Two very interesting articles are:
Langston JW, Neurology, 2006, "The Parkinson's Complex: Parkinsonism is just the tip of the iceberg."
Boura et al., J Motor Disorders, 2025, "Non Motor Fluctuations in Parkinson's disease: Underdiagnosted yet important."
AI Table:
Parkinson's disease has motor syptoms that respond VARIABLY to levodopa (Sinemet). There are also an important range of non-motor symptoms. See table.
Table: Parkinson’s Symptoms – Levodopa Response
| Symptom | Levodopa Response | Notes |
|---|---|---|
| Bradykinesia (slowness) | ✅ Strong improvement | One of the most responsive symptoms |
| Rigidity (stiffness) | ✅ Strong improvement | Often improves in tandem with bradykinesia |
| Resting tremor | ⚠️ Variable | Often improves, but 30–50% cases are poorly responsive |
| Postural instability | ❌ Often unresponsive | Increases fall risk; responds better to PT/exercise than meds |
| Gait freezing | ⚠️ Variable | May respond early, but often returns in later stages |
| Dyskinesia (involuntary movements) | ⚠️ Can be caused by levodopa | More common after years of treatment; a dose-related side effect |
| Alertness/fatigue fluctuations | ❌ Not reliably improved | Tied to brainstem/reticular activating system and limbic networks |
| Apathy, anhedonia | ❌ Poor response | Often requires SSRIs, dopamine agonists, or structured activity |
| REM behavior disorder (RBD) | ❌ No levodopa effect | May respond to melatonin, clonazepam, or sleep hygiene |
| Constipation, urinary hesitancy | ❌ Autonomic system issue | Related to Lewy pathology in vagal and pelvic nerves |
| Blood pressure instability | ❌ Poor response | Often needs separate autonomic management (e.g., midodrine, compression) |
