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Stroke Therapy Study

News of a second stroke rehabilitation study in Southampton was released today (click here for news about another recent stroke rehabilitation study in Southampton). This new study, lead by Dr. Jane Burridge, will combine transcranial Direct Current Stimulation (tDCS) with robotic training for the hand and arm.

tDCS uses a low constant current delivered to the part of the brain of interest using small electrodes. It has been discovered that such a current can result in cortical modulations (modified brain activity) that lasts longer than the current itself. Currently, tDCS is primarily used in applications involving psychological disorders, like anxiety and depression, and is used experimentally in motor rehabilitation.

tDCS is readily compared to Transcranial Magnetic Stimulation (TMS), which uses high voltage pulses of electricity through coils located close to the head to induce a small electrical charge in a desired region of the brain.

The £80,000 (approximately $126,000USD) study, funded by Wessex Medical Trust, will enroll stroke patients in the following treatment regime:

  • 20 minutes of electrical stimulation to increase the “excitability” of the brain cells, which send the messages to the muscles in the arm.
  • three 20-minute sessions with the robotic arms to build strength and get the arm and hand moving again.

The research team hopes that the combination treatment will speed up recovery by increasing activity of the damaged portion of the brain using tDCS, better preparing it to create new connections during the course of robotic therapy.

If successful, the team hopes to create a version of the tDCS machine for use in home-based stroke therapy.

Another similar clinical trial is wrapping up in Israel, although it uses conventional occupational therapy instead of a robotic system:

The purpose of this study is to determine whether a non-painful, non-invasive, brain-stimulation technique called transcranial direct current stimulation (tDCS) combined with occupational therapy (OT) will improve motor function in patients with chronic stroke.

This study is scheduled to be completed this month (December, 2010).

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Robot-Assisted Therapy in New Jersey

During his presentation at Neuroscience 2010, Dr. Sergei V. Adamovich’s suggested that stroke rehabilitation involving video-gaming in combination with a robotic system could improve a patient’s abilities.

“In virtual environments, individuals with arm and hand impairment practiced tasks such as reaching and touching virtual objects. They took a cup from a shelf and put it on a table, hammered a nail, and even played a virtual piano.” – Dr. Adamovich, New Jersey Institute of Technology

The study’s 24 subjects, who had suffered a stroke at least six months prior to therapy, played with the video game system for about 22 hours over a two-week period. The subjects were helped by a robotic arm, and were challenged to perform increasingly difficult tasks.

“Our preliminary data suggest that, indeed, robot-assisted training in virtual reality may be beneficial for functional recovery after chronic stroke. Furthermore, our data imply that this recovery may be particularly due to increased functional connections between different brain regions.” – Dr. Adamovich

The following is a video of Dr. Adamovich’s robotic system.

Sources: Science Daily, RAVR Lab

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New EMG-Controlled Hand Rehabilitation Robot

Tommy Chan at Deltason, a Hong Kong medical devices distributor with an impressive array of rehabilitation products, has recently added the “Hand Of Hope” to his company’s line.

Hand Of Hope

Hand Of Hope

Developed at the Hong Kong Polytechnic University, the Hand Of Hope combines non-invasive EMG sensors with a robotic exo-skeleton to help the patients perform tasks related to rehabilitation. The device is controlled by non-invasive EMG pickup electrodes that detect patients’ attempts to move their hands. Once an attempted movement is detected, linear actuators are used to drive each finger. The system is used to increase performance of hand grasp (palmar grasp and pinch) and hand opening. The range of motion of each finger actuator can be customized for each patient.

Hand Of Hope

Hand Of Hope - Prototype

Hand Of Hope

Hand Of Hope - Prototype

Here are some pictures of the device:

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Efficacy of Stroke Rehabilitation Devices

Here’s an interesting article about the Myomo, a robotic device developed at MIT and sold by Myomo Inc.  Part of the article addresses the lack of scientific evidence demonstrating efficacy of the device. Here’s an excerpt:

But there is no rigorous scientific evidence demonstrating how well it works. And the $7,000 device casts a spotlight on the hard-to-navigate world of rehabilitation devices — in which patients who are often desperate face a growing number of products whose effectiveness is still being determined.

“While there’s some suggestive, tiny studies — that are really pilot studies — that it might be useful, there’s no proof of efficacy using the usual criteria,’’ said Dr. Joel Stein, chairman of the rehabilitation and regenerative medicine department at Columbia University. He is also on Myomo’s scientific advisory board.

