Head and trunk movement responses in healthy children to induced versus self-induced lateral tilt.

The purpose of our study was to determine head and trunk movement responses that occur in healthy 7-year-old children during induced and self-induced lateral tilt. Twenty subjects, while tailor sitting on a tiltboard, participated in three trials of both induced and self-induced left and right lateral displacements. Measurements of neck and trunk lateral flexion; trunk counterrotation; and neck, trunk, and body anterior-posterior movement were obtained from slide transparencies made at three stages of tilt (original position, initial tilt, and full tilt). For each subject in the two test conditions, changes in these measurements between the stages of tilt were determined and compared. Based on the results of multivariate analysis of variance procedures, we concluded that 1) a significant difference in trunk counterrotation existed between the two types of tilt, with the greatest degree of counterrotation occurring with induced displacement; 2) no significant difference existed in neck or trunk lateral flexion; and 3) no significant differences existed in neck, trunk, or body anterior-posterior movement between tilts. We also found that a wide variability of response existed among the children over the three testing trials. Clinical application of our results suggests that different and unique motor programs exist for automatic and willed balance responses. These differences should be considered when planning treatment strategies.