Robot-Assisted Walking Training for Individuals With Parkinson's Disease

A Pilot Randomized Controlled Trial

Patrizio Sale; Maria F De Pandis; Domenica Le Pera; Ivan Sova; Veronica Cimolin; Andrea Ancillao; Giorgio Albertini; Manuela Galli; Fabrizio Stocchi; Marco Franceschini


BMC Neurol. 2013;13(50) 

In This Article



This study was a pilot Randomized Controlled Trial (RCT). We recruited idiopathic PD patients from rehabilitation centres. They had been on stable doses of Parkinson's medications for at least 4 weeks prior to study onset, and showed an endurance sufficient to keep an upright position, assisted or unassisted, for at least 20 minutes. A preliminary medical examination included a physical and a neurological test, and a gait analysis. The inclusion criteria for all groups were: (a) diagnosis of idiopathic PD by UK Brain Bank criteria, without any other significant neurological or orthopedic problems; (b) age between 18 and 90 years old; (c) capability to walk, unassisted or with little assistance, for 25 feet. The following exclusion criteria were identified: (d) inability to understand instructions required by the study (Informed Consent Test of Comprehension); (e) primarily wheelchair bound; (f) chronic and ongoing alcohol or drug abuse, active depression, anxiety or psychosis that might have interfered with the use of the equipment or testing; (g) diagnosis of atypical parkinsonian syndrome; (h) implantation of deep brain stimulation.


After providing written informed consent, the twenty patients were divided into two groups randomly: Experimental Group (EG) and Control Group (CG). The random allocation to treatment was concealed and based upon a custom computerized system, using a purpose-built software. In order to allow a balanced subject allocation into EG and CG groups, the Lehemer algorithm was applied. Therapists were assigned to each group of patients randomly. Blinded assessors conducted clinical assessments at the beginning (T0) and at the end of the treatment (T1).


Clinical Assessments. Trained professionals, who were not involved in the research treatment and blind to patients' group allocation, performed all instrumental and clinical assessments. All outcome assessments were collected in ON phase one hour and half after the oral assumption of the usual dose of levodopa. Clinical and instrumental outcomes were performed using valid and reliable tools for PD. They included: Hoehn and Yahr scale (HY),[18] Unified Parkinson's Disease Rating Scale (UPDRS),[19] and multifactorial 3D Gait Analysis (3D-GA) (ELITE2002, BTS, Italy).

3D Gait Analysis. The 3D-Gait analysis (3D-GA) was conducted using the following equipment: a 12-camera optoelectronic system with passive markers (ELITE2002, BTS, Italy) to measure the kinematic of the movement; 2 force platforms (Kistler, CH), to obtain the kinetic data of the movement (i.e. ground reaction forces); 2 TV camera Video system (BTS, Italy) synchronized with the optoelectronic and force platform systems for video recording. To evaluate the kinematics of each body segment, markers were positioned as described by Davis and colleagues.[20] Subjects were asked to walk barefoot, at their own natural pace (self-selected and comfortable speed), along a 10 meter walkway where the two force platforms were placed. At least seven trials were collected for each subject in order to ensure the consistency of the data. All graphs obtained from GA were normalized as % of gait cycle, and kinetic data were normalized for individual body weight. In order to quantify the gait pattern of participants involved in this study, a specific software (Smartanalyser, BTS, Italy) enabled the calculations of some indices (time/distance parameters, angles joint values in specific gait cycle instant, peak values in ankle power graph) starting from those data.

Primary and Secondary Outcomes. A primary outcome was the gait velocity assessed by mean velocity (m/sec), which measured the rate of change of position, recorded in meters per second.[21] The other outcomes were: the cadence (step/min) that measured the number of steps taken in a given period of time, which was then converted into the number of steps taken per minute,[21] the step length (mm) that measured the average distance (in meters) between two successive placements of the same foot,[22] the stride length (mm) that measured the average distance (in meters) between two successive placements of the same foot,[22] the step width (mm) that measured medio-lateral distance between the two feet during double support, the stance time (% stride) that measured the duration of the stance phase, the swing time (% stride) that measured the duration of the swing phase and the double support (% stride) that measured the duration of double support.

Therapeutic Intervention. Patients underwent a cycle of out-patients rehabilitation treatment, consisting of at least a daily 3-hour cycle, divided as follows: 45 minutes of treatment for lower limb either with robot device or with treadmill, according to the randomization; a treatment of occupational therapy for the upper limb, including both dexterity and neuropsychological treatment, according to individually tailored exercise scheduling. The whole therapy was performed under the supervision of a physiotherapist.

Experimental group (EG). Each subject was asked to perform 20 sessions (5 days a week for 4 weeks) of robot assisted gait training, using the commercially available end effector system machines G-EO system device (Reha Technology AG; Olten, Switzerland).

The engineering characteristic of G-EO robot is based on end effector device with BWS and a foot plates placed on a double crank and a rocker gear system, and with 3 DoF each, which allows the control of the length and the height of the steps. The foot plate angles can be used to simulate a real over-ground high repetitive walk.[23] The trajectories of the foot plates and the vertical and horizontal movements of the centre of mass are fully programmable, enabling wheelchair-bound subjects not only for the repetitive practice of simulated floor walking, but also to climb up and down the stairs. Heart rate and blood pressure were monitored at the beginning and at the end of each session. During the training, the therapist followed the treatment standing in front of the patient, to help if necessary. The parameters of the treatment were noted for each session, and the steps taken during the simulated walking were converted into the distance covered, based on the step length previously chosen.[24]

The practice included a robot-assisted walking therapy, at variable speeds, for 45 minutes, with a partial body weight support (BWS). All participants started with 30-40% of BWS and an initial speed of 1.5 km/h; afterwards, speed was increased to a range of 2.2 to 2.5 km/h maximum and initial BWS was decreased. After 45 minutes the session was stopped.

Control Group. Each subject received 20 sessions (5 days a week for 4 weeks) of treadmill rehabilitation treatment. All subjects were asked by the therapist to perform a treadmill training treatment, at their best convenience, for 45 minutes, according to a protocol setting. The patients received video feedback to improve the gait quality. The Gait Trainer 3, equipped with Visual Biofeedback Screen, provided the necessary stimulus for retraining neural pathways, thus improving the patient's gait pattern and assessing the patient's ambulation progress The biofeedback parameters could be set by the therapist according to patient's characteristic (i.e. impairment) and to the desired goals (i.e. improvement in velocity and/or step length and/or cadence). In particular, the patients could follow a graphical representation of the foot, on the treadmill screen, having a visual feedback of their performance simultaneously.

Heart rate and blood pressure were monitored at the beginning and at the end of each session. During the training sessions, the therapist followed the treatment standing on one side of the patient. The treatment parameters were noted for each session.

In both groups, subjects who did not retrieve sessions and interrupted the treatment for more than 3 consecutive days were excluded from the study.

Statistical Analysis

All the previously defined parameters were computed for each participant. Mean values and standard deviations of all indexes were calculated for each group. The Kolomogorov–Smirnov tests were used to verify if the parameters were normally distributed. As this was not the case, we used Wilcoxon's tests in order to detect significant change between data at baseline (T0) and endpoint (T1). The T0 and T1 data of all patients and CG were compared with Mann–Whitney U tests. Statistical significance was set at p < 0.05. The Mann–Whitney test was used to compare median scores between groups.

Ethical Aspects

This study was performed in accordance with the Declaration of Helsinki and was approved by the ethics committees of IRCCS San Raffaele Pisana. Informed consent was obtained from all subjects enrolled in this study.