THE GROWTH IN LIFE expectancy has generated a significant

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1 1746 ORIGINAL ARTICLE Effects of Intensive Arm Training With an Electromechanical Orthosis in Chronic Stroke Patients: A Preliminary Study Rodrigo C. de Araújo, PhD, Fábio Lúcio Junior, MSc, Daniel N. Rocha, PhD, Tálita S. Sono, MSc, Marcos Pinotti, PhD ABSTRACT. de Araújo RC, Junior FL, Rocha DN, Sono TS, Pinotti M. Effects of intensive arm training with an electromechanical orthosis in chronic stroke patients: a preliminary study. Arch Phys Med Rehabil 2011;92: Objectives: To evaluate the use of an electromechanical device, comprising an exoskeleton, a static orthosis, and a glove, for functional rehabilitation of the elbow and hand in patients with hemiparesis, and to compare it with physical therapy rehabilitation. Design: Pretest-posttest design. Setting: Rehabilitation laboratory. Participants: Volunteer sample of persons (N 12) with persistent hemiparesis from a single, unilateral stroke within the past 3 to 36 months. Interventions: The volunteers were randomly divided into 2 groups. One group was treated with a conventional program of physiotherapy, and another group participated in a training program in which an electromechanical orthosis was used. All volunteers received 24 sessions, held 3 times a week for 8 weeks. Main Outcome Measures: Modified Ashworth Scale (MAS), Fugl-Meyer Assessment (FMA), and electromyogram (EMG) amplitude. Results: No statistical difference was found in the initial and final values of the MAS. Both groups showed a significant increase for the total scores of the FMA. However, only the group treated with the orthosis showed an increase in FMA scores related to the wrist and hand joint. The EMG analysis showed increased EMG amplitudes for all muscles in the group treated with the orthosis, whereas the group treated with physiotherapy showed gains in electromyographic activity only in the extensor digitorum communis. Intergroup comparison showed that the initial FMA scores of the wrist/hand were higher in the group treated with physiotherapy. However, after training, the scores in the group that used the orthosis were equivalent to those of the physiotherapy group. Conclusions: The results suggest that this device can be an auxiliary tool to help the conventional rehabilitation program of motor function of the affected upper extremity. Key Words: Cerebrovascular accident; Paresis; Rehabilitation; Upper extremity by the American Congress of Rehabilitation Medicine THE GROWTH IN LIFE expectancy has generated a significant increase in the worldwide elderly population and an associated increase in comorbidities related to aging. Among these, stroke is one of the main causes of death and functional incapacity in the world. 1-4 The World Health Organization estimates that the incidence of stroke in developed countries will grow approximately 30% between 2000 and 2025, 5 predicting that approximately 49 million individuals worldwide will survive stroke and live with a functional incapacity that will increase health care system expenses and significantly decrease the quality of life of these individuals. 6 Hemiparesis has been reported as the principal effect of stroke and occurs in more than 80% of all cases. 7,8 The degree of motor function recovery is strongly correlated with the severity and location of the lesion. 9 The recovery process may be stimulated and molded by rehabilitation programs that use different techniques and exercises for motor relearning. 10 Published studies indicate that only 5% to 20% of stroke patients with hemiparesis regain upper extremity function and that only 6% are satisfied with the level of functionality of the affected upper extremity. 14 Therefore, it is necessary to search for more effective therapeutics for the rehabilitation of these patients. Because of the limited success of traditional rehabilitation programs in restoring upper extremity function after stroke, researchers have been searching for other solutions, especially those using new technologies. Different research groups have developed robotic devices to assist in motor function recovery These devices allow the performance of repeated time-specific tasks in a controlled and reliable manner, which has been demonstrated to be a determining factor in the facil- From the Department of Mechanical Engineering, Universidade Federal de Minas Gerais UFMG, Belo Horizonte (de Araújo, Junior, Rocha, Sono, Pinotti); Department of Physical Therapy, Universidade de Pernambuco UPE, Recife (de Araújo); and Department of Mechanical Engineering, Instituto Federal de Minas Gerais IFMG, Congonhas (Rocha), Brazil. Supported by The National Council for Scientific and Technological Development (CNPq) (Proc. n / ). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated. Clinical Trial Registry: ACTRN Correspondence to Rodrigo C. de Araújo, PhD, Universidade de Pernambuco, Departamento de Fisioterapia, BR 203 Km 2 S/N, Vila Eduardo, Petrolina, PE-Brasil , rodrigocappato@yahoo.com.br. Reprints are not available from the authors /11/ $36.00/0 doi: /j.apmr BB EDC EMG FDS FMA MAS MVIC ROM RMS TB List of Abbreviations biceps brachii extensor digitorum communis electromyogram flexor digitorum superficialis Fugl-Meyer Assessment Modified Ashworth Scale maximal voluntary isometric contraction range of motion root mean square triceps brachii

