Cerebellar Exam

 

Yesterday we learned about how to do a neurologic exam of the cerebellum. Here is a recap for those of you unable to attend:

1) The Cerebellum 

• Coordination of volitional movements: adjusting the rate, range, force and sequence
• Motor deficits from the cerebellum are ipsilateral to the lesion, while deficits to the motor cortex of the cerebral cortex are contralateral to the lesion.
• Clinical localization in the cerebellum: The cerebellum can be divided sagitally for purposes of localization of function
• Midline: concerned with posture, locomotion, position of head relative to trunk. Midline cerebellar disease presents with disorders of stance/gait, truncal postural disturbances.
• Intermediate: Paravermal region of cerebellum. Concerned with velocity, force of volitional movements.
• Lateral: Concerned with planning of volitional movements in connection with the Rolandic region of the cerebral cortex.

2) Cardinal Signs of Cerebellar Dysfunction:

• Hypotonia
• Ataxia: defective timing of contraction of antagonistic/agonistic muscles, results in a disurbance of the smooth performance of voluntary movements.
• Dysarthria
• Abnormal ocular movements
• Tremor

3) Inspection

• Level of Consciousness
• Acute cerebellar strokes can cause raised ICP that can impair LOC
• Tone:
• Hypotonia can occur with acute cerebellar infarcts

4) Gait

• Have patient walk normally, then heel to toe (tandem gait)
• Walk is wide based, staggering, lurching.
• Lesions of the lateral cerebellum result in Patients falling towards the ipsilateral side of the lesion
• Lesions of the midline result in movements in all directions.
• Ataxia secondary to vestibular disease may appear similar (patients fall towards the affected vestibular apparatus)

5) Test of Station

• Romberg Test - Not positive in cerebellar disease (positive Romberg = patient falls). With eyes open and closed patient has a sway (towards ipsilateral side of there is a lateral lesion of the cerebellum. Visual orientation does not improve the ataxia.

6) Cranial Nerves

• Test for any bulbar abnormalities which may accompany a cerebellar stroke

7) Nystagmus

• Midline lesions: Gaze evoked nystagmus, up beat, opticokinetic, rebound nystagmus. Opsoclonus - multivectorial, fast, involuntary eye movements.
• Lateral lesions: unidirectional with fast phase towards the affected side
• Non-fatiguable

8) Speech

• Scanning, staccato, explosive speech. Unable to control volume.
• Ask the patient to take a deep breath and say "ahhhh". This tests for control of the expiratory muscles and vocal cords 
• Ask the patient to say "la, la, la" and "me, me, me" to test for rapid alternating movements of the tongue and lips.
• Ask patient to say the ABC's to assess the meter and volume of speech

9) Ataxia of the extremities:

• Ask patient to extend arms out in front and observe for tremor. Sharply tap the arms proximally and observe for oscillations of the arm as they return to baseline. The affected side has more violent oscillations.
• Test for Rebound: Ask the patient to flex their arm against your resistance, place an arm on their shoulder to protect their face. Suddenly let go of the flexed arm and observe if the patient is able to arrest the rebound of the flexed arm. Patients with Cerebellar dysfunction will be unable to do this.
• Dysmetria: abnormal excursions of movement, frequently undershooting or overshooting the target
• Tested by finger to nose testing. Must extend arm completely.
• Dysdiadochokinesia: Difficulty with rapid alternating movements
• Test with hand tapping on thigh or foot tapping
• Test with alternating fingers touching the opposing thumb.

10) Reflexes:

• Test for Pendullar reflexes with excessive sway

For more information refer to: Cerebellar exam