The relationship between speech in noise perception and auditory working memory capacity in monolingual and bilingual adults.

Objective: Speech-in-noise perception is dependent on the interaction between sensory and cognitive processes. One factor that can relate to both processes is bilingualism. This study aimed to determine the correlation between auditory-working-memory and speech-in-noise in Persian monolinguals and Kurdish-Persian bilinguals.

Design: Speech-in-noise tests (sentences-in-noise and syllables-in-noise) and auditory-working-memory tests (forward and backward digit span, and n-back) were performed.

Study sample: Participants were 48 Kurdish-Persian bilinguals with a mean age of 24 (±4) years and 48 Persian monolinguals with a mean age of 25 (±2) years with normal hearing.

Results: Both language groups scored within normal limits in all memory and speech-in-noise tests. However, bilinguals performed significantly worse than monolinguals on all auditory-working-memory tests and the sentences-in-noise test. Monolinguals outperformed bilinguals in sentences-in-noise test (∼1.5 dB difference) and all auditory-working-memory tests (∼1 digit difference). The two groups did not significantly differ in syllables-in-noise test. Both groups had a significant correlation between working memory capacity and sentences-in-noise test. However, no significant correlation was found between syllables-in-noise and working memory capacity at any SNR.

Conclusions: Cognitive factors such as auditory working memory appear to correlate with speech-in-noise perception ability (at least at the sentence level) in monolingual and bilinguals young adults.