Longitudinal Study to Investigate Different Transcranial Electrical Stimulation

Inclusion Criteria: * ability to read, write and speak English fluently * MoCA score between 5 and 24 Exclusion Criteria: * Being diagnosed with Parkinson's disease, Parkinsonian dementia, Huntington disease, speech significant aphasia and intellectual disability, major depression/anxiety, bipolar disorder, schizophrenia or any other major mood disorder. * Having a history of epileptic seizures or epilepsy * Inability to adequately communicate in English * Impaired vision or hearing severe enough to impair performance in cognitive tests * Current substance abuse disorder * Currently participating in another therapeutic study for dementia * Plan to change the medication during any treatment period (5 weeks including the pre-post assessments)