P88 Intra and inter-rater reliability of the MFM32 in myotonic dystrophy type 1.

Myotonic dystrophy type 1 (DM1) is an autosomal dominant neuromuscular disease. The disease is slowly progressive, and motor signs include muscle weakness and myotonia. Early motor signs are handgrip myotonia and distal weakness, and weakness of neck and abdominal flexors. Monitoring of motor function is important to track disease progression and to assess effects of prescribed exercise or medical treatment. The 32-item Motor Function Measure (MFM32) is a tool to assess motor function, developed for patients with neuromuscular disorders. MFM32 is validated in people between 6 and 60, and a range of different neuromuscular disorders including DM1. MFM32 consists of 32 items, scored on a scale from 0: Cannot perform the task to 3: Performs the task fully and normally. The items are classified in 3 domains: D1; Standing and transfers. D2; Axial and proximal motor function and D3; Distal motor function. Item scores in each domain are added up. The sum is divided by the maximum score of the domain and multiplied by 100 to give a percentage score. The sum of the 3 domains divided by 96 and multiplied by 100 constitutes the total percentage score. In this study, we use data from a large cross-sectional study "Symptoms and outcome measures for upper limb function in myotonic dystrophy type 1" (the SOUL-DM1 study) to assess the intra- and inter-rater reliability of MFM32 in DM1. A total of 60 participants will be recruited to perform MFM32, and recruitment is ongoing. Performance is recorded on video and stored on a platform for secure data at the University of Oslo. Intra- and inter-rater reliability of the MFM32 is conducted by two assessors. Both are certified as MFM raters and are specialized physiotherapists with knowledge and experience in neuromuscular disorders. Test of participants, video filming and initial scoring (S1) is conducted by assessor 1. Subsequently assessor 1 performs two scorings, around 3 (S2) and 6 (S3) months post S1. Assessor 2 does a scoring of the MFM32 (A1) at the same time as assessor 1 does S2. All assessor scoring is based on the recorded videos of the participants performing the MFM32 except for S1 which is done live during the performance. Preliminary results based on the first 30 participants' total percentage score show excellent ICC2,1 values of both intra- and inter-rater reliability. ICC with 95% confident intervals were calculated using SPSS statistical package version 29 (SPSS Inc, Chicago, IL) based on a single-rating, absolute-agreement, 2-way random-effects model. Intra-rater reliability based on physical scoring (S1) and digital scoring at three months (S2) show excellent reliability with an ICC of 0,994 (0,988-0,997). Intra-rater reliability at three months (S2) and six months (S3) show excellent reliability with an ICC of 0,999 (0,997-1). Inter-rater reliability between assessor 1 (S2) and assessor 2 (A1) show excellent reliability with an ICC of 0,998 (0,998-1). [ABSTRACT FROM AUTHOR]