Non-invasive Nerve Stimulation and Cognitive Training to Improve Cognitive Performance in Healthy Older Adults

Primary outcomes

1. Hopkins Verbal Learning Test (Total Immediate Recall)

   Time frame: At baseline (intake assessment) and at the post-intervention assessment conducted following completion of the 2-week cognitive training intervention (approximately 2 to 3 weeks after baseline, depending on scheduling).

   The Hopkins Verbal Learning Test (HVLT-R) is a verbal learning and memory task with a 12-item word list learned over 3 trials. The total immediate recall score is the sum of correct words recalled after each of the 3 learning trials, which can range from 0 to 36.

2. Hopkins Verbal Learning Test (Total Delayed Recall)

   Time frame: At baseline (intake assessment) and at the post-intervention assessment conducted following completion of the 2-week cognitive training intervention (approximately 2 to 3 weeks after baseline, depending on scheduling).

   The Hopkins Verbal Learning Test (HVLT-R) is a verbal learning and memory task with a 12-item word list learned over 3 trials. The total delayed recall score is the number of total correct words recalled (ranging from 0 to 12) after a 20-25 minute delay.

3. Hopkins Verbal Learning Test (Total Retention)

   Time frame: At baseline (intake assessment) and at the post-intervention assessment conducted following completion of the 2-week cognitive training intervention (approximately 2 to 3 weeks after baseline, depending on scheduling).

   The Hopkins Verbal Learning Test-Revised (HVLT-R) is a verbal learning and memory measure involving learning a 12-item word list across three learning trials followed by delayed recall after approximately 20-25 minutes. The Total Retention score is calculated by dividing the delayed recall score (range: 0-12) by the higher score from Learning Trial 2 or Learning Trial 3 (range: 0-12) and multiplying by 100 to yield the percentage of words retained following the delay period. Higher percentage scores indicate better retention of learned information. A score of 100% indicates that delayed recall performance was equal to the participant's best learning trial. Percentage scores greater than 100% are possible when delayed recall performance exceeds the participant's highest score on Learning Trial 2 or Learning Trial 3.

4. Hopkins Verbal Learning Test (Recognition)

   Time frame: At baseline (intake assessment) and at the post-intervention assessment conducted following completion of the 2-week cognitive training intervention (approximately 2 to 3 weeks after baseline, depending on scheduling).

   The Hopkins Verbal Learning Test (HVLT-R) is a verbal learning and memory task with a 12-item word list learned over 3 trials. Within the delayed yes-no recognition part of the task, the participant is presented with a larger list or words and responds to whether each was on the original 12-item list. The recognition discrimination index score is calculated as number of hits (correctly identified words from the list) - number of false positive words (incorrectly identified words that were not on the list), with scores ranging from 0 to 12 (perfect score).

5. NIH Toolbox Fluid Cognitive Composite

   Time frame: At baseline (intake assessment) and at the post-intervention assessment conducted following completion of the 2-week cognitive training intervention (approximately 2 to 3 weeks after baseline, depending on scheduling).

   The National Institutes of Health (NIH) Toolbox Fluid Cognition Composite is a standardized measure of fluid cognitive functioning derived from performance on five tests assessing attention, executive function, working memory, episodic memory, and processing speed (Dimensional Change Card Sort, Flanker Inhibitory Control and Attention, Picture Sequence Memory, List Sorting Working Memory, and Pattern Comparison). Scores are reported as Fully Corrected T-scores derived from NIH Toolbox normative data and adjusted for demographic characteristics including age, sex, race/ethnicity, and education. Fully Corrected T-scores have a normative mean of 50 and standard deviation of 10. Higher T-scores indicate better fluid cognitive functioning, whereas lower T-scores indicate poorer fluid cognitive functioning. A T-score of 50 represents average performance relative to the normative population.