Influence of Spinal Sagittal Alignment in Sitting Posture on the Swallowing Speed of Older Adult Women: A Cross-Sectional Study.

Thoracolumbar kyphosis in sitting posture is associated with forward head posture and may adversely affect swallowing function. However, few studies have investigated the effect of spinal alignment in the sitting posture on the swallowing function of older adults. This cross-sectional study aimed to investigate whether spinal alignment in the sitting posture influences the swallowing function of older adult women. Overall, 18 older adult women (mean age, 69.78 ± 3.66 years) without dysphagia were enrolled. Participants were positioned in two sitting postures, namely, comfortable sitting (CS) and thoracic upright sitting (TUS). In each sitting posture, the kyphosis index (using a flexicurve), sagittal angles (head, cervical, shoulder, and pelvic angles; using a digital camera), and cervical range of motion (ROM) were evaluated. Swallowing speed (100-mL water swallowing test), maximum tongue pressure (MTP), and oral diadochokinesis (ODK) were also evaluated. Compared with TUS, CS showed a greater kyphosis index, anterior head translation, and posterior pelvic tilt. CS had greater flexion (p < 0.001) and less extension (p < 0.001) of cervical ROM than TUS. Swallowing speed was significantly decreased in CS compared with TUS (p = 0.008). MTP and ODK were not significantly different between CS and TUS. Thus, changes in sitting posture with spinal alignment may affect swallowing speed. Consequently, adjustments to reduce sitting postural kyphosis in older adult women may improve swallowing speed.