Can the repetition effect maximize learning in multiple sclerosis?

Objective: The 'repetition effect' stipulates that recall ability improves as the number of learning trials that a person receives increases. While the repetition effect has been supported through many empirical investigations in healthy individuals, it has not yet been applied to clinical populations. The present study tested the hypothesis that an increased number of learning trials improves recall ability in persons with a neurological disorder, namely multiple sclerosis (MS). Design: Prospective between-group design with 30-minute, 90-minute and one-week assessments. Setting: Private, nonprofit, research facility. Subjects: Sixty-four MS subjects; 20 healthy control subjects (HC). Interventions: Subjects were given a modified Selective Reminding Test (SRT), a list of 10 words to remember in a selective reminding format. To control for the amount of information initially learned, the learning trials were repeated until the subject recalled all 10 words on two consecutive trials. Main outcome measures: SRT word recall and recognition was tested 30 minutes, 90 minutes and one week subsequent to initial acquisition. Results: Interestingly, the antithesis of our hypothesis was found. That is, persons with MS who required more learning trials to reach the perfect learning criterion performed significantly worse on the recall trials. However, this was not the case in a sample of healthy individuals undergoing the same protocol. Conclusions: These results indicate that individuals with MS may not benefit from repetition in isolation, but rather require the use of more intensive cognitive rehabilitation strategies (i.e., increased organization) to help improve their depth of encoding of new information.