Relationship between accelerometer data from extremities and the Bouchard Physical Activity Scale

In order to assess caloric expenditure by physical activity, the Bouchard scale is often used. One instance in which this information is important is to assess caloric needs in patients with ALS. We collected 24-hour data using the Bouchard physical activity scale and accelerometers in all four extremities in 59 ALS patients and 12 controls. These measurements were repeated longitudinally in the ALS patients at 4 month intervals for up to a year. One of the objectives of the study was to assess the usefulness of accelerometers to monitor progress of progressive weakness in the ALS patients. Unlike the Bouchard scale, the accelerometer is an objective measurement that provides data on count and force of movement. We will present detailed explanation of how the accelerometer data were converted into categories for the purpose of comparing them with the Bouchard scale, the data for each of the extremities, and the comparison of both physical activity measurements. Additionally, we will present details of the statistical methods used. Since accelerometers are small devices that can be easily worn, and they provide objective data on physical activity, they will be very useful in future studies. Supported by National Institute of Neurological Disorders and Stroke (NINDS) Grant RO1 NS045087.