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Biomedical subjects

D P Currier

Publications and source records attributed to D P Currier.

At least 19 recordsLinked to original sources
PubMed1992

Effect of variation in the burst and carrier frequency modes of neuromuscular electrical stimulation on pain perception of healthy subjects.

The purpose of this study was to explore the effect of various combinations of burst and carrier frequencies of neuromuscular electrical stimulation (NMES) on subjects' perception of pain intensity associated with induction of high intensity muscle contractions. Twenty-seven healthy volunteers completed the study. After the initial test session, all subjects were treated in three additional sessions with nine combinations of burst frequencies (50, 70, and 90 bursts per second [bps]) and carrier frequencies (2,500, 5,000, and 10,000 Hz) at an NMES amplitude that produced torque equivalent to 50% of maximal voluntary contraction of their quadriceps femoris muscle. Subjects rated each frequency combination for perceived pain intensity with a visual analog scale. The combinations of burst frequencies (50, 70, and 90 bps) and carrier frequencies (2,500 and 5,000 Hz) do not differ from each other in perceived pain intensity but do differ significantly in perceived pain from the combinations of burst frequencies at the carrier frequency of 10,000 Hz. Thus, the clinician may have to try different stimulus combinations on patients at different current training levels to obtain the least individually perceived pain.

Adult↗
PubMed1991

Effect of motor neuromuscular electrical stimulation on microvascular perfusion of stimulated rat skeletal muscle.

The purpose of this study was to determine the effect of neuromuscular electrical stimulation (NMES) (2,500-pps sine wave interrupted at 50 bps) on the degree of microvascular perfusion in stimulated skeletal muscle. The tibialis anterior (TA) and extensor digitorum longus (EDL) muscles of 36 male rats were treated with NMES for 30 minutes at current amplitudes sufficient to produce a sustained muscle contraction (motor NMES). Muscle tissue was removed at 0, 5, 10, 15, and 30 minutes after NMES. The perfused vessel/muscle fiber ratio (PV/F) of the stimulated animals at time 0 minutes was greater than that of the unstimulated control animals. A gradual decrease in the magnitude of the PV/F increase was noted over time. Depending on the muscle's fiber-type composition, the PV/F values returned to control levels by 10 to 30 minutes after motor NMES. The results indicate (1) that motor NMES significantly increases the degree of microvascular perfusion in stimulated rat skeletal muscle and (2) that the increased degree of perfusion persists for various lengths of time, depending on the fiber-type composition of the muscle. Thus, if responses in an animal model can be used as indicators of similar human responses, then the results of this study suggest that NMES can be used to increase the degree of microvascular perfusion in human skeletal muscle.

Animals↗
PubMed1989

Electrophysiologic responses of human sural nerve to temperature.

The purpose of this study was to assess the conduction, specifically the latency and amplitude of the sensory nerve action potential (SNAP), of the sural nerve as a function of intraneural temperature of the leg. The electrophysiologic responses of the sural nerve were determined at different temperatures in 22 healthy adults. Distal sensory latency and amplitude of the sural SNAP was determined at 1 degree C intervals over a limb temperature range of 23 degrees to 40 degrees C. Limb temperature was monitored with a thermistor probe placed subcutaneously near the sural nerve. Ice bath soaks were used for cooling and infrared radiation for warming the limbs. An analysis of covariance was performed for the SNAP latencies and amplitudes to determine the effect of gender and leg (right or left) at each temperature level. No effect of gender or leg on neural conduction was detected in individual subjects. A regression analysis was then used on pooled data to determine the effect of temperature on sural SNAP latency and amplitude. An inverse linear change in the latency of sural SNAP was observed over the temperature ranges used. Mean latency increased 0.1 msec per 1 degree C increase in subcutaneous temperature. A direct relationship between amplitude of the SNAP and temperature was determined. Mean amplitude increased 0.3 muV per 1 degree C increase in subcutaneous temperature. The results of this study support previous reports, which state that SNAP latency is indirectly related to the intraneural temperature. Clinical electromyographers must monitor the temperature of the lower leg and foot whenever sensorineural conduction of the lower limbs is performed.

