Cerebellar Flashcards
Role of the cerebellum
- Multiple roles in motor learning and skill acquisition
- Modifying movements based on learning
- Motor learning and skill acquisition
- Gaze stability
- Postural responses
- Learning
Primary actions of cerebellum
- coordination of voluntary movement
- maintenance of balance and posture
- cognitive function
- motor learning
- comparator
cerebellar coordination of voluntary movement
- Refines control of multiple joints working together
- Coordinate timing and force
cerebellar maintenance of balance and posture
- Postural adjustments
- Comparison of intention with
afferent information- cerebellum alters signals to motor efferents to modify body position
cerebellar cognitive function
- attention
- rhythm of language
cerebellar motor learning
- Trial and error in learning
- Procedural learning- adaptation, fine tuning based on intention and feedback
Cerebellum acting as comparator
- Cerebellum Predicts Movement as Movement Occurs
- Compensates for errors in movement by comparing
intention of movement with performance - This drives adaptation and learning
Gaze stability
Direct Projections from vestibular nuclei to cerebellum allow us to compare head movement to the clarity of visual image, to adjust and modify VOR as necessary
Cerebellum has a role for objects that are….
in motion, at variable speeds, and variable directions
Things to watch for when observing voluntary movements
- Accuracy
- Velocity
- Range
- Direction
- Rhythm
- Speed
- Safety
Postural control
- Compare our movements to
movements of environment and modify responses to intention - Direct projections from sensory systems allow this to happen automatically based on previous experiences
- Short Latency Responses
- Medium Latency Responses
- Long Latency Responses
inputs to cerebellum
- Information into cerebellum from cortex regarding intended movements
- Information from brainstem and spinal cord from sensory receptors regarding actual movement
Anatomical input to superior peduncle
primary motor efferent effect limb movement
anatomical input to middle peduncle
sensory afferent including proprioception, auditory, visual, and somatosensory information
anatomical input to inferior peduncle
afferent tracts of proprioception information, efferents affecting axial muscle activity and postural control
functional anatomy - spinocerebellum
- Output primarily focused on axial and limb musculature
- Produces adaptive motor coordination- error correction
Injury to spino-cerebellum can produce:
- Hypotonia with weakness/ fatigue
- Truncal ataxia
- Static postural tremor and increased postural sway
- Wide BOS, high guard arm position
- Poor anticipatory postural control
- Impaired adaptive motor coordination
- Abnormal balance responses
- Difficulties with automatic gait
- Dyssynergia
Functional anatomy - cerebrocerebellum
- Planning and Timing of Movements
- Cognitive Functions related to Cerebellum/Important in visually guided movements
- Ipsilateral symptoms typical
injury to cerebrocerebellum can result in:
- Impaired coordination- planning/timing of movements * Deficits in motor learning
- Impaired initiation of movement
- Impaired speech patterns
- Multi-segmental movement decomposition (dyssynergia)
- Dysmetria
- Dysdiodochokinesia
- Intention Tremor
Functional Anatomy - Flocculonodular Lobe
- Central vestibular symptoms- poor eye pursuit, VOR,
impaired eye-hand coordination - Gait and trunk ataxia, poor postural control, wide based gait
- Complaints of dizziness/imbalance
- Little change in tone or dyssynergia of extremities
Possible diseases/ lesions to cerebellum
- Hereditary ataxia, Friedreich’s ataxia
- Neoplastic or metastatic tumors
- Infection
- Vascular stroke
- Developmental- ataxia, cerebral palsy, Arnold-Chiari syndrome
- Trauma-TBI
- Drugs, heavy metals
- Chronic alcoholism
Cerebellar Stroke - Anterior Inferior Cerebellar Artery (12%)
- Isolated vestibular syndrome- vertigo, with auditory symptoms such as hearing loss
- Lateral Pontine Syndrome
- Mid-basilar Syndrome
- Hemifacial paralysis, Horner
syndrome, gait and ipsilateral limb ataxia
Cerebellar Stroke - Superior Cerebellar Artery (36%)
- Acute Gait or trunk instability with associated dysarthria, nausea, vomiting
- Lateral midbrain Syndrome
- Top-Basilar Syndrome
- Oculomotor palsy
Cerebellar Stroke - Posterior Inferior Cerebellar Artery (40%)
- Isolated acute vestibular syndrome without auditory symptoms
- Lateral medullary syndrome
- Vertebral artery syndrome
- Leaning ipsilateral to lesion (lateropulsion)
Mass Effect impact on cerebellum
- Hemorrhagic CVA to cortex or cerebellum can cause
mass effect - Risk of herniation of brainstem and Cerebellum
What is Arnold Chiari Malformation?
