To compare the effects of cycling exercise with different types of virtual reality on processing/thinking speed in persons with multiple sclerosis (MS).

The purpose of this research study is to learn how different types of cycling exercise can improve short-term processing speed, or speed of thinking, in persons with MS. In this study, we will compare the effects of cycling alone to cycling with two different types of virtual reality. Participants will complete all three cycling conditions, one per week. We are studying these types of cycling because there are currently no effective treatment options to improve processing speed in persons with MS and combining exercise with virtual reality is a promising technique.

Inclusion Criteria:

• Speak English as their primary language
• Confirmed MS diagnosis by a neurologist
• Be relapse and steroid-free for at least 30 days
• Mild-to-moderate self-report mobility disability

Exclusion Criteria:

• History of neurological disorders besides MS or history of uncontrolled psychiatric disorders (ex: major depression)
• Have contraindications to exercise, based on the Physical Activity Readiness Questionnaire (PAR-Q)
• Currently use medications that may impact cognition (ex: steroids, benzodiazepines)
• Currently pregnant
• Severe cognitive impairment as measured by the Modified Telephone Interview of Cognitive Status (TICS-M)
• No indication of age-related mild cognitive impairment or dementia, based on the MOCA-Blind (i.e., MOCA-Blind ≥19).
• High likelihood of motion sickness
• Regular cyclist, defined as cycling for at least 150 minutes/week

Participants will be blinded to the hypothesized effect of each exercise condition.