WOQ-9 (published in 2006) and WOQ-19 (published in 2007) were derived from WOQ-32, developed in 2005 as a prototype tool.
WOQ-9 was preferred for its shorter length.
Stacy M; Hauser R; Oertel W; Schapira A; Sethi K; Stocchi F; Tolosa E
Stacy M, Hauser R, Oertel W, Schapira A, Sethi K, Stocchi F, Tolosa E. End-of-dose wearing off in Parkinson disease: a 9-question survey assessment. Clin Neuropharmacol. 2006 Nov-Dec;29(6):312-21 (PubMed abstract)
Stacy M, Hauser R. Development of a Patient Questionnaire to facilitate recognition of motor and non-motor wearing-off in Parkinson's disease. J Neural Transm (Vienna). 2007 Feb;114(2):211-7 (PubMed abstract)
Stacy MA, Murphy JM, Greeley DR, Stewart RM, Murck H, Meng X; COMPASS-I Study Investigators. The sensitivity and specificity of the 9-item Wearing-off Questionnaire. Parkinsonism Relat Disord. 2008;14(3):205-12 (PubMed abstract)