Gait initiation is impaired in subjects with Parkinson's disease in the OFF state: Evidence from the analysis of the anticipatory postural adjustments through wearable inertial sensors.
People with Parkinson's disease (PD) typically demonstrate impaired anticipatory postural adjustments (APAs) that shift the body center of mass forward (imbalance) and over the stance leg (unloading) prior to gait initiation. APAs are known to be smallest when people with PD are in their OFF-medication state compared to ON-medication or healthy controls. The aim of this pilot study is to validate a previously developed method for the assessment of gait initiation on PD patients in OFF state with body-worn, inertial sensors. Ten subjects with mild-to-moderate idiopathic PD and twelve healthy controls of similar age performed three gait initiation trials. The spatio-temporal parameters of APAs were extracted from three wearable sensors, placed on the shins and on the lower back, and validated with two force plates. Temporal parameters extracted from sensors and force plates, as well as the trunk medio-lateral acceleration and the correspondent displacement of the center of pressure, were significantly correlated. Subjects with PD showed hypometric adjustments in the medio-lateral direction (p-value<0.003) and increased duration of the unloading phase (p-value=0.04). The unloading phase was significantly longer than the imbalance (p-value=0.003) only in subjects with PD. The validity of the method of quantifying APAs from inertial sensors was confirmed in PD subjects by comparison with force plates. Sensitivity in discriminating PD patients from healthy controls was proven by both spatial and temporal parameters. Objective measures of gait initiation deficits with wearable technology provides valuable instrument for the assessment of gait initiation in clinical environments.
Biomedical Technology Department, IRCCS Foundation Don Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy.
Gianluca
G
Bonora
Department of Neurology, School of Medicine, Oregon Health & Science University, 3181 Sam Jackson Park Road, Portland, OR, 97239-3098, USA.
Martina
M
Mancini
Biomedical Technology Department, IRCCS Foundation Don Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy. Electronic address: icarpinella@dongnocchi.it.
Ilaria
I
Carpinella
Department of Electrical, Electronic and Information Engineering "Guglielmo Marconi", University of Bologna, Viale Risorgimento 2, 40136, Bologna, Italy.
Lorenzo
L
Chiari
Department of Neurology, School of Medicine, Oregon Health & Science University, 3181 Sam Jackson Park Road, Portland, OR, 97239-3098, USA; Department of Research, Portland VA Medical Center, 3710 SW US Veterans Hospital Road, Portland, OR, 97239-9264, USA.
Fay B
FB
Horak
Biomedical Technology Department, IRCCS Foundation Don Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy.
Maurizio
M
Ferrarin
D061725:Accelerometry / Q000295:instrumentation*; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005684:Gait; D020233:Gait Disorders, Neurologic / Q000503:physiopathology*; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000503:physiopathology*; D010865:Pilot Projects; D004856:Postural Balance; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted
APA phases; Accelerometry; Force plate; Inertial sensors; Levodopa; Spatio-temporal parameters