A randomized, sham-controlled, double-blind clinical trial to examine the safety and effectiveness of tRNS on unmedicated pediatric patients (7-12 years) with ADHD. Subjects will undergo either tRNS or sham treatment for 10 days during a two-week period in a home-simulated environment. Each treatment session is 20 minutes, during which their attention will be maintained using a software game.

INCLUSION CRITERIA:

1. Age between 7-12 years old at the time of enrollment
2. Estimated Full Scale IQ ≥ 85 based on WASI-II (Two-subtests Form) NOTE: Results of an equivalent and validated IQ test that were performed in the previous 12 months from the date of enrollment are acceptable. The Investigator must ensure that no significant head injuries, particularly significant head trauma, occurred in this period from the previous test to the enrollment.
3. Score above the standard clinical cut-off score for ADHD symptoms on the ADHD DSM-5 scales
4. Meet criteria for ADHD according to DSM-5, using the "gold standard" procedure as described by the American Academy of Pediatrics, which includes a semi-structured interview of the subject and parent(s)/legal guardian(s)
5. Moderate to severe ADHD as defined as having a minimum score of 12 on either the inattention subscale or the and hyperactivity-impulsivity subscale of the baseline ADHD Rating Scale (ADHD-RS), and a Clinical Global Impression-Severity (CGI-S) score at baseline of greater than 4
6. Parent(s)/legal guardian(s) fluent in English, able to complete ADHD-RS scale and attend all study visits
7. Has not taken any medication with central nervous system effects, including prescription medications for ADHD, within 7 days of enrollment, as determined by the investigator based on the subject's medical history from the parent(s)/legal guardian(s) and, as applicable, medical and pharmacy records

EXCLUSION CRITERIA:

1. Has a history of any medical or psychiatric disorder, disease, condition, injury, symptoms or circumstance that, in the opinion of the principal investigator, may: (1) reduce the subject's ability to fulfill the study requirements as per protocol; or (2) adversely impact the integrity of the data or the validity of the study results
2. Primary DSM-5 axis-1 disorder other than ADHD, which consists of one or more of severe ODD, bipolar psychosis, major depressive disorder, severe oppositional defiant disorder that would pose adherence challenges by the investigator
3. Substance abuse, that, in the opinion of the investigator, may: (1) reduce the participant's ability to fulfill the study requirements as per protocol; or (2) adversely impact the integrity of the data or the validity of the study results
4. Impaired functioning to a degree that requires immediate initiation of ADHD medication in the opinion of the Investigator
5. Known hypersensitivity to Polyamide or Elastomer
6. Any suicide risk as assessed with the Columbia-Suicide Severity Rating Scale (Pediatric (≤11 years) Quick Screen)
7. If female, began menstruation, based on a self- or parent(s)/legal guardian(s)-report
8. Any other condition, which would make the participant unsuitable to participate in this study as determined by the Investigator
9. Inability to provide informed consent and assent (participant and parent(s)/legal guardian(s))

The study is double-blind, meaning participants, parents/legal guardians/caregivers, the investigator and all study personnel are blinded. Participants will be randomized in a 1:1 allocation ratio to receive active (Group A) or sham (Group B) tRNS. Randomization will be stratified by age, gender, and baseline ADHD-RS score. Three staff members with no contact with participants will generate balanced random samples throughout the course of the study, using Smith's randomization algorithm based on the variance minimization procedure, and program the respective device to discharge sham/active stimulation according to each participant's allocation.