Stimulating the brain’s alpha rhythm may take the edge off anxiety under stress

A study published in the Journal of Affective Disorders indicates that a brief, rhythm-based brain stimulation session could help alleviate short-term anxiety in healthy middle-aged and older adults. The treatment did not significantly alter participants' overall perception of stress or most physical stress indicators, suggesting its impact may be limited to immediate emotional responses.

Researchers focused on alpha brain rhythms, which occur around 10 times per second and are associated with attention and emotional regulation. Transcranial alternating current stimulation (tACS) delivered a weak electrical current to the scalp following a specific rhythm. Participants, aged around 59 on average, were randomly assigned to receive active stimulation or a sham procedure.

Active stimulation involved 10 Hz pulses for 20 minutes over the left frontal and parietal areas of the scalp. State anxiety scores decreased by 3.16 points in the active group after treatment, while they increased by 1.17 points in the sham group. The difference was statistically significant but only slight. Perceived stress appraisal did not change, implying the intervention impacted emotional reactivity rather than the perceived difficulty of the task.

Brain activity during the stress task showed a trend toward higher alpha activity in the left frontal region of the active group compared to the sham group, potentially indicating stronger emotional information regulation. Unlike the treatment, physical stress measures, such as skin conductance and pupil responses, did not demonstrate a specific effect.

As the study involved only healthy adults with low baseline anxiety levels, further research is needed to determine its applicability to individuals with anxiety disorders. The small sample size, technical challenges, and one-session intervention also limit the findings' generalizability.