Measuring symptoms and wellness in the multiple sclerosis patient: issues in measurement

Abstract

Appropriate measurement of any state of health or disease depends on several factors. First and foremost is the scientific question to be answered, which can range from basic science to clinical processes to societal impact. Questions primarily address either the current state of the patient or are designed to measure change over time. Although it is sometimes possible to accomplish both objectives with one set of questions, this can be difficult and may not be appropriate. Questions must be designed appropriately to ensure reliability of the answer, validity of the concept being measured and the sensitivity or responsiveness of the measure to change. It is also becoming standard to evaluate all parameters for the clinical (or scientific) relevance of the measured value or change in value over time. The design of a measurement tool must consider the type of data to be collected, the difficulties in collecting complete data and the plan for data analysis. Ever-increasing computing power has provided novel approaches to analysis allowing for a broader range of measurement instruments. This review examines some important basic principles of measurement and considers issues as they apply to examples of measures used for patients with multisymptomatic illnesses such as multiple sclerosis, with a particular focus on application of the spasticity 0–10 Numerical Rating Scale and its correlation with the Patient Global Impression of Change scale.

Keywords::

• measuring scales
• multiple sclerosis
• Numerical Rating Scale
• Patient Global Impression of Change scale
• quality of life
• spasticity

Financial & competing interests disclosure

JT Farrar has received grant support for his research from Altarum Institute, Cephalon, Depomed Inc, GW Pharma and Pfizer. He has received honorarium for consulting on clinical trial research design issues from Bayer, Bristol-Myers Squibb, Janssen, Merck, Prolong Pharmaceuticals and Teva Pharmaceuticals. He has received an honorarium from Laboratorios Almirall, S.A. (Barcelona, Spain) for participating in the symposium and producing this supplement article based on his presentation. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Initial transcription of Farrar’s presentation and writing assistance was provided by Content Ed Net with funding from Laboratorios Almirall, S.A. The ideas and opinions expressed in this article are Farrar’s alone and do not necessarily reflect those of Almirall, Content Ed Net or any other organization.