2 INTENSIVE ARM TRAINING WITH AN ELECTROMECHANICAL ORTHOSIS, de Araújo 1747 itation of cortical reorganization, with a concomitant increase in motor ability and an improvement in functional activity performance. 16 Of the new devices, the most studied are the MIT-Manus, 17 MIME, 18 ARM-Guide, 19 NeReBot, 4 and ARMin. 20 Despite their good results in preliminary studies, these robotic devices have several drawbacks: they focus on the rehabilitation of the upper extremity proximal joints, have high costs, and do not allow the accomplishment of daily life activities. Therefore, the objective of this study was to evaluate the use of an electromechanical device, composed of an exoskeleton, static orthosis, and a glove, for functional rehabilitation of the elbow and hand in patients with hemiparesis, and to compare it with physiotherapeutic rehabilitation. METHODS Participants The study was conducted with 12 right-handed patients of both sexes (10 men, 2 women) who were older than 18 years and had received a clinical diagnosis of primary stroke caused by ischemia or hemorrhage at least 3 months previously and exhibited hemiparesis of the right side. Subjects were included in the sample if they had reduced motor function in the affected limb and did not have comprehension deficits. Subjects were excluded from the sample if they had bilateral motor sequelae, a history of 2 or more strokes, or severe spasticity that is, a value above 3 on the Modified Ashworth Scale (MAS). Before beginning the study, the volunteers signed a consent form approved by the ethical review board of the University of Pernambuco. Functional Evaluation A physical evaluation, including a history and a physical examination, was initially completed for each volunteer, during which personal and anthropometric data were collected, a history of the stroke was taken, and questions related to the stroke were answered. The volunteers were subsequently randomly (through a raffle) divided into 2 groups (a physical therapy group and an orthosis group) and submitted to a functional evaluation in which the Fugl-Meyer Assessment (FMA) test 21 was performed to evaluate the motor impairment of the upper limb. The examination of the motor impairment of the upper limb from the FMA scale included items related to movements of the shoulder, elbow, forearm (proximal arm), wrist/hand (distal arm), and coordination/speed. The total scores range between 0 and 66, with 66 points representing complete accomplishment of all the assigned tasks. The motor impairment was classified as severe (point total, 0 20), moderate (point total, 21 55), or light (point total, 56 66). 22 The elbow flexor and the wrist and finger muscle tone were evaluated using an MAS. 23 EMG Evaluation Four channels of a Myosystem BrI system a were used to record myoelectric signals, with simultaneous acquisition and sample frequency of 10kHz per channel for visualization. Myosystem BrI version 2.12 software a was used for signal processing. Myoelectric signals from the biceps brachii (BB), triceps brachii (TB), extensor digitorum communis (EDC), and flexor digitorum superficialis (FDS) were measured using superficial differential active electrodes a composed of 2 rectangular parallel bars with a gain of 20. Before placing the electrodes, the skin was shaved and cleaned with alcohol. Electrode placement on the biceps and triceps was oriented according to Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles recommendations. 