The%20Cerebellum

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The Cerebellum

• Clinical Examination

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Objectives

• To be knowledgeable about the aspects of the
  neurological examination pertaining to the
  cerebellum
• To understand how to localize lesions within the
  cerebellum on the basis of clinical findings
• To develop a framework about the presentation of
  nervous system illness

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Cerebellar Examination

• Midline cerebellar function
• Cerebellar hemispheric function

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Clinical localization in the cerebellum

• For purpose of localization, cerebellum can be
  viewed as a saggitally-oriented structure
  containing 3 zones on each side
• Midline
• Intermediate
• Lateral

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• Midline zone
• Consists of the anterior and posterior parts of
  the vermis, fastigial nucleus and associated
  input and output projections
• concerned with posture, locomotion, position of
  head relative to trunk, control of EOMs
• Cerebellar signs resulting from midline
  cerebellar disease
• disorders of stance/gait, truncal postural
  disturbances, rotated postures of the head,
  disturbances of eye movements

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• Intermediate zone
• Consists of paravermal region of cerebellum and
  interposed nuclei (emboliform, globose)
• concerned with control of velocity, force and
  pattern of muscle activity
• Clinical disorders related to disease of this
  zone not clearly delineated

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• Lateral zone
• cerebellar hemisphere and dentate nucleus on each
  side
• concerned with the planning of movement in
  connection with neurons in the Rolandic region of
  the cerebral cortex (fine, skilled)
• Lesions result in abnormalities of skilled
  voluntary movements hypotonia, dysarthria,
  dysmetria, dysdiadochokinesia, excessive rebound,
  impaired check, kinetic and static tremors,
  past-pointing

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Midline Cerebellar Function

• Observation
• Posture, head position
• Gait
• Eye movements
• Rhomberg Test
• Tests of gait- tandem, toe heel walking,
  walking backward
• Hop on each foot

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Cerebellar Hemispheric Function

• Finger-to-nose test
• Rapidly alternating movements
• Heel-to-shin test

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Cardinal Features of Cerebellar Dysfunction

• Hypotonia
• Ataxia
• Dysarthria
• Tremor
• Ocular Motor Dysfunction

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Classic signs of cerebellar damage

• Depending on extent, an individual may have one
  symptom or a combination
• In all cases, symptoms from unilateral damage
  appear on the side ipsilateral to the injury
• Ascending spinocerebellar pathways are uncrossed
  and descending corticoopontocerebellar fibers are
  crossed thus motor deficits from cerebellar
  damage are ipsilateral to the lesion whereas
  motor deficits from damage to motor areas of the
  cerebral cortex are contralateral to the lesion

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• postural instability
• delayed initiation and termination of motor
  actions
• inability to perform continuous, repetitive
  movements
• errors in smoothness and direction of a movement
• lack of coordingation or synergy of movement,
  especially complex movements
• lack of motor plasticity or learning

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Hypotonia

• usually accompanies acute hemispheric lesions
• Interestingly less often seen in chronic lesions
• Ispilateral to the side of a cerebellar lesion
• More noticeable in upper limbs and proximal
  muscles
• (beware of increased tone with a cerebellar
  lesionmay reflect compression of
  brainstem/corticospinal tracts)!!
• Probably due to ? fusimotor activity, secondary
  to cerebellar injury (especially the dentate),
  with a ? response to stretch in muscle spindle
  afferents

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Ataxia

• Defective timing of sequential contraction of
  agonist /antagonist muscles
• Results in a disturbance in smooth performance of
  voluntary acts (errors in rate, range, force,
  duration)
• Without cerebellar modulation, skilled movements
  originating in cerebral cortex are inaccurate,
  poorly controlled
• May affect limbs, trunk, gait (depends on part of
  cerebellum involved)
• usually persists despite visual cues (unlike
  ataxia due to posterior column disease affecting
  the spinal cord)

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• Asynergia lack of synergy of various muscles
  while performing complex movements ( movements
  are broken up into isolated, successive parts--
  decomposition of movement)
• Dysmetria abnormal excursions in movement
• Dysdiadochokinesia impaired performance of
  rapidly alternating movement
• Past-pointing
• Excessive rebound when an opposed motion is
  suddenly released

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Cerebellar Dysarthria

• Abnormalities in articulation and prosody
  (together or independent)
• scanning, slurring, staccato, explosive,
  hesitant, garbled
• May result from a generalized hypotonia (disorder
  of muscle spindle function)
• Hemisphere lesions are associated with speech
  disorders more often than vermal lesions

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Posterior Fossa Syndrome

• Acute, bilateral injury to both cerebellar
  paravermal regions, including the dentate, may
  lead to transient muteness
• Seen in up to 20 of posterior fossa tumor
  resections in children (cerebellar mutism
  syndrome)
• May last for several months, with severe
  dysarthria after return of speech

