title: Analyzing 180 degrees turns using an inertial system reveals early signs of progression of Parkinson's disease.
abstract: Changes in turning are one of the early motor deficiencies in Parkinson's Disease (PD). We have proposed a system based on wearable, inertial sensors and a novel automatic analysis algorithm that can assess 180 degrees turns. Twelve patients in early stages of PD and 14 age-matched healthy subjects were enrolled in this study. Inertial sensors were attached on shanks and sternum. Measurement protocol included walking on a straight pathway, turning 180 degrees and returning back. Subjects were measured 4 times, once every 6 months during an 18 months period. At the baseline, 9 subjects from each group repeated the test twice to assess test-retest reliability. Patients with mild PD had a very low Postural Instability Gait Difficulty (PIGD subscore of UPDRS III) score (average 0.67, min 0, max 3). The analysis showed that the patients had a significantly longer turning duration (2.18+/-0.43 vs. 1.79+/-0.27 seconds, p<0.02) and longer delay in their last step before initiating a turn (0.56+/-0.04 vs. 0.52+/-0.04 seconds, p<0.03). Estimated turning duration and other metrics had a high test-retest reliability (rho>0.85). Turning duration also showed a significant Group *Time interaction (p<0.03) during the longitudinal study highlighting early signs of the progression of the disease.
authors: Department of Neurology, Oregon Health & Science University, Portland, OR, USA. arash.salarian@ieee.org
authors: Arash
authors: A
authors: Salarian
authors: Cris
authors: C
authors: Zampieri
authors: Fay B
authors: FB
authors: Horak
authors: Patricia
authors: P
authors: Carlson-Kuhta
authors: John G
authors: JG
authors: Nutt
authors: Kamiar
authors: K
authors: Aminian
mesh_terms: D000054:Acceleration; D056044:Actigraphy / Q000295:instrumentation / Q000379:methods*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods*; D009068:Movement; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity