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:

1. Whether favourate taste stimulation of oral and tounge is better than traditional thermal stimulation in improving swallowing function of patients with dysphagia.
2. 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.
3. 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.

Inclusion Criteria:

1. diagnosed as first-ever stroke and diagnosed as dysphagia with modified water swallowing test, duration of dysphagia was more than one month;
2. can complete all the test with MMSE >15;
3. agree to participate the experiment, and sign the written informed consent.

Exclusion Criteria:

1. 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;
2. lose of taste perception;
3. combined with other major disease that can not tolerate the examination and swallowing training;
4. surgery of cranial allogeneic plasticity, scalp ulcer or damage that thought as contraindications of fNIRS.
5. with other neurological conditions (eg, Parkinson's disease, dementia).