- Parts of the cerebellum or brainstem herniate
into spinal column - Three types- 1, 2, 3 (3 being most severe)
Symptoms of Arnold Chiari Malformation
- Neck Pain (type 1)
- Unsteady gait
- Poor coordination
- Numbness/tingling
- Dizziness
- Swallowing issues
- Speech and breathing problems
Impairments involved with Arnold Chiari Malformation
- Reduced ability to use predictive, fast, automatic movements
- Reduced ability to learn from errors in movements or use trial and error learning
- Impaired motor coordination of voluntary muscle movement
- Impaired movement adaptation
3 hallmarks of impaired motor coordination
- ataxia
- intention tremor
- dysmetria
Cerebellar impairments - motor forces
- Poor prediction of inertia of extremity
- Poor perception of active forces
- Poor prediction of torque interactions
- Impaired force scaling
- Longer lever arm, more impairment likely observed
- Passive proprioception likely to remain intact
Lateropulsion
leaning to side of lesion
what is the hallmark of a PICA stroke
ipsilateral lateropulsion
grading severity of lateropulsion
- 1- Head and body tilt without imbalance
- 2- head and body tilt, with considerable
sway/imbalance, no falls - 3- head and body tilt, falls with only eyes closed
- 4- head and body tilt, falls with eyes open
Prognosis for lateropulsion
- Grade IV to become Grade III- 25 days
- Grade III to become Grade II- 19 days
- Grade II to become Grade I- 32 days
** they will recovery but it delays the process
cognitive impairments
- Executive function
- Visual Spatial Processing
- Affective Dysregulation
- Linguistic Impairments
Motor planning/ motor execution stages
- Initiation
- Execution
- Timing
- Due to deficits in timing, accuracy, smoothness
Cerebellar ataxia
- Due to damage or dysfunction affecting the cerebellum and/or its input/output pathways
- Cerebellum can’t use error information to update its prediction
- Hereditary or Acquired
Signs/ Symptoms of cerebellar ataxia
- Limb movement
- Balance and gait dysfunction * Oculomotor
- Dysarthria
Deficits in motor planning
- Increased reaction time/ initiation time- slow to start movements
- Movements are prolonged in duration
- Movements show decreased maximal velocity
- Movements show an increase in spatial variability- path varies from trial to trial
What is dyssynergy
- Decomposition of movement * Lack of coordination between agonist, antagonist, and other synergic muscles resulting in an absence of the normally smooth, sequential performance of various components of an action
Errors occur in the relative timing of segmental components and multi-joint movements
- Inability to compensate for movement-associated interaction torques
- Decompose their movements into simpler, more accurate single joint movements
deficits in countering interaction torques
- Move faster- unable to adjust interaction torques
- Abnormal patterns/path of movement
- Hypermetric and overshooting of target
- Move slower and accurately- tend to decompose the reach into a series of shoulder movements, then elbow movements, then over/ undershoot target
- Incoordination between eye, arm, leg or head
Dysmetria
- Inaccurate amplitude of
movement due to impairment in timing of muscle force - Prolonged duration of initial
agonist contraction that accelerate the limb - Delay in onset of subsequent
antagonist muscles to decelerate - Results in difficulty
controlling the termination of movement, decelerating movement - Rebound phenomenon
Action Tremor
impairment due to
alternating contractions of agonists and antagonists
Postural tremor
seen while trying to maintain a posture
intention tremor
- seen while moving, oscillatory movement about a joint.
- Most marked at end range because of delay in visuomotor processing
compounding the presence of an already incoordinate movement
6 Areas of deficits in cerebellar strokes
- Poor coordination and grading of muscle power
- reduced postural control, muscle tone and tremor
- altered timing
- reduced ability to consolidate learning
- reduced ability to adapt to environmental changes
- reduced ability to learn from movement error
poor coordination and grading of muscle power
- Impaired cerebellar processing of simultaneously incoming information from cerebral cortex (intended movement) and sensory
receptors (actual movement) - Cerebellum processes to produce movement with appropriate power –> Injury gives inappropriate coordination and grading
poor coordination and grading of muscle power - rehabilitation strategies
- Exercises to improve postural stability
- Reducing degrees of freedom
- Provision of external support- AD, orthotics
- Target underlying postural instability, minimize compensations
- Slow movements down
- Limit complex combinations
Reduced postural control, muscle tone and tremor
altered regulation of descending motor pathways
Reduced Postural Control, Muscle Tone and Tremor- Rehabilitation Strategies
- Specific strength and balance training
- Compensatory strategies to increase stability – wider base of support, slower movement
- Environmental cues to prepare
- Assistive Devices
- Caution about progressing to fast
Altered timing - mechanisms
impaired functioning of automatic control centers
altered timing - rehabilitation strategies
- Conscious attention
- Use of visual cues
- Use of assistive device
- Avoidance of secondary tasks
reduced ability to consolidate learning - mechanism
impaired plasticity within deep cerebellar nuclei
Reduced ability to consolidate learning- Rehabilitation Strategies
- High Intensity of Practice
- Conscious attention to activity
** high reps
Reduced ability to adapt to environmental changes
- Impairment in climbing fiber- Purkinje cell system
- Climbing fibers in inferior olive usually fire when there is an unexpected body movement (error signal)
