Exam2 material: spinal cord, MS, cerebellar Flashcards
Cerebellar function
- skilled, voluntary movements of extremities and speech
- balance and equilibrium
- VOR
- planning and initiation of movement, rhythm
- timing of neural processes
- cognition and emotion
3 lobes of cerebellum
- anterior
- posterior
- flocculonodular
middle region of cerebellum
vermis
cerebellum outer layer is white or gray matter?
gray is out
flipped from spinal cord
What are the 3 deep nuclei in cerebellum?
FID
fastigial
interposed
dentate
What are the 3 layers of cerebellar cortex? (superficial to deep)
Molecular layer (superficial) parking cell layer granular layer (deep)
What cells are for input?
climbing fibers
mossy fibers
What cells are for output?
parking cell axon
Mossy fibers give input from what?
brainstem nuclei, spinal cord
Climbing fibers give input from what?
inferior olivary nucleus in medulla
Are purkinje cells excitatory or inhibitory? what what NT do they use?
inhibitory
-uses GABA
Vestibulocerebellum output
- output is vestibular nuclei in brainstem
- flocculonodular lobe
Spinocerebellum (vermis and intermediate output)
- vermis output to fastigial nucleus ***
- intermediate hemisphere to interposed nuclei ***
Cerebrocerebellum (nucleus is)
Lateral part of hemisphere to Dentate
initiation, planning, and timing
Vestibulocerebellum function
- equilibrium and balance
- helps with eye stuff
Spinocerebellum function
-involved with detailed execution of movement
Cerebrocerebellum function
-planning, initiation, timing, visual guidance of movement
Overall role of cerebellum (5 things)
- comparator (actual vs intended)
- compensator (predict impact of other joints)
- motor learning (learning new skills)
- role in cognition (thinking, attention)
- role in timing (“forward model” in motor tasks)
Cerebellar impairments
- Hypotonia
- Asthenia (general weakness)
- impaired eye movement
- Ataxia (gait, balance, dysmetria, dysdiadochokinesia, asynergia, intention tremor)
*** delay initiation, inaccurate range and direction, irregular alt movements
Asthenia def
generalized weakness
dysmetria defintion
inaccuracy in range and direction of movement
dysdiadochokinesia def
-rapid alt movements
asynergia
error in timing of complex movements
intention tremor
-tremor at end of movement
Cerebellar symptoms and lesion location
- they are ipsilateral
- decussates twice!
- at superior cerebellar peduncle and then at corticospinal and rubrospinal tract
Cerebellar midline lesions affect what?
-axial and trunk control
also speech due to dec facial control
Cerebellar lateral lesions affect what?
-motor control of limbs and digits
Friedreich’s ataxia (spinal ataxia)
- hereditary
- early onset
- progressive ataxia, weakness, loss of sensation and proprioception
- scoliosis, cardiomyopathy, foot deformities typical
- life expectance 35-40
Spinocerebellar Ataxia (SCA)
- genetic (CAG-trinucleotide repeats)
- multiple genes known
- causes degeneration of spinocerebellar tracts and the cerebellum occur
- *most common is SCA#6
- onset 30-50
- **loss of coordination, gait ataxia, impaired saccades, speech
- life ex = close to normal
Olivopontocerebellar atrophy (OPCA) -cerebellar ataxia– What is it, where is it, associated with what?
- degeneration in inferior olives, pons, and cerebellum (look at name)
- both inherited and non-inherited neurodegen syndromes
- *** primarily associated with MSA (multiple system atrophy with cerebellar predominance)
OPCA -olivopontocerebellar. symptoms
- progressive ataxia with involved gait, weakness, incoordination
- eventually pyramidal tract signs, autonomic disturbances, dementia
- onset 30-5-
- poor prognosis.
Multiple system atrophy (MSA) -characterized by, cause, survival
- damage to ANS which leads to postural hypotension, dysuria, and/or abnormal breathing during sleep
- parkinsonism
- ataxia due to OPCA
cause = unknown
survival less than 10 years after onset
Pure cerebellar degeneration -cerebellar ataxias
- atrophy of cerebellum itself WITHOUT spinal involvement
- slow progressing
- onset =40+
***ataxia of gait, imbalance, dysarthria (speaking), impaired gaze stabilization
Cerebellar ataxias - nutritional disorders
- Vit B1 (1/3 alcoholics)
- Vit B12 (leads to pernicious anemia)
-treat with vitamin therapy. Some sx may be reversible
Cerebellar ataxias - neoplastic and paraneoplastic disorders
- primary
- metastatic
- benign tumors
Cerebellar ataxia - vascular disorders
- Ischemic stroke (PICA, AICA, SCA from basilar artery) ***presents with acute nausea, vomiting, dizziness, unsteady gait
- hemorrhagic stroke (less common) ***presents with HA, vertigo, nausea, unsteady gait
Cerebellar ataxia - traumatic injuries
-TBI to occipital or frontal region (coup - countercoup)
Cerebellar ataxia - demyelinating disorders
- MS
- may have lesion in cerebellum or in spinocerebellar tracts, resulting in cerebellar signs
Ataxia rating scales - SARA
- scale for assessment and rating of ataxia
- 8 items, 40 points
Ataxia rating scales - ICARS
- international cooperative ataxia rating scale
- 19 items, 100 points
Ataxia rating scales - MICARS
- modified ICARS
- 26 items, 120 points
Ataxia rating scales - BARS
- brief ataxia rating scale
- 5 items, 30 points
MS commonly affects what CNS areas?
- optic nerve
- cerebellar peduncles
- periventricular white matter
- Spinal cord (corticospinal tract, and post columns)
In order for a SCI to be incomplete it needs?
- sensory or motor S4-5 AND
- either anal sphincter contraction OR sparing of motor fn. >3 levels below motor level
SCI : Type A
-complete
SCI: Type B
incomplete. no motor. sensation below level of lesion
SCI: Type C
incomplete. at least half of key muscles below level less than or equal to 3/5 MMT
SCI : Type D
incomplete. motor, key muscles greater than or equal to 3/5 MMT
SCI : Type E
incomplete, normal motor and sensation
Autonomic dysreflexia
- overactive sympathetic NS
- spinal cord injury ~T5 and above
- cause: any noxious stim below level of injury
- ascending info reaches major splanchnic sympathetic outflow stimulating a sympathetic response
- *results in HTN, pounding HA, visual changes etc..
- **parasympathetic NS is unable to counteract due to spinal cord injury (impulses cannot descend past the lesion)
