Treatment Principles and Rationale Flashcards
What are the 3 different types of recovery post brain injury?
- Spontaneous
- Behavioural strategies (compensation and learnt non-use)
- Neuroplasticity (network level changes (changes in the pathways that are used), structural level neural repair “true recovery”/synaptic level changes/neural restitution)
What is neuroplasticity?
The ability of neurones to change their function, chemical profile or structure
Underpins learning in the intact brain
Underpins recovery in the damaged brain
Can also have negative maladaptive consequences (e.g. pain, spasticity, learnt non-use etc)
What are the 6 levels at which plasticity can occur?
- Brain level (glial and vascular support)
- Intracellular level (mitochondrial and ribosomal function)
- Biochemical level (protein conformation, enzyme mobilization)
- Genetic level (transcription, transduction, and post translational modification)
- Intercellular /synaptic level
- Neuronal network level
What is neuromodifiability?
Short term changes causes changes in efficiency/strength of synoptic connections
Long term structural changes in the organisation of neurones and the number of connections (which happens over a longer period of time)
What are the names of the two distinct time-dependent patterns of functional changes in the brain that are associated with learning?
Early learning (cognitive) Later learning (automatic)
Describe the neural activity seen in the early learning/cognitive stage.
Activity in widely distributed, predominantly cortical regions; prefrontal, bilateral sensorimotor & parietal cortices
Describe the neural activity in the later learning/automatic stage.
Decrease in neural activity in primary motor cortex
Increased activity in subcortical motor regions, cerebellum & BG
Describe the effect of Braille reading on the cortical sensorimotor representation of the reading finger.
Skilled Braille reading is associated with an enlargement of the cortical sensorimotor representation of the reading finger
Describe the effect of ankle immobilisation on the cortical sensorimotor representation of lower limb muscles
Unilateral ankle immobilisation for 4-6 weeks – significant shrinkage of cortical representation of inactive muscles in participants with LL #
Describe how older adults learn new task
Older adults are able to learn simple and complex novel tasks
Require more training
Pattern of brain activity similar for both groups (older and younger) before and after training but older group recruited more areas
Required greater amounts of activity as older adults had more cortical involvement than younger adults
May explain difficulty with dual tasking
What brain chemical diminishes after 3 months and what is the consequence of this?
Neurotrophic growth factor (NGF) drives recovery. After 3 months recovery is still possible but it takes much longer
What is another name for neural regeneration? Define it.
Regenerative synaptogenesis.
Neuron will send out a a regenerative sprout to re-establish a connection with the neuron next to it (triggered by neurotrophic growth factors (NGF)).
What is the name of the structural level changes that occur during neuralplasticity following a brain injury?
Neural restitution which occurs at the synapse. This is the re-activiation of neural pathways and the restoration of their functions
What is another name for collateral sprouting? Define it.
Reactive synapotogenesis
Neuron grows an axon, which is triggered by NGF, and synapses to the neuron below it
Why are many synapses silent? What does unmasking silent synapses mean?
- As another neural pathway has more receptor sites or not enough neurotransmitter being released and is the preferred pathway
- The alternative pathway is chosen over the preferred pathway
What is denervation supersensitivity?
The growing of receptor sites so it’s more likely to pick up transmission across the cleft. Causes an overreaction and may lead to spasticity and hypertclonus.
How can movement be restored post brain injury?
Through neural restitution/synaptic changes i.e. regenerative and reactive synapatogenesis, unmasking silent synapses and denervation supersensitivity
Define neural restitution. Give an example
A cortical remapping
Changes in the patterns of neuronal activity
A functional recovery is achieved. Damage to the primary motor cortex can cause the pre-motor cortex and the supplementary motor area (SMA) to take over which is not as efficient
What are the 10 principles that maximise plasticity?
- Use it or lose it
- Use it and improve it
- Specificity
- Repetition Matters
- Intensity Matters
- Time Matters
- Salience Matters
- Age Matters
- Transference
- Interference
What does the use it or lose it principle mean?
Neuronal circuits not engaged in task performance for an extended period of time begin to degrade.
Deprivation results in reallocation rather than loss with a reduced representation in the cortex (fewer neurones devoted to that function)