In March 2013, Mr Jason Khoo (A MSc SLP graduate from NUS) presented this scientific poster on CTAR at the Dysphagia Research Society Meeting at Seattle, Washington, USA in 2013. Little did we expect that CTAR actually drew so much interest at the DRS meeting and was also awarded first place for the Scientific Abstract Poster.
Comparison of suprahyoid muscles activity between chin-tuck-against-resistance (CTAR) and the Shaker exercises
Jason KHOO, Susan J. RICKARD LIOW, YOON Wai Lam
For patients with pharyngeal dysphagia, therapeutic exercise such as the Shaker exercise to strengthen the suprahyoid muscles is effective in restoring oral feeding. However, observations revealed that the Shaker exercise is physically demanding for the elderly patients, thereby affecting compliance of the exercise goals. A less strenuous exercise, CTAR, was compared to the Shaker exercise by measuring the surface electromyography (sEMG) activity of the suprahyoid muscles during both exercises. The sEMG activity of the suprahyoid muscles during CTAR was similar or superior to the Shaker exercise. Therefore, CTAR exercise has the potential to achieve the same therapeutic effect as Shaker exercise and may improve compliance.
Aim: To find out if CTAR is as effective as Shaker exercise in exercising the suprahyoid muscles.
- The Shaker exercise has been shown to be effective for patients with dysphagia due to incomplete upper esophageal sphincter (UES) opening (Shaker et al, 2002).
- Performing Shaker exercise significantly increased the anteroposterior diameter of the UES (Easterling et al, 2005) and significantly reduced post-swallow aspiration (Logemann et al, 2009).
- A key component of Shaker exercise is in exercising the suprahyoid muscles, thereby strengthening it (Shaker et al, 2002).
- Easterling et al (2005) found out that muscle discomfort or time constraints were main reasons for the failure of their participants in attaining the Shaker exercise goals.
- Clinical observations suggest the Shaker exercise may pose a physical challenge for elderly dysphagic with chronic disease (Yoshida et al, 2007).
- Developing a less strenuous therapeutic exercise would potentially benefit patients who find Shaker exercise physically challenging, thereby facilitating the attainment of the exercise goals.
- The CTAR exercise, performed in a seated position, is less strenuous as the patient is not required to lift the weight of her head.
- Performing the CTAR exercise in a seated position would make it more convenient for dysphagic patients who are actively mobile to comply with, thereby improving compliance.
- The CTAR will adopt the same regime as Shaker exercise; a set of isometric (sustaining the effort) and isokinetic (repetitions) exercise with equal time base.
Research question: Would the sEMG activity of the suprahyoid muscles be higher during CTAR exercise?
N=40 healthy adults (21-40 yrs). Each participant performed a total of 4 exercise tasks, with a minimum 5 minute rest in between each task. The order of the 4 tasks are randomly assigned and counter-balanced across participants.
4 exercise tasks:
- CTAR isometric
- CTAR isokinetic
- Shaker isometric
- Shaker isokinetic
CTAR exercise (see Figure b):
- Seated upright in chair
- An inflatable rubber ball (diameter 12cm) is placed between chin and base of neck to provide resistance
- Chin tuck against the ball and sustaining it for 10 sec (isometric)
- Chin tuck against rubber ball for 10 repetitions (isokinetic)
Shaker exercise (see Figure c):
- Supine position
- Lift head high enough to see their toes
- Sustaining the head lift for 10 sec (isometric)
- Lift head for 10 repetitions (isokinetic)
sEMG (see Figure a):
- The activity of the suprahyoid muscles was measured using sEMG via an electrode patch attached to the participant’s suprahyoid area
- The CTAR exercise appears to be similarly effective or superior to Shaker exercise in utilising the suprahyoid muscles.
- If Shaker exercise is effective in strengthening the suprahyoid muscles and increasing the anteroposterior diameter of the UES, CTAR exercise may be able to achieve a similar or greater effect.
- CTAR exercise may be a potential alternative for elderly dysphagic patients who find Shaker exercise physically challenging.
- This study is limited to healthy young adults. Replication of this study on an older population will enable further understanding of the impact of age.
- Future clinical studies are necessary to evaluate the therapeutic potential of CTAR in dysphagic patients with incomplete UES opening and the compliance of CTAR exercise amongst the elderly patients.