The Digital Diary is intended to give clinicians administering ambulatory blood pressure or ecg recordings, and researchers evaluating pharmaceuticals and biologicals, a device that will improve subject compliance with study protocols, improve quality of data collected, and reduce time required to collect ant analyze data. The Digital Diary will be microcomputer controlled, having voice conversion/compression circuitry, and real-time clock/calendar, and memory for voice and database storage. The device will prompt a subject when actions are needed to be taken. Pressing the play button will give verbal and/or visual instructions. Responses will be recorded by answering questions displayed on an LCD. At the end of the study, subject data would be downloaded through the serial port to a PC for analysis. During Phase I, six prototypes will be constructed. Data will be collected to determine ease of use and efficacy as a replacement for current methods of obtaining activity and mood data. In phase II, the design will be modified to reduce the size of the unit and to incorporate improvements resulting from the phase I evaluation. Additional units will be built, and more extensive testing will be conducted.National Heart, Lung, and Blood Institute (NHLBI)