Chin Closure Against Resistance Exercise for Swallowing Rehabilitation
Condition: Dysphagia
MeSH terms: Deglutition Disorders
Study type: Interventional

Summary: 
      Swallowing is a set of functions that start with the acceptance of food and end with its
      delivery to the stomach. One of the most important problems associated with swallowing
      disorders is insufficient airway closure and the risk of aspiration. It is due to the
      inadequacy of laryngeal elevation that should occur during swallowing. Suprahyoid muscles are
      the most basic structures responsible for laryngeal elevation. Insufficient activation of the
      suprahyoid muscles causes insufficient laryngeal elevation.

      The suprahyoid muscles consist of a group of muscles located in the anterior region of the
      neck between the hyoid bone and the mandible. The muscles which forming SH muscles m.
      digastricus, m. stylohyoideus, m. mylohyoideus and m. geniohyoideus muscles work as a group.
      SH muscles play a primary role in controlling hyoid bone movement during swallowing due to
      their relationship with the hyoid bone. It has been reported that the muscle with the highest
      potential to move the hyoid anteriorly is the geniohyoid muscle, and the mylohyoid muscle has
      the highest potential to move the hyoid in the superior direction. In addition, in another
      study, it was stated that since the geniohyoid and mylohyoid muscles have greater structural
      potential than other SH muscles for anterior and superior displacement of the hyoid,
      respectively. By understanding the potential for hyoid excursion arising from the structural
      properties of these muscles, therapists can target specific muscles with exercises designed
      to promote hyolaryngeal elevation.

      Exercises such as Shaker exercise and resistance chin tuck in the literature either directly
      involve concentric training of the suprahyoid muscles or indirectly aim to gain strength by
      strengthening the neck flexors. In the light of the available evidence in the literature,
      eccentric training is also a viable method in swallowing rehabilitation. In eccentric
      training, the muscle is positioned by shortening its length. Eccentric training can be done
      by applying resistance to the jaw while the mouth is open and asking the mouth to be closed
      in a controlled manner against the resistance. In addition, swallowing exercise can be
      planned by adjusting the mouth opening and placing the SH muscles at the most appropriate
      angle to generate force. The aim of this study is to compare the effects of these three
      different exercises on suprahyoid muscle activation, muscle strength, dysphagia limit and
      perceived fatigue level.
    

Detailed description: 
      Swallowing is a set of functions that start with the acceptance of food and end with its
      delivery to the stomach. The oral preparation consists of 4 phases, namely the oral,
      pharyngeal and esophageal phase. Swallowing disorder (dysphagia) is defined as problems
      occurring in at least one of the swallowing phases. One of the most important problems
      associated with swallowing disorders is insufficient airway closure and the risk of
      aspiration. It is due to the inadequacy of laryngeal elevation that should occur during
      swallowing. Suprahyoid muscles are the most basic structures responsible for laryngeal
      elevation. Insufficient activation of the suprahyoid muscles causes insufficient laryngeal
      elevation.

      The suprahyoid (SH) muscles consist of a group of muscles located in the anterior region of
      the neck between the hyoid bone and the mandible. The muscles which forming SH muscles m.
      digastricus, m. stylohyoideus, m. mylohyoideus and m. geniohyoideus muscles work as a group.
      SH muscles play a primary role in controlling hyoid bone movement during swallowing due to
      their relationship with the hyoid bone. It has been reported that the muscle with the highest
      potential to move the hyoid anteriorly is the geniohyoid muscle, and the mylohyoid muscle has
      the highest potential to move the hyoid in the superior direction. In addition, in another
      study, it was stated that since the geniohyoid and mylohyoid muscles have greater structural
      potential than other SH muscles for anterior and superior displacement of the hyoid,
      respectively, these two muscles can be targeted for neuromuscular stimulation preferably.
      Studies have also shown that exercise can increase motor unit involvement for certain
      functions. By understanding the potential for hyoid excursion arising from the structural
      properties of these muscles, therapists can target specific muscles with exercises designed
      to promote hyolaryngeal elevation.

      Interventions to protect the airway in case of swallowing disorder are aimed at increasing
      the hyolaryngeal elevation. SH muscles provide elevation of the hyolaryngeal complex and also
      support the opening of the upper esophageal sphincter (UES). The cricopharyngeal muscle,
      which opens the UES, is opened by the contraction of the SH muscles and the anterior-superior
      traction of the hyoid and larynx. Insufficient elevation of the hyoid and larynx causes
      insufficient opening of the UES, resulting in an increase in the amount of pharyngeal residue
      and the risk of aspiration. Superior hyolaryngeal excursion during swallowing is thought to
      contribute to airway protection, preventing aspiration. Anterior hyalaryngeal excursion is
      thought to be associated with the patency of the UES. Exercises such as Shaker exercise and
      resistance chin tuck in the literature either directly involve concentric training of the
      suprahyoid muscles or indirectly aim to gain strength by strengthening the neck flexors.

      Shaker Exercises were the first exercise developed to increase suprahyoid muscle activation.
      This exercise, which is characterized by raising the patient's head in the supine position,
      has been accepted as one of the most basic exercises in dysphagia rehabilitation for many
      years. In the following years, the Chin Tuck Against Resistance (CTAR) exercise was developed
      due to the challenging protocol and positional discomfort of the Shaker exercise. In the CTAR
      exercise, the patient is asked to press a standard size and inflatable ball, which he puts
      under his chin, towards his sternum. CTAR has become the most commonly used exercise in
      dysphagia rehabilitation. In the light of the available evidence in the literature, eccentric
      training is also a viable method in swallowing rehabilitation. In eccentric training, the
      muscle is positioned by shortening its length. Eccentric training can be done by applying
      resistance to the jaw while the mouth is open and asking the mouth to be closed in a
      controlled manner against the resistance. In addition, swallowing exercise can be planned by
      adjusting the mouth opening and placing the SH muscles at the most appropriate angle to
      generate force. The aim of this study is to compare the effects of these three different
      exercises on suprahyoid muscle activation, muscle strength, dysphagia limit and perceived
      fatigue level.

      H0 Hypothesis: There is no difference between CTAR, Shaker and Chin Closure Against
      Resistance exercises against resistance in terms of suprahyoid muscle activation, suprahyoid
      muscle strength, dysphagia limit and perceived fatigue level in healthy individuals.

      H1 Hypothesis: There is a difference between CTAR, Shaker and Chin Closure Against Resistance
      in terms of suprahyoid muscle activation, suprahyoid muscle strength, dysphagia limit and
      perceived fatigue level in healthy individuals.
    

Intervention name(s): Exercise Training
Intervention type(s): Procedure
Intervention description(s): Exercise training will be applied in sets of 10x3, 3 times a day for 8 weeks.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: Electromyography; Exercise Training; Dysphagia Limit