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Ataxia is most frequently caused by _______ damage.
The cerebellum can be damaged by:
- brain injury
- end-stage alcoholism
What does cerebellum mean?
The cerebellum has a large role in:
- motor learning
- motor control
- connecting regions of the brain and spinal cord
The cerebellum is responsible for:
- coordinating movement
- motor actvities
- learning and remembering
- physical skills
- some cognitive function
The size of this brain region w/in any mammal species is a good indicator of:
its physical capability
The cerebellum controls movement by:
collecting sensory nerve inputs, such as limb position, blaance info, and vision, and synthesising them together to control movement by sending nerve transmissions down motor nerve outputs
In the cerebellum, learning physical tasks is largely:
- trial and error
- This learning is stored into cerebellar memory
Why do we never forget certain skills such as riding a bike?
There is some evidence that mental activities are also co-ordinated in the cerebellum which could explain why:
cognitive dysfunction is sometimes associated w/ damage to the cerebellum
The cerebellum is divided into ____ hemispheres by the ______ _____.
The suface of each hemisphere is made up of:
grey matter surrounding a large mass of white matter (nerve cells w/ myelinated axons)
The whole structure of the cerebellum is connected to the rest of the CNS by three very broad tracts of white matter called the:
What are the cerebellar peduncles?
brachium pontis which connects to the pons, the restiform body which connects to the medulla, and the brachium conjunctivum which connects to the mesencephalon
The cerebellum plays an important role in movements which require:
- careful timing and interaction of many mm
- maintaining posture
- playing musical instruments
- tracking movements with the eyes
Individuals w/ cerebellar damage may still be able to walk, gesture and eat, but the movements may appear...
difficult and clumsy
In the cerebellum, connections to the motor systems are:
In the cerebellum, connections w/ the cortex and other brain structures are:
Damage to the cerebellum affects motor control on ______ side of the body.
The cerebellum communicates with the rest of the brain through 3 sets of _________.
When the cerebellum is damaged, quite predictable syndromes can result. This include:
- predictable ataxia
- muscle tone problems
- among others
Doctors and other health care professionals frequently refer people w/ cerebellar ataxia to OT and PT to assist w/:
incoordination or clumsiness of movement that is not the result of muscle weakness
Ataxia can affect:
- eye movements
How do people react to ataxia?
- automaticity is gone
- the movements of my normal arm are done subconsciously, but I have to think out each movement of my affected arm.
- can't do anything at the same time (walking and chewing gum)
Causes of cerebellar ataxia:
- result of damage to cerebellar input and output structures
- -vestibular nucleus
- -result of sensory neuropathy
Medial and intermediate zones of the anterior lobe appear to control:
- involved in gait and stance
People w/ lesions to the medial and intermediate zones of the anterior lobe have difficulty w/:
- standing still
- higher level gait
Lateral cerebellar structures control:
- multijointed limb movements especially reaching and pinching
- movement to visual targets
People w/ lesions to the lateral cerebellar structures have difficulty with:
What is the oldest lobe in the cerebellum?
Flocculonodular lobe is highly connected w/ the ______ system.
Lesions to the flocculonodular lobe cause what disruptions?
- balance and equilibrium
- pronounced oculomotor disturbances
- produce most severe mobility
What might you observe in a client w/ ataxia during an assessment?
- balance and equilibrium problems
- muscle tone changes
- movement decomposition
- eye movements
balance and equilibrium problems-
- increased postural sway
- delayed equilibrium reactions
- lack of response to environmental cues
- loss of motor learning about gait
muscle tone changes-
in isolation, cerebellar lesions generally produce hypotonicity...however lesions are seldom in isolation
Patients can correct hypotonicity w/ attention to:
the task at hand, but when attention is diverted, the limbs get weak
The problem of muscle tone is essentially a decrease in the ability to:
- stabilize a limb...thereby making distal movements almost impossible
- joint coordination w/in limbs become very difficult
When the limb is supported, it is easier to do:
If part of the limb is supported, the rest may be able to:
- move quite appropriately
- this may clue you into an intervention technique
deficit in reaching a target
Clients w/ dysmetria can't control:
direction, extent, force, or liming of limb movement...all functions of the cerebellum
Dysmetria is tested clinically by:
the finger to nose test
Sudden release of force by examinar (as in a MMT) can lead to:
People w/ dysmetria can't make appropriate...
anticipatory control movements
People w/ dysmetria lack the ability to:
- dampen and control multi-joint activities
- including reaching grasping and gait
Movements of the shoulder in people with dysmetria thus become separated from movements of the:
- movements of the knee become separated from the hip
Strength of grip is not appropriate for the task at hand for people with dysmetria.
People w/ ataxia will crush a paper or styrofoam cup if they walk while carrying it
inter joint movements are disconnected
inability to perform rapid alternating movements -- loss of range and rhythm
Bastian speculated that decomposition of movement may actually be a compensatory strategy that reduces..
the complexity of the multijointed movement
inability to make rapid, alternating movements of a limb and seems to reflect abnormal agonist- antagonist muscle control
- attention tremor
- postural tremors can occur
people are unable to hold a posture against resistance, or are unable to stabilize an arm or leg on a stable trunk w/ or w/o resistance
deficits include nystagmus, impaired ability to smoothly track objects, and abnormal vestibulo-ocular reflex (VOR)
How do clinicians test eye movements of clients?
ask them to track moving objects and to fixate on objects while turning their heads back and forth
- difficulty in controlling the mm (including vocal cords) that control speech
- speech is distorted, slurred, or difficult to understand
Testing for ataxia: Primary importance is functional testing-
- bed mobility and posture
- ability to move supine to sit
- maintain a sitting posture
- sit to stand
- maintaining a standing posture
- dress, groom, eat, toilet, etc
Clinical tests for ataxia:
- postural sway
- -in quiet standing
- -w/ eyes closed
- -w/ feet close together
- gait analysis
- reaching analysis
- sensory testing
- strength testing
- endurance testing
Cerebellar Clinical testing
- finger-to-nose test
- to maximally elicit deficits, make sure that the finger-to-nose test require movement at more than one joint
- people w/ ataxia tend to move more normally when they limit movement to only one joint
Intervention: therapist need to synthesize the results of assessment
what systems are involved?
what systems are intact?
Intervention - things that help:
- require compensation
- little to NO neuro-plasticity exists in cerebellum
- tend to worsen over time and w/ normal aging
- add an assistive device
- add splints and orthotics
- add bracing if possible
- use power mobility
- modify the household
- change tasks and make ADLs easier
- change movement patterns (reduce number of joints needed to control; reduce speed of movement)
- strength and endurance training
- if sensation not involved, teach clients to compensate w/ either vision, or by conscious proprioception