Immediate Effect of Irradiation With Low-level Laser Therapy on the Electromyographic Activity of the Upper Trapezius Muscles and the Level of Pain Among Patients With Non-specific Neck Pain

Immediate Effect of Irradiation With Low-level Laser Therapy on the Electromyographic Activity of the Upper Trapezius Muscles and the Level of Pain Among Patients With Non-specific Neck Pain: a Randomized, Double-blinded, Sham-controlled, Crossover Study

The aim of the present study is to assess the immediate effect of irradiation with low level laser therapy (LLLT) on the electromyographic activity of upper trapezius muscles and the amount of pain felt by patients with non-specific neck pain (NS-NP).A total of 20 patients with non-specific neck pain will be enrolled in a randomized, single-blind, crossover study. Each subject will receive two forms of treatment in random order: a single session of LLLT and placebo LLLT. In order to eliminate carry-over treatment effects, a one-week wash-out period will be respected between sessions. Surface electromyography will be used to determine nerve conduction velocity and activity in the upper trapezius muscles before and after treatment. The outcome measures will be determined by a numerical pain rating scale. Comparisons before and after irradiation with LLLT will determine the activity of the upper trapezius muscles and the level of pain. The data will be submitted to statistical tests considering a p-value of p < 0.05.

Inclusion Criteria:

• 18 to 40 years
• Male and female volunteers
• History of neck pain for a period of more than two months
• Score ranging from 15 to 24 on the Neck Disability Index
• Score ranging from three to seven points on an 11-point (range: 0 to 10) numerical rating scale (NRS) for perceived pain intensity

Exclusion Criteria:

• history of neurological disorders
• neck surgery
• chronic neck pain resulting from a traumatic incident
• chronic musculoskeletal condition
• medical diagnosis of fibromyalgia; systemic disease
• connective tissue disorder
• having undergone physical therapy use of analgesic, muscle relaxant.