Vocal tremor (VT) is a debilitating problem, but remains challenging to treat. Its pathophysiology remains indeterminate and there is a lack of consensus on phenotypes. Clinically, VT is often noted to be present in muscles outside of the larynx, including tongue, soft palate and pharyngeal constrictors, leading to the hypothesis that VT could impact swallowing as well as communication. In this article, the authors present a pilot study investigating the impact of vocal tremor on swallowing to support further understanding of VT phenotypes. They recruited 11 participants with essential tremor-related voice tremor (ETvt) and eight participants with isolated vocal tremor (iVT). Each participant completed two patient-reported outcome measure questionnaires – Quality of Life in Essential Tremor & Swallow Quality of Life (SWAL-QOL). A modified barium swallow study (MBSS) and analysis with Swallowtail™ software was completed to capture information on aspiration, penetration and swallow biomechanics. Cued and uncued swallows were included to capture potential differences. Sustained /a/ was recorded and analysed to provide rate and extent of fundamental frequency modulation. The results showed that hypopharyngeal transit was faster in participants with both VT phenotypes compared to normative data. However, total pharyngeal transit time was only faster in the iVT sub-group. There were no differences between VT subtypes for the SWAL-QoL or the penetration aspiration scale (PAS) scores. Participants rarely reported difficulties swallowing, suggesting a mismatch between the underlying biomechanics of swallowing and functional impact. The authors conclude that the slight differences in swallowing biomechanics relating to speed of bolus transit between VT phenotypes warrant further large-scale studies to investigate this phenomenon in more detail.
Does vocal tremor lead to changes in swallowing function?
Reviewed by Gemma Clunie
The Impact of Vocal Tremor on Deglutition: A Pilot Study
CONTRIBUTOR
Gemma Clunie
BA (Hon), MSc, PhD, MRCSLT, Imperial College Healthcare NHS Trust; Honorary Research Fellow, Imperial College London, UK.
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