Cognitive Dysfunction: Comparison in Multiple Sclerosis with Human Controls

Background: Cognitive dysfunction (CD) has been reported in approximately 60% of patients with multiple sclerosis (MS). CD is a cause of significant disability and affects modalities such as memory and information processing speed (IPS). Establishing CD in MS patients compared to human controls could afford earlier intervention and management of distressing symptoms. 

Objectives: To compare the IPS domain of CD in MS patients with human controls. Secondary objective was to compare the results of IPS from the computerized cognitive testing program (NeuroTrax) to those obtained from the Brief International Cognitive Assessment for MS (BICAMS). 

Methods: To address the question of the difference in the IPS domain of CD between the groups, we utilized two tests: computerized cognitive testing (NeuroTrax) and the BICAMS test battery. Results from other cognitive modalities were measured and IPS was selected for comparison between MS and controls. The NeuroTrax test comprises three levels of timed arithmetic problem sets to measure IPS. The Symbol Digit Modalities Test (SDMT) from the BICAMS test was used to evaluate IPS. There were 28 MS patients age-matched to 28 controls in the study. 

Results: Cohort (n = 28 MS patients) included 86% females. The cohort age ranged from 25 to 56 years with a mean age of 41.5 (SE = 9). The duration since MS diagnosis ranged from 1 to 26 years. Data were analyzed by paired t-test to measure the difference in IPS of MS patients compared to controls. We found significant differences in IPS between MS patients and controls that are detectable by both the BICAMS and NeuroTrax tests (p < .0001). We observed a strong correlation (r = .57) between the BICAMS and NeuroTrax tests when measuring the IPS modality. 

Conclusions: The study reveals significant differences in the IPS domain between MS patients and controls as demonstrated by the BICAMS and NeuroTrax tests. Our study is unique due to utilization of both the BICAMS and NeuroTrax tests and the comparison of MS patients to human controls. It reinforces the existing literature regarding CD in MS. The findings can be applied clinically to anticipate deficits and intervene early in the course of multiple sclerosis.