Validity and Responsiveness of VELO: A VPI QoL Instrument

Abstract

Objective: In a study of patients with velopharyngeal insufficiency (VPI) diagnosed by pediatric speech pathologists, test the VPI Effects on Life Outcomes (VELO) instrument for criterion validity, construct validity, reliability, and responsiveness (ability to detect change in quality of life). Method: VPI subjects/parents completed the VELO at baseline, 2 weeks later, and 3 months posttreatment. Criterion-validity tested correlation between VELO score and VPI severity; construct-validity tested correlation with speech intelligibility. Test-retest reliability tested intraclass-correlation between baseline VELO score and 2-week score. Responsiveness tested mean baseline and posttreatment scores with the paired t test. Results: Parental responses are reported (n = 83); youth responses (obtained in 8+ year-olds only; n = 24) showed similar results. VPI severity (minimal n = 11, mild n = 31, moderate n = 27, severe n = 14) and speech intelligibility were rated by pediatric speech pathologists. The VELO instrument did not meet criterion validity (Spearman r = −0.21, P = .07) but did meet construct validity (Spearman r = −0.36, P = .001). VELO scores demonstrated excellent test-retest reliability ( r = 0.85, P < .001, n = 40). Treatments included Furlow palatoplasty (n = 20), sphincter pharyngoplasty (n = 14), or an obturator (n = 2) with n = 28 (78%) completing the VELO posttreatment. The VELO showed responsiveness to treatment improving from baseline 54 ± 15 to posttreatment 70 ± 18 ( P < .001). Conclusion: VELO provides a VPI specific quality of life instrument that demonstrates construct validity, test-retest reliability, and responsiveness to change in quality of life with treatment.