Weak Vestibular Response in Persistent Developmental Stuttering

Abstract

Vibrational energy created at the larynx during speech will deflect vestibular mechanoreceptors in humans (Todd et al., 2008; Curthoys, 2017; Curthoys et al., 2019). Vestibular-evoked myogenic potential (VEMP), an indirect measure of vestibular function, was assessed in 15 participants who stutter, with a non-stutter control group of 15 participants paired on age and sex. VEMP amplitude was 8.5 dB smaller in the stutter group than the non-stutter group (p = 0.035, 95% CI [−0.9, −16.1], t = −2.1, d = −0.8, conditional R2 = 0.88). The finding is subclinical as regards gravitoinertial function, and is interpreted with regard to speech-motor function in stuttering. There is overlap between brain areas receiving vestibular innervation, and brain areas identified as important in studies of persistent developmental stuttering. These include the auditory brainstem, cerebellar vermis, and the temporo-parietal junction. The finding supports the disruptive rhythm hypothesis (Howell et al., 1983; Howell, 2004) in which sensory inputs additional to own speech audition are fluency-enhancing when they coordinate with ongoing speech.

Sensorimotor Account of Multimodal Prosody

“…Such work will allow us to develop a more detailed understanding of vestibular contributions to the production and comprehension of speech, and may lead to the discovery of clinical interventions. In the meantime, theoretical details are not necessary for the identification of reliable biomarkers useful for early diagnosis and therapeutic routing (see Gattie et al, 2021; see also Efimova & Nikolaeva, 2020;Emami et al 2012).…”

“…In humans, vestibular-sensitive regions of the cortex are very diverse, and have been identified in areas near the temporoparietal junction, including the supramarginal and angular gyri, and posterior superior temporal gyrus, parietal operculum, and posterior insular cortex (Frank & Greenlee, 2018;see Lopez et al, 2012 for review). Notably, there is considerable overlap between vestibular-sensitive regions of the cortex and traditional areas of the language network as defined by Hickok and Poeppel (2007), including the superior planum temporale (SPT), BA 21, BA 22 (Wernicke's area), and BA 44/45 (Broca's area) (Gattie et al, 2021).…”

Sexual Dimorphism in VEMP peak to trough Latency

“…The current study assessed VEMP using a methodology developed for a pre-registered project (Gattie et al, 2019) assessing differences between groups who do and do not stutter . The study appraised VEMP amplitude and latency, using peak to trough measures with SCM tension controlled using biofeedback and a custom head bar apparatus, and analysis via linear mixedeffects regression modelling.…”