HD-tDCS over Frontal Cortex and Neuropsychological Functioning in Cognitively Impaired Older Adults

Alzheimer's Clinical Syndrome (ACS) is projected to triple in incidence over the next 30 years and is characterized by a gradual loss of cognitive and functional abilities. Mild cognitive impairment (MCI) is an earlier stage of cognitive impairment that often represents a prodromal stage of ACS. Individuals with MCI may have trouble completing complex instrumental activities of daily living such as managing medication regimens or multiple medical appointments, though they can maintain a level of independence with use of compensatory strategies. MCI and ACS commonly have an amnestic presentation (inability to learn and recall new information), though additional problems in executive functions, language, and/or visuospatial skills are typically present at the time of clinical diagnosis. As ACS progresses, the ability to function independently becomes compromised, and at this stage, assistance with complex activities of daily living (e.g., driving, financial management) is often necessary. Neuropsychiatric symptoms (NPS), such as depression, anxiety, and apathy, are common in MCI and ACS and are also associated with a faster rate of decline. Current treatments used to manage cognitive symptoms include acetylcholinesterase inhibitors (AChEIs) and NMDA-receptor blockers, while selective serotonin reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI) are common first-line medications for NPS, though all demonstrate short-lived efficacy in symptom control. Lifestyle changes such as dietary interventions, physical exercise, and therapeutic approaches (e.g., reality orientation training, cognitive training, rehabilitation) aim to reduce symptoms and some may stave off decline, though all are unproven to be a restorative treatment for ACS. As such, there exists an urgent need for investigation of novel treatment approaches. Given the unmet treatment needs for MCI and ACS, it is important to evaluate new potential treatments that might provide symptom improvement. One line of possible treatment ...