Reaction time test. Participants will be assessed on measures of simple and complex reaction time using a computerised test (programmed on SuperLab software by DMU). For the simple reaction time test, participants will be presented with a stimuli on a laptop screen (an asterix) and will be asked to press the space bar on the keyboard as quickly as the stimuli is presented. Data will be converted into elapsed time in milliseconds. For the complex reaction time test, testing higher order cognitive functions, participants will be asked to only respond when the letter ‘p’ is presented on the screen, not when the letter ‘d’, a distractor stimuli is presented. The tests take around 13 minutes to administer and will be based on those described by Xxxxxx et al. [20] a full description of the tasks is quoted from the original paper in full below: "For the first ‘simple’ vigilance task, 110 asterisks would sequentially appear on the screen on the same location but with variable and random time intervals of between 1 and 10 s. Prior to the task, there was a brief training session of five targets, allowing the subjects to get acquainted with the task and the screen layout. Subjects were instructed to press the left of the two mouse buttons with their dominant hand as quickly as possible whenever they saw the target. They were told that the task had a duration of approximately 13 min and were asked to maintain their concentration as well as they could throughout the task. In the second task, the ‘complex’ vigilance task, either the target letter ‘p’ or the distracter letter ‘d’ would appear in the middle of the screen. The stimuli were drawn randomly from a list of 10 targets and 10 distracters without replacement, such that the maximum (though very unlikely) number of targets or non-targets appearing consecutively would be 10. The time intervals between successive stimuli changed randomly between 0.5 and 5 s. This ensured that the average interval between targets, the number of targets and the duration of the task would be the same as for the ‘simple’ vigilance task. The target and distracter letters ‘p’ and ‘d’ were chosen because the shape and size of the letters were the same, whereas they differed only in their orientation. There was a brief training session of 10 stimuli (five targets) preceding the task. Subjects were instructed to respond as accurately and as quickly as possible to the targets while ignoring the distracters. A total of 220 stimuli were presented on the screen, of ...
Reaction time test. The healthy elderly control group norm for lapses on the proposed reaction time test is 8.2 (SD = 2.6). Following DOREMI, we would expect values to fall within 1 SD of this healthy range >5.6. For false positives on the reaction time test (control mean =1.9, SD= 0.15) we would expect average false positives to fall with 1 SD of this healthy range <1.75. To ensure reliability of the reaction time computer programmed test, and provide norms for reaction time in milliseconds for people with MCI and healthy controls, the test will be administered to a group of people with MCI and a group of healthy controls (the reference groups from WP5) prior to the intervention. We will take the mean and standard deviation from the healthy control group trial and use this to inform a clinically significant outcome value. Following DOREMI, we would expect participants to fall within 1 standard deviation of the healthy control group reaction time mean. Scores used as cut-off and the final score represent a value adjusted according to age and education, they are not the rough test outcome. For each participant, however, the final test score will be put in relation with the possible health worsening. Age-related frailty is always a factor that must be taken into account within projects dealing with the elderly.
