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Noise affects speech-signal processing differently in the cerebral hemispheres.
Y Shtyrov1, T Kujala, R J Ilmoniemi
1Department of Psychology, University of Helsinki, Finland.
Neuroreport
|July 29, 1999
Summary
Acoustic noise impacts speech perception differently in brain hemispheres. The left auditory cortex shows reduced responses, while the right auditory cortex may increase activity, suggesting a greater right hemisphere role in noisy conditions.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Speech Perception
Background:
- Cerebral asymmetry influences speech perception.
- Understanding how noise affects auditory processing is crucial for speech comprehension.
Purpose of the Study:
- To investigate the effects of acoustic noise on cerebral asymmetry in speech perception.
- To determine how noise modulates neural responses in the auditory cortex.
Main Methods:
- Magnetoencephalography (MEG) was used to measure brain activity.
- Responses to consonant-vowel syllables were recorded in silence and white noise.
- Analysis focused on differences in brain responses between hemispheres.
Main Results:
- Background noise differentially affected brain responses in the left and right auditory cortices.
- The left hemisphere showed a depressive effect on cortical responses to speech sounds.
- The right hemisphere was unaffected or showed increased activity, with altered P1, N1, and P2 source locations.
Conclusions:
- Noise may increase the involvement of the right hemisphere in speech sound processing.
- Additional right auditory cortex structures might be recruited to process speech in noisy environments.