Measurement properties of a new wireless electrogoniometer for quantifying spasticity during the pendulum test in ARSACS patients.
BACKGROUND
Autosomal recessive spastic ataxia of Charlevoix/Saguenay (ARSACS) is a neuromuscular disorder that induces spasticity in lower limbs. The Wartenberg pendulum test is a classical method of assessing lower limb spasticity based on the dynamics of the pendular leg motion. However, in its original form, this test only provides subjective results and do not allow accurate assessment of spasticity.


METHODS
Thirteen ARSACS patients were assessed using a new wireless electrogoniometer to measure spasticity by quantifying oscillation amplitudes and relaxation indices during the Wartenburg pendulum test. The validity of the instrument was evaluated by comparing its measurements to a known precise goniometer whereas discriminant validity was evaluated by comparing healthy participants and ARSACS patients. Reliability was measured using intraclass correlation (ICC) between pendulum test scores obtained at different moments in time.


RESULTS
Data from different tests show that the proposed device is accurate (standard error of measurement of 0.0005°), discriminates healthy and ARSACS patients (most variables have p=0.00) and provides repeatable results (significant ICC usually higher than 0.64 and p<0.05).


CONCLUSIONS
The proposed tool allows the clinician to analyze pendulum oscillation amplitudes and ratios and thus, provide an index of spasticity for the patients affected by ARSACS. This is important as the original procedure is only evaluated visually and the progression cannot be detected until the condition changes drastically. Thus, the system proposed meets the requirements of being useful, precise and user-friendly in the evaluation of patients in a research as well as a clinical environment.
Department of Applied Sciences, Université du Québec à Chicoutimi, Canada.
Hung Tien
HT
Bui
Faculty of Medicine and Health Sciences, Université de Sherbrooke, Canada.
Cynthia
C
Gagnon
Department of Health Sciences, Université du Québec à Chicoutimi, Canada.
Olivier
O
Audet
Faculty of Medicine and Health Sciences, Université de Sherbrooke, Canada.
Jean
J
Mathieu
Department of Health Sciences, Université du Québec à Chicoutimi, Canada. Electronic address: mario.leone@uqac.ca.
Mario
M
Leone
D000328:Adult; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009128:Muscle Spasticity / Q000150:complications / Q000175:diagnosis* / Q000209:etiology*; D015203:Reproducibility of Results; D020754:Spinocerebellar Ataxias / Q000150:complications / Q000151:congenital*; D059015:Wireless Technology; D055815:Young Adult
Assessment of symptom; Ataxia; Inertial measurement unit; Spasticity