|
 |
|
Comfort In Electrical
Stimulation
 Adove Reader Version
Alon G., Kantor G., and Ho
H.S. (1994) Effects of electrode size on basic excitatory responses and on
selected stimulus parameters. J. Orthop. Sports Phys. Ther. 20,
29-35.
Abstract: Recent data have implicated the size of surface
electrodes as an important factor affecting peripheral nerve excitation.
Therefore, we studied the effects of electrode size on the basic
excitatory responses and on stimulus characteristics. Four different sizes
of self-adhesive surface electrodes were applied over the medial and
lateral gastrocnemius muscle of 20 healthy subjects. The excitatory levels
were sensory threshold, motor threshold, pain threshold, and maximally
tolerated painful stimulation. Stimulus parameters included a symmetric
biphasic waveform, 200 microseconds phase duration, and a pulse repetition
rate of 50 pps. Amplitude was increased until the appropriate excitatory
response was achieved. At this amplitude level, the computerized recording
system collected data of stimulus peak current, peak voltage, and phase
charge as well as isometric plantar flexion force. Repeated measure
analysis of variance and Newman-Keuls post hoc tests revealed that
increasing electrode size significantly decreased voltage but increased
current and phase charge magnitudes. With increasing electrode area, the
ratios of voltage/current decreased nonlinearly, while the ratios of
charge/voltage increased nonlinearly. The comfort of stimulation for the
same amount of plantar flexion force improved significantly as electrode
size became larger. We concluded that electrode size affects the stimulus
parameters, comfort, and force generation associated with electrically
induced excitatory responses. Electrode size should be considered an
integral part of the attempt to improve subject response to transcutaneous
electrical stimulation
Baker L.L., Bowman B.R., and
McNeal D.R. (1988) Effects of waveform on comfort during neuromuscular
electrical stimulation. Clin. Orthop. 75-85.
Abstract:
Electrical stimulation is a commonly used clinical tool, but subject and
patient comfort is still a major problem retarding its widespread
application. Stimulus waveform in combination with pulse duration can play
a major part in subject comfort. An asymmetric balanced biphasic square
waveform was perceived as comfortable and was clinically effective in
stimulating wrist flexor and extensor muscles. Subjects preferred the
square waveforms over a paired spike monophasic waveform. In the larger
quadriceps muscle group, a symmetric biphasic square wave was perceived as
more comfortable than either a monophasic paired spike or any of three
medium frequency waveforms. There seemed to be, however, a small
subpopulation of subjects who consistently preferred the medium frequency
waveforms. Medium frequency stimulation should be tried for those patients
who have considerable difficulty adapting to the sensory input inherent
with the use of surface electrical stimulation
Bowman B.R. and Baker L.L.
(1985) Effects of waveform parameters on comfort during transcutaneous
neuromuscular electrical stimulation. Ann. Biomed. Eng 13,
59-74.
Abstract: Twenty-three females between the ages of 19 and 35
were studied in order to compare the effects of variations in pulse
duration, waveform symmetry, and source regulation on comfort during
quadriceps surface stimulation at amplitudes necessary to produce 27 Nm
torque. Stimulation parameters compared were: 1) 50 and 300 microseconds
pulse durations, 2) asymmetrical and symmetrical biphasic waveforms, and
3) current and voltage source regulation. Subjects overwhelmingly
preferred the 300 microseconds pulse duration regardless of waveform or
source regulation, strongly preferred the symmetrical biphasic waveform,
and had inconsistent preference for either regulated voltage or regulated
current sources
Campbell J.M., Meadows P.M.
(1995) Electrical Stimulation in the Management of Muscle Disuse or
Temporary Muscle Denervation Can Be Effective and Comfortable.
Proc RESNA Annual Conference, Vancouver, CANADA,
393-396.
Delitto A. and Rose S.J.
(1986) Comparative comfort of three waveforms used in electrically
eliciting quadriceps femoris muscle contractions. Phys. Ther. 66,
1704-1707.
Abstract: The purpose of this study was to compare the
relative comfort levels of electrical stimulation having different
waveforms, but otherwise identical current characteristics, delivered
percutaneously to normal quadriceps femoris muscles contracting at the
same intensity level. The quadriceps femoris muscles of 20 healthy
subjects were stimulated to a torque level 60% of that obtained in a
maximal voluntary isometric contraction, using pulsed current with a
carrier frequency of 2,500 Hz, at 50 pulses per second of 10-msec pulse
duration. Three different waveforms were used: sinusoidal, sawtooth
(triangular), and square. The relative comfort level of each electrically
elicited contraction for each waveform was determined for each subject
using a 20-cm-long visual analog scale. The results showed that no one
waveform was most comfortable (least uncomfortable) and the difference was
significant in what the subjects perceived to be the most comfortable
contraction, regardless of waveform (p less than .01). These results
indicate that a subject's perception of discomfort changes as the waveform
of stimulation varies and that individual preferences exist for different
waveforms. Selection of the most comfortable waveform could prove
beneficial when the intensity of muscle stimulation is
increased
Dumoulin C., Seaborne D.E.,
Quirion-DeGirardi C., and Sullivan S.J. (1995) Pelvic-floor
rehabilitation, Part 1: Comparison of two surface electrode placements
during stimulation of the pelvic-floor musculature in women who are
continent using bipolar interferential currents. Phys. Ther. 75,
1067-1074.
