Upper Extremity Rehabilitation using Robotics
Robotic upper limb rehabilitation therapy has been gaining traction in the rehabilitation field as technology advances. It is used to supplement or facilitate rehabilitation by assisting in the repetitive labor-intensive manual therapy that are normally administered by therapists. This decreases the time demands on therapists as the robotic devices can help move the patient’s limbs during exercises, thereby increasing the amount of therapy for each patient and increasing the number of patients undergoing therapy simultaneously .
There are two main types of robotic devices for upper limb rehabilitation: the end-effector-based and the exoskeleton- based robots. The main advantage of the end-effector system is that it adapts to patients with different body sizes. In contrast, the exoskeleton upper limb robot requires various modifications in different patients because they need an optimal joint adaptation to work correctly . Examples of the types of robotic devices are: The T-WREX  , the ARMin , the MIME , the ARM guide  , the Bi-Manu-Track , the GENTLE , the Armeo   , and the Amadeo .
The hand serves very important role with functionality. It is used in everyday activities such as eating, dressing, object manipulation and handwriting. Therefore, re-training reach and grasping skills is critical to improving quality of life and hand therapy is used to re-learn these basic skills. Upper-extremity impairment is the most significant disability in stroke survivors as it is reported in about 70% of patients on admission of a stroke . Patients with Parkinson’s and Multiple Sclerosis also often have upper limb dysfunction. Emerging evidence shows that robotics can be useful in these populations as well . Hemiparesis is often seen in spinal cord injuries where the right or the left side of the upper limbs are affected. A full or even partial recovery depends on repetition, intensity and task-orientation . Hence, within good reason, the use of robotics to increase the amount of motor repetitions can aid in recovery . The dose-response relationship in stroke rehabilitation has showed that the more intensive therapies are associated with a greater rate of motor recovery with no ceiling effect being observed .
Despite what the research shows, traditional hands on therapy are not delivered with a high enough frequency and intensity because of labor limitations and cost . Traditional therapies can also result in repetitive strain injuries and fatigue by therapists . The variability between therapists are also factors that could affect or lead to inconsistent outcomes . The advanced robotic devices are capable of providing consistent training to measure performance with high reliability and accuracy . Above all, the robotics can permit patients to train independently with less supervision from a therapist .
Stroke and Spinal Cord Injuries
Several robotic machines have shown to be effective in patients with stroke. For example, the Armeo Spring helps to recover function in the hemiparetic arm, forearm and wrist in patients who have experienced a stroke and have consequent hemiparesis. The Armeo Spring is an adjustable suspension system for the upper limb that connects to virtual reality (VR), which has settings with several degrees of complexity . The system is an exoskeleton that supports the patient’s arm and magnifies any residual active movement of the hemiparetic arm in 3-dimensional space . Distally, it detects grasp pressure and the sensitivity may be adjusted depending on the patient’s condition . VR settings are designed to bring varying levels of difficulty in the velocity, direction and moving area . The system provides information about specific movement parameters (strength, range of motion, and coordination) to allow for proper adjustment of the difficulty level for the patient during the recovery process . A study of the effects of the Armeo spring system and the benefits in subacute spinal cord injury patients showed that there is significant improvement in the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) sensibility scores of subjects with partial hand function at baseline .
Specific to the fingers and hand, the Amadeo is another robotic system that has shown to be useful in those recovering from stroke. A randomized control trial conducted on acute stroke patients looked at the effectiveness of robot- assisted hand therapy using the Amadeo Robotic System by Tyromotion. Amadeo Robot is an end-effector based system that has five degrees of freedom and provides the motion of one or all five fingers through a passive rotational joint placed between the fingertip and an entity that moves laterally (the thumb has two passive rotational joints) . All five translational degrees of freedom are independent and provide an almost entire coverage of the fingers’ workspace . The interface between the human hand and the machine is achieved thanks to elastic bands or plasters and the wrist is restrained from movement by a Velcro strap . The Amadeo treatment composed of:
1) Continuous passive therapy
2) Assisted movement therapy
3) Balloon training (active training in a virtual environment by carrying out target oriented tasks) .
Comparable to traditional Occupational Therapy methods, patients within the robotic therapy group made significant improvements in Fugl-Meyer Scale (FM), and Box and Block Test (BB) at the end of treatment (4/5 weeks) and maintained improvements after a 3-month follow-up . This result is very important because the gain achieved is not exercise or time dependent, but could be secondary to reorganization of brain structures .
More evidence demonstrated the clinical feasibility of using other types of robotics than the Armeo or Amadeo. MIT-MANUS, MIME, ARM-Guide, T-WREX and NeReBot . The results are just as expected, when conventional therapy is matched with robotic therapy in terms of duration/intensity, there is no statistically significant difference in the Fugl Meyer assessment scores . However, when robotic therapy was added on top of conventional therapy, there was a significant improvement in Fugal Meyer scores . The same results were seen in motor control measured by the Motor Status Scale. The presiding theme that more is better exists whether it is therapy is conventional or robotic. However, functional abilities (measured by the FIM) did not see the same improvements with additional robotic therapy . This difference can be attributed to the fact that robotic therapy programs focus mainly on motor recovery rather than functional abilities of the upper limb . This can have a negative impact on treatment as patients participate in rehabilitation to try to regain functional abilities and they want to see better results in that regard.
Limited evidence has also shown the Armeo Spring to be an effective rehabilitation tool in those with Multiple Sclerosis (MS). While no changes in muscle strength were observed, functional capacity tests significantly improved after treatment, and improvements were maintained at 2 month follow up . It is important to note that these patients were considered to have an elevated level of upper limb disability. More recent research using the HapticMaster robot combined with a virtual reality system showed positive effects on perceived function in MS patients, but no significant clinical changes at the group level . However, when researchers observed their raw data, they noticed that those with upper limb function considered marked-to- severe did show considerable improvement on clinical tests .
Most research on robotics in Parkinson’s rehabilitation seems to be related to gait. However, one 2014 study examined the effects of the Bi-Manu-Track robot on upper limb function. After ten, 45-minute treatment sessions with the robot, patients showed significant changes in the nine-hole peg test and the upper limb portion of the Fugl-Meyer. At two-week follow up, improvements in the nine-hole peg test were still present . Although this is just the results of one study with a small sample size (n=10), it seems to be a promising area of research.
The Armeo has also been shown to be a valid measurement tool to access upper limb movement performance in sub-acute stroke patients . Construct validity has been proven for the hand patio, the mean velocity and the number of peaks in the velocity profile which accesses the movement accuracy, velocity and smoothness respectively . So an accurate initial assessment test using robotics such as Armeo spring can be done and training with the robot can demonstrate improvement and have a valid post test to evaluate treatment .
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