Psychometric properties of a modified self-rating version of the ADL taxonomy for people with Parkinson´s disease

Objective: To investigate the reliability and validity of a modified self-rated version of the ADL taxonomy targeting personal activities of daily living (P-ADL) for people with Parkinson’s disease (PD).

Background: People with PD develop ADL-difficulties early on. There is a need for a reliable and valid self-administered questionnaire targeting P-ADL.

Methods: A postal survey was sent to 282 non-demented persons with PD; 191 responded of whom 158 (mean±SD age 70±9 years, 41% women, duration of disease 6±5.5 years) answered all items of the following questionnaires: the P-ADL taxonomy, the Parkinson’s disease Activities of Daily Living Scale (PADLS), the Visual Analogue Scale of the EuroQoL-5-Dimensions Questionnaire (EQ-5DVAS), as well as demographic questions. The P-ADL taxonomy was analysed regarding corrected item-total correlations, reliability (Cronbach’s alpha) and floor/ceiling effects; Spearman’s rho (rs) was used to explore external validity relative to the PADLS and EQ-5D-VAS.

Results: Item-total correlations were above 0.5 and Cronbach’s alpha was 0.98. Floor effect was 15% and there was no ceiling effect. The P-ADL taxonomy correlated 0.75 with the PADLS and -0.63 with the EQ-5D VAS.

Conclusions: In this PD sample, the modified and selfadministered version of the P-ADL taxonomy showed satisfying reliability and validity; these findings suggest a promising potential for use in clinical practice and research.