Auditory processing in individuals with auditory neuropathy

Behavioral and Brain Functions

Ajith U Kumar²  M Jayaram¹ 

[1] Director, All India Institute of Speech and Hearing, Manasagangothri, Mysore, Karnataka, 570006, India

[2] Junior Research Fellow, Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysore, Karnataka, 570006, India

关键词: LLRs and MMN;    temporal processing;    speech perception;    Auditory neuropathy;   

Others  :  800193
DOI  :  10.1186/1744-9081-1-21

 received in 2005-06-06, accepted in 2005-12-01,  发布年份 2005

【 摘 要 】

Background

Auditory neuropathy is a disorder characterized by no or severely impaired auditory brainstem responses in presence of normal otoacoustic emissions and/or cochlear microphonics. Speech perception abilities in these individuals are disproportionate to their hearing sensitivity and reported to be dependent on cortical evoked potentials and temporal processing abilities. The disproportionate loss of auditory percept in presence of normal cochlear function is suggestive of impairment of auditory neural synchrony.

Methods

We studied the auditory evoked potentials and psychophysical abilities in 14 adults with auditory neuropathy to characterize their perceptual capabilities. Psychophysical tests included measurement of open set speech identification scores, just noticeable difference for transition duration of syllable /da/ and temporal modulation transfer function. Auditory evoked potentials measures were, recording of P₁/N₁, P₂/N₂ complex and mismatch negativity (MMN).

Results

Results revealed a significant correlation between temporal processing deficits and speech perception abilities. In majority of individuals with auditory neuropathy P₁/N₁, P₂/N₂ complex and mismatch negativity could be elicited with normal amplitude and latency. None of the measured evoked potential parameters correlated with the speech perception scores. Many of the subjects with auditory neuropathy showed normal MMN even though they could not discriminate the stimulus contrast behaviorally.

Conclusion

Conclusions drawn from the study are

1. Individuals with auditory neuropathy have severely affected temporal processing.

2. The presence of MMN may not be directly linked to presence of behavioral discrimination and to speech perception capabilities at least in adults with auditory neuropathy.

【 授权许可】

   
2005 Kumar and Jayaram; licensee BioMed Central Ltd.

【 图 表 】

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