CEREBELLAR DODS PARTS 1-3 Flashcards
Functions of cerebellum in motor performance
tone
smoothness
coordination
accuracy
postural control
Functions of cerebellum in motor learning
-small movements integrated into complex behaviors –> consolidate movements into motor programs
-acquisition and modification of skilled action
-acts as a comparator in real time; predictions for movement initiation and termination
-may predict upcoming sensory events
-learning based on error-driven motor learning process
What are the 3 functional zones of the cerebellum?
vestibulocerebellum
spinocerebellum
cerebrocerebelum
vestibulocerebellum functions
maintenance of balance, control of eye movements, regulates VOR, postural control
IF DAMAGED: impaired VOR, nystagmus, postural instability/impaired balance
spinocerebellum functions
regulation of muscle tone, coordination of skilled voluntary movement
-limb movements
-balance
-locomotion
-gaze and eye movements
IF DAMAGED: oculomotor deficits, hypotonia, gait ataxia, lack of check, dysmetria, dysdiadochokinesia, tremor, imbalance/falls
cerebrocerebellum functions
planning and initiation of voluntary activity
-visually guided movements
-motor planning
-sensorimotor error assessment
-agonist-antagonist coordination –> rapid alternating movements
*capabilities are very refined
IF DAMAGED: dysdiadochokinesia, dysmetria, dyssynergia, decomposition
3 layers of each functional zone of the cerebellum
cerebellar cortex - superficial
white matter layer - intermediate
nuclei - deep
3 layers of each functional zone of the cerebellum
cerebellar cortex - superficial
white matter layer - intermediate
nuclei - deep
vestibulocerebellum nuclei
vestibular nuclei located in pontomedullary junction of the brainstem- 4 TOTAL NUCLEI
the inner ear apparatus has a fast track connection to the cerebellum, bypassing the nuclei
spinocerebellum nuclei
fastigial nucleus
interposed nucleus
–globose
–emboliform
**buried deep in each cerebellar hemisphere
cerebrocerebellum nucleus
dentate nucleus
How to test for hypotonia
test by asking person to relax and move their limbs
floppy feels
due to decreased drive to vestibulospinal and reticulospinal tracts
usually does not present with problems in physical function
Postural tremor vs kinetic tremor
postural- occurs in muscles maintaining a static position against gravity
kinetic- during voluntary mvmt
—intention tremor: one form of kinetic tremor that occurs during the termination of visually guided movements toward a target
What are the two main types of nystagmus?
spontaneous
gaze evoked- when they move in a specific plane of movement
TESTS OF OCULOMOTOR CONTROL
saccades
smooth pursuit
VOR
VOR cancellation
gaze-evoked nystagmus
Dyssynergia def:
impairment of multi-joint movement related to dysmetria and deficits in limb dynamics predictions
movement decomposition def:
Breaking down of a movement sequence or multi-joint movement
into a series of separate movements to simplify the movement
-this may be considered a compensatory strategy
dysmetria
Impaired ability to scale movement distance; slow movements tend to produce hypometria and fast produce hypermetria
** go not far enough or too far from target
dysdiadochokinesia
deficits in coordinating agonist-anatagonist muscle pairs, elicited during rapid alternating movements/rapid reversals
TEST: alternate flipping hands on lap, DF/PF alternating, heel to shin
lack of check
inability to halt an unintended movement
-excessive rebound
ex: large rebound on MMT
-could cause LOB or a fall
Common balance deficits in ppl with cerebellar disorders
increased postural sway- observed in sitting or standing
-excessive (hypermetric) or diminished (hypometric) postural responses- observe ankle, hip, stepping strategies
-poor postural control during head or limb movement
What are the characteristics of gait ataxia that is common among individuals with cerebellar disorders?
