Background and aims
Binaural Beats (BB), consisting of two artificial acoustic stimuli, with small difference in wave frequency, synchronize brain activity and have been found to decrease intraoperative pain. The aim of this study was to evaluate whether brain entrainment in lower function rhythm, with the application of BB, decreases pain perception and analgesic medication use, in patients suffering from chronic pain (CP).

Methods
Twenty-one CP patients of AHEPA Hospital outpatient Pain Unit, Thessaloniki, Greece, participated in a double blind, randomized, cross-over trial comparing BB at 5Hz (theta rhythm), with soft music in background, to placebo (soft music, no frequency difference), applied for 30 minutes on site and subsequently on patient demand for a week. Pain (numeric scale, NRS), stress (STAI) and medication usage (defined daily doses, DDD) were assessed at baseline, 30 minutes and week ending.

Results
Perceived pain (NRS) was significantly reduced in the BB group during the 30 minute phase (5.6±2.3 to 3.4±2.6, p<0.001), compared to placebo group (5.2±2.1 to 4.8±2.3, p=0.78), as well as at the week's end (to 3.9±2.5 vs 5.5±2.6 respectively, p<0.001). Stress was equally and significantly reduced in both groups at 30 minutes, but remained reduced at the week ending only in the BB group. Analgesic consumption (DDD) during the week was significantly less in the BB group (3.9±3.7 vs 4.6±4.1, p=0.02), while reporting equal mean levels of perceived pain (5.9±1.8 vs 6.3±1.7, p=0.22).

Conclusions
Acoustic BB reduced perceived pain severity, stress and analgesic consumption, compared to placebo, in CP patients.

REDUCED PAIN PERCEPTION AND ANALGESIC MEDICATION CONSUMPTION AFTER ACOUSTIC BINAURAL BEATS APPLICATION IN PATIENTS SUFFERING FROM CHRONIC PAIN - A RANDOMIZED CONTROL TRIAL