SMR, beta and the ADHD brain

This is the topic where the gap between what the research shows and what gets sold is widest, so it is worth walking carefully.

The sensorimotor rhythm

SMR is a rhythm around 12–15 Hz recorded over sensorimotor cortex. It is associated with still alertness — attentive, physically settled, not agitated. The classic description is a cat waiting motionless before it pounces.

SMR neurofeedback is one of the older and better-explored protocols in the field, with a history in attention difficulties and in seizure thresholds. If you have read that "SMR helps ADHD", this is the literature that claim comes from.

The distinction that decides everything

That research is about neurofeedback. Neurofeedback is not audio entrainment.

In an SMR neurofeedback session, electrodes read your EEG in real time. When your own 12–15 Hz activity rises, you get a reward signal — a tone, a game responding, a video continuing. Over many sessions you learn, without being able to describe how, to produce more of that rhythm.

It is a training procedure. The mechanism is operant conditioning of your own brain activity, and the loop is closed: your brain drives the sound.

An audio session is the opposite. It plays a fixed 14 Hz rhythm regardless of what your brain is doing. The loop is open. Nothing is measured, nothing adapts, nothing is learned.

Presenting neurofeedback evidence as support for a listening track is the most common misuse of research in this space. We are not going to do it. There is a whole article on why this distinction matters more than any frequency choice.

About the theta/beta ratio

You will see the theta/beta ratio described as the electrophysiological marker of ADHD — elevated slow theta, deficient beta, a clean number that explains everything.

That account is roughly a decade out of date.

TBR was proposed by Lubar in 1991, and early work reported striking sensitivity and specificity. On that strength, a TBR-based device received FDA clearance as an adjunctive assessment tool in 2013.

Then the evidence moved. A meta-analysis by Arns and colleagues the same year found that TBR did not reliably differentiate children with and without ADHD, and — the more telling finding — that effect sizes had declined markedly across successive studies. Later work has reinforced this; a 2024 paper is titled, plainly, Challenging the Diagnostic Value of Theta/Beta Ratio. Current thinking is that elevated TBR probably identifies a subgroup rather than a condition.

So if a product tells you it will "lower your theta/beta ratio", it is invoking a biomarker the field has substantially walked back.

What is left that is actually useful

Quite a lot, once the overclaiming is stripped out.

Pick 12–15 Hz over 18–25 Hz. This is the practical recommendation with the best footing, and it runs against intuition. Focus feels like it should mean faster, so products reach for high beta. But high beta at its upper end is the range most associated with anxiety, and if you are unfocused because you are wired, a 22 Hz session compounds the problem. Start at 14 Hz and only go faster if slower genuinely does not work.

Use the session as a container. For task-initiation difficulty specifically, the useful property of a session is that it has a beginning and an end. Starting audio is a smaller action than starting work, and it reliably leads to the second thing. That is a behavioral scaffold, not a neurological one, and it is probably where most of the real-world benefit lives.

Mask, and mask properly. Speech is uniquely disruptive because it recruits the machinery you are using to read. A pink bed at a level just above the intrusion does more than the beat rate does.

Shorter blocks than you think. 19 minutes finished beats 45 minutes abandoned.

What this is not

Brainwavest is a wellness tool, not a medical device. It does not diagnose, treat or prevent ADHD or anything else, and no audio session is a substitute for assessment or for prescribed treatment.

If you suspect you have ADHD, the useful step is an assessment, not a frequency. If you are already being treated, audio can sit alongside that — and any change to medication is a conversation with the clinician who prescribed it, not something to work around with a soundtrack.