Head and Trunk Rotation During Walking Turns in Parkinson’s Disease Frances Huxham, PhD, 1,2,3,4* Richard Baker, PhD, 1,3,5 Meg E. Morris, PhD, 1,3 and Robert Iansek, PhD, MBBS, BMedSci, FRACP 1,2 1 Centre for Clinical Research Excellence in Gait Analysis and Gait Rehabilitation, Victoria, Australia 2 Geriatic Research Unit, Kingston Centre Southern Health, Victoria, Australia 3 School of Physiotherapy, The University of Melbourne, Victoria, Australia 4 Monash Institute of Health Services Research, Monash University, Victoria, Australia 5 Murdoch Children’s Research Institute and Hugh Williamson Gait Laboratory, Royal Children’s Hospital, Victoria, Australia Abstract: Head and trunk axial rotation during walking to align with a new path are integral components of direction change (turning). Turning is problematic in people with Par- kinson’s disease (PD), who appear to move en-bloc when turning and when walking straight. Axial rotation has been little investigated in this group. Accordingly, head, thorax, and pel- vis rotation relative to the laboratory axes (global rotation) was investigated in 10 patients with PD and 10 matched comparison subjects when walking straight and when turning 60 and 120°. Data were selected at three footfalls before and three after a pole denoting the corner. Although rotation was reduced over- all in patients with PD, final differences were minimized by rotation commencing at an earlier step in the patient group. When rotation was measured at various distances relative to the corner, the patient group demonstrated greater rotation than their peers. In support of clinical observations, patients con- strained thorax and pelvis closely together around the corner, while control subjects maintained a pattern of reciprocal oscil- lation when turning. Stride length reduction appears to contrib- ute more to inefficient turning in PD than under-scaled ampli- tude of rotation. © 2008 Movement Disorder Society Key words: Parkinson’s disease; rotation; turning; trunk Almost all activities performed during walking incor- porate the need to change direction. Within the home, daily tasks such as toileting require as many as five turns. 1 Although performed automatically and safely in health, turning often become problematic with ageing or pathology, 2-5 and is associated with increased falls risk. Turning is a complex three-dimensional action. Head and trunk transverse plane rotation (referred to as “rota- tion ” henceforth) is vital, to seek out and align with the new path when direction changes. 6,7 Head rotation to visualize the new path or target precedes turning. 7-10 In people with PD, turning typically becomes slower and less efficient. 11 The already shortened step length re- duces further, 11,12 and the head and trunk appear to move en-bloc. 11,12 Head stabilization appears inflexible in PD, 17 and may impact on patients’ ability to locate and visually fixate on the target during turning. Trunk impairments occur early in PD. 18 Deficits in range and torque production, 19 and decreased trunk ro- tation in walking 15 have been reported. Trunk rotation deficits correlate to disease severity 15,18 and deep brain stimulation status. 20 Altered reciprocal oscillation be- tween the thorax and pelvis that is independent of walk- ing speed has been demonstrated in this population. 21 The extent to which these various difficulties impact on turning in people with PD remains unknown, although thoracic and pelvic rotation velocities in 180° turns are slower. 22 Patients whose gait parameters are within nor- mal limits when walking straight have demonstrated abnormalities of rotation when turning 90°, 16 yet the majority of patients with PD suffer gait impairment. This study examines the contribution of head and trunk rotation to turning in patients with PD whose straight walking is characteristically slow and short- stepped. It was predicted that these patients with PD *Correspondence to: Frances Huxham, Geriatric Research Unit, Kingston Centre Southern Health, Warrigal Road, Cheltenham Victoria 3192, Australia E-mail: fhuxham@bigpond.net.au Received 11 April 2007; Revised 11 December 2007; Accepted 13 December 2007 Published online 4 June 2008 in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/mds.21943 Movement Disorders Vol. 23, No. 10, 2008, pp. 1391-1397 © 2008 Movement Disorder Society 1391