Circadian Performance Simulation Software (CPSS) 2.0

The Circadian Performance Simulation Software (CPSS) is designed to predict the effects of sleep/wake schedules and light exposure on the human circadian pacemaker, and the combined effects of circadian phase and homeostatic sleep pressure on cognitive performance and subjective alertness. While the interface is substantially different from previous versions of CPSS, the mathematical model used to generate predictions is identical to that used in CPSS 1.21. As in previous versions of CPSS, alertness and performance predictions are derived from laboratory studies. These outputs represent self-reported alertness and score on a standard task, respectively.

CPSS 2.0 offers an enhanced interface for entering sleep/wake times and light intensities to define a schedule, and for obtaining simulation results both graphically and numerically.

CPSS Screenshot

Screenshot of CPSS 2.0

New features in CPSS 2.0
Raster plot shows a schedule as the user is entering it, and displays simulation results
Input table allows modification of existing events and schedules
Simulates both cognitive performance and subjective alertness
Allows opening of multiple schedules for side by side comparison
Displays summary statistics for user defined portions of the schedule

CPSS 2.0 is designed for greater ease of use in evaluating both experimental and operational schedules. In addition, it provides the ability to quickly compare different variations of a schedule. It can also be useful in validating changes to the circadian model, and as an educational tool.

Please contact us at to inquire about using the new version.
To obtain a download of CPSS 1.2, click here.


Copyright © [2008] The Brigham and Women's Hospital, Inc.
The Brigham and Women's Hospital, Inc. and its agents retain all rights to this software. The software is being made available without warranty of any kind, expressed or implied, including but not limited to implied warranties of merchantability OR fitness for a particular purpose. The Brigham and Women's Hospital, Inc. and its agents shall not be liable for any claims, liabilities, or losses relating to or arising from any use of this software.

Contact Information
For any questions or issues regarding the CPSS software, please contact us at

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