Week 8.2 - Motor Learning in Clinical Populations Flashcards
memory trace
controls initial definition of the action
perceptual trace
- generated by the memory trace once the action is initiated
- compares feedback to the reference of correctness (which stored in memory)
- carries out the action
would adam’s closed loop theory lead to better or worse learning when providing KR every trial?
better learning because providing feedback all the time
would adam’s closed loop theory lead to better or worse learning with regard to variable practice?
worse learning because you are not strengthening the perceptual trace because you are constantly changing the parameters
recall schema
stores the relationship between the size of the parameter and movement outcome
- relationship is refined through practice
- contains information about the task conditions and environment
regression equation
explains a good variance of the data (the line of best fit)
Y=a+BaX1+B2X2+B3X3
factors that affect the data in a linear regression
beta-weights
- things about environment, task or individual
recognition schema
relationship between the initial conditions, environmental conditions and sensory consequences
sensory consequences
what is this movement supposed to feel like (efference copies)
efference copies
copy of motor command = predict what the action is supposed to feel like
steps to schmidt’s schema theory
- recall schema specified parameters depending on initial conditions and intended outcomes
- recognition schema specifies expected sensory consequences and adjusts relationships once movement outcome and KR is received
movement disorders
conditions characterized by impaired voluntary movements, the presence of involuntary movements or both
characteristics of movement disorders
- impaired velocity (ex. slowing)
- involuntary movements (ex. twitch)
- abnormal posture (ex. dystonia)
- presence of tremor
the two broad categories movement disorders are classified in
- hyperkinetic disorders
- hypokinetic disorders
hyperkinetic disorders
excessive movement
hypokinetic movement
reduction in ability to perform movement
motor dysfunction
movement disorder type symptoms
tests of motor control
often used as diagnostic tools
1. involve reaches to body positions (cerebellar dysfunction)
2. involve dual-task paradigms
3. involves walking in a straight line
goals of clinical research in designing time efficient tasks
- inexpensive
- easy to perform
- easily interpretable
causes of motor dysfunction
- abnormalities in neural processes
- almost all movement disorders have a neurological origin
- degenerative diseases
- inflammation that affects nervous system tissue
- vascular disorders that affect nervous tissue
- trauma
can people with motor dysfunction learn new motor skills?
- most studies focus on adaptation
- many find impaired performance in acquisition of new tasks
stroke
focal brain ischemia or hemorrhage leading to acute neurological injury
ischemia
blood clot/blockage resulting in limited blood flow in brain
hemorrhage
bursting of clot/excess blood flow in brain
motor dysfunction with stroke
the development of acute and long-term movement disorder is uncommon in stroke (less than 1% of patients)
what are most movement disorders linked to?
vascular supply of the basal ganglia
when is motor dysfunction fairly common?
- spasticity and flaccidity
- weakness (paresis)
- mobility disorders
spasticity and flaccidity
changes in muscle tone
weakness (paresis)
changes in force output, strength, and control
mobility disorders
impaired balance and sensation
systemic reviews dedicated to motor learning in stroke
- few studies use retention and transfer designs
- most use adaptation paradigms
vandermeeren at al (2020) study
assessed motor learning in acute strokes
vandermeeren at al (2020) results
- participants with stroke showed improvements in acquisition
- improvements in performance in CIRCUIT task was maintained in retention and transfer
- individuals with stroke can learn new motor skills with the paretic arm (may be task specific and can occur right after injury)
mooney et al (2020) study
motor learning during stroke recovery
mooney et al (2020) results
- participants improved performance and showed learning (no decrements in short and long-term retention)
- absolute scores were lower in patients compared to healthy control
transcranial magnetic stimulation (TMS)
suggests that inhibitory motor networks function differently in patients vs control
chronic motor disorders
- include traumatic and neurodegenerative disorders
- could involve systemic changes in both peripheral nervous system and central nervous system
traumatic and neurodegenerative disorders associated with chronic motor disorders
- multiple sclerosis
- muscular dystrophy
- parkinsons
- spinal cord injury
- neuropathies
muscular dystrophies
group of inherited primary diseases of muscle
1. progressive, chronic weakness
2. pathological by degeneration of muscle fibres
3. necrosis
4. connective tissue infiltration
genetic disease
- easily recognizable clinical phenotype
- covers a wide range of possible pathologies
malheiros et al (2016) study
how DMD group and TD group performs the same maze over 5 trials
malheiros et al (2016) results
- DMD patients had lower movement times in transfer compared to beginning of training
- group differences remained stable during the training protocol
motor learning and muscular dystrophy
the sparse evidence suggests the ability to learn motor tasks is not impaired by muscular dystrophy
why may the ability to learn motor tasks not be impaired by muscular dystrophy?
central motor networks may still be intact and memory systems related to action may remain unaffected
multiple sclerosis (MS)
chronic inflammatory demyelinating disease of the CNS
- most common cause of non-traumatic disability in young adults
etiology of multiple sclerosis
- genetic
- inflammation
- infection
- autoimmune
- research into relationship with gut health
clinical features of multiple sclerosis
recurring episodes of demyelination and inflammation in the CNS
affects of multiple sclerosis
- ambulation and postural control (most severe forms requires assistive devices)
- vision
- sensation in limbs
how do patients often describe multiple sclerosis?
a missing connection between the brain and the affected areas
tablerion (2020)
completed a recent systematic review on motor learning in multiple sclerosis
systemic review results by tablerion (2020)
found that upper-limb motor skill learning is conserved in people with MS - review was TERRIBLE
hatzitaki et al (2006) study description
participants performed visuomotor tracking task by controlling shifts in posture
- completes 3 blocks of 5 training trials
hatzitaki et al (2006) results
participants with MS failed to reduce variability and retain movement control after learning
re-establishing the connection in MS
spinal stimulation
spinal stimulation
reconnect brain and spinal netowrks
findings in multiple sclerosis
greater variability in patients with MS
- this topic lacks evidence
brain-behaviour relationships
could be established using patient populations
learning paradigms with a patient population
allowed us to understand the role of the cerebellum in motor learning
topka et al (1998) study description
looked at savings score of normal participants vs cerebellar degeneraton patients
topka et al (1998) results
- patients with cerebellar degeneration were able to improve performance through training
- patients showed similar “savings” to healthy control
cerebellum
may play more of a role in movement execution and motor program refinement than learning processes
motor control as a tool for diagnosis
by examining different parts of a trajectory, you can gain insight into underlying mechanisms
developmental disorders in children
welsh and elliott (2000) conducted a study looking at simple reaching movements in children with DS and normal children
welsh and elliott (2000) results
- normal individual has similar acceleration vs. deceleration phases
- DS was very unsymmetrical and had wonky deceleration phase
what was impaired in individuals with DS?
- control (discontinuations in deceleration)
- corrections may be done cause participant didn’t have an initial plan (didn’t pre-plan)