Noninvasive Brain Stimulation in Mild Cognitive Impairment and Dementia

The RAVLT is a verbal episodic memory task where a list of 15 words is read aloud for 5 consecutive trials followed by a 20 minute delayed recall trial. The number of items recalled immediately after each trial are summed to create a total learning score, ranging from 0-75. Also, the number of items recalled for the delayed trial are recorded as a delayed recall score, ranging from 0-15. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better episodic memory performance. Changes from baseline for the total learning and delayed recall scores at the last HD-tDCS session and the 2-month follow-up will be measured as the primary outcomes.

The BVMT-R is a visual episodic memory task where 6 simple designs are shown for 10 seconds in a 2 x 3 matrix for 3 learning trials followed by a 25-minute delayed recall trial. The number of items recalled immediately after each trial are summed to create a total learning score, ranging from 0-36. Also, the number of items recalled for the delayed trial are recorded as a delayed recall score, ranging from 0-12. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better visual episodic memory performance. Changes from baseline for the total learning and delayed recall scores at the last HD-tDCS session and the 2-month follow-up will be measured.

The Boston Naming Test Short Form is a 30 item version of the task (odd and even item versions of the full test) and a measure of language. The subject is shown pictures of objects and is required to correctly name them as quickly as possible. The outcome measure for this task is the total number of correct responses, ranging from 0-30. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better performance. Changes from baseline to the last HD-tDCS session and the 2-month follow-up will be measured.

The DKEFS phonemic verbal fluency task is a measure of language. The subject is required to name as many words as possible that begin with specified letters within 1 minute. Three different letter trials are completed. The outcome measure for this task is the total number of correct responses across the trials, ranging from 0-90. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better performance. Changes from baseline to the last HD-tDCS session and the 2-month follow-up will be measured.

The DKEFS semantic verbal fluency task is a measure of language and involves 3 conditions. The subject is required to name as many animals and people names as possible within 1 minute. The outcome measure for this task is the total number of correct responses for both conditions combined, ranging from 0-90. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better performance. Changes from baseline to the last HD-tDCS session and the 2-month follow-up will be measured.

The Trail Making Test is a measure of cognitive flexibility and executive functions. The task requires the subject to as quickly as possible complete two conditions, involving number sequencing and then number-letter switching. The outcome measure for this task is the time in seconds to complete the number-letter switching condition, ranging from 15-300. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better performance. Changes from baseline to the last HD-tDCS session and the 2-month follow-up will be measured.

The Southwestern Assessment of Processing Speed is a measure of psychomotor processing speed. The subject is required to transcribe numbers to their corresponding written symbol as quickly as possible within 60 seconds. The outcome measure for this task is the total number of correct responses, ranging from 0-75. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better performance. Changes from baseline to the last HD-tDCS session and the 2-month follow-up will be measured.

The DKEFS Color-Word Interference test is a measure of information processing speed and complex attention. The task requires the subject to as quickly as possible complete four conditions, involving color naming, word reading, response inhibition, and then switching back-and-forth between two response patterns. The outcome measures for this task was the response inhibition trial and the switching trial, which are scored as the time in seconds to complete the conditions, ranging from 20-180. Scores were converted to standardized scores (T-scores) using normative data, ranging from 2-86. Higher scores reflect better performance. Changes from baseline to the last HD-tDCS session and the 2-month follow-up will be measured.