24 Placement on the EDC and FDS was oriented as described by Perotto et al. 25 To reduce acquisition noise, a ground electrode was placed into the sternal notch region with conducting gel. Three maximal voluntary isometric contractions (MVICs) were completed in the muscular function test position 26 to obtain the electromyogram (EMG) signal amplitude for each muscle. The MVIC of each muscle was maintained for 8 seconds, with 5-minute intervals between contractions to minimize the muscular fatigue effect. The electromyographic signals, obtained in microvolts, were rectified (full wave) and filtered (low pass at 10Hz, using a fourth-order Butterworth filter). The data from the first and last seconds of the 8-second trial were excluded from all observations to reduce the influence of the time required for a volunteer to stabilize the MVIC. Therefore, the 6-second window presented a more homogeneous electromyographic signal, compatible with the desired effort level. Simultaneous acquisition of electromyographic signals was sampled by a 12-bit analog-to-digital converter board with a 10-kHz frequency, and raw electromyographic data were digitally filtered at a frequency bandwidth of 10 to 500Hz, and the root mean square (RMS) was calculated to derive the EMG amplitude values as described by de Araújo et al. 27 The electromyographic signals were not normalized, because the comparisons were made between the same muscles and not between different muscles and different people. Electromechanical Device An electromechanical device was developed for different functional modules as follows: Exoskeleton and static orthosis. Two plastic static orthoses were used to accommodate the patient s upper limb to the exoskeleton. These plastic pieces were separately molded to the arm and forearm/wrist of each patient from thermoplastic material and prepared to be fixed to the exoskeleton. These orthoses were responsible for stabilization and setting of the upper limb segments inside the exoskeleton in a functional position, especially the forearm, which was stabilized in a neutral position. The forearm-fixed piece was also responsible for stabilization of the wrist joint in moderate extension and of the thumb in abduction. The upper limb of the patient was properly accommodated and fixed in the static orthosis/exoskeleton by means of Velcro strips. The exoskeleton structure consisted of 2 segments made of nylon positioned along the forearm and arm, separated by metallic spacers and connected by an articulated shaft that coincided with the axis of the elbow joint. A pulley was attached to the exoskeleton shaft, and the movement of elbow joint during the rehabilitation/training of the patient is achieved by producing appropriate antagonistic torques through the cables connected to this pulley driven by the actuator (fig 1). The diameter of the pulley was calculated as a function of engine speed and the time required for the flexion and extension at an angular velocity of 30 o /s. The joint movement of the exoskeleton was responsible for elbow flexion and extension, which were defined as flexion between 10 and 110. This range of motion (ROM) was selected because it is considered a functional ROM for the elbow. 28 Extreme flexion and extension amplitudes were avoided to prevent excessive stress on joint and ligament structures. Glove. A Lycra glove was made for each volunteer to assist in flexion and extension of the fingers. Polymeric artificial tendons (a 55-lb multifilament line b ) were connected to glove fingers in both ventral and dorsal faces. These artificial

3 1748 INTENSIVE ARM TRAINING WITH AN ELECTROMECHANICAL ORTHOSIS, de Araújo tendon in a direction promoting elbow flexion. When activated by the electromyographic signal from the TB muscle, the actuator turned in the opposite direction, promoting elbow extension. The same logic was used in the traction system responsible for the fingers, which were set in motion by electromyographic signals from the finger flexor and extensor muscles. Fig 1. Exoskeleton and static orthosis. tendons were connected to an electromechanical actuator that produces bidirectional torques for flexion and extension of the fingers, providing hand movement. An inelastic material was used as a fixation point and guide for artificial tendons, reproducing a system of tunnels and tendons in the human hand. To perform the movements, the tendons slide through these artificial tunnels, located inside the glove, moving back and forth freely (fig 2). Actuator modules. Two actuator modules, which were responsible for elbow and finger flexion and extension, were composed of an electromechanical actuator, a traction system, conduits, and a pulley. The electromechanical actuator corresponded to a direct-current motor drive system coupled to and driven by a control module composed of an electric circuit. This circuit was used to capture electromyographic signals from the active electrodes and to generate the motor drive. A visual system formed by light-emitting diodes was used to check the functionality of the control circuit. On being triggered by the electromyographic signal from the BB muscle, the actuator turned the shaft, pulling the artificial Training The volunteers were divided into 2 groups of 6. The first group (physical therapy group) was treated with a conventional rehabilitation protocol, and the second group (orthosis group) was treated with a rehabilitation