Abstract
The
hypothesis is that subjects will show significantly greater improvement in real
world outcomes shortly after the sub-acute stroke period assigned to three
weeks of Functional Electrical Therapy (FET) than control subjects left with
the traditional therapy. Functional electrical therapy was applied for three
weeks using a
Introduction
Neurorehabilitation comprises methods and technology for maximizing the efficiency of preserved neuro-muscular structures in a human with sensory-motor impairment. Maximizing function relates to developing of new sensory-motor mechanisms that benefit from the preserved, yet unused systems. The primary objective of the neurorehabilitation is to promote and develop processes underlying sensory-motor systems and change the dynamics of “learning” by providing the substrate that would not be available under normal circumstance [7].
Electrical stimulation of sensory-motor systems contributes to the facilitation of voluntary movement, strengthening of atrophied muscles, change of the muscle length and bulk, change of the muscle type and function, interaction between agonist and antagonist muscles, increasing the range of movement, and the moderation of spasticity [1-6].
This study presents functional electrical stimulation of paretic arm. FET generates function (e.g., grasping, reaching): it results in extensive physical training with feedback, and electrical stimulation of afferent (sensory) and efferent (motor) pathways.
Methods
Subjects. This study presents the results after the first group of six male and two female subjects finished the three-week long FET (Table I). The cerebro-vascular infarction (CVI) caused the contralateral weakness, sensory loss, diminished shoulder/elbow/hand co-ordination, and somewhat disturbed spatial perception. Motor and sensory losses are greatest in the hand.
|
Subject |
Age |
Time of CVI |
Ashworth |
Diagnosis |
A
|
62 |
11.2000 |
1+ |
Hemi. l. sin. |
|
B |
61 |
12.2000 |
1+ |
Hemi. l. sin. |
|
C |
50 |
11.2000 |
2-3 |
Hemi. l. sin. |
|
D |
52 |
10.2000 |
4 |
Hemi l. sin. |
|
E |
62 |
11.2000 |
1+ |
Hemi l. dex. |
|
F |
65 |
12.2000 |
2 |
Hemi l. sin. |
|
G |
61 |
11.2000 |
3 |
Hemi l. sin. |
|
H |
72 |
12.2000 |
2-3 |
Hemi. l. sin. |
Table I: Subjects were randomly
assigned to FET group (A to D) and controls (E to H). All subjects use medications
against high blood pressure, anticoagulants, and spasticity reduction. Ashworth
scale was used as the measure of spasticity. CVI stands for cerebro-vascular
infarction.
Volunteer candidates for study
participation received general medical and physical therapy examinations. The
neuropsychological assessment was performed in order to determine which
individuals have cognitive deficits that could negatively affect their ability
to follow directions appropriately on the motor evaluation tests employed in
the project. The subjects were characterized as high or low functioning prior
to inclusion in the study upon their active range of motion capability at the
wrist and fingers.
The determinations were made with the
subject sitting, the forearm resting on a supported surface, and the forearm in
pronation. The hand was hanging over the edge of the supporting surface (e.g.,
the arm of a chair) to allow for maximum wrist flexion with gravity. The
subjects were identified as belonging to a Higher Functioning Group (HFG) if
they were able to actively extend the paretic wrist further than 20 degrees and
actively extend the MP and IP joints of all digits at least 10 degrees (i.e., the
upper cut-off of the lower functioning group). The subjects were assigned to a
Lower Functioning Group (LFG) if they were able to actively extend the paretic
wrist at least 10 degrees and actively extend the MP and IP joints of the thumb
and at least two additional digits 10 degrees. The study included seven
subjects from the HFG subjects, and one subject form the LFG (subject F). Table
I summarizes the status of the study participants.
Procedure. The stimulation was applied for 30 minutes, twice a day, for at least
five days a week, during three consecutive weeks. The Functional Electrical
Therapy (FET) was applied with the four channel stimulator and surface
disposable electrodes. Two channels were used to stimulate the finger flexors
and finger extensors. The cathodes were placed over the extensor digitorum
communis m. and flexor digitorum profundus and superficialis muscles. The
anodes of these two channels were placed above the carpal tunnel (wrist) and
cover the major arm nerves. The subjects use a switch, which sequentially
triggers opening and closing synergies of the hand. The stimulation intensity
was set individually for each of the muscle groups by using an external
potentiometer. Two remaining channels could be used for control of the elbow
joint, employing the simplified synergistic control developed for the reaching
neuroprostheses [8]. The tasks for all subjects were to actively reach and
grasp/release different objects. The following objects were included for the
exercise: juice or beer can, VCR tape, glass, telephone receiver, paper, pen,
and similar objects that are used for typical daily activities. The pulse
duration and the frequency were set for each subject in such a manner to
minimize unpleasant sensation and pain, yet to provide active, externally
assisted grasp or elbow movement. The typical values for stimulation are:
frequency f = 50 pulses/second, pulse duration T = 300 ms, stimulation current I = 15 – 45 mA. The control
group was required to perform the same tasks as the FET group, yet without
electrical stimulation.
Outcome
measures. Evaluations are planned at
the beginning, three weeks later, and every two months thereafter for 18
months. Here we present only two outcome measures: the Upper Extremity Function
Test (UEFT), and the drawing of selected geometric shapes. The purpose of UEFT was to determine the differences
in the performance of certain activities of daily living before and after the
FET. The performance of the tasks was graded as Success (YES) and Failure (NO),
and if “YES” quantified as the number of repetitions of the desired task during
a two-minute interval.
The following tasks were tested: 1) combing hair; 2) using a fork; 3) picking up a VHS tape; 4) picking up a full beer can; 4) picking up a full small (pop/soda) can; 6) writing with a pen; 7) handling the telephone receiver; 8) brushing teeth; 9) pouring from a one litter juice box; 10) drinking from a mug; and 11) handling finger food (Fig. 1). The drawing at the digitizing board of selected forms (e.g., rectangle, circle, figure eighth) was used to assess the improvement in the body/arm to space co-ordination (Fig. 2).
Results
Fig. 1 shows the UEFT for FET and control group before and at the end of the three weeks of therapy. Each plot is for a single subject and shows the performance of the eleven listed tasks. Fig. 2 shows the drawings of the square at the digitizing board for the FET group. Plots illustrate the difference in co-ordination of the body/arm to external space before and after the FET for the group assigned to therapy.
Discussion/Conclusions
Fig. 1 shows an improvement in functioning of Subjects assigned to the FET group after only three weeks of therapy. A method of summarizing data (Table II) of this preliminary phase of the project was to compare N, the number of tasks that subjects could not accomplish at the beginning/at the end, and improvement index R, the ratio between the increased number of repetitions and the number of repetitions after three weeks in percent.