Right prefrontal transcranial magnetic stimulation for adults with ADHD: electrophysiological correlates and prognostic biomarkers

Background:

Reduced excitability of the right prefrontal cortex (rPFC) is implicated in attention deficit/hyperactivity disorder (ADHD).

Objective:

Determine if TMS can become a treatment alternative for ADHD patients who cannot tolerate pharmacotherapy.

Methods:

Drug-free adult with ADHD (N=40) received 15 daily sessions of high-frequency repetitive TMS directed to the rPFC, using deep(H-1R), standard (Figure-8), or sham coils. ADHD questionnaires wereadministered, and EEG recordings were taken before, during and afterthe first and last days of treatment. EEG was recorded during a stopsignal task (SST), following single TMS pulse over the rPFC and duringthe treatment session itself. Healthy controls (N=41) were recordedonce under the same conditions without rTMS treatment.

Results:

At baseline, significantly lower amplitudes of both the TMS evoked potential (TEP), and the SST’s N200 and P300 components, were evident in the ADHD group. TEP and SST amplitudes correlated with ADHD symptoms and behavioral inhibition measures.Improvement in ADHD total symptoms was only evident in the dTMS group. TEP was enhanced following the first deep and figure-8 treatment sessions, but only dTMS caused long lastingcumulative changes. Specific EEG bands recorded during the first treatment session highly correlated with dTMS effect, yielding a prognostic marker that explained 90% of variance in therapeutic outcome.

Conclusions:

High frequency dTMStreatment is a novel treatment for adult ADHD, possibly by attenuating excitability of the rPFC. Furthermore, electrophysiological activity elicited during the first treatment session can serve as a prognostic marker, increasing treatment response rates through patient selection.

Related Resources: