The Unified Huntington’s Disease Rating Scale for Advanced Patients (UHDRS-FAP) may better differentiate between patients with severe Huntington disease than the Unified Huntington’s Disease Rating Scale (UHDRS), according to a study published in Movement Disorders Clinical Practice.
The ceiling and floor effects of the UHDRS, the standard clinical assessment tool for Huntington disease, can interfere with the detection of changes in patients with more advanced cases. For this reason, the UHDRS-FAP was created for late-stage cases of Huntington disease. For the current cross-sectional study, researchers tested the utility of the UHDRS-FAP by examining whether it could better differentiate between patients with advanced cases of Huntington disease than the UHDRS. Forty institutionalized and day-care patients were assessed by each scale, as well as the Care Dependency Scale (CDS) and the Total Functional Capacity (TFC), to measure disease severity. Comparisons between the consecutive TFC stages were performed for all UHDRS, UHDRS-FAP, and CDS domains using Mann-Whitney U tests.
The only subscales with significantly worse TFC stage 5 scores compared with stage 4 were the motor scores of the UHDRS and UHDRS-FAP (.466 and .525, respectively), and in both TFC stage 4 and 5 the motor score range of the UHDRS-FAP was broader (17.9% vs 8.9%), the effect size r was higher, and the standard error of measurement was lower (1.89 vs 5.63) than for the UHDRS motor score. CDS scores declined significantly across all stages of TFC.
Study investigators conclude that because the UHDRS-FAP motor score can differentiate more effectively between Huntington’s disease in TFC stages 4 and 5, “this subscale can possibly improve disease monitoring and, subsequently, care in patients with advanced [Huntington disease] in long-term care facilities. Cognitive and behavioral assessments do not seem useful for differentiating between patients in late-stage [Huntington disease] (TFC stages 4–5). However, behavioral evaluation is useful for clinical care.”
Winder JY, Achterberg WP, Marinus J, Gardiner SL, Roos RAC. Assessment scales for patients with advanced Huntington’s disease: comparison of the UHDRS and UHDRS‐FAP [published online August 24, 2018]. Mov Disord Clin Pract. doi: 10.1002/mdc3.12646