OTM 507 Cerebellum Week 6

Cerebellum ("little brain")

Coordinates movement: adjusts intended movements with actual movements

- maintains postural control and muscle tension

- controls timing and rhythm of movements, learning?

- synchronization of movements

- use sensory info to make changes

Necessary for smooth accurate movements including eye movements for maintaining balance

- all functions are nonconscious

Damage here = poor coordination of movement and postural control

Feedback loop: ensures movement is smooth and precise

- sends signals to the thalamus and brainstem

- receives signals from the spinal cord and brainstem

Anterior (superior) lobe

Receives input from the spinal cord

- mediates unconscious proprioception

Lobe of the cerebellum

Posterior (inferior) lobe

Receives input from the cortex and brainstem for movement coordination

Lobe of the cerebellum

Flocculonodular lobe

Sends info to vestibular nuclei and modulates equilibrium

AKA vestibulocerebellum

Lobe of the cerebellum

Spinocerebellum

Extensive connection with the spinal cord

- coordinates gross limb movements

- functional name for the vermis

Cerebrocerebellum

Named for connection to the cerebral cortex

- coordinates precise (fine motor) and distal limb voluntary movements

- functional name for the lateral hemispheres

Spinocerebellar Tract

Info in the SC destined for the cerebellum

- unconscious proprioception

- anterior and posterior (lower limbs) pathways

Intended for unconscious movements to occur

Automatic movements

Info from muscle spindles

Anterior pathway

- transmits proprioceptive info from lover limbs and trunk

- crosses the SC then again in pons (ipsilateral)

Posterior (dorsal) pathway

- proprioceptive info from the lower extremity

- ascends ipsilaterally with no crossing

Cuneocerebellar tract

Proprioceptive info from the upper extremities

Ascends ipsilaterally in the dorsal column

Spinocerebellar Ataxia

Group of degenerative disorders that cause atrophy of the spinocerebellar tracts and cerebellum

- depending on the type, multiple structures can be damaged

Etiology/Prognosis

- hereditary

- degenerative

Symptoms/Signs

- problems with coordination and balance

- uncoordinated walk

- poor hand-eye coordination

- abnormal speech

- involuntary eye movement

- vision problems

- difficulty processing, learning, and remembering info

- usually wheelchair dependent 10-15 yrs from onset of symptoms

Multiple system atrophy

Etiology/Prognosis

- degenerative, inherited

- adult onset 50-60

Symptoms/Signs

- impaired movement and coordination

-- unsteady gait and loss of balance

- slurred, slow, or low volume speech (dysarthria)

- visual disturbances

--- blurred or double vision and difficulty focusing eyes

- difficulty swallowing (dysphagia) or chewing

- autonomic function changes

Ataxia (cerebellar clinical sign)

Movement disorder common to all lesion of the cerebellum

- voluntary, normal-strength, jerky and inaccurate movements that are not associated with tight muscles or weakness

- can be caused by sensory deficits and not direct injury to the cerebellum or spinocerebellar tract ---> need to test sensory to rule out

To test which type

- Romberg

- vibration

- touch

observation, tone, coordination, balance, sensation?

What 5 neuro tests should you perform to test the cerebellum?

Romberg

Tests for proprioception

Cerebellar Ataxia = positive with or without vision

Sensory Ataxia = positive only with eyes closed

Observation (neuro testing)

Part of the neuro exam for the cerebellum

Looking for involuntary movements

- trunk, extremities, head/neck

Muscle function screen (neuro testing)

Part of the neuro exam for the cerebellum

- Active ROM upper and lower extremities

- Passive ROM upper and lower extremities

--- looking for any spasticity, rigidity, or flaccid

--- symmetrical?, muscle strength

Coordination (neruo testing)

Part of the neuro exam for the cerebellum

Finger to nose

finger to finger

Heel to shin

Rapid alternating movements

- dysdiadochokinesia

Hand, finger, foot tap

Balance (neuro testing)

Part of the neuro exam for the cerebellum

Gait observation

- ataxia, arm swing

Tandem walk/stance

Heel (dorsiflexion) and toe (plantarflexion) walk