Quantitative biomechanical assessment of trunk control in Huntington's disease reveals more impairment in static than dynamic tasks.

Postural instability is common in individuals with Huntington's disease (HD), yet little is known about control of the trunk during static and dynamic activities. We compared the trunk motion of 41 individuals with HD and 36 controls at thoracic and pelvic levels during sitting, standing, and walking using wearable iPod sensors. We also examined the ability of individuals with HD to respond to an auditory cue to modify trunk position when the pelvis moved >8° in sagittal or frontal planes during sitting using custom software. We found that amplitude of thoracic and pelvic trunk movements was significantly greater in participants with HD, and differences were more pronounced during static (i.e. sitting, standing) than dynamic (i.e. walking) tasks. In contrast to the slow, smooth sinusoidal trunk movements of controls, individuals with HD demonstrated rapid movements with varying amplitudes that continuously increased without stabilizing. Ninety-seven percent of participants with HD were able to modify their trunk position in response to auditory cues. Our results demonstrate that wearable iPod sensors are clinically useful for rehabilitation professionals to measure and monitor trunk stability in persons with HD. Additionally, auditory cueing holds potential as a useful training tool to improve trunk stability in HD.