INFORMATION PROCESSING IN MULTIPLE SCLEROSIS PATIENTS

SANDRA VANOTTI; JUAN E KAMIENKOWSKI; MILENA WINOGRAD; MARIA LAURA SALATINO; FERNANDO CACERES; MARIANO SIGMAN

Montreal, Canada

Congreso; 24th ECTRIMS/13th ACTRIMS/5th LACTRIMS; 2008

ECTRIMS/ACTRIMS/LACTRIMS

Introduction: Cognitive Impairment (CI) affects 46% of patients in Argentina. Speed of information Processing deficit is often seen in patients with Multiple Sclerosis (MS). It refers to the rate at which cognitive processes can be executed. When two tasks are presented simultaneously or at a short stimulus onset asynchrony (SOA), a systematic delay in the execution of the second task is observed while response times (RT) to the first task are unaffected. This phenomenon, referred as Psychological Refractory Period (PRP), has been widely used in normal subjects to understand the temporal organization of different stages of information processing. Here we investigate PRP performance in patients with MS. Since a primary aspect of the physiopathology of MS is demyelination of long distance fibers, we hypothesized that the dynamics of information processing may be affected, even at early stages of the disease when no other CI are evident. Methods: 10 MS patients with Relapsing-remitting pattern and 10 healthy controls were evaluated. Age: 36.92 ±10.97; Education: 14.98 ±2.60; EDSS: 1.18 ±0.64; Disease evolution: 6.36 ±4.99. In order to evaluate the PRP a computerized test was used. Cognitive Battery: Brief Repeatable Battery- MS, Symbol Digits, Trail Making and Conners Test. Results: The performance in dual-task is significantly impaired in MS patients. First, MS patients perform slower than controls in PRP tasks. This is particularly accentuated in the response time to the second task, which is affected by dual-task interference. Second, we observed a strong effect of notation in the patient group: the difference between the RT´s in words-written numbers vs digits-written numbers trials was significantly higher than in the control group. In addition, patients manifested a systematic difficulty in executing both tasks in close succession. Conclusion: We can conclude that MS patients with no evident signs of CI, have already compromised some particular aspects of information processing.