Humm it's not just the sound produced by my doubts about this device. It's the name of the device itself! A brain electrostimulator that promises to improve cognitive function and memory.
The devices that exploit the principle of transcranial alternating current stimulation (tACS) have become many in recent years. The aim is to modulate the activity of the brain by applying a weak electric current to the skull (usually on the forehead).
In the case of Humm the stimulation is applied at a frequency of 6Hz, which in the company's statements should enhance the theta waves of the prefrontal cortex.
"Memory works at a specific low frequency, that of theta waves. With age, the strength of our theta waves naturally decreases and the brain loses sync with them, with the result that memory begins to deteriorate. Humm uses the well-known tACS method. to restore synchrony and strengthen memory by gently stimulating the brain at a frequency of 6Hz. tACS acts like an orchestra conductor making neurons play together, allowing different areas of the brain to communicate better. "
I was struck by the study that would have shown the effectiveness of Humm beyond the placebo effect. I was expecting something closer to marketing than science: I must say, however, that it seems well written and the criteria adopted are such as to pass a revision, also because otherwise it would not have been published.
Humm's team distributed a random number of stimulations or placebos to a group of 36 volunteers. Moreover, the experiment was conducted blindly, without explaining to any volunteer the nature of the stimuli or their purpose.
The Humm-stimulated group performed better tests both during and after the stimulations than the placebo group.
In the punctuality of the reports, the Humm paper goes beyond the standards, even incorporating data and graphics on the individual results of each test participant.
Humm, my doubts
In other words, it seems to me a very well structured experiment, except for one problem: the number of participants. Too small, 36 volunteers divided into two groups is very small. It's not a tiny block, but it's not that relevant either, and I personally would like to see experiments on larger samples before buying such a product.
Besides, I don't think Humm is likely to actually improve memory cognition. The device's tACS stimulation distributes over the prefrontal cortex of the brain a current of 6Hz. But theta waves vary in frequency depending on the person in a range that goes from 4 to 7Hz. Not everyone has "exactly" 6Hz theta waves. And the others?
If my theta waves travel at the frequency of 5Hz for example, a stimulation of 6Hz will not help me. It might even "disharmonize" things, as far as I know.
In short, in the scientific debate on transcranial AC stimulation I, a layman of science, do not take sides for or against, knowing full well that there are studies for and against this method.