The relationship between information processing and functional performance in multiple sclerosis

Abstract

Most tasks that have been developed to assess functional performance in Multiple Sclerosis (MS) have limited sensitivity across the spectrum of disease severity. Given that difficulties with information processing are frequently reported early in the disease course, existing functional tools may not accurately detect subtle everyday impairment in early MS when initial cognitive problems emerge. This study examined the relationship between information processing, functional performance, and disease severity (as measured by the Multiple Sclerosis Functional Composite; MSFC) in MS by comparing participants’ performance on functional tasks with increasing cognitive demands.A total of 23 participants with MS (mean Ambulation Index of 1.7) completed a battery of tests targeting information processing and functional performance which included subtests from the Direct Assessment of Functional Status (DAFS), the Executive Function Performance Test (EFPT), and a virtual reality driving simulator (VRDS).Information processing measures were related to the cognitive component of the MSFC. There were no significant relationships between disease severity and the primary functional measures; however, a relationship between disease severity (upper extremity function) and response time on the EFPT was found. Although the primary functional measures were not significantly related to information processing performance, response time on the EFPT modestly correlated with processing speed. Taken together, these findings suggest that the DAFS was the least appropriate functional tool to use in a high functioning MS sample. Although the EFPT showed more promise, time to completion may be a more sensitive measure in a high functioning sample. Gross measures of driving may not be the best way to capture difficulties in mildly impaired individuals; however, there was more variability in the challenging portion of the drive. Despite the low power and restricted variability, this study adds to the literature concerning the relationship between functional performance and the MSFC. Furthermore, this is one of the few studies of functional performance in MS that includes driving simulation. This study can help inform future research as to which functional measures may be sensitive for capturing impairment in MS.%%%%Ph.D., Clinical Psychology – Drexel University, 2011