[Rating scales and questionnaires in Parkinson's disease]

Rating scales and questionnaires used as measurement tools in Parkinson's disease are carefully constructed with well-defined items. The validity of a scale is its capacity to provide the intended measurement. One can distinguish perceived, content, and criteria-based validity as well as construction and sensitivity to change validity. The reliability of a scale is the capacity of a scale to produce statistically equivalent data in comparable situations. Reliability is composed of the following qualities: interobserver reliability, test-retest reliability, and internal coherence. UPDRES, mood scales (Hamilton, MADRS, CES-D, BDI), scales assessing cognitive disorders (MATTIS, MMSE), and quality of life questionnaires designed specifically for Parkinson's disease (PDQL, PDA-39, PDq-8) or for the general population (SF-36, SIP, NHP) are used in routine practice, and are particularly useful for clinical research. The metrological properties of these scales are analyzed here.