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Movement disorders represent a group of neurologic disorders where there is either “too much” movement or hyperkinesias, or “too little” movement or hypokinesias. Some movement disorders combine features of both, such as parkinsonism where there is tremor (a hyperkinetic phenomenon) and rigidity or bradykinesia (both hypokinetic phenomena). While a significant proportion of movement disorders are “extrapyramidal” or resulting from basal ganglia dysfunction, a number of other movement disorders can involve any portion of the neuraxis from the cerebrum to the peripheral nerves. Therefore, movement disorders should no longer be considered synonymous to extrapyramidal or basal ganglia disorders.

The most important step in the diagnosis of these disorders is the recognition and classification of the abnormal movement (see Table 34-1). The most common hypokinetic phenomenology is parkinsonism, whereas among the hyperkinetic disorders, the most common ones are tremors, dystonias, choreas, tics, restless legs, and myoclonus.

Table 34-1.

Classification of Movement Disorders


CASE 34-1

You receive a neurology consult regarding a 60-year-old man who just had a right hip replacement but is not recovering as expected. He has noted having great difficulty ambulating and not moving his right arm well. Your colleague in Orthopedics thinks he has had “a minor stroke.” He was in good health preopearatively with all his gait difficulties attributed to his bad right hip. His wife mentions to you that he had been complaining of pain in the right shoulder in the preceeding 8 months, and had difficulties raising the arm above his head. However, repeated x-rays had not revealed any abnormalities. You also notice an intermittent rest tremor in both hands, more prominent on the right.

How do you define parkinsonism?

  • Parkinsonism is a clinical syndrome defined by the presence of bradykinesia and one or more of the following motor features: rest tremor, rigidity, and postural instability (that is not caused by other identifiable etiologies such as neuropathy, vestibulopathy, etc).

  • The major differential diagnoses of parkinsonism include primary or idiopathic parkinsonism (such as Parkinson disease), “atypical” or Parkinson-plus syndromes, vascular parkinsonism, and drug-induced parkinsonism.

What is Parkinson disease?

  • Parkinson disease (PD) is a neurodegenerative disorder characterized by the gradual and progressive onset of parkinsonism pathologically characterized by degeneration of pigmented brainstem nuclei (specifically, the pars compacta of the substantia nigra) presence of intraneuronal alpha synuclein-positive Lewy bodies in the remaining nerve cells.1

  • PD is the second most common neurodegenerative disease after Alzheimer disease (AD) with a prevalence of 1–2 % for people 65 ...

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