Information processing deficits in multiple sclerosis: Does choice of screening instrument make a difference?

Objective: To examine the clinical utility of the Letter-Number Sequencing (LNS) subtest of the Wechsler Adult Intelligence Scale-III and the Paced Auditory Serial Addition Test (PASAT) to detect cognitive decline in persons with multiple sclerosis (MS). Design: Case-control study. Setting: Outpatient rehabilitation research institution. Participants: Fifty-two adults with clinically definite MS. Main Outcome Measures: LNS standard score and number correct on the PASAT. Results: The PASAT was more sensitive to information processing deficits in persons with MS than was the LNS, perhaps due to a significant processing speed component in the former. Conclusions: The PASAT and the LNS have differential clinical utility, inasmuch as the PASAT assesses not only working memory ability but processing speed as well.