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The Val30Met familial amyloid polyneuropathy specific Rasch‐built overall disability scale ( FAP‐RODS © )
Author(s) -
Pruppers Mariëlle H. J.,
Merkies Ingemar S. J.,
Faber Catharina G.,
Da Silva Ana M.,
Costa Vanessa,
Coelho Teresa
Publication year - 2015
Publication title -
journal of the peripheral nervous system
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 67
eISSN - 1529-8027
pISSN - 1085-9489
DOI - 10.1111/jns.12120
Subject(s) - rasch model , medicine , scale (ratio) , reliability (semiconductor) , clinical trial , physical therapy , psychology , developmental psychology , power (physics) , physics , quantum mechanics
Familial amyloid polyneuropathy ( FAP ) is a chronic debilitating multi‐organic disorder, mainly assessed using ordinal‐based impairment measures. To date, no outcome measure at the activity and participation level has been constructed in FAP . The current study aimed to design an interval activity/participation scale for FAP through Rasch methodology. A preliminary FAP Rasch‐built overall disability scale (pre‐ FAP‐RODS ) containing 146 activity/participation items was assessed twice (interval: 2–4 week; test‐retest reliability) in 248 patients with Val30Met FAP examined in Porto, Portugal, of which 65.7% have received liver transplantation. An ordinal‐based 24‐item FAP ‐symptoms inventory questionnaire ( FAP‐SIQ ) was also assessed (validity purposes). The pre‐ FAP‐RODS and FAP‐SIQ data were subjected to Rasch analyses. The pre‐ FAP‐RODS did not meet model's expectations. On the basis of requirements such as misfit statistics, differential item functioning, and local dependency, items were systematically removed until a final 34‐item FAP‐RODS © was constructed fulfilling all Rasch requirements. Acceptable reliability/validity scores were demonstrated. In conclusion, the 34‐item FAP‐RODS © is a disease‐specific interval measure suitable for detecting activity and participation restrictions in patients with FAP . The use of the FAP‐RODS © is recommended for future international clinical trials in patients with Val30Met FAP determining its responsiveness and its cross‐cultural validation. Its expansion to other forms of FAP should also be focus of future clinical studies.