Action Potentials↗
PubMed1988

Augmenting voluntary torque of healthy muscle by optimization of electrical stimulation.

The purpose of this study was to evaluate the ability of electrical stimulation (2,500-Hz sine waves, interrupted for 50 pulsed bursts per second) to improve muscle torque using low-dosage training characteristics. Fifteen healthy subjects (9 men, 6 women), 20 to 32 years of age, participated in the experiment. All subjects received electrical stimulation of the right anterior thigh musculature while their left leg served as the control. Electrical stimulation was repeated eight times per session, each stimulation producing isometric torque equal to 50% of the subject's maximum voluntary isometric contraction. The sessions were repeated twice a week over a period of five weeks. Results showed that electrical stimulation, when used with the specified low-dosage training characteristics of this study, will augment quadriceps femoris muscle torque of men.

Adult↗
PubMed1988

Osteoarthritis. Effects on synovial joint tissues.

The purposes of this article are 1) to provide an updated summary of some aspects of research into osteoarthritis and 2) to stimulate physical therapy inquiry on its causes, effects, and treatments. The current literature concerning the pathological changes associated with osteoarthritis is reviewed in the context of specific joint tissues (ie, articular cartilage, bone, synovial membrane, capsule and capsular ligaments, muscle, and nerve). Correlations are drawn between the pathological effects of osteoarthritis on these tissues and commonly observed clinical changes. Gaps in the current research literature are discussed, and areas needing further research are highlighted.

Animals↗
PubMed1988

Effects of high voltage pulsed electrical stimulation on blood flow.

The purpose of this study was to determine whether high voltage electrical stimulation would increase blood flow to skeletal muscle in healthy subjects. Subjects were assigned to one of three groups: 1) an Electrical Stimulation (ES) Group (n = 16), 2) an Exercise (EX) Group (n = 14), or 3) a Control Group (n = 8). Isometric contractions were induced electrically at 30 Hz in the ES Group and performed volitionally in the EX Group for five minutes at intensities of 10% and 30% of predetermined maximal voluntary isometric contraction (MVC) efforts. Blood flow, heart rate, and blood pressure were unaffected in the ES Group, but blood flow and systolic blood pressure increased and decreased, respectively, for the EX Group at 30% of MVC. High voltage stimulation at a pulse rate of 30 Hz and at intensities needed to evoke contractions at 10% and 30% of MVC for plantar flexion did not increase blood flow at the popliteal artery.

Adult↗
PubMed1988

Comparison of selected pulse frequencies from two different electrical stimulators on blood flow in healthy subjects.

The purpose of this study was to measure the effects of selected frequencies from two different pulsed electrical stimulators on blood flow, blood pressure, and heart rate. Each of 30 healthy subjects attended 10 study sessions: 1 torque-testing session, 1 control session consisting of no electrical stimulation (ES), and 8 sessions of ES. All subjects received ES at an intensity sufficient to produce torque equal to 15% of the predetermined maximal voluntary contraction of their right quadriceps femoris muscle. The results of a multivariate analysis of variance showed that changes in blood flow during and after ES were dependent on pulse frequency but independent of stimulator type. Further analysis showed significant increases in blood flow with ES using 10, 20, and 50 pulses per second compared with 1 pulse per second. Inconsistent changes in blood pressure and heart rate were produced by ES. Based on the results of this study, effective clinical use of ES for promoting arterial blood flow to muscle would involve pulsed frequencies of 10 to 50 pulses per second.

Adult↗
PubMed1987

Circulatory response of digital arteries associated with electrical stimulation of calf muscle in healthy subjects.

The purpose of this study was to investigate the effects of electrical stimulation (2,500-Hz sine wave modulated at 50 bursts per second) of the posterior calf musculature on the blood circulation of an unexercised part of the body, the ipsilateral digital arteries. Intensities of electrical stimulation sufficient to produce 15% and 30% of isometric maximum voluntary contraction (MVC) of the plantar flexor muscles were used. Twenty-four healthy subjects participated in this study and were assigned either to an Experimental Group receiving electrical stimulation (n = 13) or to a Control Group not receiving electrical stimulation (n = 11). Analysis of data revealed significant differences in finger blood flow when the calf musculature was stimulated electrically. We found significant differences in blood flow of the finger when torques produced by electrical stimulation of the calf musculature were raised to 15% and 30% of MVC. The results of the study indicate that blood flow in the ipsilateral finger decreases significantly when the posterior calf musculature is exercised artificially with electrical stimulation bursts.

