Effects of Whole Body Vibration and Direct Laryngeal Vibration on Perilaryngeal Relaxation
Channel: Alex Schenck
Date: 2020-05-14

Alexandra Schenck, BM, Graduate Student, Northwestern University Feinberg School of Medicine: Department of Otolaryngology-Head and 
  
Jonelyn Langenstein, MM, MS, CCC-SLP, BCS-S, Clinical Faculty, Northwestern University Feinberg School of Medicine: Department of Otolaryngology-Head and Neck Surgery, Chicago, IL

Michiel J Bove, MD, Laryngologist, Northwestern University Feinberg School of Medicine: Department of Otolaryngology-Head and Neck Surgery, Chicago, IL

Caroline P.E. Price, BA, CCRC, Research Coordinator, Northwestern University Feinberg School of Medicine: Department of Otolaryngology-Head and Neck Surgery, Chicago, IL

ABSTRACT:
Importance:
Muscle tension dysphonia (MTD) is defined as excessive tension in the perilaryngeal and laryngeal muscles resulting in discomfort in the affected musculature and complaints of hoarseness. Lower frequency vibration (20−50 Hz) has been used to release muscle tension by inhibiting muscle activity. Localized vibration on the perilaryngeal muscles and whole-body vibration have both shown to be effective methods for relieving vocal fatigue. Due to the convenience of application, direct vibration is used more widely than whole-body vibration. However, there may be additional benefits, to whole-body vibration when postural adjustments are considered. Vocal production is a whole-body activity which can be affected by postural issues and tension outside of the peri laryngeal musculature. Emerging research suggests that whole-body vibration may improve rounded shoulder posture.
 
Objective:
We aimed to test whether whole-body vibration and resultant whole-body postural adjustments leads to greater relaxation of laryngeal musculature than direct vibration. We predicted that whole-body vibration would have a greater effect on the degree of laryngeal muscle tension due to possible posture-improving effects of the treatment. 
Previous studies have established qualitative improvement using self-reported measures of vocal fatigue. We aimed to show improvements in laryngeal relaxation through direct assessment of laryngeal structures using quantitative measurement. The Laryngeal Palpatory Scale (LPS) is a valid and reliable instrument for quantitative measurements of severity of tension and postural issues in the head, neck, and shoulders which impact voice production.

Design/Setting/Participants: 
A multiple treatment reversal design was conducted at Northwestern Memorial Hospital, affiliated with Northwestern University on a single subject. The subject was a 23-year-old female with primary MTD. Data collection was performed by an expert clinician, blinded to the experimental condition, who administered the LPS following each session during all phases. 
In phase A1, a baseline level on the LPS was established. In phase B, the treatment of whole-body vibration was introduced, in phase C, direct laryngeal vibration (C).  The participant will then be returned to a baseline phase before reintroducing each treatment in reverse order to control for carryover effects.  

Interventions:
Direct laryngeal vibration: Fovel massager was used to apply vibration to the perilaryngeal muscles at 40 Hz for 10 minutes.
Massage targeted the bilateral sternocleidomastoid muscle, bilateral thyrohyoid space, and submental muscles for 1 minute in each position for two cycles.
Whole-body vibration: Subject stood on a Best Choice Products SKY3197 Full Body Vibration Platform set on a low-frequency setting (40 Hz) for 10 minutes.

Outcome and Measures: 
The outcome measure was totaled scores on the LPS compared before and after each treatment. 
Data was analyzed and compared between adjacent experimental phases. 

Results and conclusions: 
The results suggest that both direct laryngeal vibration and whole-body vibration promote relaxation of the perilaryngeal musculature
We did not find that measures on the LPS were lower during full body vibration trials than indirect laryngeal vibration trials.