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.