Biomedical subjects

Alex R Ward

Publications and source records attributed to Alex R Ward.

3 recordsLinked to original sources

PubMed2002

Optimal frequencies for electric stimulation using medium-frequency alternating current.

OBJECTIVE: To determine the effect of single cycles of alternating current of various frequencies on sensory and motor thresholds and on relative thresholds (motor threshold/sensory threshold). DESIGN: Repeated-measures design. SETTING: Laboratory setting. PARTICIPANTS: University student and staff volunteers (N=16; mean age, 34y). INTERVENTIONS: Single cycles of sinewave frequencies between 1 and 35kHz were delivered at 50Hz. The frequencies were applied in a random order. MAIN OUTCOME MEASURES: The motor and sensory thresholds were recorded at each applied frequency. RESULTS: Both sensory and motor thresholds showed a smooth decrease to a minimum at approximately 3kHz. The relative threshold reached a minimum close to 9kHz. Comparison with previous studies showed that although absolute thresholds reach a minimum at a frequency that depends on electrode size, the frequency at which the relative threshold is a minimum was independent of electrode size and independent of whether the stimulus was applied as single pulses or in burst mode. CONCLUSIONS: The optimal frequency for transcutaneous stimulation using medium-frequency alternating current depends on the outcome measure used. It would therefore be desirable for clinical stimulators to provide a selection of carrier frequencies.

Adult↗

PubMed2002

Vastus medialis electrical stimulation to improve lower extremity function following a lateral patellar retinacular release.

STUDY DESIGN: A single-case study design. OBJECTIVES: To examine the effect of electrical stimulation of the vastus medialis muscle on stiffness, pain and function for a patient with delayed functional progress following a lateral patellar retinacular release. BACKGROUND: Five months after an arthroscopic lateral patellar retinacular release, the patient, although highly motivated, had made little progress using routine exercises and taping. METHODS AND MEASURES: An electrical stimulation program producing approximately 300 contractions daily of the vastus medialis muscle was implemented. The electrical stimulation applied for 33 of the 36 days was a rectangular and balanced biphasic pulse of 625-micros duration, 70-Hz frequency, 8-second peak on-time, 3-second off-time, 1-second ramp-up, and 0.5-second ramp-down. Objective measures of stair climbing and hopping, together with the subjective measure of therapist-palpated superomedial patella displacement force, were recorded for each treatment visit. Other subjective measures were the patient's daily recordings of knee pain and stiffness. RESULTS: Patient-reported stiffness reduced rapidly as the actual and cumulative number of daily contractions of the vastus medialis muscle increased. After 8 days of electrical stimulation, the patient was able to ascend stairs unassisted and after another 21 days to hop unsupported. CONCLUSIONS: Stiffness rapidly reduced and function started to improve once the electrical stimulation program was implemented. Recovery during the 36 days of treatment with electrical stimulation was greater than during the previous 5 months using other methods. Compliance was not an issue, nor was muscle soreness.

Arthroscopy↗

PubMed2002

Russian electrical stimulation: the early experiments.

Russian forms of electrical stimulation became popular to a large extent as a result of the activities of Kots, who claimed force gains of up to 40% in elite athletes as a result of what was then a new form of stimulation. He did not provide details of his published work, nor did he give references. Russian electrical stimulation became popular despite the lack of research in the English-language literature. No studies published in English examined whether the "10/50/10" treatment regimen (10 seconds of stimulation followed by 50 seconds rest, repeated for 10 minutes) advocated by Kots is optimal, and only one study addressed whether maximum muscle torque was produced at an alternating current frequency of 2.5 kHz. The few studies that compared low-frequency monophasic pulsed current and Russian electrical stimulation are inconclusive. This article reviews and provides details of the original studies by Kots and co-workers. The authors contend that these studies laid the foundations for the use of Russian forms of electrical stimulation in physical therapy. The authors conclude that there are data in the Russian-language literature that support the use of Russian electrical stimulation but that some questions remain unanswered.

Electric Stimulation Therapy↗