program that used the electromechanical orthosis. The protocols applied to each group are described below. Physical therapy rehabilitation program. Training comprised 24 sessions attended 3 times per week over 8 weeks. The rehabilitation program for the patients in this group was led by the same physiotherapist for every session. Each session lasted 50 minutes, and the treatment applied to the patients was based on the principles of neuromotor development, including postural control and balance, scapular mobilization, weight-bearing exercises for the upper extremities and, principally, functional training of the compromised hemisphere, from simple tasks to more advanced movement patterns. A typical session involved approximately 10 minutes of establishing a physical postural base of support coupled with facilitating the alignment of the shoulder. Approximately 20 minutes was devoted to graded application of the arm s use in functional self-care tasks. Subjects needed to show the ability to independently perform basic mass functional movements before progressing to more isolated advanced functional patterns. Progression within each movement was facilitated by increasing the number of repetitions and the weight of the item being handled. At least 20 minutes was dedicated to performing several repetitions of flexion and extension of the elbow and wrist/hand. The movements were initially implemented in order active-assisted progressing to active-resisted, according to evolution each patient. Fig 2. Glove. (A) Dorsal face. (B) Ventral face.

4 INTENSIVE ARM TRAINING WITH AN ELECTROMECHANICAL ORTHOSIS, de Araújo 1749 Fig 3. Volunteer using the electromechanical orthosis. Orthosis rehabilitation program. Training comprised 24 sessions conducted over 8 consecutive weeks. There were 3 weekly sessions, each with a duration of approximately 50 minutes. Initially, patients received instructions regarding the use of the device. Patients were instructed to try to execute the movements of the elbow and hand, increasing the level of muscle contraction to the activation threshold of actuators, and that from this moment, the actuators would be responsible for completing the desired ROM. During the first sessions, the patients performed during approximately 25 minutes, several repetitions of elbow and finger flexion and extension movements (therapy active-assisted). After a period of training and familiarization with the system, functional tasks were added, such as reaching and moving an object on a table, encouraging movements of grasping (fig 3). In these tasks, the volunteers were seated in front of a table and were instructed to reach and grab objects on the table, being necessary to perform coordinated movements of elbow extension and fingers. Later, the volunteers would make the movement of grip and elbow flexion in order to bring the object to their mouth. After performing the task described previously, they were asked to put the object back on the table. The objects used were plastic cups and balls of different sizes, materials, and weights. These tasks were performed for approximately 20 minutes. Progression within each task was facilitated by increasing the number of repetitions and varying the locations of the objects on the table. In all cases, the functional and physical limits of each patient were observed. After the end of the training protocols, all the volunteers were reevaluated. Data Analysis All statistical analyses were performed using the statistical package SPSS c (version 16.0). Before analyzing each variable, data distribution normality was verified by the Kolmogorov- Smirnov test. The Wilcoxon test was used for pretraining and posttraining comparisons of the scores registered in the clinical tests (FMA and Ashworth) and comparisons of EMG data. Intergroup comparisons of anthropometric and demographic data were evaluated by the Mann-Whitney U test (ordinal data) and the chi-square test (nominal data). For intergroup analyses, the Mann-Whitney U test was used to compare the scores from the FMA. For all analyses, P.05 was considered significant. RESULTS Physical and Functional Evaluation No significant differences between the 2 groups with respect to age, sex, body mass index, time since stroke, or test scores were found in the pretraining functional evaluation, demonstrating sample homogeneity with respect to these variables (table 1). Table 1: Data on the Participants at Admission Characteristic Group 1 (n 6) Physical Therapy Group 2 (n 6) Orthosis Test P Age (y) t.31 Months poststroke t.60 Sex Men Women Body mass index (Kg/cm 2 ) t.06 FMA (0 66) t.24 MAS Elbow (0 5) U.99 Wrist (0 5) U.06 NOTE. Values are mean SD, n, or as otherwise indicated. Abbreviations: t, unpaired t test; U, Mann-Whitney U test.

