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Overview of Movement and Cerebellar Disorders

By

Hector A. Gonzalez-Usigli

, MD, HE UMAE Centro Médico Nacional de Occidente

Last full review/revision May 2020| Content last modified May 2020
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Voluntary movement requires complex interaction of the corticospinal (pyramidal) tracts, basal ganglia, and cerebellum (the center for motor coordination) to ensure smooth, purposeful movement without extraneous muscular contractions.

The pyramidal tracts pass through the medullary pyramids to connect the cerebral cortex to lower motor centers of the brain stem and spinal cord.

The basal ganglia (caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra) form the extrapyramidal system. They are located deep in the forebrain and rostral midbrain. The basal ganglia direct their output mainly through the thalamus to the cerebral cortex (see figure Basal ganglia Basal ganglia Voluntary movement requires complex interaction of the corticospinal (pyramidal) tracts, basal ganglia, and cerebellum (the center for motor coordination) to ensure smooth, purposeful movement... read more ).

Most neural lesions that cause movement disorders occur in the extrapyramidal system; thus, movement disorders are sometimes called extrapyramidal disorders.

Basal ganglia

Basal ganglia

Classification of Movement and Cerebellar Disorders

Movement disorders are commonly classified as those with

  • Decreased or slow movement (hypokinetic disorders)

  • Increased movement (hyperkinetic disorders)

The classic and most common hypokinetic disorder is

Hyperkinetic disorders refer to

However, this classification does not account for overlap between categories (eg, tremors that occur in Parkinson disease).

Cerebellar disorders are sometimes considered hyperkinetic disorders.

Hyperkinetic disorders

  • Rhythmic

  • Nonrhythmic

Rhythmic disorders are primarily tremors—regular alternating or oscillatory movements, which can occur mainly at rest, while maintaining a position, and/or during attempted movement. However, in some cases, a tremor, though rhythmic, is irregular, as occurs when tremor is associated with dystonic disorders.

Nonrhythmic hyperkinetic disorders can be

  • Slow (eg, athetosis)

  • Sustained (eg, dystonias)

  • Rapid (eg, myoclonus, chorea, tics, hemiballismus)

Rapid nonrhythmic hyperkinetic disorders may be

  • Suppressible (eg, tics)

  • Nonsuppressible (eg, hemiballismus, chorea, myoclonus)

Classification of common hyperkinetic disorders

Classification of common hyperkinetic disorders
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