Entraining alpha activity using visual stimulation in patients with chronic musculoskeletal pain. A feasibility study

Abstract

Entraining alpha activity with rhythmic visual, auditory, and electrical stimulation can reduce experimentally induced pain. However, evidence for alpha entrainment and pain reduction in patients with chronic pain is limited. This feasibility study investigated whether visual alpha stimulation can increase alpha power in patients with chronic musculoskeletal pain and secondarily, if chronic pain was reduced following stimulation. In a within-subject design, 22 patients underwent 4-minute periods of stimulation at 10 Hz (alpha), 7 Hz (high-theta, control), and 1 Hz (control) in a pseudorandomized order. Patients underwent stimulation both sitting and standing and verbally rated their pain before and after each stimulation block on a 0-10 numerical rating scale. Global alpha power was significantly higher during 10 Hz compared to 1 Hz stimulation when patients were standing (t = -6.08, p <.001). On a more regional level, a significant increase of alpha power was found in the right-middle and left-posterior region when patients were sitting. With respect to our secondary aim, no significant reduction of pain intensity and unpleasantness was found. However, only the alpha stimulation resulted in a minimal clinically important difference in at least 50% of participants for pain intensity (50%) and unpleasantness ratings (65%) in the sitting condition. This study provides initial evidence for the potential of visual stimulation as a means to enhance alpha activity in patients with chronic musculoskeletal pain. The brief period of stimulation was insufficient to reduce chronic pain. This study is the first to provide evidence that a brief period of visual stimulation at alpha Visual alpha stimulation to reduce chronic pain 2 frequency can significantly increase alpha power in patients with chronic musculoskeletal pain. Further study is warranted to investigate optimal dose and individual stimulation parameters to achieve pain relief in these patients.

Alpha entrainment drives pain relief using visual stimulation in a sample of chronic pain patients: a proof-of-concept controlled study

“…As in previous analysis, we showed the possibility of modulating alpha activity in patients with long term chronic pain by using rhythmic visual stimulation [20].…”

“…The current study is an extension of a preliminary study by Arendsen [20] with eight new participants added (28 participants in total). All participants had a diagnosis of chronic musculoskeletal pain (pain present for at least three months).…”

“…Average alpha power across all 2 second windows was calculated for each rhythmic visual stimulation condition (7 and 10 Hz) and its corresponding baselines. It was then averaged across the electrodes corresponding to the frontal Region of Interest (ROI) (Fp1, Fp2, Fpz, AF3, AF4, F1, F2, FZ) [20] to obtain a spectrum of frontal alpha power for each condition. It was not averaged over frequency, but instead we kept the averaged alpha power for each individual frequency within this range.…”

Brainwave entrainment for the treatment of chronic pain: comment on Br J Pain 2020; 14: 161–70

“…Of note, the authors are in the process of publishing a randomized trial using visual flashes of various frequencies: 1, 7 and 10 Hz. 6 The authors here demonstrate enhancement of 10 Hz neural oscillations in midline posterior electrodes. Intriguingly, this study finds that while sitting comfortably entrainment from 10 Hz visual flashes shows the greatest reduction in self-reported ‘unpleasantness’ aspect of pain (65% of participants with a minimal clinically important difference (MCID)) compared to 40% with 1 Hz and 30% with 7 Hz.…”