Myotonometry demonstrates changes of lingual musculature in obstructive sleep apnoea

Abstract

Upper airway dilator muscles are important in the pathogenesis of obstructive sleep apnoea (OSA). Previously, soft palate and tongue muscles of patients with OSA have been studied from a histological point of view. Electromyographic studies revealed increased activity of upper airway dilator muscles. We used computerized endopharyngeal myotonometry (CEM) to measure the biomechanical properties of lingual musculature, mainly the genioglossal muscle, to characterize changes of tongue muscles in patients with OSAS. The method records and analyzes the response of the tongue sublingually after a brief mechanical impact. It enabled us to evaluate the most important parameters of tissue tone--stiffness, which is expressed as a frequency, and elasticity, as a logarithmic decrement of the damped oscillation. The results of CEM indicated that patients with OSAS show an increased stiffness (14.1 +/- 0.7 Hz) of the tongue in comparison with non-snoring subjects (11.5 +/- 0.2 Hz). The elasticity of the tongue is decreased, which is numerically expressed as an increased decrement (4.0 +/- 0.2) in patients with OSA in comparison with non-snorers (2.2 +/- 0.2). Changes in the biomechanical characteristics of lingual musculature during wakefulness could result from pathophysiological processes caused by obstructive sleep apnoea.

Increased muscle belly and tendon stiffness in patients with Parkinson's disease, as measured by myotonometry

“…The previously reported greater stiffness in the muscle belly3, 4 and hypothesized stiffening of muscle tendon in PD may together contribute to an increased tonic stretch reflex7–10 and shortening reaction,11–14 which are considered potential mechanisms of parkinsonian rigidity at the spinal level. Separate assessment of passive stiffness in the muscle belly and tendon in PD has not yet been reported, although it can be evaluated by myotonometry, a reliable,19 sensitive3, 4, 20, 21 method for measuring mechanical properties in human soft tissues. Findings from the present study can contribute to a better understanding of parkinsonian rigidity mechanisms and may also have therapeutic and diagnostic implications.…”

Obstructive Sleep Apnea: MR Imaging Volume Segmentation Analysis

“…Mechanic and mathematic models of airway dynamics consistently implicate airway elasticity in airway dynamics and collapse (33,37,39,40). Increased airway tissue elasticity in adults with OSA has been demonstrated with a variety of in vivo and ex vivo methods (32,34,35,41,42). Hypotonia and increased elasticity are associated with OSA in children in the absence of lymphoid tissue hyperplasia, with certain syndromes such as Down syndrome, and with other anatomic causes of obstruction (43).…”

“…OSA is known to result from anatomic obstructions, which include enlarged tonsils, macroglossia, micrognathia, and retrognathia (9 -13). Airway compliance or elasticity, however, has also been implicated in OSA (32)(33)(34)(35)(36)(37)(38). Mechanic and mathematic models of airway dynamics consistently implicate airway elasticity in airway dynamics and collapse (33,37,39,40).…”

Perceptual and instrumental assessments of orofacial muscle tone in dysarthric and normal speakers

“…The Myoton was originally developed to measure muscle tone in large muscles of the torso and limbs, and recent reports indicate good reliability over time for individuals with stroke and healthy older people [46][47]. Investigations using an earlier version of the Myoton demonstrated greater stiffness and lesser elasticity of the tongue and velum in middle-aged adults with obstructive sleep apnea than in adults who did not snore [48][49][50]. The acceleration curve, generated via an 8 ms perturbation, yielded two outcome variables: frequency of oscillation (in hertz; an indicator of stiffness) and logarithmic decrement of damped oscillation (reflecting elasticity).…”