Poster D84, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
The Neurobiology of Speech Perception in Noise in Amateur Singers and Non-Singers
Maxime Perron1,2, Valérie Brisson1,2, Émilie Belley1,2, Josée Vaillancourt1, Johanna-Pascale Roy1, Philip L. Jackson1,2, Pascale Tremblay1,2;1Université Laval, Quebec City, 2CERVO Brain Research Centre, Quebec City
INTRODUCTION. Compared to non-musicians, professional musicians show evidence of functional and structural neuroplasticity (Fauvel et al., 2014; Sluming et al., 2007) that has been associated with auditory and cognitive benefits (Alain, et al., 2014; Parbery-Clark et al., 2011), including better sensitivity to speech in noise. In contrast to professional musicians, amateur musicians, such as choral singers, have been less extensively studied. In addition to being cognitively demanding, singing relies on language and speech functions, and is likely to be associated with plasticity within and beyond the neural system supporting language. The aim of this study was to investigate speech perception in noise in younger and older adult choral singers and non-singers in relation with brain structure. METHODS. 41 choral singers and 41 non-singers aged 20 to 87 years underwent cognitive (MOCA) and hearing (pure tone thresholds) evaluations and completed an auditory syllable discrimination task under three conditions of babble noise (no noise, high intelligibility, low intelligibility). For each condition, sensitivity (d’), response bias (c), reaction time (RT) and overall accuracy were calculated. MPRAGE (1 mm3) sequences were acquired on a Philips 3.0T MRI and were processed with Freesurfer 6. Volume, thickness and surface were calculated for each region and corrected for head size (region value/total hemisphere value). ANALYSES. Preliminary analyses focused on a subgroup of 10 singers and 10 non-singers that were matched for age (t = -.339, p = .739), sex (χ2 = .202, p = .653) and MOCA (t = -.290, p = .775). A series of moderation analyses was conducted (one for each dependent variable d’, c, RT, and overall accuracy) with group (singers, non-singers) as the independent variable, ratio of gray matter measures as the moderator, and hearing as a covariate. FINDINGS. Main effects of group were found for overall accuracy (β = -111.24, t = -2.88, p = .012) and d’ (β = -2.20, t = -2.82, p = .013) at low intelligibility, with better performance for the singers. Interactions between group and thickness was found at high and low intelligibility for overall accuracy (high: β = 68.12, t = 2.18, p= .046; low: β = 97.61, t = 2.93, p = .010) and d’ (high: β = 1.35, t = 2.16, p = .048; low: β = 1.93, t = 2.86, p = .01) in the left premotor (LPM) cortex. These interactions were characterized by a positive relationship between thickness and accuracy for singers and a negative (low) relationship or no relationship (high) between thickness and accuracy for non-singers. DISCUSSION. Our results suggest that amateur singing was associated with better speech perception in noise due to structural changes within the neural speech system, in particular within the LPM. It has been proposed that LPM contains sublexical speech representations (Guenther & Vladusich, 2012). Amateur singers may have access to richer top-down information from the LPM, which could facilitate speech perception in degraded listening conditions, supporting modern versions of the motor theory of speech perception (for a recent review, see e.g. McGettigan & Tremblay, 2018).
Themes: Speech Perception, Perception: Auditory
Method: Other