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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
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