- Usually this triggers strong Purkinje response and adaptive movement
is initiated - When injured this dysfunction negatively impacts the ability to respond to error signal
- Normal learning from trial and error will be impaired
Reduced ability to adapt to environmental changes- Rehabilitation Strategies
- Graded exposure to environmental challenges
- Set up environment to reduce unexpected movement demands
- Sensory cues/prompts
- Conscious attention to walking rather than relying on automatic response execution
Reduced ability to learn from movement error- Mechanism
- Impaired plasticity between Purkinje cell and parallel fibers
- Cerebellar stroke- significantly impacts procedural memory- unconscious recall
- May mean required to focus on declarative memory- conscious recall- may mean increased need for practice to not have skill deteriorate
Impaired plasticity between Purkinje cell and parallel fibers
- Simultaneous firing of climbing fiber (which can signal error in movement)
and parallel fiber (signaling intended movement) causes a long-term depressing of synapses that control that movement - Weakening this pathway and therefore subsequent learning
Reduced ability to learn from movement error- Rehabilitation Strategies
- Use stepwise prompts to learn rather than trial and error (explicit cues)
- Consider patient discussion of task before task performed * High Levels of repetition
- Conscious attention to activity (walking for example) rather than relying on automatic execution
- Learning in short sequences
- High repetitions
- Salient highly engaging activity
General Therapeutic principles
- Train to control during performance of functional movement
- Safely challenge the patient
- Reinforce learning not focus on error learning
- Consider practice environment
- Slowly increase complexity
training to control during performance of functional movements
- Reduce complexity of movement
- Slow down movement
Slowly increasing complexity
- Decrease external control and supports
- Reduce attentional demands to encourage automaticity
- Speed alterations, changes in amplitude, direction, and force
Gait training
- Task specific training- Emphasis on short sequences of stepping and increasing difficulty gradually
- Emphasis on conscious perception and control of body stability, limb control, and stepping
- Subjects memorized and focused on sensory information
should you add weighting?
- may provide immediate benefit but no long term benefit
- continue to reinforce inaccurate torque and grading issues and postural control once removed
- just probs dont even do it
rhythmic auditory stimulation
may have short term effect on improving stride length and velocity and decreased variability
early management
- Use Declarative Learning
- Sensory Cues
- Success or failure of task
- External supports
- Fewer degrees of freedom
- High repetitions
- Short sequences of movement
Four point position
Positioning patient in four point position limits degrees of freedom and can produce opportunities to practice movements in simpler, controlled positions
Tall kneeling
Positioning patient in tall kneeling position, transition from four point to tall
kneeling, intermediate position prior to standing
Later management
- Carefully graded challenges
- Increase dual task and task complexity
- Increase challenge of environment
- Increase speed of movement
What is meningitis
inflammation of the membranes of the brain or spinal cord
what causes meningitis
typically an infection
- can be bacterial or viral
symptoms of meningitis
- headache, fever, stiff
neck; may also include irritability, confusion, light sensitivity, increased HR and RR, lethargy
Kernig’s Sign
resistance to extension of leg while hip is flexed
medical management of meningitis
Antibacterial if Bacterial, treatment of viral meningitis is symptomatic- fluids, pain, corticosteroids if brain swelling, seizure medications, antivirals
PT treatment of meningitis
support symptomatic therapy, bed positioning, PROM, managing complications of immobility, safety to regain function when appropriate
What is encephalitis
inflammation of the brain due to infection
primary encephalitis
caused by virus (herpes, Epstein Barr) or mosquito borne (West Nile), Tick borne, rabies virus
secondary encephalitis
faulty immune reaction to infection
symptoms of encephalitis
may be mild such as fever, headaches, achy muscle/joints,
fatigue, weakness
symptoms of when encephalitis becomes life threatening
confusion, agitation, hallucinations, muscle weakness, paralysis, loss of consciousness
Treatment of mild encephalitis
bedrest, fluids, anti-
inflammatory drugs, antivirals,
cortico-steroids
Therapy goals for encephalitis
- supportive, then symptomatic
- May cause injury to the brain and require assistance for
strengthening, balance,
coordination, functional mobility- once medically stable
What is transverse myelitis
inflammation of one section of the spinal cord
etiology of transverse myelitis
viral, bacterial, fungal, immune system disorder, autoimmune disorder, other myeline disorders (MS)
when do symptoms of transverse myelitis develop
over hours to days
does transverse myelitis affect one or both sides of body below the lesion?
both
symptoms of transverse myelitis
Pain- sharp shooting back pain or down extremities,
abnormal sensation, weakness progressing to paralysis, stiffness to spasticity, fatigue, bowel/bladder
Medical Management of Transverse Myelitis
IV steroids, Plasma exchange, intravenous immunoglobulin
(IVIG), symptom management
Prognosis of medical myelitis
most achieve at least partial recovery, most recovery in
first 3 months, but can expand to 2 years
PT exam and treatment of medical myelitis
similar to spinal cord injury
