Mate Kedar K V, Mayo Nancy E
Int J MS Care. 2020 May-Jun;22(3):143-150. doi: 10.7224/1537-2073.2019-047. Epub 2020 Jun 15.
Ecological validity is an important psychometric property when assessing function. How a person with multiple sclerosis (MS) performs in clinical settings and in natural environments can be quite different. Walking is the most frequently assessed and recommended way to maintain health in a progressive disease such as MS. The objective was to estimate the extent to which clinical tests of walking capacity differ from real-world walking performance in people with MS.
Ninety-eight women and 27 men with MS were assessed using the 6-Minute Walk Test (6MWT) and wore an accelerometer for 7 consecutive days. Mean number of steps, mean number of steps at a brisk cadence or faster, and cumulative time per week spent walking at a brisk cadence or faster were regressed on 6MWT categories using quantile (median) regression. Contiguous steps were grouped into bouts of less than 5 minutes and 5 minutes or longer, and number of bouts 5 minutes or longer was regressed on 6MWT categories using a zero-inflated Poisson model.
A total of 869 patient-days of accelerometer data were available. Mean total number of steps per day was greater for people with higher walking capacity (6MWT distance, ≥600 m). However, this group spent a small proportion of time walking at higher cadence bands. Compared with people with 6MWT distance of at least 600 m, people walking less than 500 m had approximately half the rate of walking bouts of 5 minutes or longer. Positive mood and fewer exercise barriers predicted more walking bouts of at least 5 minutes.
Study participants with MS spent a small proportion of time walking at a health-promoting intensity.
生态效度是评估功能时一项重要的心理测量属性。患有多发性硬化症（MS）的人在临床环境和自然环境中的表现可能有很大差异。步行是在诸如MS这种进行性疾病中最常被评估和推荐的保持健康的方式。目的是估计MS患者步行能力的临床测试与现实世界中步行表现的差异程度。
对98名患有MS的女性和27名患有MS的男性进行6分钟步行测试（6MWT）评估，并连续7天佩戴加速度计。使用分位数（中位数）回归，将平均步数、轻快节奏或更快节奏下的平均步数以及每周在轻快节奏或更快节奏下步行所花费的累计时间与6MWT类别进行回归分析。连续的步数被分组为少于5分钟和5分钟或更长时间的步行时段，使用零膨胀泊松模型将5分钟或更长时间的步行时段数量与6MWT类别进行回归分析。
总共获得了869个患者日的加速度计数据。步行能力较高（6MWT距离≥600米）的人每天的平均总步数更多。然而，该组在较高节奏频段步行的时间占比很小。与6MWT距离至少为600米的人相比，步行距离小于500米的人5分钟或更长时间的步行时段发生率约为其一半。积极情绪和较少的运动障碍预示着至少5分钟的步行时段更多。
患有MS的研究参与者在以促进健康的强度步行上花费的时间占比很小。
