Six-Minute Walk Test Performance in Persons With Multiple Sclerosis While Using Passive or Powered Ankle-Foot Orthoses.

OBJECTIVE: To determine whether a powered ankle-foot orthosis (AFO) that provides dorsiflexor and plantar flexor assistance at the ankle can improve walking endurance of persons with multiple sclerosis (MS). DESIGN: Short-term intervention. SETTING: University research laboratory. PARTICIPANTS: Participants (N=16) with a neurologist-confirmed diagnosis of MS and daily use of a prescribed custom unilateral passive AFO. INTERVENTIONS: Three 6-minute walk tests (6MWTs), 1 per footwear condition: shoes (no AFO), prescribed passive AFO, and portable powered AFO (PPAFO). Assistive devices were worn on the impaired limb. MAIN OUTCOME MEASURES: Distance walked and metabolic cost of transport were recorded during each 6MWT and compared between footwear conditions. RESULTS: Each participant completed all three 6MWTs within the experimental design. PPAFO use resulted in a shorter 6MWT distance than did a passive AFO or shoe use. No differences were observed in metabolic cost of transport between footwear conditions. CONCLUSIONS: The current embodiment of this PPAFO did not improve endurance walking performance during the 6MWT in a sample of participants with gait impairment due to MS. Further research is required to determine whether expanded training or modified design of this powered orthosis can be effective in improving endurance walking performance in persons with gait impairment due to MS.

Walking and thinking in persons with multiple sclerosis who vary in disability.

OBJECTIVE: To examine the effect of a cognitive task on spatiotemporal parameters of gait in persons with multiple sclerosis (MS) with varying disability. DESIGN: Cohort. SETTING: Testing occurred at a local hospital. PARTICIPANTS: Community-living persons (N=78) with MS participated in this investigation. They were divided into 3 groups based on Expanded Disability Status Scale (EDSS) scores: mild (2.0-3.5 EDSS; n=21); moderate (4.0-5.5 EDSS; n=25); and severe (6.0-6.5 EDSS; n=32). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants walked at a self-selected pace on an electronic pathway, which recorded spatiotemporal parameters of gait, in 4 separate trials and completed a cognitive task in the last 2 trials. The effect of the cognitive task was quantified as the change in spatiotemporal parameters of gait. RESULTS: There was an overall decline in gait with the additive cognitive task. The magnitude of the adverse changes ranged from 1.8% for step length (P=.02) to 12% for gait velocity (P<.001). Moreover, adverse changes in gait function were greatest in the severe and moderate disability group (P<.05). CONCLUSIONS: Persons with MS have impaired walking while doing a cognitive task, and the adverse effect of a cognitive task on walking function is greatest in persons with severe and moderate disability. Difficulty walking while thinking has implications for everyday life and may be related to the risk of falls. Further work is needed to determine whether the adverse effect of an additive cognitive task can be minimized with rehabilitative interventions.

Does a waist-worn ActiGraph accelerometer quantify community ambulation in persons with multiple sclerosis?

Accelerometry has been recognized as a method of objectively measuring community ambulation in persons with multiple sclerosis (MS). However, the assumption that walking itself serves as a major contributor to the accelerometer signal has yet to be tested. This study examined the assumption that community-based walking is a primary contributor to accelerometer output in MS. Ambulatory persons (5 males/17 females; 13 without aid/9 with aid) with MS wore a triaxial accelerometer (ActiGraph GT3X, Health One Technologies; Fort Walton Beach, Florida) as well as an IDEEA system (MiniSun, Inc; Fresno, Florida) over the course of a single day. Outcome measures for the accelerometer included movement counts/hour for the vertical, anterior-posterior, and mediolateral axes. Outcomes for the IDEEA system included percent time walking, sitting, and standing, as well as walking speed. Pearson product correlations (r) were used to examine the associations between outcomes from the accelerometer and IDEEA system. Significant correlations were observed between percent walking time and movement counts/hour along the vertical (r = 0.84) and anterior-posterior (r = 0.69) axes. Significant correlations were further noted between movement counts/hour along the vertical axis and walking speed (r = 0.45) and self-report walking impairment (r = -0.50) and disability (r = -0.46). Such observations further support accelerometry as an objective marker of community ambulation in persons with MS.

Postural control in multiple sclerosis: effects of disability status and dual task.

Persons with Multiple Sclerosis (PwMS) have postural control impairments. The simultaneous performance of a cognitive task while maintaining an upright posture (i.e. dual task) negatively influences postural control in PwMS with mild disability. This investigation compares the effect of simultaneous cognitive task performance on postural control in PwMS with mild and moderate disability. Forty-five PwMS were divided into groups based on Expanded Disability Status Scale (EDSS) scores: mild (EDSS: 2.0-3.5) and moderate (EDSS: 4.0-6.5) disbaility. Each participant underwent posturography testing during a quiet baseline condition and a cognitive task condition (i.e. dual task). The cognitive task was a word list generation (WLG) task. Median sway velocity, root mean square displacement, and sway area were calculated for each condition. The moderate disability group had significantly worse postural control than the mild disability group. There was an increase in postural sway in the dual task condition. There were no significant task-by-group interactions on postural control. Postural control declines with disability status and is negatively affected by a concurrent cognitive task in PwMS. The dual task cost during a balance task is not different between disability levels and this conflicts with findings for the effect of dual tasking during walking in PwMS.

Mobility, balance and falls in persons with multiple sclerosis.

BACKGROUND: There is a lack of information concerning the relation between objective measures of gait and balance and fall history in persons with MS (PwMS). This investigation assessed the relation between demographic, clinical, mobility and balance metrics and falls history in persons with multiple sclerosis (MS). METHODS: 52 ambulatory persons with MS (PwMS) participated in the investigation. All persons provided demographic information including fall history over the last 12 months. Disease status was assessed with Expanded Disability Status Scale (EDSS). Walking speed, coordination, endurance and postural control were quantified with a multidimensional mobility battery. RESULTS: Over 51% of the participants fell in the previous year with 79% of these people being suffering recurrent falls. Overall, fallers were older, had a greater prevalence of assistive devices use, worse disability, decreased walking endurance, and greater postural sway velocity with eyes closed compared to non-fallers. Additionally, fallers had greater impairment in cerebellar, sensory, pyramidal, and bladder/bowel subscales of the EDSS. CONCLUSIONS: The current observations suggest that PwMS who are older, more disabled, utilize an assistive device, have decreased walking coordination and endurance and have diminished balance have fallen in the previous year. This suggests that individuals who meet these criteria need to be carefully monitored for future falls. Future research is needed to determine a prospective model of falls specific to PwMS. Additionally, the utility of interventions aimed at reducing falls and fall risk in PwMS needs to be established.