Development and Validation of a Clinical Scale for Rating the Severity of Blepharospasm

• Type of Material: Article
• Authors: Giovanni Defazio, "Aldo Moro" University of Bari; Mark Hallett, National Institute of Neurological Disorders and Stroke; Hyder Jinnah, Emory University; Glenn T. Stebbins, Rush University; Angelo F. Gigante, "Aldo Moro" University of Bari; Gina Ferrazzano, Sapienza University of Rome; Antonella Conte, Sapienza University of Rome; Giovanni Fabbrini, Sapienza University of Rome; Alfredo Berardelli, Sapienza University of Rome
• Language: English
• Date: 2015-04-01
• Publisher: Wiley
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2015 International Parkinson and Movement Disorder Society.
• Final Published Version (URL): http://dx.doi.org/10.1002/mds.26156
• Title of Journal or Parent Work: Movement Disorders
• ISSN: 0885-3185
• Volume: 30
• Issue: 4
• Start Page: 525
• End Page: 530
• Grant/Funding Information: This study was funded by the Benign Essential Blepharospasm Research Foundation and a Pilot Project Grant from the Dystonia Coalition (NS065701 from the Office of Rare Diseases Research and the National Institute of Neurological Disorders and Stroke).
• Keywords: Neurosciences & Neurology; Blepharospasm; Blinking; Dystonia; Science & Technology; Life Sciences & Biomedicine; severity; Clinical Neurology; rating scale
• Research Categories: Biology, Neuroscience; Health Sciences, General

Abstract

Existing scales for rating the severity of blepharospasm (BSP) are limited by a number of potential drawbacks. We therefore developed and validated a novel scale for rating the severity of BSP. The development of the scale started with careful examination of the clinical spectrum of the condition by a panel of experts who selected phenomenological aspects thought to be relevant to disease severity. Thereafter, selected items were first checked for reliability, then reliable items were combined to generate the scale, and clinimetric properties of the scale were evaluated. Finally, the confidence with which the scale could be used by people without high levels of movement disorders skill was assessed. The new scale, based on objective criteria, yielded moderate to almost perfect reliability, acceptable internal consistency, satisfactory scaling assumptions, lack of floor and ceiling effects, partial correlations with a prior severity scale and with a quality of life scale, and good sensitivity to change. Despite a few limitations, the foregoing features make the novel scale more suitable than existing scales to assess the severity of BSP in natural history and pathophysiologic studies as well as in clinical trials.