Definition of clinical features
| Clinical feature | Definition |
|---|---|
| Non-motor symptoms | |
| Dementia | DSM-IV-TR criteria17 |
| Psychosis | UPDRS-Part I, item 2 score ≥2 or the use of specific medications* |
| Depression and apathy | UPDRS-Part I, sum of item 3+item 4≥4 or the use of specific medications |
| Orthostatic hypotension | Clinical assessment† or the use of specific medications |
| Non-levodopa-responsive motor symptoms | |
| Dysphagia | UPDRS-Part II (in “ON” condition), item 7 score ≥2 |
| Frequent falls | UPDRS-Part II (in “ON” condition), item 13 score ≥2 |
| Freezing of gait | UPDRS-Part II (in “ON” condition), item 14 score ≥2 |
| Speech difficulties | UPDRS-Part III (in “ON” condition), item 18 score ≥2 |
| Gait disturbances | UPDRS-Part III (in “ON” condition), item 29 score ≥2 |
| Postural instability | UPDRS-Part III (in “ON” condition), item 30 score ≥2 |
| Motor complications | |
| Dyskinesias | UPDRS-Part IV, sum of items 32–35‡ |
| OFF state | UPDRS-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.