Key points are not available for this paper at this time.
Rotman Research Institute at the Baycrest Centre for Geriatric Care and Departments of Medicine and Psychology, University of Toronto, North York, Ontario, Canada Address for correspondence: Dr. T. W. Picton, Rotman Research Institute at Baycrest Centre, 3560 Bathurst Street, North York, M6A 2E1, Ontario, Canada.
Terence W. Picton (Wed,) studied this question.