Table 1

Definition of clinical features

Clinical featureDefinition
Non-motor symptoms
 DementiaDSM-IV-TR criteria17
 PsychosisUPDRS-Part I, item 2 score ≥2 or the use of specific medications*
 Depression and apathyUPDRS-Part I, sum of item 3+item 4≥4 or the use of specific medications
 Orthostatic hypotensionClinical assessment† or the use of specific medications
Non-levodopa-responsive motor symptoms
 DysphagiaUPDRS-Part II (in “ON” condition), item 7 score ≥2
 Frequent fallsUPDRS-Part II (in “ON” condition), item 13 score ≥2
 Freezing of gaitUPDRS-Part II (in “ON” condition), item 14 score ≥2
 Speech difficultiesUPDRS-Part III (in “ON” condition), item 18 score ≥2
 Gait disturbancesUPDRS-Part III (in “ON” condition), item 29 score ≥2
 Postural instabilityUPDRS-Part III (in “ON” condition), item 30 score ≥2
Motor complications
 DyskinesiasUPDRS-Part IV, sum of items 32–35‡
 OFF stateUPDRS-Part IV, sum of items 36–39
  • *Defined as hallucinations and/or delusions, but not confusion.

  • †Defined as fall in systolic blood pressure of at least 20 mm Hg and diastolic blood pressure of at least 10 mm Hg within 3 min of standing.18

  • ‡Defined as abnormal involuntary movements, including chorea and dystonia, that could be peak dose or diphasic; off-related dystonia was not included.

  • DSM-IV-TR, Diagnostic and Statistical Manual, Fourth Edition, Text Revision; UPDRS, Unified Parkinson Disease Rating Scale.