Relationships between gait and dynamic balance in early Parkinson’s disease Yea-Ru Yang a,b , Ya-Yun Lee a , Shih-Jung Cheng c , Pei-Yi Lin a , Ray-Yau Wang a,d, * a Department of Physical Therapy and Assistive Technology, National Yang-Ming University, 155, Sec 2, Li-Nong Street, Shih-Pai, Taipei, Taiwan b Section of Physical Therapy, Taipei City Hospital, Taipei, Taiwan c Department of Neurology, Mackay Memorial Hospital, Taipei, Taiwan d Department of Education and Research, Taipei City Hospital, Taipei, Taiwan Received 16 February 2007; received in revised form 13 August 2007; accepted 17 August 2007 Abstract This study examined the relationships between gait and dynamic balance in people with early-stage Parkinson’s disease (PD). We assessed 18 participants diagnosed with stage I–II idiopathic PD and 17 healthy age-matched volunteers. Temporo-spatial gait variables were analyzed using the GAITRite 1 system and participants were asked to walk at a comfortable walking speed. Dynamic balance was assessed using the Balance Master 1 . Movement velocity (MV), maximal excursion (ME), and directional control (DC), obtained through the limits of stability test, quantified dynamic balance. People with early stage PD exhibited significantly slower walking speed, shorter stride length, and smaller forward MV than the comparison group. In the PD group, stride length and speed significantly correlated with forward MV, forward ME, and forward DC. Thus, in people with early PD, gait speed and stride length are correlated with dynamic balance, particularly in the forward direction in standing. # 2007 Elsevier B.V. All rights reserved. Keywords: Balance; Gait; Parkinson’s disease; Physical therapy; Rehabilitation 1. Introduction Quantitative gait evaluations of people with Parkinson’s disease (PD) have shown that gait speed and stride length decrease, while double support time increases [1,2]. Morris et al. [2] have reported the control of normal stride length to be a fundamental problem in gait hypokinesia. Even in the ‘‘on’’ phase of the early stages of disease progression, people with PD have slower walking speeds. This is attributable to an internal inability to generate normal step length [3]. Some studies have suggested that gait impairment in PD is related to muscle weakness and postural abnormalities [4,5]. Others did not identify a relationship between power generation and stride length or speed [1]. In addition to musculoskeletal constraints, impaired balance and dynamic postural control may be associated with gait disturbance in PD [4,6]. Previous studies have also shown inconsistencies across patient groups for the relationships between gait and balance. A weak or no relationship between gait speed and balance was reported for healthy elderly people [7,8]. In those with neurological disorders, correlations were found between gait and balance [9,10]. Given that the association between gait and dynamic balance has not been investigated in people with PD, this study explored the extent to which these factors are related, as the basis for clinical decision making. 2. Methods 2.1. Participants Eighteen participants with idiopathic PD (11 males and 7 females) were diagnosed by a neurologist and were recruited from a medical center. All lived independently in the community and www.elsevier.com/locate/gaitpost Available online at www.sciencedirect.com Gait & Posture 27 (2008) 611–615 * Corresponding author. Tel.: +886 2 28267210; fax: +886 2 28201841. E-mail address: rywang@ym.edu.tw (R.-Y. Wang). 0966-6362/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.gaitpost.2007.08.003