-uneven step length
-irregular base of support
-absent rhythm
-feet often lifted too high
-can use a variety of gait aids–> dogs are very effective
Examples of acquired cerebellar pathologies
stroke
MS
arnold chiari malformation
toxicity- heavy metals, TOH
posterior fossa tumors
trauma
examples of hereditary cerebellar pathologies
Autosomal dominant - spinocerebellar ataxias
Autosomal recessive- Friedreichs ataxia, early onset cerebellar ataxia, X-linked disorders–> some ppl with less severe features of FA can live into their sixties or older
–MOST COMMON form of hereditary ataxia in the US
examples of idiopathic cerebellar pathologies
Multiple System Atrophy –> similar presentation to Parkinson’s at start
Idiopathic Late Onset Cerebellar Ataxia
4 main arteries that supply the cerebellum
superior cerebellar - coming off basilar
anterior inferior cerebellar - coming off basilar
posterior inferior cerebellar- coming off vertebral
vertebral artery
The anterior spinal artery and the paramedic branches of the vertebral artery supply the ______ nucleus
fastigial nucleus
The PICA supplies the _________ nucleus
dentate nucleus
The superior cerebellar artery supplies the __________ nucleus
emboliform nucleus
globose nucleus
- spinocerebellum
Main cause of spinocerebellar ataxias + progression
increase in CAG triplets produces a protein that leads to neuronal death and CB degeneration
ONSET: -typically midlife
PROGRESSION: slowly progressive
Friedrich ataxia symptoms and progression
-autosomal recessive
-both male and female children can inherit
-can live into sixties or older with less severe presentation
-ONSET: 5-15 years of age
–15% begin after age 25
(EARLY ONSET disease)
10-20 years after onset of symptoms –> confined to a wheelchair
can become completely incapacitated at later stages of the disease
life expectancy often shortened (due to heart disease)
What has a better prognosis, limb or trunk ataxia?
trunk ataxia
What has a better prognosis, ischemic or hemorrhagic stroke?
ischemic
What has the worst prognosis if damaged due to MS: PICA, AICA, or SCA?
SCA has the worst prognosis
PICA AND AICA have better prognoses
When the CB nuclei are involved–> this leads to a _____ prognosis.
Worse
People with ataxia also can commonly have these symptoms:
lack of coordination
slurred speech
trouble eating and swallowing
eye movement abnormalities
deterioration of finer motor skills
difficulty walking
gait abnormalities
tremors
heart problems
Scanning speech/ataxic dysarthria DEF
spoken words broken up into separate syllables, noticeable pause, spoken with varying force
-breath control impaired
What often happens to motor learning in ppl with cerebellar disorders?
It often becomes impaired–> particularly procedural learning and errors requiring sensory prediction
-use declarative learning strategies with verbal cues
-use trial and error
What kind of training should be considered when taking into account motor learning?
increased intensity, longer duration
ex: 1 hx 3 d/wk x 4 weeks
wrist weighting or weighted cutlery may be helpful for ___
controlling movement, incoordination, speed, timing
Recommendation of training duration for coordination training and compensation?
3 h/w for 4 weeks plus 1 h/d of HEP
-retention dependent on continuous training
COMPENSATIONS:
-add slower movement
-break down multi joint to single joint
-rehearse eye movement for goal directed stepping
-train fall strategies and fall prevention
Children with SCA will benefit from:
intensive and continuous PT
-benefits may equal one or more years of natural disease progression
Frenkel’s three main tenants to coordination training and compensation for ppl with cerebellar disorders:
- reduce the complexity of movements
- perform slowly, with client watching the moving limb carefully
- progress from moving limb with support, to moving without support at one joint of a limb, to moving the limb as a whole
What can treadmill training improve in those with CB stroke?
intra-limb coordination
increase difficulty by adding decline and obstacles
What type of training may be beneficial for individuals with spinocerebellar ataxia?
high intensity motor training
preparatory phase- to learn the pt’s perception of their body, spatial awareness, simple motor movements
operational phase- pt progressively learns complex tasks through repetition and improves anticipatory capabilities
Example exercises for postural control:
-moving platforms for reactive balance
-getting up from chair or floor
-holding and throwing objects
-trunk/prox strength on physioball
-wall squats, single wall squats, lunges, weighted ball pass
-CLOSED CHAIN EXERCISES
DANISH mnemonic
D- dysmetria or dysdiadochokinesia
A- ataxia
N- nystagmus
I-intention tremor
S-speech
H-hypotonia
SARA outcome measure
scale for the assessment and rating of ataxia
40 total points possible
What are the 4 main categories of the International Cooperative Ataxia Rating Scale
Posture and Gait disturbance
Kinetic functions
oculomotor disorders
speech disorders
4 categories of the Brief Ataxia Rating Scale (BARS)
gait
knee-tibia test
finger to nose test
dysarthria
30- max score with severe abnormalities
