Linking the Pre-Assessment Information Form (PIF) to the ICF: Enhancing Standardized Functional Assessment in...

Systematic documentation of functioning in people with Parkinson's disease (pwPD) requires a standardized language to enable comparability across services and countries. The International Classification of Functioning, Disability and Health (ICF) provides this framework; however, instruments recommended by the European Physiotherapy Guideline for Parkinson's disease have not previously been linked to its categories. This study aimed to link items from the Pre-Assessment Information Form (PIF) to ICF categories using the refined linking rules.

Methodological study. Two independent evaluators with extensive knowledge of the ICF taxonomic framework applied 10 refined linking rules to 26 PIF items, working independently and blindly. Disagreements were resolved by a third evaluator with prior ICF experience. Inter-rater agreement was assessed using the Kappa coefficient (95% confidence interval).

Initial inter-rater agreement was moderate across all ICF taxonomy levels (k = 0.42-0.54; p < 0.001), decreasing as category specificity increased. Following a final consensus, 26 PIF items were linked to 25 unique ICF categories and 34 linked concepts across two components: Activities and Participation (21 categories; 84.0%) and Body Functions (4 categories; 16.0%). Within Activities and Participation, categories were predominantly distributed in the d4 Mobility domain (14 categories; 66.7%), followed by d5 Self-care (4; 19.0%), d6 Domestic Life (2; 9.5%), and d2 General Tasks and Demands (1; 4.8%). Secondary concepts were identified for seven items.

The resulting set of 25 ICF categories provides a structured description of the mobility and body function domains represented in the instrument. The application of ICF qualifiers to grade the severity of patient-reported limitations represents a potential next step, subject to implementation and validation in applied clinical settings.