2.2. The Evaluation Protocol

The study protocol was approved by the Ethics Committee of the Municipal Clinical Hospital Cluj-Napoca (SCMCJ), being in accordance with the Helsinki principles for biomedical research; all patients signed an informed consent. The study started in October 2019 and lasted until December 2019. A total of 23 patients (12 men and 11 women) were enrolled, all inpatients of the Neurology Department of the SCMCJ. A common characteristic of the participants was upper limb motor deficit, but plegic patients were not included. Patients with excessive spasticity, which did not allow the upper limb joint movements, were excluded. Demographic data and age-dependent difference analysis is shown in Table 1.

Demographic data showing the age and gender distribution, with no significant difference between the groups.

Three patient groups were formed, according to their pathology. The first group, referred as Vascular, consisted of patients with ischemic stroke and included six men and six women with variable degree of motor deficit. Stroke patients were with chronic ischemic stroke, by definition. Right brachial motor deficit benefited from robotic rehabilitation; left brachial motor deficit performed the rehabilitation sessions with the physical therapists. A second group consisted of patients with extrapyramidal pathology, named Extrapyramidal, at the end all being diagnosed with Parkinson’s disease, and included six patients, three women and three men. Motor disturbances were bilateral; physical therapy for the right upper limb was made by the robot and for the left by the physical therapist, to have an objective comparison method. The two sides were their own controls. A third group was formed by patients with neuromuscular pathology, named Neuromuscular (motor neuron disease-amyotrophic lateral sclerosis–5). The patients included in this group were two females and three males. To summarize: in the case of the Vascular group. we had 6 patients with left, and 6 patients with right hemiparesis, a total of 12 records, 6 with robotic and 6 with physiotherapist rehabilitation, the deficit being unilateral. For the Neuromuscular and Extrapyramidal groups, there were 5 and 6 patients, respectively, but in these cases, both limbs were affected. For these groups we had 10 and 12 records, but 5 or 6, respectively, were right upper limbs, trained by the robot and 5 or 6 were left upper limbs, rehabilitated by the therapist. Therefore, for each individual group, there are 10 to 12 records, a total of 34 records, taken from 23 patients. The physical therapy program was provided for the right upper limb with the help of the modular robotic system, and for the left upper limb by the therapist. For Extrapyramidal and Neuromuscular patients, the debut of symptoms is chronic. We enrolled patients still able to move their upper limbs. Both the robots and the therapists performed the same protocol, for one exercise cycle. Only passive physical therapy was used, using the same protocol and exactly the same exercises, carried out on each patient of a subgroup, regardless if the rehabilitation was done by the robot or the therapist, as shown below in Table 2.

The applied physical rehabilitation protocol.

On enrolling, patients were informed about the study and subsequently signed the informed consent. The baseline multimodal neurophysiological evaluation was performed. To establish whether the rehabilitation method, through the proprioceptive signaling and afterwards parieto-frontal stimulation has any effect on the motor system, we used a high density, standardized EEG cap with 128 electrodes and a CareFusion NicOne EEG, with qEEG facility. Electrodes over the motor zone were selected. Electrode impedance levels were kept under 5 kΩ. The EEG amplifiers had a band-pass from 0.5 to 40 Hz. Twenty minutes of EEG trace were recorded. During the evaluation, the eyes of the patients were kept closed. A total of 60 s of artifact free epochs were selected, with an average length of 2–2.5 s. On the obtained epochs, Fast Fourier Transformation was performed, and frequency values were then converted into relative power, the percentage of total power within each frequency band, for each investigated channel. The highest power density peak was also evaluated, for both activity and frequency.

The link from the motor cortex to the effectors is established by the central motor tracts, roots, plexuses and the peripheral nerves. To evaluate whether repetitive exercises might have an effect on conduction, total, peripheral and central motor conduction time measurements were carried out. The stimulus was delivered over the motor cortex using an R20 MagVenture system with an MMC-40 coil (provided by the Nexus Medical Association) and for the recordings on the target muscle, a 4 channel EMS Surpass EMG/ENG/EP system. The intensity was around 65–70%, to overcome the resting motor threshold, and the target muscle was for almost every patient the abductor pollicis brevis, and for those with atrophy of this muscle, the abductor digiti minimi.

Patients were evaluated for the effectors of the motor system, the muscles, using turn/amplitude analysis and needle EMG. Easily reachable target muscles, like extensor carpi radialis, were examined, assessing the changes of turns/amplitude values, in order to characterize the state of motor units, both as a result of the influence of the peripheral and the central pathological process. Thereafter, patients were retested, in order to determine the impact of rehabilitation, both in terms of physical therapy and in relation to robotic recovery. A four-channel Surpass EMG device was used to examine the extensor carpi radialis muscle. The patient was asked to extend the wrist with graded muscle contraction until a maximum of 5 kgf, measured with a dynamometer. The maximal force of extension at the initial examination was noted. The turn/amplitude values were recorded at maximum contraction. The final examination (after 7 days, twice a day physical therapy/or robotic rehabilitation) was performed at the same force.

After the baseline assessments, a 7 day, 2 cycle/day rehabilitation program was implemented (see Table 1) to each patient, either by the modular robotic system (Figure 2) or therapist. A second examination, with all the mentioned tests, was made at the end of the 7 day physical therapy sessions.

Images with patients during rehabilitation exercises with: (a) ParReEx wrist; (b) ParReEx elbow; (c) ASPIRE.

All the obtained data was gathered in databases and pre-processed using MS Excel, and afterwards the statistical analysis was performed using IBM SPSS Statistics 20. After the descriptive statistics, the chosen method was non-parametric testing, given the low number of participants, and since each person was its own control, the Wilcoxon Matched Pairs Signed Ranks Test was used. The exception from this is the case of the Vascular group, where there are different individuals with left hemiparesis as a control group. In this case the Mann–Whitney U test for independent variables was used. Regardless the test, the significance threshold was p < 0.05.