This free neuropsychological evalu …
This free neuropsychological evaluation software, Repeat, examines performance on a serial reaction time task thought to depend upon implicit memory. Participant's acquisition of a repeating stimulus sequence is assessed in this task.

Repeat is a modification of procedures reported by Nissen and Bullemer (1987) and by Lewick, Hill and Bizot (1988). The computer screen is divided into quadrants. A single "X", appears in one of the quadrants. The participant's task is either, depending on response modality, to strike as quickly as possible the key (4, 5, 1, 2 on the numeric keypad) corresponding to the quadrant in which the "X" appears or to position the mouse pointer over the quadrant and click it. The "X" then appears according to a repeating pre-programmed sequence in a different quadrant and the participant is required to respond as quickly as possible to that "X". A trial is made up of a series of the repeating sequence. Sequence order and length and the number of iterations of the sequence are predetermined by the experimenter. CATs Repeat also allows for the interleaving of a randomly positioned "X" between each sequenced "X". Alternatively a series of random presentations can be programmed to allow for assessment of the baseline speed of responding, that is a condition under which the participant can acquire no anticipatory information to enhance speed of responding.

Repeat also contains a dual-task or split attention component modeled after a task reported by Nissen and Bullemer (1987). This task is identical to the one described above except that either a low or high tone is presented with each "X" presentation and the participant is asked to count the number of low tones they heard during a trial. The relative frequency of low tones is experimenter definable.

Finally Repeat allows for the assessment of the explicit knowledge the participant may have acquired of the sequence. This component of the task is modeled after the "generate" procedure reported by Nissen and Bullemer (1987). At any point in the experiment the participant can be asked to begin predicting where the "X" will appear next.