Electromyographic activation patterns during swallowing in older adults

Abstract

Age-related weakness due to atrophy and fatty infiltration in oropharyngeal muscles may be related to dysphagia in older adults. However, little is known about changes in the oropharyngeal muscle activation pattern in older adults. This was a prospective and experimental study. Forty healthy participants (20 older [> 60 years] and 20 young [< 60 years] adults) were enrolled. Six channel surface electrodes were placed over the bilateral suprahyoid (SH), bilateral retrohyoid (RH), thyrohyoid (TH), and sternothyroid (StH) muscles. Electromyography signals were then recorded twice for each patient during swallowing of 2 cc of water, 5 cc of water, and 5 cc of a highly viscous fluid. Latency, duration, and peak amplitude were measured. The activation patterns were the same, in the order of SH, TH, and StH, in both groups. The muscle activation patterns were classified as type I and II; the type I pattern was characterized by a monophasic shape, and the type II comprised a pre-reflex phase and a main phase. The oropharyngeal muscles and SH muscles were found to develop a pre-reflex phase specifically with increasing volume and viscosity of the swallowed fluid. Type I showed a different response to the highly viscous fluid in the older group compared to that in the younger group. However, type II showed concordant changes in the groups. Therefore, healthy older people were found to compensate for swallowing with a pre-reflex phase of muscle activation in response to increased liquid volume and viscosity, to adjust for age-related muscle weakness.

Effects of Olfactory Stimulation on Swallowing Function in Taiwanese Older Adults

“…The participants using the odor and flavor inhalation demonstrated the maximum amplitudes of muscle contractions across all testing textures of water, semi-liquid, and solid. Although evidence of this is lacking in the previous literature, similar swallowing patterns were revealed ( Ko et al, 2021 ; Molfenter et al, 2019 ). Muscular amplitudes were consistently increased in aged people while changing food/liquid viscosity or volume in swallowing.…”

“…Muscular amplitudes were consistently increased in aged people while changing food/liquid viscosity or volume in swallowing. Ko et al (2021) found that greater viscosity of bolus consistency resulted in a higher amplitude, in particular the maximum amplitude seen prior to the “main-onset” motion in a geriatric swallow. Such adaptation during the swallowing process was observable in those with presbyphagia, as well.…”

“…When conducting a baseline measure, the difference of muscle contraction was observed while drinking water bolus. Muscle contractions in drinking water vary largely among older adults ( Butler et al, 2009 ; Ko et al, 2021 ). The small sample size may impact the sEMG results as well as other group comparisons.…”

Directed Functional Coordination Analysis of Swallowing Muscles in Healthy and Dysphagic Subjects by Surface Electromyography

“…Koyama et al found a significantly higher prevalence of inverted muscle activation patterns in dysphagic subjects, with the activation of infrahyoid muscles preceding the suprahyoid muscles [15]. Pre-onset muscle activation is a protective mechanism to prevent neuromuscular degeneration leading to kinematic and functional loss [51] and gives rise to prolonged swallowing times, which has been widely described in dysphagic subjects [52][53][54]. In fact, the appearance of swallowing with a pre-reflex phase of muscle activation was reported as a compensatory mechanism to adjust for age-related muscle weakness [51].…”

Compensatory Effects of Sequential 4-Channel Neuromuscular Electrical Stimulation for the Treatment of Acute, Subacute, and Chronic Dysphagia in a Prospective, Double-Blinded Randomized Clinical Trial

“…13,14 A recent study for young and older healthy populations showed that sequential contractions of the suprahyoid and infrahyoid muscles cause a circular movement of the hyoid bone during swallowing. 15,16 Hypothetically, NMES could be used not only for rehabilitation but also for the compensatory mechanism. 17,18 The compensatory mechanism of NMES means that, unlike the simultaneous stimulation of the suprahyoid and infrahyoid muscles via the conventional 2-channel NMES, the stimulation of these muscles via the sequential 4-channel NMES may lead to a better modification of the abnormal hyoid and laryngeal motion in patients with dysphagia.…”