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• Cerebellar affective disorder
• Impaired executive function, personality,
  emotional and behavioral changes
• Can be seen as part of the mutism syndrome

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Tremor

• rhythmic, alternating, or oscillatory movements
• can be a normal exaggeration of movement, a
  primary disorder, or a symptom of a cerebellar
  disorder or Parkinson's disease
• Diagnosis is usually clinical
• Treatment varies by etiology

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Tremor- Framework/ Categories

• Trigger Resting or action-- includes postural
  tremors and intention tremors (triggered by a
  purposeful movement)
• Cause Physiologic, essential, parkinsonism, or
  secondary to drugs or other disorders (including
  cerebellar disorders)
• Amplitude of oscillation Fine or coarse

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Tremor- General features

• Resting tremor maximal at rest, decreases with
  activity usually a symptom of Parkinson's
  disease
• Postural tremor maximal with limb in a fixed
  position against gravity gradual onset suggests
  physiologic or essential tremor acute onset
  suggests toxic / metabolic disorder
• Intention tremor maximal during movement toward
  a target (finger-to-nose testing) suggests a
  cerebellar disorder but may result from other
  diseases (MS, Wilsons)

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Tremor- Physiologic

• Physiologic tremor present normally -- usually
  so slight that it is noticeable only under
  certain conditions predominantly postural,
  fine and rapid (8 to 13 Hz)
• most visible when hands are outstretched
• Amplitude may be increased (enhanced) by
• Anxiety
• Stress
• Fatigue
• Metabolic disorders (eg, hyperadrenergic states
  such as alcohol or drug withdrawal or
  thyrotoxicosis)
• Certain drugs (eg, caffeine, other
  phosphodiesterase inhibitors, ß-adrenergic
  agonists, corticosteroids)
• Alcohol and other sedatives usually suppress it

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Tremor- Essential tremor

• benign hereditary tremor, senile tremor
• coarse or fine, medium frequency (4 to 8 Hz)
  min or absent at rest
• usually bilateral
• can affect the hands, head, voice
• tends to increase with aging
• In 50 of patients, inheritance is autosomal
  dominant
• may be enhanced by any factor that enhances
  physiologic tremor (not always required)
• Some consider essential tremor a variant of
  physiologic tremor

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Tremor- Cerebellar Disease

• an intention tremor no effective drug
  available physical measures (eg, weighting the
  affected limbs or teaching patients to brace the
  proximal limb during activity) sometimes helps
• Asterixis not a tremor muscle tone lapses
  when wrist extension is attempted, resulting in
  repetitive, nonrhythmic, non-oscillatory wrist
  flexion a sign of chronic renal or liver
  failure (differentiate from tremor)
• 3-5 Hz
• Usually bilateral
• Can be a sign of hepatic encephalopathy
  (inability of liver to metabolize ammonia to
  urea)
• Patient is usually drowsy or stuporous

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Oculomotor dysfunction

• Nystagmus frequently seen in cerebellar disorders
• Gaze-evoked nystagmus, upbeat nystagmus, rebound
  nystagmus, opticokinetic nystagmus may all be
  seen in midline cerebellar lesions
• Other ocular lesions seen include opsoclonus,
  skew deviation, ocular bobbing
• Most of the disorders giving rise to these affect
  brainstem structures, too cerebellar role in
  their onset not well-defined
• Overall, most cerebellar eye signs cannot be
  localized to specific areas of the cerebellum

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Features to Examine
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Gait

• Ataxia
• In cerebellar disease, the walk is
  staggering/lurching/wavering
• Not benefitted by patients view of his
  surroundings
• Lesion in mid-cerebellum movements are in all
  directions
• Lesion in lateral cerebellum staggering/falling
  are toward the side of the lesion
• Somewhat steadied by standing or walking on a
  wide base
• (ataxia secondary to vestibular disease may
  appear similar)

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Gait

• Gait
• have patient walk across room under observation
• Watch for normal posture coordinated arm
  movements
• ask patient to walk heel-to-toe across room, walk
  on toes to test for plantar flexion weakness, and
  on heels to test for dorsiflexion weakness
• Abnormalities in heel to toe walking ethanol
  intoxication, weakness, poor position sense,
  vertigo -- exclude before poor balance is
  attributed to a cerebellar lesion
• elderly patients have difficulty with tandem gait
  (heel to toe walking) -- general neuronal loss
  impairs combination of position sense, strength,
  coordination

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blumentandemgait
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blumenTipToeGaitandHopping
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impairedTandemGait.flv
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CerebGait.flv
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Testing of Station (equilibratory coordination)

• Position of Feet
• Ataxia from spinocerebellar disease is less when
  the patient stands on a broad base (feet widely
  apart)
• Eyes open or closed
• Cerebellar ataxia is not improved by visual
  orientation ataxia from posterior column disease
  (disordered proprioception) is worsened with the
  eyes closed
• Direction of Falling
• Disease of lateral lobe of cerebellum causes
  falling to ispilateral side
• Lesions of midline/vermis cause indiscriminate
  falling, depending on initial stance of the
  patient

