Effects of seat surface inclination on respiration and speech production in children with spastic cerebral palsy

Background: Respiratory and speech problems are commonly observed in children with cerebral palsy (CP). The purpose of this study was to identify if inclination of seat surface could influence respiratory ability and speech production in children with spastic diplegic CP. Methods: Sixteen children with spastic diplegic CP, ages 6 to 12 years old, participated in this study. The subjects' respiratory ability (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), and maximum phonation time (MPT)) were measured in three sitting conditions: a seat surface inclined 0 degrees, anterior 15 degrees, and posterior 15 degrees. Results: FVC was significantly different across three inclinations of seat surface, F(2, 45) = 3.81, P = 0.03. In particular, the subjects' FVC at a seat surface inclined anterior 15 degrees was significantly greater than at a seat surface inclined posterior 15 degrees (P < 0.05). However, FEV1, PEF, and MPT were not significantly affected by seat surface inclination (P > 0.05). Conclusions: The results suggest that anterior inclination of seat surface may provide a positive effect on respiratory function in children with spastic diplegic CP.