Unveiling New Insights into ADHD with tACS and EEG

Kannen et al. (2024) explored the potential of using transcranial alternating current stimulation (tACS) combined with electroencephalography (EEG) to enhance individual alpha power in adults with Attention-Deficit/Hyperactivity Disorder (ADHD). This innovative approach aimed to investigate whether such neurophysiological changes could lead to improvements in behavioural symptoms typically associated with ADHD, such as inattention, hyperactivity, and impulsivity.

The researchers employed a crossover trial where participants underwent both active tACS and sham (placebo) stimulation on separate days. The tACS aimed to stimulate individual alpha frequencies (IAF), which are brainwaves typically associated with relaxed yet alert states. These frequencies were personalised for each participant, ensuring that the stimulation was tailored to their unique brain activity. Participants were placed in a Virtual Seminar Room (VSR), a carefully designed virtual environment that simulates real-world scenarios to measure attention and behavioural responses. This setting allowed researchers to standardise measurements of inattention, hyperactivity, and impulsivity while participants engaged in a continuous performance task (CPT).

How tACS and EEG Worked Together

tACS was used to modulate brain activity by applying a weak electrical current to specific regions of the scalp, particularly those associated with ADHD symptoms. The active stimulation was applied at the participants' IAF, while sham stimulation involved only a brief burst of current, creating a placebo effect for comparison. EEG, on the other hand, played a crucial role in both the delivery and monitoring of tACS. The Smarting EEG device, known for its high precision and wireless capabilities, was instrumental in capturing real-time brain activity throughout the experiment. This EEG system allowed researchers to monitor changes in alpha power, providing immediate feedback on the neurophysiological effects of tACS.

The Role of the Smarting EEG Device

The wireless EEG system provided continuous, high-fidelity data on the participants' brain activity during both the tACS intervention and the CPT. This real-time monitoring was essential for accurately adjusting the tACS to match the individual alpha frequencies of the participants. Given that the experiment took place in a virtual reality setting, the mobility offered by the Smarting EEG device allowed participants to move freely without being tethered by wires, enhancing their immersion in the virtual environment. The device's ability to maintain low impedance levels ensured high-quality data collection, which was critical for analysing the subtle changes in alpha power that the study aimed to measure.

The Findings

Kannen et al. (2024) revealed a significant increase in alpha power post-intervention, particularly in the active tACS condition. This increase in alpha activity suggests that tACS can effectively modulate brain activity in regions associated with ADHD symptoms. Interestingly, while the behavioural measures of inattention and impulsivity did not show significant differences between active and sham conditions, the neurophysiological data provided by the Smarting EEG device offered a more nuanced understanding of how tACS affects brain function. The researchers also noted a trend towards improved behavioural outcomes in the post-tACS condition, although these did not reach statistical significance. This indicates that while the immediate behavioural effects of tACS might be subtle, the neurophysiological changes it induces could have longer-term implications for ADHD treatment.