Expansion
Bradykinesia plus rigidity, tremor or postural instability
Expansion
TRAP:
- T - Tremor: 4 to 6 Hz, at rest, asymmetrical, pill rolling, improved by action, worsened by distraction such as counting backwards
- R - Rigidity: lead pipe, becoming cogwheel when tremor is superimposed. Enhanced by asking the other arm to draw circles
- A - Akinesia or bradykinesia: progressive reduction in amplitude and speed on repetitive finger tapping, hand opening and foot tapping. This decrement is the defining feature
- P - Postural instability: a late feature, tested by the pull test
Supporting findings: hypomimia, hypophonia, micrographia, reduced blink rate, reduced arm swing, a stooped festinant gait with difficulty turning, glabellar tap, and a positive response to levodopa.
Red flags suggesting a Parkinson plus syndrome or another cause
| Feature | Suggests |
|---|---|
| Symmetrical onset, early falls, vertical gaze palsy | Progressive supranuclear palsy |
| Early autonomic failure, cerebellar signs, stridor | Multiple system atrophy |
| Early dementia and visual hallucinations | Lewy body dementia |
| Alien limb, apraxia, marked asymmetry | Corticobasal degeneration |
| Drug history of antipsychotics or metoclopramide | Drug induced parkinsonism |
| Stepwise, lower body predominant, vascular risk factors | Vascular parkinsonism |
| Poor or absent response to levodopa | Any of the above |
Distinguishing tremors: Parkinson’s tremor is at rest and asymmetrical; essential tremor is postural and action related, symmetrical, faster, improved by alcohol and often familial; cerebellar tremor is intention tremor, worsening towards the target.