Hoehn and Yahr scale

The Hoehn and Yahr scale is a commonly used system for describing how the symptoms of Parkinson's disease progress. It was originally published in 1967 in the journal Neurology by Melvin Yahr and Margaret Hoehn. The original scale included stages 1 through 5. Since then, stage 0 has been added, and stages 1.5 and 2.5 have been proposed. This modified scale allocates stages from 0 to 5 to indicate the relative level of disability.

• Stage 0: No signs of disease.
• Stage 1: Unilateral symptoms only.
• Stage 1.5: Unilateral and axial involvement.
• Stage 2: Bilateral symptoms. No impairment of balance.
• Stage 2.5: Mild bilateral disease with recovery on pull test.
• Stage 3: Balance impairment. Mild to moderate disease. Physically independent.
• Stage 4: Severe disability, but still able to walk or stand unassisted.
• Stage 5: Needing a wheelchair or bedridden unless assisted.

References

• Hoehn M, Yahr M (1967). "Parkinsonism: onset, progression and mortality.". Neurology 17 (5): 427–42. PMID 6067254. 

• Goetz CG, Poewe W, Rascol O, Sampaio C, Stebbins GT, Counsell C, Giladi N, Holloway RG, Moore CG, Wenning GK, Yahr MD, Seidl L (2004). "Movement Disorder Society Task Force Report on the Hoehn and Yahr Staging Scale: Status and Recommendations. The Movement Disorder Society Task Force on Rating Scales for Parkinson’s Disease.". Movement Disorders 19 (9): 1020–1028. doi:10.1002/mds.20213. PMID 15372591.