Transcranial Direct Current Stimulation for the Treatment of Inattention in Adult Patients With ADHD: Results From the TUNED Trial

ABSTRACT

Background: Our main goal was to evaluate the efficacy of transcranial direct current stimulation (tDCS) for improving attention in adult patients with attention-deficit/hyperactivity disorder (ADHD) without concurrent treatment with stimulants. Methods: In this parallel, double-blind study, patients with ADHD were randomly assigned to receive active (A-tDCS) or sham tDCS (S-tDCS) using a home-based device. Treatment consisted of one daily stimulation session (30-min, 2-mA, prefrontal cortex) for 4 weeks. The primary outcome measure was a clinician-applied Adult ADHD Report Scale (AARS), inattention section (range 0-36, higher values indicating increased inattention). Analysis of the primary outcome was performed using an ANCOVA controlled for prespecified covariates (baseline AARS, sex, age, ADHD subtype). Results: From July 2019 to July 2021, a total of 147 subjects were assessed for eligibility, and 64 were randomized (mean age=38 years, 30 females). A total of 9 subjects dropped out of the study (4 due to the COVID-19 pandemic). The remaining 59 performed an average of 25 tDCS sessions. Baseline (mean±SD) AARS was 27±3.6 in S-tDCS and 27.6±4 in A-tDCS. In the intention-to-treat analysis (missing data imputed using last observation carried forward), there was a significant decrease of 3.9 (1.50 - 6.44 95% CI) points in the AARS after A-tDCS when compared to S-tDCS (p = 0.002, partial η2 = 0.15). Mild headache and moderate skin redness were more common in A-tDCS. Conclusions: A-tDCS was efficacious in improving symptoms of inattention when compared to S-tDCS and is a promising treatment for patients with ADHD who do not respond or do not tolerate stimulants. Supported By DTL was supported by a CNPq postdoctoral fellowship (grant number 154116/2018-1), and supported by a NARSAD Young Investigator Grant from the Brain and Behavior Research Foundation (grant number 29486). Keywords Adult ADHD, Transcranial Direct Current Stimulation (tDCS), Inattention, Clinical Trials