Fig. 1.

Seven-day continuous activity recordings and average 24-h waveforms of 5 representative individuals: a young adult, an elderly control, an elderly with early-stage AD, a very old control, and a very old late-stage AD patient. (Left) Shown are the individuals' continuous activity recordings. (Right) Shown are the same individuals' activity recordings averaged over 24 h. The individual data and average waveform of activity is expressed in arbitrary units. Black bars indicate the individual sleep episodes.