The Study on Swallowing ability by INterferential current frequency Electrical Stimulation (SINE Stim Study)

INTERVENTION: ICF (2000Hz, 2050Hz), 2‐3mA, 15 min./session 2 sessions/day 5 days/week 2 weeks (total 20 sessions) ICF (2000Hz, 2050Hz), 0.0mA, 15 min./session 2 sessions/day 5 days/week 2 weeks (total 20 sessions) CONDITION: Dysphagia PRIMARY OUTCOME: Silent aspiration assessed by cough test.; (One night and 7 days after intervention period) SECONDARY OUTCOME: Swallowing ability assessed by Functional Oral Intake Scale.; Amount of nutritional intake by mouth. INCLUSION CRITERIA: Dyaphagic inpatients whom SLP gives dysphagia rehabilitation and who are expected to receive rehabilitation for 3 or more weeks.