BASIC FUNCTIONS OF THE CEREBELLUM

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BASIC FUNCTIONS OF THE CEREBELLUM

• COORDINATION A COMBINER OF MULTIPLE MUSCLES AND
  BODY PARTS IN SMOOTH COORDINATED MOVEMENTS
• MOTOR LEARNING OF THE ABOVE A ROLE IN
  NEUROREHAB?

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RIGHT SCA TERRITORY INFARCT (INVOLVING DENATE)
REACH AND PINCH IMPAIRED, WRIST MOVEMENT NORMAL
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Bastian et al., 1996
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• A Cerebellar Role in Rehabilitation?
• The facts are that patients with cerebellar
  disease have long been known to make compensatory
  behavioral adjustments to account for their
  incoordination. Yet, there is relatively little
  written about or using these adjustments to train
  patients in rehabilitation the assumption is
  all too often that there is nothing that can be
  done about it What follow are some of these
  behavioral compensations that patients have
  developed on their own. While some of them, like
  the wide-based gait, are well known, others have
  more rarely been appreciated. The following
  examples have all been documented by film in
  patients in chronic care programs. The
  suggestion here is that they be formally
  instituted in rehabilitation training practice.
• The general philosophy is to recognize and
  encourage decomposition of movement, and train
  the use of the simple motor elements.
• Upright stance and gait
• In standing and walking, encourage the wide base.
  Developing a fixed angle at both hips, with
  feet widely laterally placed on the floor. This
  forms a stable tripod that helps to prevent
  falling. . It may also prove to be helpful in
  having lockable knee braces to prevent knee
  movement. It might also prove beneficial to have
  a trunk brace to restrict unwanted axial
  movements.
• In walking, use canes to assist balance and
  restrict movement of trunk with emphasis on
  controlling movement at hip and shoulder. Use
  Loftstrand canes to minimize need for combined
  wrist/elbow activities that are required for
  simpler canes.
• In walking, keep head and neck extended (rather
  than looking down at floor/feet) to enlist
  brainstem postural antigravity reflexes (A number
  of workers have begun to comment on thisJohn
  Milton, Thomas L. Clouse.
• Use walkers and, ultimately, wheel chairs,
  progressing from arm operated to motorized. .
• Sitting, Rising from Sitting
• In sitting upright in bed, abduct arms at the
  shoulder and place hands on the bed, developing a
  tripod for the trunk as in the wide-based
  stance and gait.
• In rising from sitting, in standing, in walking,
  hold on with hands and arms to fixed
  objectstable tops, car doors, stair rails, walls.

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• Arm Movements
• In drinking from a glass, place elbow on table
  and move only at the elbow to avoid use of
  combined elbow-shoulder movement.
• Finger Movements
• Substitute single digit movements for combined
  movements (e.g., winkling of forefinger,
  replacing attempted thumb-forefinger precision
  pinching).
• Go Slow!
• Encourage slowing of movements to minimize
  interaction torques.
• A Cerebellar Role in Shifting Control from One
  Cerebral Cortical Hemisphere to the Opposite
• A series of patients sustained infarct of the
  left cerebral cortical frontal speech area with
  immediate onset of aphasia. After time and
  speech training, they recovered the ability to
  speak. FMRI study showed that on speaking,
  symmetrically opposite portions of the opposite
  right cerebral hemisphere were active. Further,
  the regions of the cerebellum now active in
  speech had shifted to the left cerebellar
  hemisphere. This suggests that 1) the primary
  property of the cerebellar hemispheres is not
  speech (right) or spatial operations (left), but
  rather 2) their cooperation/training of the
  opposite cerebral hemisphere cortex, whatever
  activities it is engaged in47.
• An ongoing series of studies is exploring this
  potential role in neurorehabilitation of gait
  after hemiplegia due to cerebral hemispheric
  cortical infarcts or hemispherectomy for seizure
  control. Subjects repeatedly walk on a split
  treadbelt. The belt on the defective side can
  be made to move faster to bring gait in the
  impaired leg up to match that on the normal side.
  This training appears to carry over to over
  ground gait for a period of time. Further
  studies will determine whether additional
  intensive training can induce a permanent
  learning effect Bastian, in progress.

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REPAIR SHOP/RELEARNIING FUNCTIONS?

• Connor, DeShazo Braby, Snyder, Lewis Blasi,
  Corbetta Cereellar activity switches hemispheres
  with cerebral recovery in aphasia
  Neuropsychologia 200644(2)171-7
• Bastian, Morton, Reisman, Choi Split treadbelt
  training after hemiplegia from motor cortex
  infarcts and hemispherectomy for seizure control
  (ongoing studies)

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Motor cortex Type II neurons (Schieber) appear to
control spinal Cord gamma MNs (Koeze
Phillips, Fromm Evarts)
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How do we move digits individually? Lesions of
Motor Cortex and CST preferentially impair
movement of single joints.
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• HYPOTHESIS
• In certain individuals, there is selective
  activation of the gamma motor neurons over and
  above that of the alphas.
• This gamma drive increases over time and
  practice.
• This increases the gain of the segmental stretch
  reflex, which in turn increases automatic servo
  control of force, length, and velocity
  sensitivity of the movements (the good news).
• But, over time, the afferent drive spills over
  into adjacent spinal cord segments and the many
  muscles which here-to-fore have been
• cooperating under motor cortex control to
  move the one digit while holding other digits
  still.
• This leads to cocontraction of these muscles
  during the trained act, and dystonia (the bad
  news).
• HOWEVER, the action of Botox is relatively
  selective for the smaller gamma motor terminals
  to the muscle spindle.
• Therefore, botox can reduce the gain of the
  stretch reflex without impairing alpha motor
  neuron terminals and the strength of contraction.
• Test Measure the gain of the stretch reflex
  during the trained movement and non-trained
  movements in
• individuals before and after their next
  botox treatment.

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Stretch reflex spread One Ia afferent axon
branches to contact several segments above and
below its entry into the spinal cord
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BOTOX QUESTIONS

• Q In writer's cramp and the musical dystonias,
  which/how many muscles do you inject?
• A Those that are cramped in the task...physical
  exam, palpation, EEG.
• Q How do you gauge the amount/concentration  of
  Botox injected?
• A As tiny as possible, so as not to cause
  weakness.  E.G., 5 units per site.
• This compares with 2.5 units for eyelids,
  and up to 750 units total for severe neck
  dystonias undergoing surgery or to permit use of
  Thomas collar...

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REPAIR SHOP/RELEARNIING FUNCTIONS?

• Connor, DeShazo Braby, Snyder, Lewis Blasi,
  Corbetta Cereellar activity switches hemispheres
  with cerebral recovery in aphasia
  Neuropsychologia 200644(2)171-7
• Bastian, Morton, Reisman, Choi Split treadbelt
  training after hemiplegia from motor cortex
  infarcts and hemispherectomy for seizure control
  (ongoing studies)
• Overuse dystonia Hypothesis of excessive gamma
  drive with enhanced stretch reflexes responsive
  to Botox (Granit, Kuffler, Hunt cf Perlmutter
  Thach, studies planned)