THE DIFFERENCE BETWEEN ACTIVITY WHEN IN BED AND OUT OF BED .1. HEALTHY-SUBJECTS AND SELECTED PATIENTS

The activity records of five groups of healthy or ill subjects have be en measured for 4-26 days by an accelerometer placed on the nondominan t wrist. These data, together with a record of times retiring to/risin g from bed, have been used to produce a series of dichotomy indices fo r comparing the amounts of activity when in bed and out of bed. Reliab le differences between individuals were found, with healthy subjects s howing a greater degree of dichotomy than one subject with delayed sle ep phase syndrome or three subjects with colorectal cancer. The method is convenient for extended data collection and offers the possibility of describing an individual's activity profile in a variety of circum stances.