Comparison of combined therapy with ultrasound-associated interferential current in healthy subjects

Abstract

BACKGROUND AND OBJECTIVES:Although used in the therapeutic field, there is a shortage of studies that evaluate combined therapy or the association of electrical currents with therapeutic ultrasound, the present study aimed to compare the two forms in healthy individuals, analyzing the pain, number of accommodations and current intensity. METHODS: Thirty healthy volunteers took turns for three weeks in three groups. Nociception was evaluated by means of pressure and thermal stimuli in the lumbar spine and respective dermatomes. Then, the volunteer's dominant foot was submerged in cold water to evaluate the threshold of pain and its intensity. Shortly after, electroanalgesia (combined therapy, only current association with ultrasound, or placebo) was applied for 15 minutes. The application of the bipolar interferential current used a frequency of 4kHz, and amplitude modulation frequency of 100Hz, with one electrode on L3 and the other on S1. When combined therapy was used, the ultrasound head (1MHz) played the role of the electrode positioned over the L5-S1 region, in continuous form, at a dose of 0.4W/cm 2 . The intensity of the initial and final current was evaluated, as well as the number of accommodations. RESULTS: There was no significant difference between the pain thresholds of pressure and cold, but the combined therapy required more current intensity despite having a smaller number of accommodations. CONCLUSION: None of the therapies produced a difference in pain thresholds, but the combined therapy had fewer accommodations. Keywords: Analgesia, Pain measurement, Physical therapy modalities, Transcutaneous electric nerve stimulation, Ultrasonic therapy. RESUMO JUSTIFICATIVA E OBJETIVOS: Apesar de utilizada no campo terapêutico, há escassez de estudos que avaliem a terapia combinada ou a associação de correntes elétricas ao ultrassom terapêutico. O objetivo deste estudo foi comparar as duas formas em indivíduos saudáveis, analisando o limiar de dor ao frio e à pressão, número de acomodações e intensidade da corrente. MÉTODOS: Trinta voluntários saudáveis revezaram em três grupos de forma cruzada durante três semanas. A nocicepção foi avaliada por meio de estímulos pressóricos e térmicos na coluna lombar e dermátomos. Em seguida, o voluntário teve seu pé submerso em água fria, e avaliado o limiar e a intensidade da dor. Logo após foi aplicado a eletroanalgesia (terapia combinada, apenas associação da corrente com ultrassom, ou placebo), por 15 minutos. Para corrente interferencial bipolar, foram utilizados frequência de 4kHz e frequência modulada pela amplitude de 100Hz, com um eletrodo sobre L3 e o outro sobre S1. Quando se utilizou a terapia combinada, o cabeçote do ultrassom (1MHz) fez o papel do eletrodo posicionado sobre a região de L5-S1, na forma contínua, com dose de 0,4W/cm 2 Comparison of combined therapy with ultrasound-associated interferential current in healthy subjects