Main content
Course: Health and medicine > Unit 8
Lesson 10: Parkinson's disease- What is Parkinson's disease?
- What is Parkinson's disease?
- Movement signs and symptoms of Parkinson's disease
- Non-movement symptoms of Parkinson's disease
- The basal ganglia - The direct pathway
- The basal ganglia - Concepts of the indirect pathway
- The basal ganglia - Details of the indirect pathway
- Putting it all together - Pathophysiology of Parkinson's disease
- Genetics and Parkinson's disease
- Diagnosing Parkinson's disease
- Managing Parkinson's disease with medications
- Managing Parkinson's disease with surgery
© 2024 Khan AcademyTerms of usePrivacy PolicyCookie Notice
Managing Parkinson's disease with surgery
Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content.
These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Emma Giles.
Want to join the conversation?
- So does the DBS kind of take the place of the substantia nigra? Fine tuning the indirect pathway?(4 votes)
- Because the substantia nigra is where the pathology lies (and is presumably less amenable to treatment), DBS more commonly focuses on the globus pallidus internal and the subthalamic nucleus (as Emma states at6:27). But otherwise, you are correct - DBS is pretty much about fine-tuning the indirect pathway.(2 votes)
- In the video Emma shows an MRI of a brain with electrodes in and I'm wondering how a person can have a (presumably metal) electrode and the batteries for them on their chest and still have an MRI? I thought that the magnetic properties of the scanner can pull out bits of metal like that, are they non magnetic? Does the scan effect the batteries? Does it not distort the image? Many thanks!(2 votes)
- Lots of modern implants and implanted devices are designed to be MRI safe. MRI safe implants don't affect the images. In a typical MRI machine, the fluctuating magnetic field is more likely to dangerously heat up implanted magnetic metals than to actually pull them out.(2 votes)
- Is the electrodes .. can give problem to the other parts of the body as it's an metal.. any oxidation or reaction may happen due to several chemicals in the brain .. or it's deposit if it get accumulated can cause any problem?(2 votes)
- It is said that DBS is used when the medicine can't keep up with the progress of the disease. Why is it not efficient or possible to use DBS beforehand? Is DBS the last solution because of its side effects and discomfort or is there another reason?(2 votes)
- is this the brain test?(1 vote)
- What the video is showing describes the procedure for deep brain stimulation placement. When they are describing getting results, it is more to assure the correct location of the electrodes within the brain. The diagnosis of PD is a clinical diagnosis as opposed to a test based diagnosis.(2 votes)
- can you also anticholinergics to manage parkinson's disease? and how?(1 vote)
- Yes you can, but they are rarely used in practice. Acetylcholine (ACh) and Dopamine (DA) have opposing effects in the basal ganglia in that ACh inhibits the direct pathway via their binding to muscarinic receptors, and ACh excites the indirect pathway via their binding to muscarinic receptors. So for academic purposes, yes anticholinergics can treat Parkinson's. However, they have systemic effects and we have better treatments now (COMT inhibitors, MAO inhibitors, glutamate antagonists, etc) that are very effective as adjunctive therapies to L-DOPA and Carbidopa combinations.(1 vote)
- hi guys,
Why is pro-longed use of L-DOPA can result in more involuntary movement?(1 vote)- When l-dopa is used, the amount of dopamine in the brain can increase abruptly, causing the levels in the synapse to peak too quickly for the dopamine-producing cells to control. L-dopa kind of overloads the system. Again when the effects of l-dopa start disappearing, dopamine-producing cells lose dopamines too quickly. As Parkinson’s progresses the doses of levodopa needed to maintain control over symptoms increases. Thus, the side effects of l-dopa and overload crises increase.(1 vote)
- What happens when the battery for the stimulus dies?(1 vote)
Video transcript
- [Voiceover] So, we know that when the movement symptoms
of Parkinson's disease start to interfere with a
person's day-to-day living, that's when we would normally try to find some medications that can help manage, help minimize the problems, right? But we also know that the
most effective medication that we currently have, L-DOPA, can cause some side effects
after several years of use that also need to be managed, like dyskinesia and "wearing off," and because Parkinson's disease is a progressive disease,
because it continues to worsen over the years
following diagnosis, sometimes medications just can't keep up with how bad the symptoms get, and as a result, they just can't manage the symptoms anymore. So, if our person with Parkinson's disease gets to the point where
their quality of life is just too impacted
by the disease itself, or by the side effects of medications that they have to be on, well, that's when surgery to
help manage the symptoms might be considered, and
the particular operation that's often useful in Parkinson's disease is called "deep brain
stimulation," or DBS, and DBS is actually really interesting. It's kind of like a pacemaker. You know, those electronic implants that help you regulate your heartbeat, but instead of being for your heart, DBS is like a pacemaker for your brain, so what it does is, it's
actually kind of interesting, because we don't really know how it works. This is just what's been observed over the past 20-odd years or so, but what it does is it helps to reduce the movement symptoms
of Parkinson's disease, the bradykinesia and the
tremor, and the rigidity, and it can also help with the dyskinesia that can result from the
long-term use of L-DOPA. So, let's actually take a quick look at how this procedure is carried out here. So, a DBS operation is actually
