Does Aerobic Exercise Affect Memory and Fatigue After Acquired Brain Injury?

Primary outcomes

1. Memory

   Time frame: From enrolment to the end of participation at 8 weeks and at a 3 month follow up

   Memory, measured by the following test:

   Rey Auditory Verbal Learning Test (RAVLT), a test of verbal learning and long-term memory (25). The RAVL Test consists of a 15 noun-word list (list A) that is read to the participants. After the presentation of list A, the participant is requested to recall as many words as possible. The procedure is repeated 5 times, and after each trial recall is recorded and all five recall trials are summed into one score (= immediate recall score). After 5 presentations of list A, an interference-list of 15 other nouns (list B) are read and the participants are asked to recall as many words as possible. Immediately after the recall of list B, the participants are again asked to recall list A. Delayed recall of list A is measured 30 min after the immediate recall (= delayed recall score). The higher the value the better result.

2. Executive functions

   Time frame: From enrolment to the end of participation at 8 weeks and at a 3 month follow uo

   Executive functions measured by the following test:

   Kaplan executive function system (D-KEFS) Color Word Test, measures the ability to inhibit automized verbal responses and the ability to use cognitive shifting. The test has four conditions: 1) naming the colors of squares (red, blue or green, 2) reading color words printed in black, 3) naming the printed color of the color words red, blue, or green printed in a different color, which means inhibition of an over-learned function of reading the word; 4) repeatedly switching between a) naming the printed color of the color words red, blue, or green and b) reading the words as quickly as possible. In this condition the person needs to keep track of clues that indicate rule change. Sub tests 1 and 2 are contrast tests and used for comparison between the sub tests 3 and 4 i.e. the more complex tasks. The faster the time, the better which give that lower values represent better results.

3. Attention

   Time frame: From enrolment to the end of participation at 8 weeks and at a 3 month follow up

   Attention measured by the following tests:

   Paced Auditory Serial Addition Test (PASAT) Measures auditive processing speed, attention, and working memory. The test consists of 60 digits from 1-9 presented at a standardized pace of 2.4 seconds between each digit. The task is to sum each digit with the previously presented one before the next digit is presented. The test was presented according to the manual. The maximum score is 60. This test was also used to measure cognitive fatigability as declining performance in terms of an increased number of incorrect responses on the PASAT. The responses were divided into five sections of 12 numbers each, where the number of correct answers in the first section was subtracted from the number of correct answers in the last section. Fatigability was defined as a lower score at the end of the test compared to the beginning, giving a negative value.

4. fatigue

   Time frame: From enrolment to the end of participation at 8 weeks and at a 3 month follow up

   Fatigability was defined as a lower score at the end of the Paced Auditory Serial Addition Test (PASAT) test compared to the beginning, giving a negative value

5. Attention

   Time frame: From enrolment to the end of participation at 8 weeks and at a 3 month follow up

   Attention measured by the following test:

   Ruff 2 & 7 Selective Attention Test (Ruff 2 & 7)

   Measures visual automatic detection speed and accuracy, and controlled search speed and accuracy. The test consists of twenty, 15-second trials, where the subject must identify and cancel the target digits 2 and 7 among distractors. The distractors consist of letters (automatic selective attention) and other digits (controlled selective attention) for ten trials each. Speed of attention is measured as the total number of correctly identified targets. The accuracy calculated as the total number of correct targets divided with the (total number of correct targets + total number of errors) multiplied with 100 according to the manual. A higher score equals better performance.

6. Attention

   Time frame: From enrolment to the end of participation at 8 weeks and at a 3 month follow up

   Attention measured by the following test:

   WAIS-IV Digit Span, measures verbal attention span and working memory. The participant is asked to repeat a series of digits in the same (attention span) or reverse order (working memory). The length starts with 2 digits and ends with 9 digits, two trials per length. After two consecutive errors at the same span length the test is aborted. The test was presented according to the manual. The higher the value the better results (27).