Assessments

The primary outcome was the difference between the proportion of patients suffering any kind of adverse effects between groups during the whole trial. Adverse effects were captured continuously during the study and at the last evaluation performed. For the continuous evaluation, patients and caregivers were instructed to report telephonically to their attending physician any kind of side effects; then, the physician would capture the symptoms and determined if an appointment was necessary to evaluate the symptoms and their cause. Also, in each appointment performed, a systematic interview looking for adverse effects was performed. All adverse effects were reported in the database where clinical outcomes were also captured. For the secondary outcomes, cognition was measured by the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-Cog), Frontal Assessment Battery (FAB) (22), semantic and phonetic Verbal Fluency Test (sVFT & pVFT, respectively), and Montreal Cognitive Assessment (MoCA) (23); daily living functionality measured by the Katz Index of Independence in Activities of Daily Living (ADL) (24) and the Lawton-Brody Instrumental Activities of Daily Living (iADL) (25); and depression measured by the Geriatric Depression Scale Short Form (GDS-15) (26). All secondary outcomes were measured by the researchers at baseline and 6 months after starting stimulation.