6.10.Trial Description

The study will include a total of 30 participants in a prospective, cross-over design. The subjects are recent (typically 3-10 weeks) stroke survivors with dense hemiparalysis involving the shoulder muscles. After giving his or her consent to participate in the study, each study participant is randomized, with half receiving BION™ TES along with conventional physical therapy and half receiving only conventional physical therapy. After six weeks of BION™ treatment, the participants who received implants discontinue stimulation for six weeks. After six weeks of conventional physical therapy, the control subjects are offered BION™ implants and TES. Complete bilateral evaluations are carried out before and after each 6-week treatment period. These evaluations assess shoulder subluxation by x-ray and palpation with calipers, thickness of the implanted muscles by ultrasonic imaging, active and passive range of motion, voluntary muscle force, self-reporting of pain, and blood composition (white blood cell count and creatine phosphokinase level).

BION™ implantation is performed in an examination room using aseptic technique and local anesthesia with lidocaine at the site of insertion. Each BION™ is presterilized by autoclaving and is tested while still in its sterile package and just prior to insertion to confirm that it is responding to the unique address. The insertion tool is a modified 12 gauge Angiocath™ in which the stainless steel trochar has been equipped with a connector. Electrical stimulation is delivered through the tip from a conventional clinical stimulator to find the location where a strong twitch of the correct muscle can be achieved with a low stimulus current. The trochar is then removed and the BION™ is slid down the lumen of the plastic sheath and expelled by a plunger into this site as the sheath is withdrawn. At the conclusion of the insertion procedures, weak stimulation is applied through each BION™ to confirm its placement and functionality and to record threshold for producing a palpable twitch. Threshold is measured and tracked at each subsequent programming session, beginning 4-6 days after implantation and at gradually lengthening intervals after implantation. The study participant is issued a Personal Trainer™, a compact controller into which the clinician downloads up to three different exercise programs and which records the times and durations of each exercise program that the participant activated. Typically by the end of the program, study participants are self-administering three 30-minute periods of intermittent stimulation (5pps; 10 seconds on, 5 seconds off)

6.11.Preliminary Results

To date, six individuals have completed the study.  Three participants were experimental subjects who received implants at the time that they entered the study.  The other three were control subjects, but two of those opted to receive BIONs™ at the end of the control period according to our protocol in which devices are offered to all control subjects after the initial study period.  In 2000, Richmond, et al., published the data gathered from the clinical study of the two initial participants.  Two more abstracts have been submitted for publication in 2001, describing some of the results that we have obtained with these subjects (Dupont et al., 2001a and 2001b). Thresholds in individuals ranged between 1-3 mA using both percutaneous and BION™ stimulation.  Marked fatigability in the first few days of TES gradually resolved so that both the strength and duration of the exercise sessions could be increased.  In one experimental participant, the device implanted in the supraspinatus failed to activate the muscle, possibly because the device was placed inappropriately.  No untoward effects were observed in this or any of the other participants.  The two control patients who opted to have BION™ therapy are now being followed and tested regularly for thresholds, subluxation, and other related outcome measures to determine if BION™ therapy will decrease their subluxation and level of disability.

Figure 3: Subluxation Index (Dv) Graph for Each Subject

Figure 3. This graph depicts the difference in x-ray measurements of the affected shoulder and the non-affected shoulder (Dv). In the two experimental subjects (solid lines no. 1 and 2), the subluxation is decreased during the 6 weeks of stimulation (indicated by thick horizontal line). During the following 6 weeks when there is no stimulation, the subluxation returns somewhat. For patient 4, who had only the deltoid stimulated (his supraspinatus was not stimulated), there was some improvement of subluxation, but not as pronounced. For the two control subjects, no improvements were seen.

Figure 4: Muscle Thickness Graph

Figure 4. This graph depicts the muscle thickness for experimental subjects 1 and 2. The graph shows that in general, muscle thickness (measured at different points on the deltoid and supraspinatus muscles) increased.