At Home Gamma tACS in Alzheimer's Disease (tACS@Home)

Incidence of Treatment-Emergent Adverse Events as assessed by the incidence of adverse events graded from 1 (mild) to 5 (fatal).

Tolerability will be evaluated with percentage of compliance (number of delivered stimulations divided by number of programmed stimulations times one-hundred). The primary outcome will be reached if compliance will be >90%.

CDR-SB scores range from 0 to 18, with higher scores indicating worse cognition and daily function.

ADAS-Cog13 scores range from 0 to 85, with higher scores indicating a greater deficit.

The Face-Name Associative Memory Test is a cross-modal associative memory test, it includes 20 face-name pairs. The administration procedure starts with the presentation of 20 faces with each name and participants should read the name underneath the faces and try to learn each face-name pair. After 5 minutes, the faces are shown one by one and participants are asked to recall the associated names from 4 different names. The correct number of pairs recalled is recorded. The score ranges from 0 (worse performance) to 20 (best performance).

ADCS-ADL scores range from 0 to 78, with lower scores indicating greater functional impairment.

CDR-SB scores range from 0 to 18, with higher scores indicating worse cognition and daily function.

ADAS-Cog13 scores range from 0 to 85, with higher scores indicating a greater deficit.

Participants are given a list of 15 unrelated words repeated over five different trials and are asked to repeat. Another list of 15 unrelated words are given and the patient must again repeat the original list of 15 words and then again after 30 minutes. The score ranges from 0 (worse performance) to 15 (best performance).

The Face-Name Associative Memory Test is a cross-modal associative memory test, it includes 20 face-name pairs. The administration procedure starts with the presentation of 20 faces with each name and participants should read the name underneath the faces and try to learn each face-name pair. After 5 minutes, the faces are shown one by one and participants are asked to recall the associated names from 4 different names. The correct number of pairs recalled is recorded. The score ranges from 0 (worse performance) to 20 (best performance).

The NPI-Q is designed to be an informant-based interview that assesses neuropsychiatric symptoms of the participant over the previous month. The score ranges from 0 (no symptoms) to 180 (severe symptoms).

The Caregiver Burden Inventory (CBI) includes 24 items and 5 dimensions: Time-dependence, developmental, physical, emotional, and social burden. There are 5 items for each dimension, except for the physical dimension, which has four items. Each item signifies a score between zero (not descriptive) and four (highly descriptive), with a higher score indicating greater care burden. Therefore the total score for time-dependence, developmental, emotional, and social burden range from 0 to 20 except for physical burden where scores range from 0 to 16. The total score ranges from 0 (no burden) to 96 (severe burden).

ADCS-ADL scores range from 0 to 78, with lower scores indicating greater functional impairment.

By using transcranial magnetic stimulation (TMS), the investigators will evaluate the effects of gamma tACS on short latency afferent inhibition (SAI), which is a marker of cholinergic transmission. SAI is expressed as % of the unconditioned motor evoked potential.

By using electroencephalography (EEG), the investigators will evaluate the change in gamma power.

Changes in plasma neurofilament light (NfL) levels (pg/mL) will be evaluated.

Changes in plasma glial fibrillary acidic protein (GFAP) levels (pg/mL) will be evaluated.

Change in plasma amyloid beta1-40 levels (pg/mL) will be evaluated.

Change in plasma amyloid beta1-42 levels (pg/mL) will be evaluated.

Change in plasma pTau217 levels (pg/mL) will be evaluated.

Change in resting state magnetic resonance imaging connectivity (default mode network) both static and dynamic.

The Trail Making Test Part B consists of 24 circles on a piece of paper, but rather than all of the circles containing numbers, half of the circles have the numbers 1-12 in them and the other half (12) contain the letters A-L. The person taking the test has to draw a line from one circle to the next in ascending order; however, he must alternate the circles with numbers in them (1-13) with circles with letters in them (A-L). In other words, he is to connect the circles in order like this: 1-A-2-B-3-C-4-D-5-E and so on. Scoring is based on time taken to complete the test with lower scores being better.

In the semantic fluency task, participants are asked to generate as many words as possible from a given category (animals) within a limited time (60 seconds); lower scores indicate greater impairment in verbal fluency.