Movement Disorders and Extrapyramidal Syndromes
Basal Ganglia Circuitry
Why circuits matter
Movement disorders reflect dysfunction in basal ganglia-thalamocortical loops, which help select desired actions and suppress unwanted ones.
Core syndromes
Common movement disorders
Parkinsonism
- Bradykinesia plus rigidity and resting tremor
- Often due to nigrostriatal dopamine deficiency
Essential tremor
- Action/postural tremor
- Often affects hands and improves with alcohol
The cardinal motor feature of parkinsonism is:
Bradykinesia is the essential feature of parkinsonism.
Correct answer: Bradykinesia
Which neurotransmitter deficiency is central to Parkinson disease?
Loss of dopaminergic neurons in the substantia nigra pars compacta reduces striatal dopamine.
Correct answer: dopamine
Tremor and Hyperkinetic Disorders
Tremor clues
| Tremor type | Typical clue |
|---|---|
| Resting tremor | Appears when limb is relaxed; common in parkinsonism |
| Action tremor | Worsens with movement; common in essential tremor |
| Intention tremor | Worsens near target; suggests cerebellar disease |
| Physiologic/enhanced | Exacerbated by anxiety, caffeine, or medications |
Intention tremor most strongly points to dysfunction of the:
Intention tremor is a cerebellar sign.
Correct answer: Cerebellum
What is chorea?
Chorea consists of unpredictable, flowing, non-rhythmic movements.
Correct answer: brief irregular involuntary movements
Localization tip
A patient with slowness and rigidity but no weakness may have extrapyramidal disease rather than corticospinal tract disease.
Which disorder is most associated with chorea plus psychiatric and cognitive decline?
Huntington disease classically causes chorea, cognitive decline, and psychiatric symptoms.
Correct answer: Huntington disease
Name one common clinical feature of dystonia.
Dystonia causes twisting postures or patterned repetitive movements.
Correct answer: abnormal sustained posturing