Influência da frequência estimulatória envolvida nos efeitos analgésicos induzidos por eletroacupuntura em cervicalgia tensional

Abstract

Objective: To assess the influence of the stimulating frequency involved in analgesia induced by electroacupuncture for neck pain. Methods: The performance of the analgesia produced by 2Hz, 100Hz, 1000Hz and 2500Hz was compared with a group with acupuncture alone (without electrical stimulation), by means of pressure algometry, a visual analog scale (VAS) and heart rate. We used an electrical stimulator with a microprocessor yielding standard, single-phase, rectangular and asymmetrical balanced pulsed waveforms with a secondary phase decreasing exponentially. Stimulation periods were 4s, and resting periods were 3s. The sample included 66 volunteers with neck pain due to muscular tension, mean age 33.67∓9.97 years, 89.5% female and 10.5% male. Results: There were no differences between the groups regarding the variables of degree of pain (according to the VAS) and heart rate, and all groups presented analgesic improvement. However, when comparing pressure algometry findings for the same individual before and after the treatment, within the same group, we found analgesic advantages in using 2500Hz (p=0.006 for the base of the occipital region, p=0.003 for the right trapezius and p=0.013 for the left trapezius), followed by 100Hz (p=0.035, p=0.016 and p=0.038 for the same regions, respectively). Conclusion: We preferentially recommend 2500Hz and 100Hz applications of electroacupuncture for analgesia of neck pain due to muscular tension.