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.
“La memoria lavora ad una bassa frequenza specifica, quella delle onde theta. Con l’età la forza delle nostre onde theta decresce naturalmente e il cervello perde sincronia con loro, col risultato che la memoria inizia a deteriorarsi. Humm sfrutta il noto metodo tACS per ripristinare la sincronia e rafforzare la memoria stimolando con gentilezza il cervello alla frequenza di 6Hz. tACS si comporta come un direttore d’orchestra che fa suonare insieme i neuroni, permettendo alle diverse aree del cervello di comunicare meglio”.
Mi ha colpito lo studio che avrebbe mostrato l’efficacia di Humm oltre l’effetto placebo. 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 theta waves of “exactly” 6Hz. 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.