title: Effect of body posture on involuntary swallow in healthy volunteers.
abstract: Clinically, reclining posture has been reported to reduce risk of aspiration. However, during involuntary swallow in reclining posture, changes in orofacial and pharyngeal movement before and during pharyngeal swallow should be considered. Further, the mechanisms underlying the effect of body posture on involuntary swallow remain unclear. The aim of the present study was to determine the effect of body posture on activity patterns of the suprahyoid muscles and on patterns of bolus transport during a natural involuntary swallow. Thirteen healthy male adults participated in a water infusion test and a chewing test. In the water infusion test, thickened water was delivered into the pharynx at a very slow rate until the first involuntary swallow was evoked. In the chewing test, subjects were asked to eat 10 g of gruel rice. In both tests, the recording was performed at four body postures between upright and supine positions. Results showed that reclining changed the location of the bolus head at the start of swallow and prolonged onset latency of the swallowing initiation. Muscle burst duration and whiteout time measured by videoendoscopy significantly increased with body reclining and prolongation of the falling time. In the chewing test, reclining changed the location of the bolus head at the start of swallow, and the frequency of bolus residue after the first swallow increased. Duration and area of EMG burst and whiteout time significantly increased with body reclining. These data suggest that body reclining may result in prolongation of pharyngeal swallow during involuntary swallow.
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan; Department of Rehabilitation, Takeda General Hospital, 3-27 Yamaga-machi, Fukushima 965-8585, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Shiino
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Takeishi
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Tsujimura
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
authors.forename: Jin
authors.initials: J
authors.lastname: Magara
authors.affiliation: Oral Rehabilitation, Niigata University Medical and Dental Hospital, 1-754 Asahimachi-dori, Chuo-ku, Niigata 951-8520, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Ito
authors.affiliation: Department of Rehabilitation, Takeda General Hospital, 3-27 Yamaga-machi, Fukushima 965-8585, Japan.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Tsukada
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan. Electronic address: inoue@dent.niigata-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000328:Adult; D003679:Deglutition / Q000502:physiology*; D004326:Drinking / Q000502:physiology; D060766:Drinking Water; D004435:Eating / Q000502:physiology; D004576:Electromyography; D004724:Endoscopy; D006801:Humans; D008297:Male; D009334:Neck Muscles / Q000502:physiology; D012275:Oryza; D011187:Posture / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D014741:Video Recording; D055815:Young Adult
chemical_list: D060766:Drinking Water
keywords: Body posture; Chewing; Electromyography; Involuntary swallow; Videoendoscopy