Parkinson’s Disease: Hoehn and Yahr Scale

The Hoehn and Yahr scale (HY) is a widely used clinical rating scale, which defines broad categories of motor function in Parkinson’s disease (PD). Among its advantages are that it is simple and easily applied. It captures typical patterns of progressive motor impairment which can be applied whether or not patients are receiving dopaminergic therapy. Progression in HY stages has been found to correlate with motor decline, deterioration in quality of life, and neuroimaging studies of dopaminergic loss. However, because of its simplicity and lack of detail, the scale is not comprehensive. It is also limited by its focus on issues of unilateral versus bilateral disease and the presence or absence of postural reflex impairment, thereby leaving other specific aspects of motor deficit unassessed.KeywordsYahr ScaleImpaired Postural ReflexesMotor DeclineDopaminergic LossClinical Rating ScalesThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.