How to identify tremor dominant and postural instability/gait difficulty groups with the movement disorder society unified Parkinson's disease rating scale: comparison with the unified Parkinson's disease rating scale

Mov Disord. 2013 May;28(5):668-70. doi: 10.1002/mds.25383. Epub 2013 Feb 13.


Background: Formulas were developed to define tremor dominant (TD) and postural instability/gait difficulty (PIGD) phenotypes of Parkinson's Disease (PD) using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). TD and PIGD designations, based on the original Unified Parkinson's Disease Rating Scale (UPDRS), provided useful designations for classifying different phenotypes of PD. With the advent of the MDS-UPDRS, a valid set of calculations for these phenotypes is needed.

Methods: UPDRS and MDS-UPDRS scores were collected on 877 PD patients. TD/PIGD scores were calculated using the UPDRS formula for all patients. Comparable TD and PIGD items from the MDS-UPDRS were used to calculate new ratios. Data were analyzed using receiver operating characteristic models.

Results: The new MDS-UPDRS TD/PIGD ratios accounted for a significant area under the curve compared with the UPDRS classification. Optimal sensitivity and specificity were obtained with MDS-UPDRS cutoff scores of ≥1.15 for TD classification and ≤0.90 for PIGD.

Conclusions: The development of comparable and valid PIGD and TD scores from the MDS-UPDRS provides a clear method for clinicians and researchers to transition from the original UPDRS to the new MDS-UPDRS in categorizing patients with different clinical phenotypes. © 2013 Movement Disorder Society.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Disability Evaluation
  • Female
  • Gait Disorders, Neurologic / diagnosis*
  • Gait Disorders, Neurologic / etiology*
  • Humans
  • Male
  • Neurologic Examination
  • Parkinson Disease / complications*
  • Postural Balance / physiology*
  • ROC Curve
  • Sensation Disorders / diagnosis*
  • Sensation Disorders / etiology*
  • Severity of Illness Index
  • Tremor