The Hoehn and Yahr classification is used for the clinical division of Parkinson's disease into 6 stages and was first published in 1967[^1].
Classification
Grade | Description |
0 | No visible symptoms of Parkinson's disease. |
I | Symptoms only on one side of the body. |
II | Bilateral symptoms and no postural or gait instability. |
III | Bilateral symptoms and mild postural and gait instability. |
IV | Bilateral symptoms and moderate postural and gait instability. |
V | Bilateral symptoms and loss of walking ability. |