Effects of Maneuvers on Breathing-Swallowing Coordination and Swallowing Kinetics in Dysphagia Patients

Research Article

Phys Med Rehabil Int. 2017; 4(5): 1132.

Effects of Maneuvers on Breathing-Swallowing Coordination and Swallowing Kinetics in Dysphagia Patients

Kubo S¹, Marui M¹, Yagi N2,3,4, Nagami S5,6, Hojo K¹, Kunieda K¹, Shigematsu T¹, Kanazawa H¹, Fujishima I¹ and Oku Y2,5*

¹Department of Rehabilitation, Hamamatsu City Rehabilitation Hospital, Japan

²Department of Swallowing Physiology, Hyogo College of Medicine, Japan

³Department of Neurology, Graduate School of Medicine, Kyoto University, Japan

4Clinical Research Center for Medical Equipment Development, Kyoto University Hospital, Japan

5Department of Physiology, Hyogo College of Medicine, Japan

6Department of Sensory Science, Kawasaki University of Medical Welfare, Japan

*Corresponding author: Oku Y, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawacho, Nishinomiya, Hyogo, 663-8501, Japan

Received: October 03, 2017; Accepted: October 24, 2017; Published: October 31, 2017


Objective: We monitored swallows before and after the ‘humming swallow’ and the ‘forehead exercise’ in dysphagia patients and evaluated whether these maneuvers were effective.

Design: For the ‘humming swallow’, a modified version of the supraglottic swallow, the subject was instructed to inhale and hum before a swallow. For the forehead exercise, the subject was instructed to place his palm firmly on his forehead and push his forehead against his hand strongly. Each patient performed the maneuvers sequentially. The breathing-swallowing coordination and kinetics of swallowing were measured before and after each maneuver and during the humming swallow.

Results: Choking was observed in 13 of 30 patients before the forehead exercise but only observed in two patients after the maneuver. The frequencies of inspiration before swallowing and inspiration after swallowing were greater when swallowing was accompanied by choking. In the humming swallow, the frequency of inspiration after swallowing tended to increase.

Conclusion: None of the parameters associated with swallowing kinetics showed significant changes during the two maneuvers. The humming swallow maneuver may increase the frequency of inspiration after swallow, so caution should be exercised when this technique is applied to patients with food residues in the pharynx.

Keywords: Deglutition disorders; Supraglottic swallow; Humming swallow; Forehead exercise; Swallowing kinetics; Breathing-swallowing coordination


E-SW: Expiration-Swallow; I-SW: Inspiration-Swallow; SW-E: Swallow-Expiration; SW-I: Swallow-Inspiration; LRT: Laryngeal rising time; LAD: Laryngeal activation duration


Respiration after swallowing is usually followed by expiration, which could be an airway protective mechanism, as expiration can prevent the inhalation of residual material left in the pharynx after swallowing [1]. Indeed, it has been reported that Parkinson’s disease patients with decreased swallowing safety, as measured by the penetration-aspiration scale, tend to inspire after swallows (SWI pattern) and tend to have shorter swallowing apnea duration [2]. Recently, we developed a swallowing monitoring device that can detect the laryngeal motion and evaluate the coordination between breathing and swallowing [3]. Comparing the kinetics of swallowing between healthy elderly subjects and patients with dysphagia, we found that the prolongation of ‘swallowing latency’ (interval between the onset of respiratory pause and the onset of swallowing) leads to delayed timing of the swallow and results in an increase in the SW-I pattern in patients with dysphagia [4].

Here, we evaluate the effects of two new maneuvers by analyzing the coordination between breathing and swallowing and the timing of swallowing within the respiratory cycle. The first maneuver is the ‘humming swallow’, a modified version of the supraglottic swallow maneuver. In the supraglottic swallow maneuver, each subject is instructed to inhale and hold his breath before and during swallowing and to exhale after swallowing [5]. Therefore, the subject is expected to swallow at a high lung volume and naturally resume his respiration with expiration after swallowing, which would reduce the chance of aspiration. However, it is difficult to objectively confirm when someone is holding their breath, and thus, it is difficult to judge whether the subject followed the instructions. In about half of healthy subjects, the vocal folds are not fully closed when they try to follow the ‘easy’ breath-holding instructions [6,7]. In the humming swallow, the subject is instructed to hum while swallowing instead of holding is breath. Humming induces vocal fold adduction, thereby securing the airway closure to prevent aspiration. The humming swallow has an additional benefit of clearing the food residue from the airway. However, humming decreases lung volume, which could deteriorate the breathing-swallowing coordination.

The second maneuver is the forehead exercise. The head-lifting exercise protocol known as the Shaker exercise consists of isometric and isotonic exercises to strengthen the suprahyoid muscles. However, since the head-lifting exercise requires the physical ability to lift the subject’s own head, its use for the elderly population may be limited [8]. To overcome this limitation, alternative exercises, aiming at the same goal, have been devised [8-10]. One of the authors (I.F.) has also invented an exercise to strengthen the suprahyoid muscle; in this exercise, the subject firmly attaches his hand on his forehead and strongly pushes his forehead against his hands. Anecdotal evidence suggests that this ‘forehead exercise’ instantaneously reduced the chance of choking in some patients. However, the mechanisms of the improvement remain unknown. We hypothesize that the forehead exercise maintains the larynx at a higher position, shortens the swallowing latency, and makes the swallow occur earlier in the respiratory cycle, consequently improving the breathing-swallowing coordination.

Materials and Methods

The protocol was approved by local ethical committees of Hyogo College of Medicine (No. 1715) and Hamamatsu City Rehabilitation Hospital. All subjects gave written informed consent in accordance with the Declaration of Helsinki. Chronic stable patients with dysphasia with Food Intake Level Scale [11] 4-8 (30 subjects, 21 men and 9 women, 75.3±13.3 years old) were enrolled in this study. Aspiration or residue in vallecula and/or the pyriform recess was confirmed by video endoscopy or video fluorography in all subjects. All subjects could understand instructions; patients with severe dementia who could not follow the instructions of swallowing maneuvers were excluded from the study.

Study protocol

Subjects were seated upright on a chair and performed the humming swallow maneuver and the forehead exercise sequentially. The subjects voluntarily swallowed four types of test foods. They swallowed each type of food before, during, and after the humming swallow maneuver, as well as after the forehead exercise (Figure 1). These swallows were monitored by a non-invasive monitoring device [3], and signals were stored in a micro SD card for later analyses.