J Audiol Otol.  2018 Jul;22(3):128-133. 10.7874/jao.2017.00283.

Brainstem Correlates of Comodulation Masking Release for Speech in Normal Hearing Adults

• Rostami S
• Moossavi A
• Ahadi M
• Jalaei S

• KMID: 2418916
• DOI: http://doi.org/10.7874/jao.2017.00283

Abstract

BACKGROUND AND OBJECTIVES
Weak signals embedded in fluctuating masker can be perceived more efficiently than similar signals embedded in unmodulated masker. This release from masking is known as comodulation masking release (CMR). In this paper, we investigate, neural correlates of CMR in the human auditory brainstem.
SUBJECTS AND METHODS
A total of 26 normal hearing subjects aged 18-30 years participated in this study. First, the impact of CMR was quantified by a behavioral experiment. After that, the brainstem correlates of CMR was investigated by the auditory brainstem response to complex sounds (cABR) in comodulated (CM) and unmodulated (UM) masking conditions.
RESULTS
The auditory brainstem responses are less susceptible to degradation in response to the speech syllable /da/ in the CM noise masker in comparison with the UM noise masker. In the CM noise masker, frequency-following response (FFR) and fundamental frequency (F0) were correlated with better behavioral CMR. Furthermore, the subcortical response timing of subjects with higher CMR was less affected by the CM noise masker, having higher stimulus-to-noise response correlations over the FFR range.
CONCLUSIONS
The results of the present study revealed a significant link between brainstem auditory processes and CMR. The findings of the present study show that cABR provides objective information about the neural correlates of CMR for speech stimulus.

Keyword

Comodulation masking release; Auditory brainstem response; Speech

MeSH Terms

Adult*
Brain Stem*
Evoked Potentials, Auditory, Brain Stem
Hearing*
Humans
Masks*
Noise