Balance control in people with multiple sclerosis : mechanisms, experiences, design and feasibility of an exercise trial

Background: Everyday living entails navigating complex environments and perform-ing activities often requiring simultaneous motor and cognitive actions/tasks (dual-tasking). Disease-related impairments in people with multiple sclerosis (MS) often impact sensorimotor and cognitive functions, both of which may contribute to a vicious cycle of decreased mobility, muscular weakness, impaired balance control, walking limitation, falls, and fall-related injuries. Reduced dual-task capacity is suggested to be more common among people with MS compared with healthy controls, which in turn might impact balance control. A more detailed understanding of the underlying mechanisms contributing to impaired balance control, as well as the experiences of how this affects activities and participation in people with MS’ everyday lives, is still lacking. Furthermore, balance training interventions with a gradual progression of difficulty and highly challenging tasks designed specifically for people with MS are rare. To develop a balance training intervention specifically targeting balance and walking problems for people with MS, both quantitative and qualitative preparatory studies are needed. Aim of thesis: To explore mechanisms, explore and describe experiences of balance control in people with MS, and furthermore to design and evaluate the feasibility of a highly challenging balance training intervention specific to MS. Methods: This thesis consists of four papers based on three data collections, including people with mild to moderate overall MS disability and healthy controls. Paper I was a test–retest reliability study of a balance assessment scale, the mini-BESTest, with repeated measurements one week apart; 54 people with MS were included. Paper II was a case-control study evaluating dual-task performances of the motor tasks standing with eyes closed and walking, and a cognitive task, auditory Stroop; 55 people with MS and 30 healthy controls were included. Paper III was a qualitative interview study exploring how impaired balance control affects participation in activities in people with MS’ everyday life; 16 people with MS were included. Paper IV was a single-group feasibility trial of a balance training intervention developed specifically for MS through a co-design workshop series with stakeholder involvement; 12 people with MS were included. Results: Paper I showed that the mini-BESTest total score is reliable for assessment of balance control in people with mild t