Adult↗
PubMed1986

Effect of graded electrical stimulation on blood flow to healthy muscle.

The purpose of this study was to determine whether 2,500-Hz sine-wave electrical stimulation modulated at 50 bursts per second producing graded muscular responses affects blood flow. Healthy volunteer subjects were assigned randomly to an Experimental group (n = 14) that received bursts of electrical stimulation to the gastrocnemius muscle or to a Control group (n = 14) that received no treatment. Using a Doppler device, pulsatility index (PI) values were determined for multivariate statistical analysis. Electrical stimulation graded to simulate isometric torques equivalent to 10% and then 30% of the subjects' isometric maximum voluntary contraction resulted in respective mean increases in PI values of 20.5% and 19.6% over prestimulation PI values. We found no significant difference in PI values between the two levels of torque. No significant change in PI values was found among the Control group subjects. Our results indicate that electrical stimulation, as used in this study, can alter the blood flow to the muscle being stimulated.

Adult↗
PubMed1986

Effects of short-term electrical stimulation on the ultrastructure of rat skeletal muscles.

The purpose of this study was to determine the effects of short-term, 2,500-Hz carrier-wave frequency electrical stimulation on the ultrastructure of fast-twitch rat skeletal muscles. Thirteen Sprague-Dawley male rats were divided into three groups: daily treatment (Group 1), every-other-day treatment (Group 2), and control (Group 3). The medial quadriceps femoris and hamstring (semitendinosus and semimembranosus) muscles of the right thigh were treated with short-term electrical stimulation. After treatment, the animals were sacrificed, and their treated and sham quadriceps femoris and hamstring muscles were removed, fixed by immersion, and processed for electron microscopy. Morphometric measurements were made on electron micrographs using a Videoplan computer system, and the results were analyzed statistically. The results revealed that mitochondria, triads, and glycogen content of the fast-twitch muscles changed to resemble those of slow-twitch muscles. In view of these results, clinicians should consider the possibility that similar changes also might occur in human subjects under clinical conditions.

Animals↗
PubMed1985

Effects of clinical infrared laser on superficial radial nerve conduction.

The purposes of this study were to demonstrate the effects of infrared laser radiation on the sensory nerve conduction of a specified peripheral nerve in man and determine temperature changes in the tissue surrounding the treated nerve. Twenty healthy adults were divided into three groups: control (n = 5); experimental (n = 10), infrared laser radiation at 20 sec/cm2; and experimental (n = 5), infrared laser radiation treatment at 120 sec/cm2. Antidromic sensory nerve conduction studies were performed on the superficial radial nerve of each subject's right forearm. The infrared laser radiation was applied at a fixed intensity for five 1-cm2 segments. Latency, amplitude, and temperature measurements were recorded pretest; posttest; and posttest intervals of 1, 3, 5, 10, and 15 minutes. An analysis of variance with repeated measures was used to examine the data. No significant change was noted in the distal sensory latency or amplitude of the evoked sensory potential in either experimental or control groups as a result of the applications of the infrared laser radiation treatment. This study demonstrates that infrared laser used at clinically applied intensities does not alter conduction of sensory nerves nor does it elevate the subcutaneous temperature.

Adult↗
PubMed1979

Electrical stimulation in exercise of the quadriceps femoris muscle.

Thirty-seven healthy subjects took part in an investigation to determine if the application of electrical stimulation to normal muscle, in combination with exercise, augments strength. Subjects were divided into three groups. Grwoup A (n = 14) was a control group (no exercise, no electrical stimulation). Group B members (n = 11) engaged in 10 sessions of maximum isometric exercise, and Group C subjects (n = 12) performed 10 sessions of maximum isometric exercise while simultaneously receiving electrical stimulation. The knee extensor muscles of subjects in Groups B and C increased in strength. However, the strength gains for Groups B and C were equivalent, suggesting that electrical stimulation combined with maximum isometric contractions has no greater effect on enhancing strength than does conventional static exercise.

