- [Voiceover] So we know that someone with cerebral palsy
can kind of fall anywhere on this really wide spectrum
of movement impairments,
and we know that what sort of dictates where they'll end up
on the spectrum, well, that largely depends
on where their brain is damaged or impaired,
and how severe the damage or impairments are,
and we also know that there are three main
sort of brain regions that can be damaged
or impaired, three main movement centers,
and their associated tracks of neurons that they use
to communicate with each other, and with our muscles.
We know that if any of these are damaged
or impaired in some way, well, this is how we end up
with cerebral palsy, and depending on which
of these movement centers is primarily affected,
well that's what gives rise to the different types
of cerebral palsy, so in our spectrum here,
we've got our stiff, or spastic type of cerebral palsy,
and this type of cerebral palsy is usually due
to damage or impairments of the motor cortex
or the upper motor neurons in the pyramidal tracts
that the motor cortex uses to control our muscles.
And we can see here, that depending on which muscle
groups and how many muscle groups,
and how bad the stiffness is,
well these are the sorts of things that are dictating
where someone with this stiff type of cerebral palsy
ends up on our spectrum of movement impairments.
So let's check out our next movement center
in our brain that can be damaged
or impaired in someone with cerebral palsy,
so we can see where they will end up
on our spectrum of movement impairments.
So this next area is the basal ganglia.
So let's highlight the basal ganglia here.
And the basal ganglia is actually a collection
of individual nuclei, and here,
when we say nuclei, what we're talking about
are clusters of neuron cell bodies.
So the basal ganglia, they work together,
to help us initiate the movements that we want
to make, and help us prevent the movements
that we don't want to make,
so to do that, they use these highways of neurons
called the extrapyramidal tracts
to send messages to other structures
in the brain that ultimately help
to control our muscles, so we call these tracts
extrapyramidal because they do not go through
the medullary pyramids on their way
to the spinal cord.
So when the basal ganglia or these extrapyramidal
tracts are damaged or under-developed
or impaired in someone with cerebral palsy,
the basal ganglia can't really do their job
of helping us to prevent unwanted muscle movements.
So the sort of net result is that we end up seeing
involuntary movements, so muscle movements
that the person does not want to make.
So let's pop down involuntary movements here
as our next type of cerebral palsy.
Now, the official name for this type
of cerebral palsy is dyskinetic cerebral palsy,
so dys means ill, and kinetic means movement,
so ill movements.
So these involuntary movements can be quite
a few different things, so, they might be twisting,
so maybe the person's arms or the legs
kind of get twisted up like this when they're trying
to move them, and this twisting can get the person
into some really uncomfortable, sometimes painful
positions, or maybe the involuntary movements
are a little different, maybe they're something more like
clenching and unclenching the fingers,
making it really hard for the person to hold
and use objects, maybe something like a pen,
or maybe the movements are something else,
maybe they're more kind of random involuntary movements,
so maybe the arms and the legs kind of move around
in this unpredictable way, and maybe the person
has a combination of these different types
of involuntary movements, maybe their arms
and their legs are kind of moving around
in this random way and at the same time,
parts of their body are kind of twisting
into these unwanted, uncomfortable positions.
So with each of these different types
of involuntary movements, they usually worsen
when the person is stressed or upset, or anxious,
and they actually often go away when the person
is sleeping, so maybe if it was just one hand,
or one foot that was affected by these unwanted
muscle movements,
the person might be on the more mild end
of our spectrum.
They might be able to use their other hand to do things
like eating or writing, or maybe if it's the foot
that's affected, they might be able
to walk around okay, it just might be a little bit slower,
or maybe they'll have a little bit more trouble
with those tricky terrains like steep, and uneven surfaces.
But if more body parts are affected,
like the arms and the legs, maybe even the neck
or the muscles in the face or the throat,
these extra involuntary movements
can make it really hard for the person
to stand and walk, maybe even eat or speak.
And in someone with these involuntary movements,
something that can also happen
is the muscles can actually fluctuate between being really
stiff and really floppy.
And this can make it really hard for the person
to maintain their posture and stay upright.
So these sorts of things impair movement a lot more,
so the person can end up on the more severe end
of our spectrum of movement impairments.
So that's what happens if the basal ganglia
or the extrapyramidal tracts are impaired
or damaged, or affected in some way.
And this is where people with the dyskinetic
or involuntary movement type of cerebral palsy
might end up on our severity spectrum,
so let's check out our last movement center,
the cerebellum.
So here's the cerebellum here,
and we can think of the cerebellum as the balance
center of the brain, it helps us fine tune the movements
that we want to make.
So if the cerebellum, or balance center
is damaged or impaired or affected in someone
with cerebral palsy,
what we end up seeing are unsteady, shaky movements.
So we can put shaky down here as our last type
of cerebral palsy, and the formal name
for this type of cerebral palsy is ataxic cerebral palsy.
A, meaning without, and taxic, meaning order,
so without order.
So if the shakiness is affecting the muscles
in the arms or the hands,
the person can have a really hard time grabbing,
or using objects.
So maybe if they're going to grab for a fork,
they might kind of under or overshoot
when they're reaching for it, so they might not
quite make it to the fork, or they might go past the fork,
and once they have the fork, they might have trouble
steadying their hand enough to use it.
And if this shakiness is affecting the muscles
in the legs, they'll likely be pretty unstable,
pretty shaky when they're standing or trying to walk,
and this can often lead to falls.
And something that we often see when someone
with cerebral palsy has this shakiness in their legs
is that they kind of widen their legs like this
while they're standing or walking, and they do this
to give themselves a little bit more stability and balance.
And the shakiness doesn't just affect
the arms and the legs, it can also affect the muscles
in the face and the throat, and even the eyes,
and this can make it really hard for the person
to speak and swallow, or quickly change where they want
to look, so for someone with this shaky type
of cerebral palsy, maybe they'd be
on the milder end of our spectrum if the cerebellum
wasn't too damaged or too underdeveloped,
allowing them to get around on their own,
or maybe with some crutches or a walker
to keep their balance, but if the cerebellum
is pretty damaged and their shakiness
is pretty bad, the person might not be able
to steady themselves on their feet,
and they might not be able to steady their arms
or their hands enough to hold themselves up
on crutches or a walker.
So they might need a wheelchair to get around
and that will put them on the more severe end
of our spectrum.
So these are the three main types
of cerebral palsy, and while these are distinct types,
it's actually not uncommon for them to occur together,
so for example, someone with a stiff type
of cerebral palsy could also have involuntary movements,
or shakiness.