Gamma Frequency Stimulation in Individuals With Down Syndrome

Inclusion Criteria: * Subject is between the ages of 25-65 * Subject must have a clinically confirmed diagnosis of Down Syndrome (karyotypes optional). Individuals with mosaic Down syndrome will be excluded. * Subject or their legal guardian is willing to sign informed consent document. * If subject is deemed to not have capacity to sign the informed consent, he/she will need a legally authorized representative to provide surrogate consent. * Subject will be medically stable with consistent medication over the previous 3 months. Exclusion Criteria: * Subjects has history of a dual diagnosis Down Syndrome and Autism * Subjects with has history of seizure or epilepsy within the past 24 months. * Subjects with a new diagnosis of Attention-deficit/hyperactivity disorder (ADHD) (\< 6 months) or untreated ADHD * Active treatment with one or more anti-epileptic agent. * Subjects who have a known history a stroke within the past 24 months. * Subjects with a known history of migraine headache. * Subjects on medications that lower seizure threshold such as wellbutrin, ciprofloxacin, levofloxacin, etc. * Subjects with clinically significant suicide risk and/or suicide attempt in the past 1 year. * Subjects with behavioral problems such as aggression/agitation/impulsivity that might interfere with their ability to comply with protocol. * Active treatment with one or more psychiatric agent (e.g. antidepressants, antipsychotics, etc). * Subjects who have an active implantable medical device including but not limited to implantable cardioverter defibrillator (ICD), deep brain stimulator (DBS), cardiac pacemaker, and/or sacral nerve stimulator. * Subjects who have profound and uncorrected hearing or visual impairment. * Subjects who are pregnant (self-report).