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Rater reliability and scoring duration of the Quality Function Measure in ambulant children with hyperkinetic
Kylee Tustin1, Hortensia Gimeno1,2, Erin Morton1
1Complex Motor Disorder Service, Evelina London Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK.
Insights
The Quality Function Measure (QFM) shows excellent reliability for assessing children with hyperkinetic movement disorders (HMD). However, its extensive scoring time is a key consideration for clinical use.
Area of Science:
- Pediatric Neurology
- Movement Disorders
- Rehabilitation Medicine
Background:
- Hyperkinetic movement disorders (HMD) encompass conditions like dystonia, chorea, and tremor in children.
- Accurate and reliable assessment tools are crucial for evaluating HMD in pediatric populations.
- The Quality Function Measure (QFM) is a potential tool for assessing motor function in HMD.
Purpose of the Study:
- To evaluate the intra- and interrater reliability and scoring time of the Quality Function Measure (QFM) in children with HMD.
- To determine the measurement error associated with QFM scoring by trained raters.
Main Methods:
- Fifteen children with HMD were video-recorded performing standardized motor tasks.
- Three trained raters independently scored the QFM using these videos.
- Reliability was assessed using intraclass correlation coefficients (ICCs), Standard Error of Measurement (SEM), and Bland-Altman analysis.
Main Results:
- Excellent intra- and interrater reliability was found for the QFM (ICCs ≥0.96).
- Low measurement error was indicated by SEM and Bland-Altman analyses, with small mean differences between ratings.
- The median scoring time for the QFM was 83 minutes.
Conclusions:
- The QFM demonstrates high reliability and low measurement error, suggesting its utility in research for children with HMD.
- The significant time required for QFM scoring presents a practical challenge for routine clinical application.
- Further research is needed to assess the test-retest reliability and responsiveness of the QFM.
Aim:
To examine intra- and interrater reliability/agreement, and time taken to score, when the Quality Function Measure (QFM) is applied to children with hyperkinetic movement disorders (HMD; e.g. dystonia, chorea, athetosis, tremor, and myoclonus).
Method:
Fifteen ambulant children with HMD participated (eight males, seven females; mean age 13y 7mo, SD 3y 7mo). Three trained raters (two physiotherapists, one occupational therapist) independently scored the QFM using videos of each child performing Gross Motor Function Measure (GMFM) Stand and Walk/Run/Jump dimensions. Reliability was evaluated using intraclass correlation coefficient (ICC) model 2.1, Standard Error of Measurement (SEM), and Bland-Altman methods.
Results:
Rater reliability was excellent for all five QFM attributes: intrarater ICCs ≥0.98 (95% confidence interval [CI] 0.83-1.00), and interrater ICCs ≥0.96 (95% CI 0.91-1.00). SEM varied from 2.07% to 4.72% points for intra- and interrater scores across QFM attributes. Bland-Altman tests demonstrated close agreement between ratings, with absolute mean differences varying from 0.34% to 3.23% (intrarater) to 1.67% to 3.82% (interrater). Median scoring duration time was 83 minutes (range 56-144min, SD 16.02).
Interpretation:
Low measurement error attributable to rater effects suggests the QFM has potential as an evaluative measure in research studies involving children with HMD, though its lengthy scoring requirements are an important consideration for clinical practice. Evaluation of test-retest reliability and responsiveness is required.
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