Audio-visual analysis of vocal tremor derived from acoustics, laryngovideostroboscopy & HSDI
Acoustical, perceptual (sonographic), visual (endoscopic), or physiologic (EMG or EGG) methods are used to support clinical diagnosis of vocal tremor (VoT). The primary auditory test includes subjective clinically graded auditory impression of the generated voice while acoustics include various methods of signal analysis. Visual methods described in the literature encourage characterization of VoT using nasoendoscopy to identify whether VoT is present or absent within specific parts of vocal tract subcomponents or is a part of a more generalized tremor. Because chemical denervation of laryngeal musculature (Botox® injection) is the current VoT treatment approach, making detailed VoT analysis is imperative for determining which laryngeal muscles are involved, hence which muscle(s) are to be targeted for denervation. Consequently, we evaluated gains from a non-invasive VoT analysis using rigid stroboscopic (LVS) and from a HSDI evaluation protocol combined with acoustic patterns of VoT to improve identification of specific laryngeal musculature generating VoT.