Physical Activity in the Elderly Spine Patient

Background Spine disorders, such as low back pain, come with considerable physical limitations, and participation in social events and everyday life can be burdensome2. Efforts to increase physical ability and involvement in everyday life are essential to maintain or heighten quality of life in spite of chronic pain.

Some spine disorders can negatively affect lumbar nerve roots, where the symptoms radiate to the legs. Lumbar Spinal Stenosis (LSS) is one of many chronic spinal pain syndromes, with specific structural abnormalities that can be detected on MRI scans, including narrowing of the spinal canal. Its clinical presentation involves radiation of pain and sensory disturbance to buttocks and legs while walking3. Although there is considerable variation in the diagnostic criteria used, spinal stenosis is common in the elderly, and a recent review reported prevalences between 11% and 38% depending on criteria and study population4. The disease considerably constrains patients' walking ability, which means that patients experience problems with exercise and leisure activities5. Physical activity is significantly reduced, and a recent study shows that individuals with LSS spend 82% of their day sitting or lying down, compared to 35% in healthy adults over 60 years6, leading to an increase in lifestyle diseases such as hypertension7.

Thus, the aging patient with a spine disorder such as LSS or low back pain has to cope with the functional limitations of their disease, as well as the natural decline of function with age1. It is therefore very important for this group of patients that healthcare providers can support their pursuit of an active life. In order to do so, it is necessary for healthcare providers to have reliable knowledge about the individual patients' physical activity and functional impairment in daily life. Such information is typically collected through interviews, physical exams, questionnaires, and the occasional objective test, which only provide indirect, predominantly subjective, information about physical activity in everyday life.

Emerging technology in the form of wearable sensors is breaking new ground and becoming more widespread. Existing research has used sensors such as accelerometers to quantify and differentiate time spent standing, walking, cycling, and sitting or lying down, with high accuracy8. Previous studies have already established that accelerometer-based step counts in elderly people are accurate9-13, but they are influenced by 1) the physical location of the accelerometer on the body14, 15, 2) the method used to transform raw accelerometer data16, and 3) traits of the person wearing it, such as gait speed, use of assistive devices, and age17. As LSS can alter gait characteristics18 and can give severe walking impairment, accelerometer measures of step count developed for healthy adults could be inaccurate in these patients. Since walking impairment is the most prominent disability in LSS, we see the need for a tested and valid measure of walking activity in daily living.

The study consists of two parts, each with a corresponding aim: Part I) develop and examine the validity of an accelerometer-based method of measuring walking activity in daily living in patients with LSS. Part II) uncover objectively identifiable profiles of physical activity in elderly patients with LSS and/or low back pain.