Taste Stimulation for Post-stroke Dysphagia

Effects of Taste Stimulation on Swallowing Function of Patient With Post-stroke Dysphagia and Its Mechanism

The goal of this clinical study is to compare the effect of favourate taste stimulation of oral cavity and tounge, with sour and traditional single thermal stimulation in post-stroke patients with dysphagia. The main questions it aims to answer are: Whether favourate taste stimulation of oral and tounge is better than traditional thermal stimulation in improving swallowing function of patients with dysphagia. It has been reported that taste of sour stimulation can increase the frequency of swallowing. In this study, we want to know which is better for improving swallowing function between favourate taste stimulation and sour taste stimulation. Functional near-infrared spectroscopy (fNIRS) will be applied in this study to understand the neural mechanism of taste stimulation in improving swallowing function. Participants screened as post-stroke dysphagia will accept swallowing evaluation and fNIRS test before and after treatment. The treatment include taste stimulation and traditional swallowing training. Researchers will compare favourate taste stimulation with sour-taste stimulation and single thermal stimulation to see if the swallowing function improved faster and better in favourate taste stimulation group.

Taste perception can help to initiate swallow. Different taste has different impact on swallowing function. Patients with post-stroke dysphagia always have taste impairment and initiation delay of swallowing. In this study, patients with dysphagia after stroke will be recruited and treated with favourate taste stimulation or sour taste stimulation or non-taste stimulation for 2 weeks. Traditional swallowing rehabilitation will be applied base on the status of patients. Before and after the treatment, participants completed swallowing assessment, including quantitative measurement of hyoid displacement, functional oral intake scale (FOIS), dysphagia severity rating scale (DSRS), and standardized swallowing assessment (SSA). In order to understand the effect of taste stimulation on brain network, fNIRS will be conducted.The participants have to conduct these examination three to four weeks after the treatment to undertand the long-time effect of taste stimulation.

The swab will be immersed in sugar, salt, citric acid, or paprika mixed with water, and be placed in -18℃ refrigerator. Select the swabs of the participant favourate taste to brush oral cavity and tounge. The stimulation will last two to three minutes one time, and twice for a rehabilitation session, once per day and six days every week, three weeks totally. Swallowing rehabilitation also include standard training that carried out in the department.

Using sour swab to brush oral cavity and tounge of the participant. The treatment duration and other training method is as same as mentioned above.

Only ice-water swab to brush oral cavity and tounge. The treatment duration and other training method is as same as mentioned above.

The taste stimulaiton for swallowing is completed with long swab. Taste solution will be prepared with sugar, salt, citric acid, or paprika mixed with water. And the swab will be immersed in the solution and freezed in -18℃ circumstances. Bilateral buccal mucosa，palate and tounge will be brushed. Four swabs will be used in a training session.

The probe of ultrosound will be placed in the middle of the neck, paralled to the sagittal line. Record the video of participant drinking 1ml water, the distance between hyoid and chin at rest minus distance during hyoid and chin are nerest. Repeated three times, and the mean value is further into analysis.

Standardized swallowing assessment (SSA) include clinical examination, drinking 5mL water test and drinking 60mL water test.lowest score is 18, and the highest score is 46, high score indicationg poor condition.

The Dysphagia Severity Rating Scale (DSRS) assigns a score to the feeding status achieved by the dysphagic patient depending on the categories of feeding stage for fluid and dietary consumption in addition to the level of dependency required for feeding. The score for each category can vary between 0 and 4 points, and is added to give a composite score. These scores were calculated by a speech and language therapist with special interest in neurogenic dysphagia. SALT：speech and language therapist.

Functional near-infrared spectroscopy (fNIRS) is a tool for measuring the HbO2 concentration to reflect the excitation of cortex. Further analysis can help to explain the network of the brain.

Inclusion Criteria: diagnosed as first-ever stroke and diagnosed as dysphagia with modified water swallowing test, duration of dysphagia was more than one month; can complete all the test with MMSE >15; agree to participate the experiment, and sign the written informed consent. Exclusion Criteria: have other diseases that could induce dysphagia, such as cranial and neck tumor, history of radiotherapy or chemotherapy, tongue muscle atrophy, myasthenia gravis, parotid tumor and multiple sclerosis, etc; lose of taste perception; combined with other major disease that can not tolerate the examination and swallowing training; surgery of cranial allogeneic plasticity, scalp ulcer or damage that thought as contraindications of fNIRS. with other neurological conditions (eg, Parkinson's disease, dementia).

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