Measuring the muscle activity of the suprahyoid muscles presents a challenge due to their
location, which is difficult to access. Despite this difficulty, surface Electromyography
(sEMG) is an effective method for assessing the electrical activity of the suprahyoid
muscles. sEMG is a non-invasive, portable, and cost-effective technique that records
activity within the electrode detection area. It has been suggested as a diagnostic tool
for identifying dysphagia. Several studies have demonstrated that specific patterns in
the sEMG of suprahyoid muscles, including duration and amplitude, exhibit distinct
characteristics attributable to various etiologies.
A previous study has examined the suprahyoid muscle activity patterns in sarcopenic
dysphagia patients using sEMG. However, there was a lack of research analyzing the
swallowing dynamics of sarcopenic dysphagia alongside Videofluoroscopic Swallowing Study
(VFSS). VFSS enables the observation of swallowing in phases, offering a crucial method
for assessing the presence of dysphagia and identifying the specific phases where
dysphagia occurs.
Therefore, the present study aims to investigate the characteristics of sarcopenic
dysphagia across phases using sEMG and VFSS. Additionally, Investigators aim to analyze
the relationship between suprahyoid muscle activity patterns and swallowing dynamics
utilizing these modalities.
Videofluoroscopic swallowing study (VFSS) will done for all participants to evaluate
swallowing function. The VFSS procedure followed the Logemann protocol and will be
supervised by a rehabilitation physician and an occupational therapist. Another physician
will observe and score the test without having access to the patient's personal details.
During the VFSS, participants will seat upright in a chair, swallowing images of the
lateral projection will be obtained from participants. The participants undergo
swallowing trials with varying viscosities, including semiliquid, semisolid, solid, and
thin liquids (2cc, 5cc, 10cc). All trials are mixed with an undiluted liquid barium
solution, barium sulfate. During the procedure, participants will undergo progressively
thicker food, starting from liquids and advancing to solid materials. Following the
protocol, liquid 2 cubic centimeter (cc) trial will precede to the 5cc trial. If, the 2cc
trial indicated aspiration and the physician determined there was a high risk for
aspiration, next step of trial can be skipped and the VFSS will be stopped. If, a large
amount of aspiration occurred, the VFSS will be halted, and the participant will
encouraged to expectorate the food material.
The activity of suprahyoid muscles will be recorded using a surface electromyography.
Pairs of disposable self-adhesive electrodes will fixed to the skin surface of the
suprahyoid muscles. The electrodes positioned symmetrically between the hyoid bone and
the chin, with a center-to-center distance of 20mm. Before attaching, participants will
seated upright in a chair and the skin surface will be cleaned using alcohol swabs. After
attaching the electrodes, participant instructed to open their jaw as wide as they could
for 10 seconds to measure the amplitude, which can be used as a reference for
normalization. The amplitude of sEMG is influenced by various tissue conditions.
Therefore, normalization based on a reference muscle contraction is necessary to compare
amplitudes between individuals. Subsequently, participants will received 2ml of water on
the floor of the mouth using a syringe, and will be instructed to swallow under the
guidance of a rehabilitation physician. Each participant undergo three trials of water
swallowing, separated by 30 seconds intervals.
