Clinical Relevance Flashcards
What is the motor abundance/redundancy theory and explain the clinical relevance.
A theory that found a high variability in joint angles across trials of cutting metal with chisel hammer -> but the outcome of the hammer hitting the metal was consistent
Indicating there are multiple ways to execute a specific movement and achieve equivalent outcomes (repetition without repetition)
Clinical relevance: There are multiple ways in which a patient can reach their outcome/goals
Your pt bumps into the counter and immediately rubs the painful area. Use neurophysiology to explain what is occurring with the sensory neurons.
Nociceptive receptors are being activated when hitting the hip, by providing mechanical stimulus (fibers with larger conduction velocity) will travel faster than the pain receptors
Gate control theory – has been disputed, both signals are reaching brain and being integrated and ALTERS the experience of pain (other signal still getting through!! Its NOT blocking the pain)
You decide to perform sensation tests such as light touch, temperature, and joint position. If the test is ‘abnormal’ what does this tell you about the status of the sensory system?
are there other things you might include in your sensory testing?
- testing the DCML tract or somatosensory cortex
- test diff parts of the body, because neurons cross the midline at certain areas you’d be able to see if this abnormality is distributed across whole body or one area -> tells you which part of the neuron could be impacted (superior/inferior)
- Test other spinal reflexes to see if the lower order neurons are working
- Could ask them to to detect which orientation an object is in/direction its moving to see if the info is being integrated and the processes higher in the chain within the brain
What is the advantage of using muscle synergies to produce mov’t?
Allow efficient control of coordinated contraction and mov’ts with less processing effort
If John had a lower motor neuron lesion, what would you expect to see?
- hyporeflexia (reduced response to stretch reflex)
- paresis/paralysis (loss/decreased ability to generate muscle force)
- atrophy (neurogenic loss of muscle bulk)
- hypotonia/flaccidity (low resistance to passive stretch)
- fasciculations (random, spontaneous, brief contractions of single uscle fibres)
If you were given an object with your eyes closed, which neural structure(s) is/are activated in gathering information (e.g., size, shape, texture etc) of this item?
Primary somatosensory cortex (S1) determines the general attributes of the object such as its shape, location, texture and size whereas the Secondary somatosensory cortex (SII) determines the abstract features of the object by integrating tactile and proprioceptive info when manipulating the object
E.g., SI = determines its small, cylindrical, smooth ; SII = determines its a pen
Explain the experiment about sensory inputs and their affect on postural sway (visual, somatosensory, vestibular) and the key points of this study.
Trial began with no manipulations to sensory = postural sway (PS) very minimal. Eventually began taking away sensory inputs such as vision which increased PS. As an unstable surface was introduced the PS increased significantly. Last stage was allowinig the participant to only have vestibular input which had the greatest PS.
key points:
* NS values/places more emphasis on certain types of info compared to others.
* Weighting can be varied depending on the individual, the task and the environment. (70% somatosensory, 20% vestib, 10% vision)
what are the roles of the cerebellum and basal ganglia in balance?
Cerebellum - Will modify and adapt, based on feedback and motor learning
- the more familiar you become with the situation in your balance control improves.
Basal ganglia – which muscles activated, when, coordination of them
what is the clinical significance of orthostatic hypotension?
- Affects ability to participate in rehab
- Likelihood of experience OH greater in patients with higher SCI lesions
- The more of the autonomic NS that is impacted, the less control there is over the cardiovascular system the more likely someone’s going to experience OH
In order to address impaired standing balance, you have the paƟent throw bean bags into a bucket positioned a couple of meters away. With respect to throwing component of the task only, describe a) what you would observe with respect to the throw accuracy over 20
throwing trials (1 mark) and b) the neural structure, neural circuit and signalling underlying this change in behaviour (6 marks)
a) would expect the throw accuracy to increase througout the 20 trials
b) cerebellar cortex, climbing fiber input modifies the Purkinje response to mossy fiber input through long-term depression in the synapse between Purkinje cell and parallel fibers - after the first throw provided feedback from missing the target, the error signals were sent to supress these undesired results
Explain the BPPV pathophysiology and name which structure this typically occurs in. Briefly describe a diagnostic test & treatment.
Loose otoliths at the lowest point of canal drops into the posterior semicircular canal (the most common structure affected) after quick head movement creating abnormal flow of endolymph fluid. The cupula begins to bend an irregular way, stimulating vertibular nerve fibers even after the head stops moving. This is also occuring uniltarally in absence of head movement which causes the mismatch of signals and elicits nystagmus & dizziness
Diagnostic test: Diz-Hallpike maneuver
* causes otoliths t move to new gravity dependent position
* elicits symptoms
Treatment: Eply maneuver
* moves otoliths out of semicircular canal into the vestibule
* Immediately resolvs BPPV in 75-80% of pts
Your pt has experienced a TBI from a recent car crash, explain what could be occurring in the exctiotoxicity pathway.
Neurons deprived of oxygen release glutamate → excitotoxicity
Cell damage & death in surrounding cells through several mechanisms:
- Build up of lactic acid damages membrane
- Activation of enzymes which break down proteins & release free radicals which damage cell organelles
- cell edema
