The Zung Self-Rating Anxiety Scale (SAS) was designed by William W. K. Zung M.D. (1929–1992) a professor of psychiatry from Duke University, to quantify a patient's level of anxiety. The SAS is a 20-item self-report assessment device built to measure anxiety levels, based on scoring in 4 groups of manifestations: cognitive, autonomic, motor and central nervous system symptoms. Wikipedia