Measurement Properties of the Brazilian Portuguese Version of the PDAQ-15

BackgroundThe Penn Parkinson's Daily Activities Questionnaire (PDAQ-15) assesses the difficulty in performing cognitive instrumental activities of daily living (IADL) in people with Parkinson's disease (PD).ObjectivesTo translate, cross-culturally adapt and investigate measurement properties of the Brazilian version of the PDAQ-15 Knowledgeable Informant (KI) and Patient (PT).MethodsFollowing the translation, cross-cultural adaptation, face and content validity analyses; floor and ceiling effects, reliability (test-retest, inter-rater, internal consistency) and validity (convergent, divergent, discriminant) were evaluated in 50 persons with PD and their KI. The KI and Patient PDAQ-15 were rater-administered.ResultsThe translated and adapted KI and PT PDAQ-15 did not show floor or ceiling effects. They had appropriate internal consistency (PT = 0.825; KI = 0.923), excellent test-retest (PT = 0.97; KI = 0.99) and interrater reliability (PT = 0.92; KI = 0.99). PT and KI agreement was moderate, ICC = 0.58. The correlations with the Scales for Outcomes of Parkinson's disease - Cognition were: PT (rho = 0.50), KI (rho = 0.67); with the Direct Assessment of Functional Status: PT (rho = 0.66), KI (rho = 0.80); with Unified Parkinson's Disease Rating Scale (UPDRS) Part II: PT (rho = -0.29), KI (rho = -0.30), all P < 0.05; and with UPDRS part III: PT (rho = -0.27), KI (rho = -0.27), P > 0.05. PT and KI PDAQ-15 discriminated between the mild and moderate/severe stages of the Hoehn & Yahr Scale (P = 0.03).ConclusionThe two Brazilian versions of the PDAQ-15 have acceptable measurement properties for assessing the cognitive IADL of persons with PD. For those with suspected or diagnosed cognitive impairment, the application of both versions is suggested.