Twenty subjects will be stimulated with a single channel electrode, the Quick Fit Electrode. The values of stimulation will be recorded, as well as ankle movement (balanced Dorsiflexion, inverted or everted Dorsiflexion). Subjects will fill up a Benefit, Satisfaction, Willingness to continue (BSW) form. Next, subjects will be fitted with a segmented Electrode that enables both single and dual channel. Four configurations of current will be compared during sitting position and during gait. The first configuration (A) is segmented electrode single channel stimulation, the second configuration (B) is two currents running in parallel. The first medial channel stimulates the deep branch of common peroneal nerve (dorsiflexion/inversion) and the second lateral current stimulates the superficial peroneal nerve (eversion). In the third configuration (C), channels run diagonally. The medial channel runs between the upper medial electrode and the lateral lower electrode (dorsiflexion/inversion). The lateral channel runs between the lateral upper electrode and the medial lower electrode (eversion). The forth configuration (D) includes a common lower electrode; when it is connected to the upper medial electrode it functions as a medial channel (dorsiflexion/inversion); when it is connected to the upper lateral electrode, it functions as the lateral channel (dorsiflexion/eversion). The subjects will be asked to answer 3 questions after trying each configuration. 1. Thinking of the current system you use, did this test system provide any difference in the way the stimulation feels compared to your existing system? Yes No/Cannot tell any difference. 2. Thinking of the current system you use, did this test system provide any difference in what you think of as the 'quality' of stimulation you are used to compared to your existing system? Yes No/Cannot tell any difference. 3. Thinking of the current system you use, did this test system provide any difference in your ability to walk compared to your existing system? Yes No/Cannot tell any difference After all three dual channel configurations have been tested, subjects will be asked Question 4: Thinking of the last three test systems you used today, which test system do you believe was best among the three? B, C or D Subjects will be asked to grade their satisfaction with the one dual channel system they believe is best using the Benefit, Satisfaction, Willingness to Continue (BSW) questionnaire.
After completing evaluation of the first twenty subjects, a re-evaluation of ten subjects will take place. The anode/cathode electrodes will be re-positioned so the cathodes will be located at the upper part of the cuff and the anodes will be located at the lower part of the cuff. This re-evaluation is needed, since in the first evaluation there was an inconsistency in the anode/cathode positioning in the right and left FES cuffs. Stimulation will be given while sitting and during 2 minutes walk. Ankle movement and stimulation intensity will be recorded and compared to the input received in the initial evaluation of the ten subjects.
Fifty additional subjects were recruited to evaluate the performence of the common anode configuration (configuration D) and compare it to the QFE. configuration D was chosen because it showed an advantage over the other dual channel configurations. Same procedure will take place in order to compare the performance of the Segmented Electrode (configuration D) and the QFE. In addition, ambulation tests will be performed: 2mwt and 10 meter walk test. Gait velocity achieved when using each electrode will be compared to each other and also compared to gait velocity achieved when walking with no stimulation.
