Theta binaural beats and pain: 13 trials, but only four could be pooled

Most binaural beats reviews pool everything together: alpha, theta, gamma, anxiety, focus, pain, whatever was measured. Fatima and colleagues, at the Department of Physiotherapy at Jamia Hamdard in New Delhi, narrowed it to one band. They searched PubMed, Scopus and Web of Science for randomised trials using theta-frequency beats, 4 to 8 Hz, with pain, anxiety or cognitive outcomes, appraised what they found with RoB 2.0 and the PEDro scale, and rated certainty with GRADE. Thirteen trials and 630 participants qualified.

Then the numbers get smaller. Of those thirteen trials, four were poolable, all on pain, covering 173 participants. That analysis gives a standardised mean difference of −0.53 (95% CI −0.84 to −0.23, p = 0.001) with no heterogeneity at all, I² = 0%. The authors rate it low-certainty evidence under GRADE. A small-to-moderate reduction in pain, consistently reported across four trials, which GRADE says we should not be confident about.

For anxiety and cognition, quantitative synthesis “was not feasible due to outcomes heterogeneity”. So those outcomes are described, not measured: anxiolytic effects “were observed particularly in procedural and chronic pain contexts”, and cognitive findings “suggested that theta entrainment favored episodic memory”.

The paper’s own conclusion is that theta binaural beat therapy “may represents a promising, safe and low-cost adjunct for pain modulation, anxiety reduction and cognitive enhancement”. One of those three has a pooled estimate behind it. The other two have a narrative summary of trials too dissimilar to combine, which is a weaker thing than the sentence implies, and it is the reason we grade this mixed rather than the moderate its rubric score of 4.1 would give it.

Read alongside Xiong and colleagues’ perioperative meta-analysis, the two agree on direction for pain and disagree on confidence. Xiong pooled fifteen trials across all beat frequencies and found larger effects with heterogeneity above 90 percent. Fatima pooled four theta-only trials and found a smaller effect with no heterogeneity and low GRADE certainty. The narrower, more consistent analysis gives the more modest number, which is usually what happens.

The episodic memory line is the one to watch. It is the first thing in our library pointing at memory, and it points gently: a narrative observation across trials that could not be combined, not an effect estimate. It does not yet support a grade for memory as an outcome.

Limitations. Nine of the thirteen trials contribute nothing to any pooled estimate. Three databases were searched rather than the six or more a Cochrane review would use, and no trial registry or grey-literature search is mentioned. Low GRADE certainty means further research is likely to change the pain estimate. We could not read the full text, so the per-trial RoB 2.0 ratings, the comparators and the identity of the cognitive trials are not confirmed here; the request is logged in docs/reports/fulltext-requests.md.