Table 1. . Summary of outcome measures.
| Measure | Variable | Instrument | Assessment | Ref. | ||||
|---|---|---|---|---|---|---|---|---|
| B | 6M | 7M | 9M | |||||
| Aim 1 and Aim 3 – Exploratory | Primary | Global cognitive performance | ADAS-Cog | x | x | x | x | [32] |
| Secondary | Multiple-domain cognitive dysfunction | Digit Symbol Substitution Test | x | x | x | x | [33] | |
| Executive control/spatial selective attention | Eriksen Flanker Test | x | x | x | x | [34] | ||
| Quality of life | QoL-AD | x | x | x | x | [35] | ||
| Depressive symptoms | Geriatric Depression Scale | x | x | x | x | [36] | ||
| Satisfaction with tDCS | tDCS User Satisfaction Survey | x | ||||||
| Tolerability | Adverse events | x | x | x | ||||
| Covariates | Gender, age, medication, chronic illness and baseline cognitive status | Sociodemographics self-report; baseline results of ADAS-Cog | x | |||||
| Process measures | Intervention fidelity | Missed or incomplete sessions Data from evaluation of blinding, i.e., patient’s impression, obtained after the study, of having received either active or sham treatment |
x | |||||
| Aim 2 | Primary | Functional activation/deactivation patterns | fMRI during Digit Symbol Test and Eriksen Flanker test | x | x | x | ||
| Secondary exploratory |
Structural connectivity | Diffusion-weighted imaging | x | x | x | |||
| Covariates | Gender, age, medication, chronic illness and baseline cognitive status | Sociodemographics; self-report; baseline results of ADAS-Cog | x | |||||
ADAS-Cog: Alzheimer’s disease assessment scale–cognitive subscale; fMRI: Functional MRI; QoL-AD: Quality of life-Alzheimer’s disease; tDCS: Transcranial direct current stimulation.