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blumenRhombergTest
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Diadochokinesia

• Normal coordination includes ability to arrest
  one motor impulse and substitute the opposite
• Loss of this dysdiadochokinesia
• Characteristic of cerebellar disease
• Many simple tests for this
• Alternating movements (pronate and supinate
  forearm hand quickly) in cerebellar disease,
  movements overshoot, undershoot be irregular or
  inaccurate
• Rapidly tap fingers on table
• Open and close fists
• Stewart-Holmes rebound sign

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blumenFineFingerTap.rm
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blumenRapidlyAltMovements.rm
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dysdiadochokinesiamovie
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Dysmetria

• Finger to nose test
• With eyes open, have pt partially extend elbow
  and rapidly bring tip of index finger in a wide
  arc to tip of his nose
• In cerebellar disease, the action may have an
  intention tremor
• With eyes closed, sense of position in the
  shoulder and elbow is tested
• Heel to Shin test
• Pt places one heel on opposite knee and slides
  heel down the tibia with foot dorsiflexed
• Movement should be performed accurately
• In cerebellar disease, the arc of the movement is
  jerky/wavering
• The slide down the shin has an action tremor

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blumenFingerNoseTest.rm
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Coordinationwithpuppets.mp4
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Cerebellarintentiontremor.mp4
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Heelshintest.mp4
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Heelshinabnormal.mp4
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Checkreflexmovie.mp4
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Checkreflexabnorvideo.mp4
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Spasticspeech.flv
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Cerebellar Syndromes

• In general, precise clinical localization is
  difficult in the cerebellum
• Some syndromes can be classified anatomically
• Rostral vermis syndrome (anterior lobe)
• Caudal vermis syndrome (flocculonodular,
  posterior lobe)
• Hemispheric syndrome (posterior lobe, variably
  anterior too)
• Pancerebellar syndrome

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Cerebellar Syndromes- rostral vermis

• Wide-based stance and gait
• Ataxia of gait, proportionally little ataxia on
  heel-shin with pt lying down
• Normal or slightly impaired arm cooordination
• Infrequent hypotonia, nystagmus, dysarthria
• alcoholics (restricted form of cerebellar
  cortical degeneration)

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Cerebellar Syndromes- caudal vermis

• Axial dysequilibrium, staggering gait
• Little or no limb ataxia
• Sometimes spontaneous nystagmus
• Rotated postures of head
• Seen in diseases that damage the flocculonodular
  lobe (esp medulloblastoma in children)as tumor
  grows, a hemispheric cerebellar syndrome may be
  superimposed
• Need to also consider other signs of ? ICP
  (obstruction of CSF)

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Cerebellar Syndromes- hemispheric

• Incoordination of ipsilateral limb movements
• More noticeable with fine motor skills
• Incoordination affects most noticeably muscles
  involved in speech and finger movements
• Etiologies include infarcts, neoplasms, abscesses

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Cerebellar Syndromes- pancerebellar

• Combination of all the other syndromes
• Bilateral signs of cerebellar dysfunction
  involving trunk, limbs, cranial musculature
• Etiologies usually infectious/parainfectious
  processes, hypoglycemia, paraneoplastic
  disorders, toxic-metabolic disorders

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Cerebellum 4th ventricle

• The fourth ventricle is ventral to the cerebellum
• Anatomically and clinically important
• Mass lesions located in the cerebellum, or
  swelling of the cerebellum (eg. Edema from an
  infarct) can compress the 4th ventricle and
  result in obstructive hydrocephalus

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My patient Tamra

• 15 yr, R-handed ? previously healthy from
  Woodstock
• 3 wk progressive gait unsteadiness, ataxia,
  dizziness
• 6 wk H/A, holocephalic, worse when coughing or
  sneezing, 5/10, takes Advil
• 20 lbs weight loss over 3 wks
• admitted to Woodstock General
• Dx Mono, D/C home,next day H/A 10/10

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• HR 76, RR 16, BP 135/76 mmHg, T-35.9
• Awake, alert, oriented x3, speech OK
• Pupils 4mm bilat., brisk, full EOM
• Nystagmus up lateral gaze
• Bilateral papilledema
• Symetrical facial features
• N bulk tone, full power arms legs 5/5
• Reflexes symmetric, Plantars equivocal
• Difficulty pointing bilat., dysmetric, past
  pointing, heel to shin good
• Broad based gait

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Cerebellar dysarthria video clip
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Nystagmus video clip
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Finger to nose- Tamra
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Heel to shin- Tamra
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Lower extremity ataxia- Tamra
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Upper extremity ataxia- Tamra