5 1750 INTENSIVE ARM TRAINING WITH AN ELECTROMECHANICAL ORTHOSIS, de Araújo Table 2: Mean Values of the 2 Assessments of the Scores Obtained by MAS Assessment Elbow Wrist/Hand Group 1 Group 2 Group 1 Group 2 Baseline End therapy P NOTE. Values are mean SD or as otherwise indicated. Table 2 shows the intragroup comparison scores obtained in the first (pretraining) and second (posttraining) evaluations using the MAS, which evaluated the impact of the rehabilitation techniques on the degree of spasticity in the elbow and wrist/hand joints. Despite the decrease in the mean values of the MAS after therapies, there was no significant difference in the muscular spasticity scores for either group. The results of the FMA conducted before and after the training demonstrated an improvement in upper extremity motor function for both groups. An increase in the total FMA for each of the volunteers is depicted in figure 4. However, when evaluating the FMA subitems, the physical therapy group showed significant gains only in proximal joint (shoulder and elbow) motor function (table 3). On the other hand, the orthosis group had significant gains not only in proximal joint function but also in the function of the wrist and hand joints. With respect to the coordination and speed subitem of the FMA neither group exhibited significant differences in the pretraining and posttraining comparison (see table 3). The intergroup comparison revealed no statistical difference in the first assessment (baseline) to FMA-total (P.17), FMAshoulder/elbow (P.74), and FMA-velocity and coordination scores. However, group 2 had a lower FMA-wrist/hand score than group 1 (P.03). At the second assessment (end therapy), comparisons between groups revealed no statistical differences for all evaluated items (P.18). EMG Evaluation The results of the EMG amplitude evaluations for the BB, TB, EDC, and FDS muscles are presented in figure 5. An intragroup comparison of the pretraining and posttraining RMS values demonstrated that the orthosis group showed significant increases in electromyographic activity in all the evaluated muscles (BB, P.01; TB, P.002; FDS, P.01; EDC, P.001). The physical therapy group did not show significant alterations in electromyographic activity in the BB (P.80), TB (P.65), or FDS (P.69) muscles. However, significant increases in the RMS values of the EDC muscle were observed (P.03). DISCUSSION The objective of the present study was to evaluate 6 patients with hemiparesis caused by stroke who completed 8 consecutive weeks of intensive training for the upper extremity with an electromechanical orthosis. The effects of the orthosis training were compared with those of a conventional physical therapy program also conducted for 8 weeks. The results showed no statistical difference was found in the initial and final values of the MAS, and both groups showed a significant increase for the total scores of the FMA. However, only the group treated with the orthosis showed an increase in the FMA scores related to the wrist and hand joint. The electromyographic analysis showed increased EMG amplitudes of all muscles in the group treated with the orthosis, whereas the group treated with physiotherapy showed gains in electromyographic activity in only 1 muscle. The mean values obtained from the MAS in the second assessment were lower than those in the first. These results suggest that therapies used in this study may help in the treatment of spasticity. However, no significant difference was observed between the volunteers participating in the 2 types of training, which agrees with results from previous studies. 10,29 Other investigators 30 have reported a tendency toward reduced MAS values after training with the application of activeassisted and active-resisted tasks, both manually and mechanically, corroborating our results and demonstrating that these types of therapy do not exacerbate spasticity in patients with hemiparesis caused by stroke. With respect to motor function, increased electromyographic activity was observed during the completion of MVICs in all the muscles in the orthosis group and in only the common finger extensor muscle in the physical therapy group. These findings indicate that a greater recruitment of muscle motor units or changes in muscle size and cross-sectional area may have been induced by this type of training, increasing the amplitude of the electromyographic signal. However, in this study were assessed maximal isometric contractions with manual resistance, limiting possible conclusions about the true Fig 4. FMA scores before and after training. Group 1, physical therapy; group 2, electromechanical orthosis; S1 S12, subjects 1 12.

