Slide Slam Q12
Finding a new treatment option for speech perception in noise difficulties in the elderly: a TMS study
Valérie Brisson1,2, Pascale Tremblay1,2; 1Université Laval, Québec, Canada, 2CERVO Brain Research Centre, Québec, Canada
Older adults frequently report having difficulties following conversations in noisy environments. Available therapies are not efficient to reduce these difficulties, which are associated with reduced social participation. The etiology of these difficulties is unclear but appears to be independent from peripheral hearing . A recent functional MRI study from our group  found that the activation patterns within the ‘speech network’ are different in young and older adults, including in the superior temporal sulcus (STS), which is implicated in phonological processing, and the ventral premotor cortex (PMv), which contains articulatory representations of speech sounds. Optimizing the functioning of these regions could alleviate speech perception in noise (SPiN) difficulties in the aging population. Transcranial magnetic stimulation (TMS) is a powerful tool to induce plasticity within specific brain regions. However, the potential of this method to reduce SPiN difficulties in adults is unknown. OBJECTIVE. The aim of this study was to determine if SPiN can be improved in young and older adults by excitatory TMS over the STS and the PMv. We expected that aging would be associated with lower SPiN performance and that all participants would show performance improvement after TMS. We also expected stronger TMS-induced benefits in younger adults, as their brain is presumed more plastic. METHOD. 34 healthy right-handed adults aged 32 to 79 years were recruited. Anatomical brain images (1 mm3, Philips Achieva 3T) were acquired for each participant. The targets for TMS (left STS, left PMv) were localized based on participants’ anatomy and previous studies [3-4]. The vertex was used for the sham condition. An excitatory intermittent theta-burst (iTBS) protocol  was used. After each stimulation, a sublexical SPiN task was run, in which participants had to indicate if pairs of syllables were identical or different. Cognition (MoCA; ) and hearing (tonal audiometry) were also evaluated. Multiple regressions were used to assess age effects on baseline (sham) performance (accuracy and reaction time (RT)). Cognitive level and hearing were included as covariates. Linear mixed models (LMM) were used to assess the effects of age, target and baseline performance on TMS-induced improvement scores (experimental – sham). RESULTS. Aging was associated with lower accuracy in the baseline condition (β = -0.37, p < 0.001). LMM analyses revealed a stronger gain in accuracy after PMv compared to pSTS stimulation (F(1, 25) = 7.19, p = 0.013). A lower baseline performance was associated with stronger improvement on accuracy (F(1, 25) = 6.16, p = 0.020) and RT (F(1, 24) = 23.70, p < 0.001). CONCLUSION. TMS can successfully improve SPiN performance. A better understanding of the etiology of SPiN decline and the factors that influence TMS responses will guide the development of new strategies, based on brain stimulation, to prevent these persistent difficulties in the aging population. REFERENCES.  Pichora-Fuller & Souza (2009). Int J Audiol.  Tremblay, Brisson & Deschamps (2021). Neuroimage.  Turkeltaub & Coslett (2010). Brain Lang.  Tremblay, Sato & Small (2012). Neuropsychologia.  Huang & al. (2005). Neuron.  Nasreddine (2005). JAGS.