title: Role of tongue pressure production in oropharyngeal swallow biomechanics.
abstract: The tongue is important for orofacial movements, including swallowing. Although numerous studies have focused on tongue pressure against the palate, its physiological role has not been fully evaluated. The tongue pressure generation may have the temporal coordination with the swallowing relational organs. The aim of this study was to clarify the physiological mechanisms of tongue pressure and to investigate the temporal relationship among tongue pressure, supra-hyoid muscle activity, and videofluorographic (VF) images during swallowing. Fifteen healthy young subjects participated. Tongue pressure measured using a sensor sheet with five channels, electromyographic EMG, and VF was recorded synchronously during 4-ml barium swallowing. Swallowing behavior in VF images with and without the sensor sheet was compared. Furthermore, the temporal relationship between events measured from tongue pressure, EMG, and VF was evaluated. Swallowing behavior on VF images was not affected by placement of the sensor sheet. Tongue pressure at the posterio-lateral point of the hard palate tended to have biphasic peaks. Tongue pressure production with a monophasic pattern appeared during the same period as the second peak in the biphasic pattern. The onset of tongue pressure was later than the start of hyoid movement and onset of EMG, and offset was observed between the hyoid at the up-forward position and reposition. Onset of tongue pressure at the anterior area was correlated with the start of slight hyoid elevation. Offset of tongue pressure at the posterio-lateral points was strongly time locked with the hyoid at the up-forward position. The present results suggested the temporal coordination of tongue pressure generation with the swallowing-related organs. That is, the tongue pressure was produced for bolus propulsion, and was closely related to hyoid movement temporally during swallowing. These results may contribute to clarify the clinical state with the disorder of tongue kinetics.
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences Niigata, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hori
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences Niigata, Japan.
authors.forename: Hiroshige
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences Niigata, 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 Niigata, Japan.
authors.forename: Jin
authors.initials: J
authors.lastname: Magara
authors.affiliation: Department of Prosthodontics, Gerodontology and Oral Rehabilitation, Osaka University Graduate School of Dentistry Suita, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Minagi
authors.affiliation: Department of General Dentistry & Emergency, School of Stomatology, The Fourth Military Medical University Xi'an, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Prosthodontics, Gerodontology and Oral Rehabilitation, Osaka University Graduate School of Dentistry Suita, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ono
authors.affiliation: Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences Niigata, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
keywords: Swallowing; hyoid movement; tongue; tongue pressure; videofluorography