6 INTENSIVE ARM TRAINING WITH AN ELECTROMECHANICAL ORTHOSIS, de Araújo 1751 Table 3: Overview of the FMA FMA Baseline End Therapy Difference P Group 1 (physiotherapy) Total * Sh/El * Wr/Hd Vl/Cd Group 2 (orthoses) Total * Sh/El * Wr/Hd * Vl/Cd NOTE. Values are mean SD or as otherwise indicated. Abbreviations: Sh/El, shoulder and elbow joint; Vl/Cd, velocity and coordination; Wr/Hd, wrist and hand joint. *Intragroup comparison (P.05). Intergroup comparison (P.05). cause of the changes in EMG data, being necessary to carry out further research to assess also the torque or force generated. The initial Fugl-Meyer scores for the volunteers in both groups varied between 23 and 44 points, which can be classified as moderate impairment of motor function of the upper extremity according to scales described elsewhere. 31,32 After the training, it was confirmed that both of the applied therapies were effective for the recovery of upper extremity motor function; there was an average increase of approximately 11 points in the Fugl-Meyer score in the physical therapy group and 10 points in the orthosis group. The increase in absolute FMA test values of all volunteers, besides being statistically significant, revealed that with the training, a moderate degree of upper extremity motor impairment in the volunteers remained, and the degree of impairment of 2 patients in the control group decreased from moderate to light, according to the scale described by Michaelsen and Levin. 31 However, in figure 4, it can be seen that the 4 volunteers in the control group who had initial FMA values greater than 40 points, showed a greater increase in FMA scores. The volunteers with greater initial motor impairment showed lower development of motor function. These findings corroborate those of previous studies, which determined that the initial degree of motor impairment was the best predictor of motor recovery after a stroke. These results suggest that the physical therapy protocol applied in this study may have been more effective for patients with lower initial motor impairment. On the other hand, based on visual analysis of figure 4 and the statistical results of the intragroup comparison, it is possible to suggest that training with the orthosis shows positive results in the recovery of upper limb motor function in patients with greater motor impairment. These findings may confirm the important role of this device as an auxiliary tool in the process of motor rehabilitation of the upper limb, especially in patients with a higher deficit of motor function. Moreover, an analysis with relative values indicated increases of greater than 30% in Fig 5. EMG amplitude values before and after training. Group 1, physical therapy; group 2, electromechanical orthosis. * Indicates statistical difference in comparison before and after training. Abbreviations: 1A, first assessment; 2A, second assessment.