Adult↗
PubMed1978

Sensory nerve conduction: effect of ultrasound.

Bilateral antidromic sensory conduction measurements of the lateral cutaneous branch of the radial nerves of 5 men were performed at intervals before and for 15 minutes following ultrasonic application over a segment of the nerve. The ultrasound was applied over the area of the radial nerve for 5 minutes at a frequency of 1 MHz, continuous wave and using 1.5 watts/sq cm dosage. Nerve bed temperature was continuously recorded during the study via a subcutaneous needle thermistor probe. Eighty measurements were made of temperature latency, amplitude and duration of the nerve action potentials. Amplitude and duration of the nerve action potentials did not change following sonation. Latency and temperature values changed significantly following the application of ultrasound. The latencies decreased, indicating increased speed of conduction, as the subcutaneous temperatures increased. The ultrasound dosage used in this study increased the speed of nerve conduction.

Action Potentials↗
PubMed1977

Motor conduction of the anterior interosseous nerve.

Motor conduction examinations of the left anterior interosseous nerve were performed on 25 healthy women. The purposes of this study were to determine the optimal position for placement of the active recording electrode, and to report normal motor conduction values for the anterior interosseous nerve. The anterior interosseous nerve (branch of the median nerve) was stimulated proximal to the elbow and the evoked responses were recorded from three sites over the flexor pollicis longus. The optimal site for placement of the active recording electrode was over the lateral distal one-third of the anterior surface of the forearm at a point representing the distal 38% of the length of the forearm. A latency of 4.0 msec and an amplitude of 2.5 mv may serve as the limits of normal values for motor conduction of the anterior interosseous nerve and for action potentials of the flexor pollicis longus muscle, respectively.

Action Potentials↗
PubMed1977

Positioning for knee strengthening exercises.

Fifty normal subjects (20 men, 30 women) were tested for maximal isometric contraction of the right knee extensor muscles while their hips were at angles of 100, 110, 120, and 130 degrees to the horizontal. The tested knee was positioned in 60 degrees of flexion. Knee-extensor force attained with the hip at 110, 120, and 130 degrees differed significantly greater than the knee force attained with the hip at 100 degrees. No significant difference in knee-extensor force was found when the hip angles varied between 110, 120, and 130 degrees. The findings were similar for both men and women. The results indicate a need for changes in the design of exercise units. Exercise units should provide for back stabilization with the hip positioned at varying angles and should be narrow enough to permit short subjects to grasp the sides of the unit.

Adult↗
PubMed1977

Back stabilization during knee strengthening exercise.

Twenty normal women were tested for maximal isometric contraction of the right knee extensor muscles. The knee was positioned in 60 degrees of extension and the hip at 120 degrees of extension, with and without a backrest. The purpose of the study was to determine whether the use of a backrest resulted in greater force than when not using a backrest when the angle of back inclination was held constant and the support was varied. The results indicated that the addition of a backrest, when the body assumes an optimal position, enables the knee extensors to generate greater force then when no backrest is used. A backrest adds to the comfort and support of the subject performing resistive knee exercise and should be incorporated into the design of knee exercise units.

Adult↗
PubMed1976

Variables in recording motor conduction of the radial nerve.

Motor conduction examinations of the right radial nerve were performed on 25 healthy students. The purposes of this study were to determine the optimum position for placement of the active recording electrode, to determine the optimum position of the elbow during conduction examinations, and to report normal values for radial motor nerve characteristics. The radial nerve was stimulated at the supraclavicular notch, axilla, lateral surface of the brachium, and over the middle third of the forearm. The evoked responses were recorded from the abductor pollicis longus or the extensor pollicis brevis. The optimum site for placement of the active recording electrode was found over the medial aspect of the abductor pollicis longus or the extensor pollicis brevis and at a point that represents 28 percent of the forearm length. The optimum position for the elbow was full extension. The distal latency of 2.6 msec, the velocity of the brachium-forearm segment of 50 meters per second, and amplitude of muscle action potentials of 4.0 mv may serve as the limits of normal values for motor conduction of the radial nerve.

Action Potentials↗