Swallowing refers to the reflex activity of food being transported to the stomach through the pharynx and esophagus after being chewed and crushed in the mouth, and is divided into 5 phases: cognitive, preparatory, oral, pharyngeal and esophageal phases.
The cognitive phase refers to the stage of awareness of food. The preparatory phase refers to the stage of food intake until the completion of chewing and preparation for swallowing food. The oral phase refers to the process when the tongue advances the food mass and begins to move backward until it enters the pharynx. The pharyngeal phase is the stage from when the food mass enters the oropharynx to when it passes through the upper esophageal sphincter into the esophagus. The esophageal phase is the stage in which the esophageal mass moves from the entrance of the esophagus to the entrance of the stomach.
Impairment in any of these stages can affect the ingestion and swallowing function and nutrient absorption, and can also lead to inadvertent aspiration of food into the trachea, resulting in aspiration pneumonia, which can be life-threatening in severe cases.
Traditional treatment methods
I. Swallowing training
1.Indirect training (basic training): training without food, only for swallowing dysfunction. Indirect training starts from preventing disuse hypofunction, improving the movement and coordination of swallowing-related organs, and making necessary functional preparation for oral intake of nutrition.
2.Direct training (ingestion training): The training to improve the swallowing function by applying food, adjusting the feeding position and food properties, and instructing the application of auxiliary swallowing movements. It is suitable for patients who are conscious, have stable vital signs, can produce swallowing reflex, and can cough up a small amount of inhalation or aspiration through casual coughing.
Acupuncture treatment
Needling specific points on the tongue has the effect of dredging the tendons and channels, activating blood circulation and relieving pain, and can be used to treat a variety of pathologies. Patients with post-stroke dysphagia are mostly treated with three needles on the tongue, which are lifted and twisted without leaving needles after obtaining qi. Patients with nasopharyngeal carcinoma can also be treated with tongue three needles by applying and transporting needles to the posterior root of the tongue and the hard nodes according to the situation.
New techniques in recent years
I. Swallowing gadgets
1.Small island spoon
Located in the central position of the palatolingual arch and the pterygoid mandibular sail, a depression at the height of the posterior triangle of the molar is the K-point. By stimulating the K point with this spoon the patient will open his mouth automatically. It is mainly used for patients with swallowing dysfunction due to pseudobulbar palsy who cannot open their mouth and have a weakened swallowing reflex. Clinical use of cotton swabs, ice cubes, etc. to stimulate the K-point can also achieve satisfactory results.
2.Gas pulse stimulation/water pulse stimulation
For patients with basic loss of oral phase function, stimulation of tongue root, posterior pharyngeal wall, soft palate and other parts with air pulse or water pulse can improve the sensitivity of swallowing receptors and induce swallowing action.
3.Tongue pressure resistance feedback training
During the treatment, the amount of water injected into the balloon is selected according to the different tongue muscle strength and different target values are set, which can improve the coordination of the patient’s swallowing action and re-establish the swallowing reflex neural pathway, which also has good effect in the delayed swallowing reflex and swallowing initiation difficulty.
4.Tongue suction device
Active and passive rehabilitation training of the tongue muscle using negative pressure is beneficial to strengthen the tongue muscle and improve motor coordination, and improve the patient’s swallowing and articulatory function.
II. Esophageal dilatation
1.Non-invasive
A modified catheter balloon dilation technique is used to implement targeted treatment for patients with cricopharyngeal dysphagia. Active balloon dilation requires patients to cooperate with active swallowing action while dilating, which is conducive to increasing swallowing timing and strengthening the strength of swallowing muscle groups; passive balloon dilation (no patient swallowing action is required during dilation) pulls the cricopharyngeal muscle through repeated mechanical dilation to improve sensory input and The passive balloon dilatation (no need for the patient to swallow) can improve sensory input and relieve abnormal local muscle tone by repeated mechanical dilatation of the cricopharyngeal muscle.
2.Invasive
(1) Cricopharyngeal muscle severance: the cricopharyngeal muscle at the entrance of the esophagus is severed to facilitate the passage of food. (2) Laryngeal supination: suitable for dysphagia due to insufficient laryngeal supination or tongue root movement disorder. (3) Pharyngeal valvuloplasty: Due to the obstruction of nasal and pharyngeal atresia caused by soft palate paralysis, the food mass flows backward toward the nasal cavity during swallowing. In order to increase the swallowing pressure, pharyngeal valvuloplasty is feasible.
