Recovery from CNS Injury Flashcards
What are the two main types of recovery?
Describe each.
Compensation- accomplish the same activity level as before stroke with different kinematics, muscles or sequencing including using other limbs, techniques, etc. (ICF: activity and participation level)
Restitution- Use the same muscles, sequences, and coordinated movement patterns (kinematics, kinetics, and EMGs) as before stroke (ICF: body function level which affects activity and participation)
What are the 3 mechanisms for Restitution?
- Salvation of ischemic penumbra in the first days or weeks after a stroke
- Alleviation of diaschisis
- Promotion of neuroplasticity
What is the area which surrounds ischemic areas and the supporting cells and neurons receive just enough oxygen to stay alive for a limited time?
Ischemic Penumbra (area where medications and medical procedures are most likely to be effective)
What is diaschisis? What are the mechanisms of diaschisis?
When functional changes in brain structures remote from, but connected to, the site of focal damage
Mechanisms:
- Tissue hypometabolism
- Neurovascular uncoupling (diminished cerebral blood flow response to brain activation)
- Widespread aberrant neurtransmission
Diaschisis “at rest”
a local lesion induces a remote reduction of metabolism
Functional diaschisis
normal brain activation during a selected task may be altered, either increased or decreased after a lesion
Connectional diaschisis
distant strengths and directions of connections in a selected network may be increased or decreased
Connectomal diaschisis
a lesion of the connectome induces widespread changes in brain network organization including decrease or increase in connectivity
True or False: If you determine where the focal lesion is at in the brain you can determine which distant changes will take place.
False, it is different with every patient so you need to individualize management
How long does reversal of diaschisis take usually? What other factors help reverse diaschisis?
several weeks
activation of cell repair and absorption of debris
What is the mechanism of short term neuroplasticity?
Chemical
- transfer chemical signals between brain cells to trigger reactions to support learning
- occurs rapidly to support short-term memory or improvement in performance
What is neuroplasticity?
the lifelong capability of the brain to change its neurological architecture, organization, and physiology in response to environmental stimuli and experience
What happens to connections in the brain that aren’t used often?
they become weak (weakened synapse)
“nerve that fire out of synch fail to link”
What is neurogenesis?
continuous generation of new neurons in certain brain regions
What happens in the brain as we learn new skills and experiences and begin to practice them?
we create new neural connections and strengthen them with repetition
What are the two aspects of Synaptogenesis?
Axonal Sprouting-increase in number of synapses per neuron of primary motor cortex
Dendritic Arborization- a multi-step biological process by which neurons form new dendritic trees and branches to create new synapses, the density and grouping patterns of these new synapses higlhy correlate with the function of the neuron
Describe the principle of activity dependent neuroplasticity: Use it or lose it.
failure to drive specific brain functions can lead to functional degradation
Describe the principle of activity dependent neuroplasticity: use it and improve it
training that drives a specific brain function can lead to an enhancement of that function
Describe the principle of activity dependent neuroplasticity: specificity
the nature of the training experiences dictates the nature of the plasticity
Describe the principle of activity dependent neuroplasticity: repetition
induction of plasticity requires sufficient repetition
Describe the principle of activity dependent neuroplasticity: intensity
induction of plasticity requires sufficient training intensity
Describe the principle of activity dependent neuroplasticity: Age matters
training induced plasticity occurs more readily in younger brains
Describe the principle of activity dependent neuroplasticity: Transference
plasticity in response to one training experience can enhance the acquisition of similar behaviors
Describe the principle of activity dependent neuroplasticity: Interference
plasticity in response to one experience can interfere with the acquisition of other behaviors
What are the prognosis factors that can affect stroke recovery?
Lesion type Lesion size and position time since lesion lesion extension age peripheral changes contextual factors: personal and environmental
Which lesion type has a higher chance of mortality but lower rate of morbidity?
Hemorrhagic
Which lesion type slowly develops and results in less functional loss?
Ischemic
True or False: size is less important than area of the brain affected, but bigger lesions cause more harm than smaller ones in the same brain segment
True
True or False: occipital lobe lesion have poorer outcomes than frontal lobe lesions
False, frontal and frontal temporal lesions have poorer outcomes
True or False: Temporal lobe lesions which result in aphasia have high discharge rates and optimistic outcomes
False, they have poorer outcomes and lower % are discharged home
True or False: Patients should avoid activity and ADLs for the first 3 months after a stroke
False, pts. have a better outcome the sooner they participate in rehabilitation and ADLs
Why is early rehab important for stroke patients?
The uninvolved hemisphere begins to “take over” after a a stroke and actually inhibits signals from the affected side of the brain, early rehabilitation helps decrease this affect and helps lower functional loss
What age group has the best prognosis after a stroke? Which has the poorest?
Best- pts. under 35
Worst- pts. over 75
What peripheral affects are common after a CNS lesion?
- muscles feel stiffer
- fast twitch fibers convert to highly fatigue-able slow twitch muscle
- total number of functional motor units decrease by half 2-6 months after a stroke
- secondary problems such as loss of ROM were seen with muscle fiber changes
What are the 4 tenets for promoting neuroplasticity?
Genetic predisposition-predisposition for learning
Aerobic Exercise Primer-potentiation for learning
Practice parameters-facilitation of learning
Neuroplasticity Principles-recovery by restitution
What is Brain Derived Neurotrophic Factor? (BDNF)
a neurotrphic in the brain that is important for neuroprotection/genesis and neuroplasticity
it plays a crucial role in enhancing synaptic transmission and facilitating long-term potentiation in a manner that supports learning
BDNF release is activity dependent and there are increased levels with skill training and aerobic exercise
How does BDNF exert its affect?
by improving long term potentiation via strengthening connections of 2 neurons when activated together and increasing dendritic growth
What may be the best type of exercise for BDNF production?
high intensity interval training
True or False: BDNF improves and causes neuroplasticity.
False, it does neither, it requires motor training using skilled or challenging movements and does not improve learned movements
What is the key to enhancing cortical plasticity?
Learning
