Inter-rater and intra-rater agreement on the Nordic Orofacial Test—Screening examination in children, adolescents and young adults with cerebral palsy

Abstract

Objective. To evaluate inter-rater and intra-rater agreement on the Nordic Orofacial Test–Screening (NOT-S) examination applied to children, adolescents and young adults with cerebral palsy (CP). Materials and methods. Using the NOT-S examination, two speech and language pathologists independently assessed video recordings of 48 subjects with CP aged 5–22 years and representing all CP sub-diagnoses and levels of gross motor function and manual ability. Thirty-one subjects were reassessed. Fifteen out of 17 items in the NOT-S examination domains (1) Face at rest, (2) Nose breathing, (3) Facial expression, (4) Masticatory muscle and jaw function, (5) Oral motor function and (6) Speech were rated using a ‘yes’ (dysfunction observed)/‘no’ format, generating an overall score of 0–6. Results. Inter-rater agreement: Twelve out of 15 items and five out of six domains showed acceptable unweighted kappa values (κ = 0.46–1.00). The lowest kappa value was found for domain 4 (κ = −0.04), although it had high inter-rater agreement (92%). The linear weighted kappa value for the overall NOT-S examination score was 0.65 (95% CI = 0.49–0.82). Intra-rater agreement: All items and domains showed acceptable unweighted kappa values (items 0.58–1.00 and 0.59–1.00, domains 0.81–1.00 and 0.62–0.89) for both raters. The linear weighted kappa value for the overall NOT-S examination score was 0.81 (95% CI = 0.63–0.99) for rater A and 0.54 (95% CI = 0.25–0.82) for rater B. Conclusions. The NOT-S examination has acceptable inter-rater and intra-rater agreement when used in young individuals with CP.