Adonis A.1, Taylor G.2
1Imperial College Healthcare NHS Trust, London, United Kingdom, 2Imperial College London, London, United Kingdom
Background: Five to ten million persons, mostly living with the tropics are infected by HTLV-11 of which 3% will develop HTLV-1-associated myelopathy (HAM) a chronic, disabling inflammation of the spinal cord. High incidence of neurological symptoms and signs has recently been reported from Brazil2. HTLV-1 infection is associated with low socio-economic status and low educational attainment. The impact of HAM on quality of life is through pain, urinary and bowel disturbances, impaired mobility and sexual function3. Measuring these to assess disease and in particular change, is essential to direct therapy and to assess efficacy. Walking, a fundamental, complex, multi-functional task is demanding of multiple body systems5. Restricted walking ability compromises activity and participation levels in people with HAM (pwHAM). Therapy aims to improve mobility but validated measures are required to assess change.
Purpose: To evaluate simple tools to assess gait in pwHAM which can be performed in the community.
Methods: To explore walking capacity in pwHAM walking endurance using the 6 minute walk (6MW), and gait speed, using the timed 10m walk (10mTW) was utilized. Prospectively documented 10mTW and 6MW distance; walking aid usage and pain scores were abstracted from clinical records. Data analysis was completed for all pwHAM walking a minimum of 10m, with a second measure 18 months later.
Results: Twenty-six pwHAM, (8♂; 18♀) met the inclusion criteria. Mean age was 58.5 years and disease duration was 10.5 years. At baseline the median time to complete 10m was 17.5 seconds, 23% completed the 6MW and the median distance was 55m. At follow up these values were 21.4 seconds, 42% and 71m respectively. Pain scores did not vary significantly and did not correlate with gait. Using each patients 10mTW velocity to predict the 6MW distance overestimated the distance walked in 6 minutes (p 0.01).Initially the 10mTW velocity, accounted for 35% of the variance of the 6MW distance (F=.59; p 0.01), improving to 63% (F=.00; p= 0.01). Using a walking aid strongly correlated with the 10mTW at both time points (rs=.78 p= 0.01; rs=.85 p= 0.01).
Conclusion(s): The 10mTW velocity usefully predicted functional domains and highlighted functional decline but underestimated the degree of disability. The 6MW, independent of the 10mTW velocity, provided a functional measure of endurance. Walking capacity in pwHAM should be measured using the 10mTW for gait speed and the 6MW for endurance. The measured differences over 18 months were sufficient to reliably detect change and therefore these assessments can be useful to detect improvement or deterioration within broader disability grades. This is particularly important in a disease where change between outcome measurement grades can take years4.
Implications: These simple outcome measures can provide a wealth of information on the functional ability of patients with a progressive neurological condition. Looking at walking capacity holistically is fundamental to capturing functional walking ability.
Funding acknowledgements: Nil
Topic: Outcome measurement
Ethics approval: This study was conducted under the auspices of Communicable Disease Group Research Tissue Bank, approved by NRES reference 09/h0606/106.
All authors, affiliations and abstracts have been published as submitted.
