食塊量の違いが嚥下反射に与える影響について―電気生理学的手法および心理測定法を用いた検討

The effects of bolus volume on movement of swallowing reflex : An electro-physiological and psychometric study

　摂食・嚥下障害の臨床では，嚥下反射誘発初期の嚥下動態を「嚥下反射惹起性」として評価することが重要視されている．本研究では健常成人を対象に，食塊量を1ml，5ml，20mlと変化させ嚥下時の舌骨上筋群筋活動と喉頭運動を記録し，食塊量の違いが嚥下反射誘発初期の嚥下動態に及ぼす影響を検討した．さらに，嚥下時の嚥下困難感について官能評価を行い，運動的側面と心理的側面について検討した．

　結果は食塊量1mlで，嚥下反射誘発初期の嚥下動態を評価する「嚥下反射パフォーマンス指標」と「嚥下反射惹起指標」において他の食塊量に比し，有意な反応時間の延長を認めた．また，官能評価では1mlで「飲みにくい」と感じ，他の食塊量に比し嚥下困難感を感じていることが推察された．これらの結果より，食塊量という末梢性の感覚入力の違いが，嚥下反射誘発初期の嚥下動態と心理的な嚥下困難感に影響を及ぼすことが示唆された．

　This study examined the effect of bolus volume on the movement of swallowing reflex initiation.　Three bolus volumes of water, 1ml, 5ml, and 20ml, were used for examining 30 healthy, young persons (25.0±3.8years).　The movement of the swallowing reflex initiation was measured using surface electromyography (S-EMG) and a larynx sensor.　Subjective difficulty of swallowing (SDS) was used as a psychological scale for evaluating the subject's impression of drinking.

　The bolus volume, 1ml, resulted in a significant increase in the swallowing reflex performance index and the swallowing reflex initiation index.　These two indices reflect the movement of the swallowing reflex initiation.

　Furthermore, the SDS scale suggested that 1ml was not as easy to drink as 5ml or 20ml.　Therefore, the bolus volume seemed to influence both the movement of the swallowing reflex and the subject's impression of drinking.