Modified Hoehn and Yahr Scale for Parkinson's Disease

When to use

• Broad staging of Parkinson disease severity for clinical description, prognosis discussion, and research stratification.

Formula

Ordinal clinician-rated stage from 0 (no signs) to 5 (wheelchair/bedbound); half-stages (1.5, 2.5) were added to the original 1967 scale to capture intermediate axial and postural involvement.

Pearls and pitfalls

• Emphasizes postural stability and bilaterality rather than specific motor signs; complements but does not replace the UPDRS.
• Onset of postural instability (stage >=3) is a key prognostic transition point.

References

1. Hoehn MM, Yahr MD. Parkinsonism: onset, progression and mortality. Neurology. 1967;17(5):427-442.
2. Goetz CG, Poewe W, Rascol O, et al. Movement Disorder Society Task Force report on the Hoehn and Yahr staging scale: status and recommendations. Mov Disord. 2004;19(9):1020-1028.