“I’ve worked with many stroke patients through the years, and I’m careful to not be too paternalistic deciding for them. . . . They feel like the medical system has given up on them, and there’s a fine line between not over-promising and saying we have nothing shown to be helpful, therefore you should just give up.’’

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Rehabilitation of Arm Function After Stroke – Literature Review, Review

Here’s a great scientific literature review of Arm Function Rehabilitation After Stroke. Unfortunately, it isn’t hugely accessible to non-technical readers (not many people know what “ipsilesional corticospinal excitability” means). Here’s my review of the main points of the article, in plain terms:

  • This study examined 66 other studies published between 2004 and 2008 from Medline using the keywords “stroke”, “upper limb”, and “rehabilitation”.
  • Only randomized control studies were included in the review.
  • High intensity rehabilitation training programs during subacute stroke rehabilitaiton (less than 6-months post-stroke) resulted in significant improvements in arm function.
  • Learned non-use (gradually giving up trying to use a partially paralyzed arm) is the result of brain re-organization that starts within hours of a stroke.
  • Rehabilitation that concentrates on compensation using the healthy limb can accelerate and perpetuate learned non-use. Some of the studies examined inhibition of the healthy part of the brain’s motor cortex using TMS.
  • Natural plasticity of the brain after stroke, which is associated with a re-allocation of brain networks from one function to another, leads to a certain amount of natural upper extremity neurological recovery
  • Training by repeating tasks directly linked to daily life activities promotes recovery. An “enriched” sensory environment (proprioceptive, visual, etc.) while performing these tasks is beneficial.
  • Residual voluntary motor ability at 1-month post stroke is the best predictor of how much hand dexterity will be regained.
  • In people whose stroke occurred 6 months or more previously (referred to as ”chronic”), 2 hours of transcutaneous neurostimulation (with an FES stimulator, for example) delivered just prior to rehabilitation training sessions, improves function of the weak hand
  • The impact of acupuncture on upper limb motor recovery is not conclusive.
  • Thermal stimulation, where patients are encouraged to take their paretic arm away when they feel an uncomfortable sensation, could promote recovery.
  • Constraint-induced movement therapy is effective in reversing learned non-use of a paretic arm. It is believed that CIMT encourages the brain re-allocation referred to above.
  • For higher-functioning chronic stroke survivors, mental imagery:   imagining moving the paretic limb, or imagining movements performed by another person, are beneficial to recovery of motor function. No benefit has been demonstrated in lower-functioning stroke survivors and those with cognitive impairments. Mental imagery hasn’t been the subject of many randomly controlled studies.
  • Unilateral task practice using the paretic limb yields improvements superior to those of bimanual task practice.
  • Both transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) have been shown to facilitate some motor recovery, but the cost/benefit and risk/benfit ratios have yet to be evaluated.
  • TMS inhibition of the healthy part of the motor cortex can temporarily improve dexterity of the paretic limb, but at this stage this is not a clinically relevant treatment. In some cases, the inhibition procedure may actually be harmful.
  • Constraint of the healthy limb in CIMT doesn’t yield more functional improvements than intensive movement therapy without a constraint.
  • More intensive training very soon after a stroke doesn’t yield functional improvement beyond that of standard treatment.
  • One year after a stroke, 9 hours of movement therapy isn’t sufficient to yield clinically significant results, whereas 57 hours of rehabilitation training does yield results for people with moderate motor impairment.
  • EMG-triggered electrical stimulation eliciting hand opening, (i.e. bursts of electrical stimulation of a muscle initiated by weak voluntary activation of the muscle), has been claimed to be more efficacious than electrical stimulation triggered by other means, but there is insufficient evidence to fully validate this conclusion.
  • Electrical stimulation to open the hand during repetitive grasp and release tasks is an integral part of a functional strategy, and promotes motor relearning.
  • Several studies have concluded that CIMT is better than conventional therapy, including one study of 43 patients at less than 16 weeks poststroke.
  • In a very broad study of 222 patients, CIMT improved pinch grip and several fine motor tasks, but failed to show significant improvement in a patient’s ability to open his or her hand.
  • The following details results for various robotics systems:
    - NeReBot: A group of acute poststroke subjects (some as early as 7-days poststroke) had better voluntary hand control compared to a group who received no therapy. The results were still evident 8 months later.
    - InMotion2: “The motor improvements observed after 18 hours of therapy are not clinically significant and do not spread to distal motor capacities.”
    - Bi-Manu-Track: Bimanual and uni-manual rehabilitation yielded similar improvements with the use of this robot.
    - MIME and BACTRAC: “The functional improvements on manual dexterous ability are limited to the execution speed of tasks that the patient had already mastered before treatment.”
  • Author’s therapy recommendations:
Moderate Motor Impairment Severe Motor Impairment
Early stroke rehabilitation
(< 6 months)
Functional rehabilitation training (25 hours) including: Distal EMG-stimulation + distal bimanual movements (6 hours) Bimanual distal robot (10 hours)
or
Distal EMG-stimulation + distal bilateral movements (20 hours) Then if possible: functional rehabilitation training (15 hours)
Chronic stroke rehabilitation
(> 6 months)
Constraint-Induced movement therapy (CI therapy) (30 hours)
or
Functional rehabilitation training (30 hours) (in a virtual environment setting or with verbal feedback on the performance) + Mental Imagery
If the neurophysiological criteria are favorable:
classic rehabilitation training (50 hours) with trunk restraint including distal EMG-stimulation + distal bilateral movements (20 hours)
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Stroke Rehabilitation with Robots

