Clinical signs of cerebellar lesions

1. Big picture

The cerebellum does not primarily produce movement and does not cause true paralysis when damaged. Its job is to make movement accurate, coordinated, smooth, timed, and balanced. Therefore, cerebellar lesions cause ataxia, meaning disordered coordination.

For the exam, the most important points are:

The cerebellum controls the ipsilateral side of the body, so a right cerebellar hemisphere lesion causes right-sided limb ataxia.

Cerebellar lesions cause:

• Limb ataxia

• Gait and truncal ataxia

• Dysmetria

• Intention tremor

• Dysdiadochokinesis

• Hypotonia

• Nystagmus

• Scanning dysarthria

• Rebound phenomenon

• Wide-based, unsteady gait

The examiner usually wants you to recognize the clinical pattern, localize the lesion to the cerebellum, distinguish it from sensory ataxia and vestibular ataxia, and know which bedside tests demonstrate cerebellar dysfunction.