Abstract: BACKGROUND AND PURPOSE: Electrical stimulation of
the pelvic floor is used as an adjunct in the conservative treatment of
urinary incontinence. No consensus exists, however, regarding electrode
placements for optimal stimulation of the pelvic-floor musculature. The
purpose of this study was to compare two different bipolar electrode
placements, one suggested by Laycock and Green (L2) the other by Dumoulin
(D2), during electrical stimulation with interferential currents of the
pelvic-floor musculature in continent women, using a two-group crossover
design. SUBJECTS: Ten continent female volunteers, ranging in age from 20
to 39 years (mean = 27.3, SD = 5.6), were randomly assigned to one of two
study groups. METHODS: Each study group received neuromuscular electrical
stimulation (NMES) of the pelvic- floor musculature using both electrode
placements, the order of application being reversed for each group. Force
of contraction was measured as pressure (in centimeters of water [cm H2O])
exerted on a vaginal pressure probe attached to a manometer. Data were
analyzed using a two-way, mixed-model analysis of variance. RESULTS: No
difference in pressure was observed between the two electrode placements.
Differences in current amplitude were observed, with the D2 electrode
placement requiring less current amplitude to produce a maximum recorded
pressure on the manometer. Subjective assessment by the subjects revealed
a preference for the D2 electrode placement (7 of 10 subjects). CONCLUSION
AND DISCUSSION: The lower current amplitudes required with the D2
placement to obtain recordings comparable to those obtained with the L2
technique suggest a more comfortable stimulation of the pelvic-floor
muscles. The lower current amplitudes required also suggest that greater
increases in pressure might be obtained with the D2 placement by
increasing the current amplitude while remaining within the comfort
threshold. These results will help to define treatment guidelines for a
planned clinical study investigating the effects of NMES and exercise in
the treatment of urinary stress incontinence in women postpartum.
[Dumoulin C, Seaborne DE, Quirion-DeGirardi C, Sullivan SJ. Pelvic-floor
rehabilitation, part 1: comparison of two surface electrode placements
during stimulation of the pelvic-floor musculature in women who are
continent using bipolar interferential currents
Kramer J.F. (1987) Effect of
electrical stimulation current frequencies on isometric knee extension
torque. Phys. Ther. 67, 31-38.
Abstract: The purpose of this
study was to compare the isometric knee extension torques of male and
female subjects during maximal voluntary contractions (MVCs), electrical
stimulation only, and electrical stimulation superimposed onto MVCs at
electrical stimulation current frequencies of 20, 50, and 100 Hz. An
asymmetrical, bidirectional, nonionizing waveform of 1-msec pulse duration
was delivered through the femoral nerve and the superficial quadriceps
femoris muscles at maximally tolerated intensity for each subject. The
male subjects (n = 20) demonstrated significantly greater absolute torques
under all contraction conditions than did the female subjects (n = 20) (p
less than .01); when the torques were expressed as a percentage of each
subject's MVC torque, however, no significant differences were observed
between the sexes. Overall, the superimposed contractions at 50 and 100 Hz
and the MVCs had similar torque values, all being significantly greater
than the torque values produced by electrical stimulation only at
frequencies of 20, 50, and 100 Hz and by the superimposed contractions at
20 Hz. Superimposing electrical stimulation onto MVCs did not result in
greater torques than those produced by the MVCs alone. The three most
effective contraction conditions, in terms of subject comfort (minimal
discomfort) and increased torque, were the superimposed contractions at 50
and 100 Hz and MVCs alone, all of which involved a voluntary
component
Nelson H.E., Jr., Smith M.B.,
Bowman B.R., and Waters R.L. (1980) Electrode effectiveness during
transcutaneous motor stimulation. Arch. Phys. Med. Rehabil. 61,
73-77.
Abstract: Four types of electrodes were evaluated for clinical
effectiveness in electrically stimulating the quadriceps muscles to gain
knee extension for time periods lasting up to 4 days. These electrodes
included self- adhering pregelled pads, solvent-activated conductive tape,
carbonized conductive silicone rubber, and felt-covered metal plates. The
electrodes were compared for ability to produce knee extension torque,
electrical impedance, ease of application, durability, comfort, and skin
reactivity. Felt-pad electrodes soaked in tap water or saline produced the
highest mean torque and lowest electrical impedance, which made them
excellent choices for single session stimulation. Carbon- rubber
electrodes with either gel produced slightly less torque, slightly higher
impedances, and only minor skin reactions. They were relatively easy to
apply, and the majority remained intact for the duration of the study
period. They were found to be most suitable for prolonged functional
electrical stimulation of the quadriceps. Stimulation using pregelled
electrodes produced the lowest torque, and they displayed consistently
higher electrical impedance. Even though they were easiest to apply and
survived better than the other electrodes, they also produced the most
skin reactions. The torque and electrical impedance of the activated-tape
electrodes were extremely variable and unpredictable, and the process of
application was long and involved, making them clinically impractical for
either long or short stimulation
Rosenberg J.N. and Turchetta
J. (1993) Magnetic coil stimulation of the brachial plexus. Arch. Phys.
Med. Rehabil. 74, 928-932.
Abstract: This study establishes a
protocol and normal values for magnetic stimulation of the brachial plexus
at the mid-clavicular point. We evaluated twenty normal subjects
bilaterally, and determined normal latencies to the abductor pollicis
brevis, abductor digiti minimi, biceps, triceps, deltoid, infraspinatus,
latissimus dorsi, and rhomboid major. Our values were comparable to
latency values obtained with electrical stimulation at Erb's point and
reported in the literature. Patient's compared their comfort between
electrical stimulation and magnetic stimulation and magnetic stimulation
was found more comfortable. To demonstrate that magnetic stimulation is an
easier and less painful method to study brachial plexus injuries, we
report two cases where we were unable to record evoked responses with
electrical stimulation at Erb's point yet easily obtained magnetic
recordings
|