Electrical stimulation therapy
1.Neuromuscular electrical stimulation
By outputting specific low-frequency pulse current to electrically stimulate the neuromuscles of the mouth, face, larynx and neck, excite the nerve and swallowing muscle groups, which can relieve neuronal paralysis, promote the reconstruction and recovery of swallowing reflex arc function, and then improve swallowing and language ability. The common ones are PHYSIOMED Speech and Swallowing Diagnostic Instrument and VitalStim Swallowing Disorder Treatment Instrument.
2.Low-frequency electrical stimulation by hand-held electric wand
Hand-held single/double stick design, compact, flexible and targeted, combined with biphasic, asymmetric low-frequency pulse current with a wave width of 1ms (new type of inductive electrical stimulation), according to the patient’s functional situation, the soft palate, posterior pharyngeal wall, and even the inner tongue muscle groups can be targeted, making up for the limitations of conventional electrical stimulation that cannot be moved or electrically stimulated in the oral cavity, and improving the strength of the target muscle groups. The effect is remarkable, adding a new treatment technology for swallowing disorder.
3.myoelectric biofeedback therapy
It refers to a feedback method that measures the electromyographic signals of the muscles on the surface of the body and provides feedback by visual and auditory means, and the subject controls the muscle activity according to this feedback signal, so that the muscle relaxation or contraction is enhanced. This therapy is beneficial to increase the interest of training, improve swallowing skills, accelerate the rehabilitation process, and help patients to sustain improvement and maintain long-term results.
4.Transcranial direct current stimulation (tDCS?)
Transcranial direct current stimulation is a non-invasive technique that uses constant, low-intensity direct current (1~2?mA) to regulate neuronal activity in the cerebral cortex. Anodal stimulation of either the healthy or the affected cerebral cortex can promote improvement of swallowing function.
5.Pharyngeal intracavitary electrical stimulation (PES)
Using electrodes in the official cavity to directly stimulate the swallowing-related mucosa and muscles in the pharynx, it may regulate the plasticity of the brain through sensation and movement and improve swallowing function.
6. Intramuscular electrical stimulation
Hook-and-wire electrodes are used to activate the designated muscles by placing them directly around the nerve endings close to the target muscles, producing an assisted swallowing effect. This method avoids the non-specificity of surface electrical stimulation, and the implanted electrodes do not need to consider skin resistance because they do not pass through the skin and do not activate superficial nociceptive receptors. At present, it is mainly used for the rehabilitation of voice and airway protection.
IV. Transcranial magnetic stimulation (TMS)
Transcranial magnetic stimulation technique is a painless and non-invasive green treatment method. The magnetic signal can pass through the skull without attenuation and stimulate to the cerebral nerve, mainly by changing its stimulation frequency to excite or inhibit the local cortical function respectively, which is feasible and effective for the treatment of swallowing disorder, but there is no uniform standard of parameters yet.
V. Speaking valve
The speaking valve is a one-way ventilation valve worn on the tracheal sleeve, which opens during inspiration and closes actively at the end of expiration, allowing air to flow out of the airway through the vocal cords. It not only restores the speaking function of patients after tracheotomy, but more importantly, it reduces the degree of misaspiration and leakage and improves swallowing function.
VI. Intramuscular effect patch
Intramuscular patch is a non-invasive technique of applying muscle tape to the body surface to enhance or protect the musculoskeletal system and promote motor function. In recent years, it has been widely used in the treatment of joint and muscle pain, and now it is gradually carried out in swallowing and dysarthria to improve symptoms such as crooked mouth, salivation and slurred diction by increasing the strength of the labial and buccal muscles, and to improve the ability to push the food mass by strengthening the muscles of the pharynx.
Outlook
Modern rehabilitation medicine is an important part of medicine, and together with health care, prevention and clinical, it forms a comprehensive medicine. Swallowing rehabilitation is one of the important branches.
People’s awareness of the demand for swallowing rehabilitation mostly starts days or even months after the occurrence of swallowing disorders, and the treatment population is mostly limited to adults and stroke patients. In the future, swallowing rehabilitation will receive timely treatment or even early intervention when swallowing disorders appear, such as early intervention in the stable stage of brain disease, intervention in the degeneration of swallowing function in the elderly, intervention before swallowing and dysarthria appear after radiotherapy for nasopharyngeal cancer, etc., and cover a wider population. And the coverage of the population is broader, involving neonates and children.
In terms of swallowing therapy, the future swallowing rehabilitation will realize multidisciplinary cooperation, and in order to change the current situation of uneven quality of therapists, therapists will realize standardized training, and highly educated talents and new technologies will be gradually introduced and popularized.