Effect of SNR and Reverberation on Speech Perception of School-age children

Background: The aim of the study is to investigate the effect of SNR and reverberation on speech recognition in school-going children aged 8 to 12 years.

Methods: 36 typically developing children aged 8 to 12 years (mean age: 9.76 years, 22 males, 14 females) with Kannada as their mother tongue participated in the study. Spatial Separation Sentence Test, was administered in 12 conditions [2 reverberation times (RT) (Average RT60: 2.47sec, measured from 3 schools and short RT: Average RT-2SD i.e., 0.91sec), 2 SNRs (+10 and 0dB SNR) and noise distractor positions (distractor from right, left, and centre)]. Signal was always presented at the centre, and the children were tasked with verbal repetition of sentences in noise (speech-shaped). Adequate practice trials were given. Spatial advantage scores were calculated as the difference in the speech perception accuracy between collocated and separated conditions.

Results: Shapiro-Wilk normality test revealed normal distribution of data. Repeated measure ANOVA revealed no main effect of ear, and significant main effects of SNR [F(1,35) = 27.64, p < 0.001, ηp2 = 0.441] and RT [F(1,35) = 6.88, p = 0.013, ηp2 = 0.16]. There is no significant interaction effect between all the 3 variables, but present between RT and SNR [F(1,35) = 10.19, p = 0.003, ηp2 = 0.226]. Post hoc pairwise comparisons showed there is no effect of RT at both the SNRs, irrespective of the ear in which distractor was given. However, for 0 dB SNR, there was an effect of distractor location on spatial advantage scores. Spatial advantage was significantly (p <0.01) seen when the distractor was located in the right plane compared to left, for both short and average RT. The effect of SNR on spatial advantage scores depended on the location of the distractor. When the distractor is on the right side, significant effect was seen in average RT condition (p <0.01) and was approaching significance for short RT condition (p = 0.06).

Conclusions: The study highlights that the interaction between SNR, RT, and distractor position significantly influences speech recognition in school-going children. Lower SNR and average RT conditions presented a right ear spatial advantage. These results emphasize the need for optimal classroom acoustics, especially in noise levels and spatial layout, to facilitate effective learning in children.