Motor disorders Flashcards
a particular condition of damage to motor control structures (usually motor cortex) =
cerebral palsy
what are some of the symptoms of cerebral palsy?
stiffness/weakness in muscles
poor coordination
what motor neurons does cerebral palsy affect?
upper
why is the cortex one of the most vulnerable structures?
because it develops last
when does cerebral palsy occur?
prenatally or perinatally (lack of oxygen at birth causes damage to motor cortex)
how many cases of cerebral palsy are associated with premature birth?
about 50%
cerebral palsy is the most common movement disorder in children affecting __/1000 births
2
other than cerebral palsy what else results from damage to motor cortex?
stroke
interruption of blood supply that supplied motor cortex =
stroke
what neurons are affected by a stroke?
upper motor neurons
what artery is usually blocked during a stroke that tends to effects muscles of control to arm and speech?
middle cerebral artery
why is assessing the ‘true’ impact of brain damage on cognitive function difficult when motor cortex is affected?
impaired motor control can be wrongly interpreted as reflecting impaired cognition, due to behaviour like speech and communication involving movement.
cognitive dysfunction occurs in less than __% of children affected by cerebral palsy
50 (there is a misjudgement that theres a cognitive deficit when it is actually just impaired motor control)
knowing that you did something in the world =
agency of action
what brain areas know about what is happening in the world, monitors actions, plays a key part in computing ‘sense of agency’?
parietal areas
what brain areas develop motor plans for voluntary action?
frontal areas
there is a connection between _____ areas and ______ association areas to understand what you are trying to do and how it links physically to the world
frontal, parietal
what happens in diseases where there is disruption of normal basal ganglia function?
inability to appropriately select sequences of movement
involuntary jerky sudden movements
what diseases are affected by basal ganglia dysfunction?
parkinson's huntington's tourette's tartive dyskinesia hemiballismus
what is the 2nd most common neurodegenerative disease?
Parkinson’s disease
affects _/1000 people, 1/__ in over 60s and 1/__ over 80s
3, 100, 25
does parkinson’s affect more males or females?
more males
is there a cure to parkinson’s?
no but some semi effective treatments
what percentage of cases of parkinson’s occur due to mutation of one of several genes?
10%
what are some of the symptoms of Parkinson’s?
paucity of spontaneous movement bradykinesia (slow movement) akinesia (no movement) rigid muscles resting tremor shuffling gait/flexed posture impaired balance mask like expression
what causes parkinson’s?
no dopaminergic input from substantia nigra > striatum isn’t transiently excited > globas pallidus is tonically active > thalamus and cortex are inhibited
what is the main treatment for Parkinson’s?
try increase levels of dopamine to try restore and excite the pathway that allows disinhibition (works by enabling globas pallidus to be off sometimes)
what are the limitations of dopamine supply as a treatment for parkinson’s?
dopaminergic cells are dying
can’t just give dopamine as doesn’t cross the BBB
give some examples of dopamine treatments for parkinson’s
apomorphine (dopamine agonist)
deprenyl
cannabis
another treatment for parkinson’s is d___ b____ s_______
deep brain stimulation
interferes with activity in the globes pallidus so the basal ganglia is way more sensitive to the smallest of signals = what treatment?
deep brain stimulation
how does deep brain stimulation physically work?
tiny electrodes surgically implanted into the brain and electrical signals delivered to targeted deep brain structures
used to help control tremors and chronic movement disorders = which treatment?
deep brain stimulation
there is a lot of _______ with deep brain stimulation effectiveness
variability
what may the variability in effectiveness of deep brain stimulation be due to?
variations in causal pathways for parkinson’s disease
what disorder affects the whole command chain from cortex to muscle and both upper and lower motor neurons?
motor neuron disease
what are features of motor neuron disease
affects motor neurons degenerative progressive paralysis of movement can't be cured muscle wasting
what is ALS?
a form of motor disease
what is the difference between a normal neuron and a diseased neuron?
diseased neuron is degenerating > leads to muscle wasting because they are not being stimulated > loss of muscle tone
is incidence of motor neuron disease more common in men or women?
men
___ per 100,000 per year in men, ___ per 100,000 per year in women (motor neuron disease)
3.9, 2.6
what is a strong modulator of getting motor neuron disease?
age! (rare to get it before 40)
there is high ________ in symptoms, rate of progression and life expectancy in motor neuron disease
variability
what are distinctions of subtypes of motor neuron disease related to?
either upper or lower motor neurons or both
which motor neurons does ALS affect?
both upper and lower
are there cognitive deficits with motor neuron disorder?
yes but only a mild symptom so it’s the ability to communicate that is more of the issue
what is a strong indicator of motor neuron disease?
thenar atrophy (wasting of big muscle on palm)
disorder where the cerebellum is damaged leading to impairment in movement?
ataxia
what are the 2 types of impairment in ataxia?
disturbances of posture/gait
decomposition of movement
list the symptoms of ataxia
loss of fluid voluntary movement mechanical/slow/robot-like intention tremor drunkeness like dysarthria
disruption of fine control of speech (slurring) =
dysarthria
