Association of Transcranial Alternating Current Stimulation with Digital Cognitive Training for Cognitive Remediation in Older Adults

The FDT assesses attention, processing speed, and executive function. Participants perform tasks involving numerical stimuli under timed conditions. Performance is evaluated based on accuracy and reaction time, with faster and more accurate responses reflecting better cognitive function.

The ROCF evaluates visuospatial constructional abilities, visual memory, and organizational skills. Participants copy a complex figure (copy task) and later reproduce it from memory (recall task). Scores range from 0 to 36, with higher scores representing better performance and lower scores indicating impaired abilities.

These tasks measure verbal fluency and executive function by asking participants to generate as many words as possible within a category (semantic fluency) or starting with a specific letter (phonemic fluency) within a limited time. Higher scores indicate better fluency and cognitive flexibility, while lower scores suggest deficits in these areas.

The RAVLT assesses verbal memory, including immediate recall, learning, and delayed recall, as well as susceptibility to interference. Scores vary based on the number of correctly recalled items across trials, with higher scores indicating better memory performance and lower scores reflecting poorer memory function.

The P300 is an electrophysiological measure of cognitive processing, typically recorded using EEG during an oddball paradigm. It reflects attention and working memory processes, with shorter latencies and higher amplitudes indicating more efficient neural processing and longer latencies or reduced amplitudes suggesting impairment.

Glial fibrillary acidic protein (GFAP) is a biomarker of astrocytic activation and neuroinflammation. Higher serum GFAP levels may indicate glial activation or neurodegeneration, while lower levels are associated with normal brain health.

This analysis quantifies beta-amyloid peptides, key biomarkers of Alzheimer's disease pathology. Elevated beta-amyloid levels or an altered ratio of amyloid-beta 42/40 in serum may reflect early neurodegenerative processes, while normal levels are indicative of typical brain function.

Serum tau protein levels reflect axonal injury or neurodegeneration. Elevated tau concentrations may indicate pathological processes such as Alzheimer's disease or other neurodegenerative disorders, while normal levels suggest no significant axonal damage.

This task evaluates basic saccadic eye movement control. Participants are instructed to fixate on a peripheral target as it appears. Key metrics include reaction time, accuracy, and velocity of saccades, with faster and more accurate responses indicating better ocular motor control.

This task assesses inhibitory control and executive function. Participants must suppress a reflexive saccade to a peripheral target and instead look in the opposite direction. Metrics such as error rates, reaction times, and corrected errors are analyzed, with fewer errors and faster reaction times indicating better inhibitory control and executive function.

This task evaluates visual attention and search efficiency. Participants identify a target among distractors under varying levels of complexity. Performance is measured by reaction time and accuracy, with faster and more precise responses indicating better attentional control and visual search ability.