Researchers in the United States have found that robotic therapy can help stroke victims regain arm movement even years after their brain injuries. The study will be published in the online edition of the New England Journal of Medicine on Friday, April 23, 2010.

The study, a three-year randomized control trial (RCT) of 127 veterans in the U.S, found that stroke victims who had 12 weeks of robot-assisted therapy for their affected arm had an improved quality of life compared with those who had no additional therapy beyond the initial post-injury rehabilitation period. These findings go against conventional thinking that rehabilitation beyond the initial period had little benefit for stroke survivors.

Patients with moderate to severe disability in arm function resulting from stroke at least 6 months to five years earlier were included. After 6 months of therapy, the 49 patients in the robotic treatment group demonstrated clinically significant upper-arm function compared with the 28 patients who did not receive specific therapy for their upper limb.

Importantly, another 50 patients in the study did similar high-intensity exercises with the assistance of a therapist rather than a robot and demonstrated similar improvements.

Dr. Howard Kirshner, a professor and vice-chair in neurology at Vanderbilt Medical Center North in Nashville, commented to CBC:

“The most important take-away message for stroke survivors is that therapy, whether using new-fangled technologies, or using intensive standard therapy by trained therapists, is essential for optimal recovery of function after a stroke.”
CBC News

The study used the MIT Manus rehabilitation robot, developed at MIT, and commercialized by Interactive-Motion Technologies.

Here’s a video of the robot:

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Robot Stroke Rehabilitation Results in "Modest Improvements"

A recent randomized trial of 127 stroke survivors has shown no significant difference between rehabilitation with the assistance of a robotic workstation and more conventional rehabilitation with the assistance of a human.

The study, conducted by Dr. Albert Lo of the Providence VA Medical Center in Rhode Island, separated 127 participants into three groups: human-assisted rehabilitation (50 patients), robot-assisted rehabilitation (49 patients), and usual care consisting of treatment with antiplatelets, antihypertensives and recommendations for diet and exercise (28 patients).

Dr. Lo described improvements in both the robot-assisted and human-assisted as “fairly modest.” He went on to say that the improvements were important “because there’s very little available for people with chronic stroke.”

The study focused on rehabilitation of the upper extremity, involving repetitive rehabilitation exercises in stroke patients with moderate-to-severe arm disability. The rehabilitation programs lasted 12 weeks, three one-hour sessions per week, and involved the same number of repetitions of arm exercises.

Outcome evaluations were performed immediately after the 12 week rehabilitation program, and included the Fugl-Meyer Assessment of basic motor function (the primary endpoint), the Wolf Motor Function Test of time to complete everyday tasks, and the Stroke Impact Scale. No significant differences were found between the human-assisted and robot-assisted treatment groups.

At the end of the follow-up period (36 weeks), patients who received robot or human-assisted rehabilitation had slightly better scores on all outcome measures than those in the usual care.

There were no differences between robot-assisted and human-assisted rehab on any of the outcomes at any time point.

The cost difference in treatment was substantial: the initial cost of the robots was $200,000, and the cost of the robot-assisted rehab program was around $1200 more per patient than that of usual care over the course of the year.

From this article, I gather that the robots were made by Interactive Motion Technologies.

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