounds on the basis of frequency (pitch) differences, the FRDA subjects with AN/AD made errors that reflected an inability to perceive temporal (timing) cues in the speech sounds.
Key Words: Friedreich ataxia; auditory; speech perception
Abbreviations: ABR, auditory brainstem response; AN/AD, auditory neuropathy/dyssynchrony; FRDA, Friedreich ataxia; SN, sensorineural; SNR, signal-to-noise ratio
Received February 14, 2008. Revised April 8, 2008. Accepted May 1, 2008.