Effects of reclining posture on velopharyngeal closing pressure during swallowing and phonation E. NAKAYAMA, H. TOHARA, H. HIRABA, R. SANPEI, H. WAKASA, S. OHNO, A. KUMAKURA, K. GORA, K. ABE & K. UEDA Department of Dysphagia Rehabilitation, Nihon University School of Dentistry, Tokyo, Japan SUMMARY Velopharyngeal closure plays an important role in preventing air pressure leakage during swallowing and phonation from oropharynx to nasopharynx. Levator veli palatini muscle activity is influenced by oral and nasal air pressure, volume of the swallow bolus and postural changes. However, it is unclear how velopharyngeal closing pressure is affected by reclining posture. The purpose of this study was to investigate the effects of reclining posture on velopharyngeal closing pressure during swallowing and phonation. Nine healthy male volunteers (age range, 27À34 years) participated in this study. Velopharyngeal closing pressure during a dry swallow, a 5-mL liquid swallow, a 5-mL honey- thick liquid swallow and phonations of /P∧/ and /K∧/ were evaluated in an upright posture and at reclining postures of 60° and 30°. A manometer catheter was inserted transnasally onto the soft palate, and each trial was repeated three times. A solid-state manometer catheter with an intra-luminal transducer was used to evaluate the amplitude and duration of each trial, and data were statistically analysed. Average amplitudes during dry and liquid swallows were significantly lower in reclining postures compared with the upright posture, but the amplitude was not significantly different during the thick liquid swallow. Average durations were not affected by postural changes. The amplitudes during phonations were lower in reclining postures, but the differences were not significant. Velopharyngeal closure is significantly affected by reclining posture. This suggests that velopharyngeal closing pressure may be adjusted according to afferent inputs, such as reclining posture and bolus viscosity. KEYWORDS: velopharyngeal closure, reclining posture, deglutition, phonation, manometer Accepted for publication 8 March 2013 Introduction Velopharyngeal closure plays a role in preventing air leakage during swallowing and phonation from the oropharynx to the nasopharynx (1, 2). Dysfunction in velopharyngeal closure can cause dysarthria with rhinolalia aperta, dysphagia with pharyngeal residue and aspiration after swallowing. The movement that controls velopharyngeal closing is regulated by the levator veli palatini muscle, the palatoglossal muscle, and the pharyngopalatinus muscle (3). The levator veli palatini muscle separates the nasopharynx and the oropharynx. Previous studies have reported that levator veli palatini muscle activity is affected by oral (4, 5) and nasal pressure (6). Moon et al. (7) reported that levator veli palatini muscle activity at the time of /P∧/ phonation in a supine position was lower than that in an upright position. Moreover, the levator veli palatini muscle automatically responds to bolus vol- ume (8) and viscosity (9, 10) during swallowing. However, it is unclear how velopharyngeal closure is affected by posture during swallowing. Several reports have shown a decreased risk of aspira- tion in a reclining posture during deglutition compared with an upright posture in patients with neurological dysfunction (11), cerebral palsy (12) and oral cancer © 2013 Blackwell Publishing Ltd doi: 10.1111/joor.12050 Journal of Oral Rehabilitation 2013 Journal of Oral Rehabilitation