Functional electrical therapy: Retraining grasping in spinal cord injury Raquel Baamonde Kirwin Neural Engineering- Spring 2008 NJIT Department of Biomedical Engineering Milos R. Popovic T. Adam Thasher, Marlene E. Adams, Veronica Takes,Vera Zivanvovic,Mark I. Tonack

Purpose The purpose of the experiment is to determine the effectiveness of Functional Electrical Therapy (FET) in the rehabilitation of hand control for quadriplegics. NJIT Department of Biomedical Engineering

What is Functional Electrical Stimulation? “Functional electrical stimulation delivers a shock to the survivor’s muscle. The shock activates nerves and makes the muscle move. Theoretically, the brain may be able to recapture and relearn this movement without the stimulation.” 1 NJIT Department of Biomedical Engineering

FES & FET The differences between FES and FET: -FES- as described is the actual treatment by use of the neuroprosthesis -FET- exposure to daily use of the neuroprosthesis will train the affected muscles and regain function. This indicates plasticity, where functionality can be carried over even after the device is no longer used. Key Point- Through therapy we want to be able to regain functionality which will carry over into the daily lives of patients (GOAL). NJIT Department of Biomedical Engineering

Types of Grasping Functions There are two types of hand functions described in the text palmar and lateral. Palmar- the use of the palm heavier bulkier objects Lateral- the use of the fingertips and thumb for a more precise grasp for smaller thinner objects. The experiment is geared towards developing both of these areas. NJIT Department of Biomedical Engineering

Experiment Total of 21 patients were used in this experiment with a spinal cord injury between C1 and C7. The onset of the injury had to be at no more than eight months at time of recruitment. The subjects were separated into two groups the control group (N=9) and the intervention group (N=12). Each group followed their plan of therapy for 12 weeks, five daily sessions, lasting 45 minutes. The assignment of patients into either of these groups was truly random, and was controlled by Matlab function randperm. NJIT Department of Biomedical Engineering

Experiment Table 1 Demographic Data: -Subjects were all male. -ages range from as young as 16 to 70. -injury causes fall, MVA, Bicycle, Wrestling, Diving. -Days of intervention as early as 15 days to 243 days after the injury. NJIT Department of Biomedical Engineering

Control Group This group received conventional occupational therapy for hand function which included: muscle facilitation exercises, task specific and repetitive exercises, strengthening motor control (use of resistance), stretching exercises, and electrical stimulation (for the prevention of muscle atrophy) not to be confused with FET. NJIT Department of Biomedical Engineering

Intervention Group FET neuroprosthesis is called Complex Motion electric stimulator for reaching & grasping. This group received both the conventional therapy (same as control group) but in addition received FET. Prior to FET (pre- FES) treatment they received muscle strengthening, which consists of five phases (done by surface stimulation Figure 2) in order to prevent the further deterioration of muscles. After an injury, muscle atrophy occurs very quickly and the more inactive the more severe the deterioration. NJIT Department of Biomedical Engineering

Intervention Group The surface electrical stimulation is used to stop atrophy and reverse it. Nerves/ Muscles Stimulated: -flexor digitorum superficialis m.-flexor digitorum profundus m. -median nerve, thenar nerve-flexor pollicis longus m. -extensor digitorum m. -flexor carpi radialis m. -flexor carpi ulnaris m.-extensor carpi radialis longus -brevis m.-extensor carpi ulnaris m. The electrical impulses were measured differently in each phase (1- 5) for an allotted amount of time. Was a good indication of which candidates would be successful with FES technology because participants with enough strength would be able to advance to the next stage of treatment. NJIT Department of Biomedical Engineering

FET Intervention The next stage… FET was applied to each member of the Intervention group and they were asked to execute a task unassisted. If they were unable to do so then they would be assisted by the neuroprothesis Complex Motion stimulator. Tasks would be repeated times in a 45 minute session tasks were changed daily to different objects pen, credit card, soft drink etc. Repetition strengthened hand function functional recovery was evident 4-6 weeks after starting the FET program. NJIT Department of Biomedical Engineering

Tests The following tests were administered to all of the subjects that participated in the study. - Functional Independence Measure (FIM) -Spinal Cord Independence Measure (SCIM) -Rehab Engineering Laboratory Hand Function Test (REL) This test focuses on the and palmar grasps and includes 5 components: objects, blocks, a cylinder, a credit card, and a wooden bar. Objects were placed on a desk 20-30cm in front of the patient and they were asked to pick up the object, lift it in front of their chest move to supination, neutral, then pronation position for 20-30s. If they were unable to hold any of these positions they received 0 points for that position, 1 point was granted if they held the object for a shorter period of time, maximum of 2 point were given if they held the position for the amount of time. The cylinder, credit card, and the wooden bar were used to measure torque, pinch grasp. NJIT Department of Biomedical Engineering

Results The control group and the intervention group were further divided into subgroups. Control Group divided into complete and incomplete SCI (these groups were administered conventional therapy) Intervention Group divided into complete and incomplete SCI (these groups received FET) The results show that the groups that were treated with the neuroprosthesis showed better results than the controls. Providing repetition for the central nervous system by retaining the parts that are still intact this allows them to take over damaged areas of the CNS (plasticity, hypothesis). SCI patients show better FIM scores if they had FET intervention. Complete SCI patients benefit more from FET than incomplete SCI patient (strengthens the hypothesis about CNS). Further, the author discusses FET intervention is effective but adjusting it to the individual needs of the patient would make it ideal. NJIT Department of Biomedical Engineering

Opinions Participants were interviewed in order to receive feedback on FET: Positive: as a result of the treatment they were able to regain some independence, self-satisfaction, motivated them to work harder Negative: minimal pain associated with the prosthesis. All participants indicated that FES interventions should be included into rehabilitation programs and others would be able to benefit from this as treatment well. NJIT Department of Biomedical Engineering

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