7 1752 INTENSIVE ARM TRAINING WITH AN ELECTROMECHANICAL ORTHOSIS, de Araújo FMA test scores, further demonstrating the improvement in upper extremity motor function; changes greater than 10% are considered clinically important. 10,36,37 The joint and segment results demonstrate that both groups experienced shoulder and elbow joint motor function improvement, whereas the group of volunteers treated with the physical therapy protocol did not show a significant improvement in motor function in the distal joints (the wrist and hand). These results support the findings of various studies that have demonstrated low functional recuperation indexes of the upper extremities, 11,13 in particular for activities performed by distal musculature that demand fine motor control. 33 The orthosis group showed significant gains in the Fugl- Meyer scale scores in the tasks related to the wrist and hand joints, which indicated improved distal motor function. These results corroborate studies by Hesse et al 38,39 and Staubli et al, 40 who observed improved distal motor function in hemiparetic patients treated with the Bi-Manu-Track and ARMin II devices. Although most of the robotic devices developed for upper extremity motor function rehabilitation produce excellent results for the shoulder and elbow joints, various clinical assays have demonstrated that the MIT-Manus, MIME, Arm-Guide, and NeReBot devices produce unsatisfactory results in wrist and hand motor rehabilitation. 4,7,10,13,17-20,33 Moreover, more than 2000 articles were evaluated in the 13th edition of the Evidence-Based Review of Stroke Rehabilitation, 41 with 42 being controlled randomized clinical trials that used robotic devices, and the authors concluded that there is strong evidence that sensorimotor training with robotic devices improves upper extremity functional outcomes, and motor outcomes of the shoulder and elbow, and there is strong evidence that robotic devices do not improve motor outcomes of the wrist and hand. 41(p79) A possible explanation for the divergence between the present study and those mentioned above is the difference in methodologies. Different motor evaluation tests and scales have been reported, and the durations of the sessions and protocols vary substantially between studies, which may explain the difference in performance of the device tested in this study. The accomplishment of repeated time-specific tasks for longer periods and in a regular manner is a determining factor in the facilitation of cortical reorganization, with a concomitant increase in motor ability and improved functional activity performance. 16 Another important factor that may have contributed to the different results is the selection of volunteers for the study. The previous studies included patients with right- or left-sided hemiparesis without considering functional dominance; only right-handed patients with right-sided hemiparesis (ie, only patients with dominant-side impairment) were included in the present study. The impairment of different cerebral hemispheres not only can cause distinct intellectual and behavioral characteristics but also can influence the motor function recovery process. Patients with right hemisphere injuries can experience difficulty with movement initiation, sequence, and direction, whereas patients with left hemisphere injuries tend to exhibit visual disturbances, reduced attention, and difficulty in discriminating object size and distance. 42 Byl et al 33 compared the evolution of motor function in patients with hemiparesis after they underwent a rehabilitation protocol based on neuroplasticity principles, and observed no difference in fine motor control or muscular performance between patients with right and left hemiparesis. However, the patients with right hemiparesis showed significant improvement compared with those with left hemiparesis, mainly with respect to functional independence. The dominant-side impairment may have induced a greater motivation in the patients to rehabilitate the affected side to complete the activities of daily life. Although these findings are preliminary because of the small sample, they are important because they indicate that the orthosis tested in the present study can be an alternative for rehabilitation for stroke patients. Which can be used in conjunction with physical therapy to assist in motor recovery of the upper limb. More studies are necessary to better understand the different mechanisms and aspects involved in the rehabilitation process of patients with hemiparesis. Study Limitations This study was subject to several limitations. The location of the stroke was not known. Replication of this study with a larger sample size and longer treatment period would be beneficial. A study of the long-term effects of this treatment also should be conducted by extending the follow-up period. Moreover, future research should be conducted evaluating the single orthosis use and combined orthosis with physiotherapy. Regarding the EMG analysis, the results are limited because there was no estimation of force or torque values. Finally, considering the results obtained with this device, there remains the challenge of improving the system and expanding its applicability. The future device must be used by different patients, not only as therapeutic tool but also as functional orthosis for daily activities, contributing to an improved quality of life and inclusion of people with physical disabilities. CONCLUSIONS This study presents the preliminary results of a pilot study of 6 patients with chronic hemiparesis who used an electromechanical orthosis as a therapeutic tool. The results suggest that this device can be an important auxiliary tool to help the conventional rehabilitation program of motor function of the affected upper extremity, especially with respect to distal joints. 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