Neurodegeneration, Neuroprotection, and Disease-Oriented NeuroscienceResearch PaperSuccessful treatment of auditory perceptual disorder in individuals with Friedreich ataxia
Section snippets
Experimental procedures
Ten subjects (four females) homozygous for GAA expansion of intron 1 of the FXN gene were recruited through the FRDA clinic at the Monash Medical Centre. As each subject was given the FM device at the end of the trial and as we had a limited number of systems, preference was given to school-aged children and adult subjects known to experience communication difficulties in background noise. Age at assessment ranged from 8 to 42 years and age at disease onset ranged from 5 to 20 years. See Table 1
Results
Detection of sinusoidal amplitude modulation was poorer in FRDA subjects than matched controls. Mean detection threshold for the FRDA group was −3.3±3.6 dB (68.4% of the maximum amplitude) and for the control group was −17.3±2.1 dB (13.6% of maximum) (Fig. 2). Paired T-testing showed a significant difference between matched subjects (T=13.1, P<0.001). AM detection thresholds for each of the FRDA subjects are shown in Table 1.
The masking effect of simultaneous noise was also greater in FRDA
Discussion
These data demonstrate the presence of auditory neuropathy and severe disruption of central auditory processing in individuals with FRDA. Each subject suffered an impaired ability to detect rapid signal changes suggesting a temporally distorted representation of auditory events (Zeng et al., 2005). Furthermore, they all showed a reduced ability to extract a tonal signal from within a background masking noise. Similar results have been reported previously for AN due to other forms of
Conclusion
Basic auditory processing was affected with each FRDA individual showing poorer temporal processing and figure/ground discrimination than their matched control. Functional hearing, particularly the perception of speech in background noise, was also impaired with FRDA listeners typically able to access only around 50% of the information available to their normal peers. The use of personal FM-listening devices did however, dramatically improve their ability to hear and communicate in everyday
Acknowledgments
We would like to express our appreciation to PHONAK Pty Ltd who donated the FM-devices used in the study. Also, thanks to the Friedreich Ataxia Research Alliance (FARA) for their support to the project. The corresponding author was also supported by the Wagstaff Research Fellowship in Otolaryngology. Finally, special thanks to the participants who gave their time so willingly.
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