done in two main steps. The first step is kinda
like a surveying step. So, what happens is that a little wire called an electrode is very skillfully and carefully inserted into the brain, into the area of the basal ganglia. We can think of this
initial set of electrodes as like our undercover agents, right? They're gonna keep their
ears to the ground, so to speak, and find out where all those misbehaving neurons are, where they're hanging around in the brain, because it's one thing to, say, look at a textbook or a nice drawing and see exactly where our nuclei are, but it's an entirely different thing to be able to accurately find these areas in live human beings in surgery. So, good thing we have
our undercover agent electrodes here to help us out, right? I said that they keep
their ears to the ground, and I almost literally mean that. They actually work by analyzing the activity patterns of
neurons that are around them, and then what they do is,
they translate what they find into distinct sounds,
sounds that we can hear, so the surgeons that
are doing the procedure can hear these sounds and say, "Aha, this is the spot!" when they've actually
reached the right place in the brain, and this can
take quite a while to do. It can take several hours per hemisphere of the brain, depending on the person. Okay, step two now. Our undercovers have
done a really great job at mapping out the important
areas that we need, figuring out where we need to go, so we pull them out, and in goes some permanent electrodes to those areas, so let's draw that here on our guy, and we can also see what
that looks like on an MRI. So, here's an MRI, kind
of the same sort of view that we're looking at, and you can see those electrodes here on
both sides of the brain. So, the idea is that these electrodes, they stay in the person's
brain permanently now, on maybe just one side of the brain, or maybe on both sides of the brain, depending on the person's symptoms and the severity of those symptoms, and in case you're wondering
about a power supply, they're actually connected to a battery-powered pacemaker down here, that's normally put below the collarbone. So, now we have the
ability to continually send electrical signals to
the part of the brain where those electrodes are, the part that's causing
the movement problems, and the electrical signals that are sent, what do they do? Well, they adjust the
activity of the neurons here, so this is kinda like adjusting the knobs on a radio, right? We tune in to the station that we want, in this case, movement, and we do this by placing
those first electrodes, our undercover agents, in
some of the movement areas, like parts of the basal ganglia, and now what we're doing is
we're adjusting the volume. We're turning it down to
turn down the activity of the trouble-making neurons in these areas of the brain, and that's actually part
of the beauty of DBS. This is actually a reversible setup that allows us to fine-tune how much these neurons are turned down, and what's extra-great about that is that it means this
setup can be adjusted to individualize it
for different patients. Now, let me just make
two clarifications here. So, just from when you look at the name, "deep brain stimulation," you're thinking, "Okay, deep brain. "Well, where is that?" So, in the case of someone
with Parkinson's disease, our target is the basal ganglia area, which is pretty deep in the brain, right? So that's that, and the second thing is that the second half of
this name is "stimulation," but I just told you
that we're turning down the activity of these neurons, so I think an analogy
that I'll give you is think about when your dog
is barking uncontrollably. Well, you tell him to quiet down, right? You're talking to him. It still counts as stimulation, even though the end result is that you're turning his volume down, so that's kinda the
idea with our electrodes in our basal ganglia here. Even though we're stimulating the brain, the end result is that the activity of the neurons is turned down, and let's actually look at where in the basal ganglia we're talking about here with Parkinson's disease. So, in order to figure
out where we wanna go, let's think back to how the basal ganglia control our movements. Remember that in Parkinson's disease, our thalamus is not able
to talk to our motor cortex as much as it needs to, and so we end up with a reduction in movement, right? Remember that this happens because the subthalamic nucleus gets too active, and when it's too active, it over-excites the
globus pallidus internal, and when the globus pallidus internal is too excited, it's what inhibits our thalamus too much, so that it can't talk to the motor cortex properly. So, right away we can probably see that the globus pallidus internal is definitely one of those
problem-causing areas in Parkinson's disease
because it's too active. It's inhibiting the thalamus too much, and another area that we can probably see as a problem-causing area is the subthalamic nucleus, because it's the one
that's getting too active and over-exciting the
globus pallidus internal in the first place. So, it turns out that these are indeed the main areas that we target with DBS for someone who has Parkinson's disease, so we use DBS to turn down the activity of the neurons in these areas, these areas that are too active, and that allows us to restore the balance in our direct and indirect pathways. I mentioned this already,
but how DBS works is still a bit of a mystery. We haven't quite figured out
how targeting these areas with DBS manages to reduce
the movement problems that we get from Parkinson's disease and long-term use of L-DOPA. We just know that it consistently works, and one added bonus of DBS
is that it often allows the person with Parkinson's
disease to reduce or discontinue some of their medications, So, that's a really good thing, because we know that
some of those medications can bring on some bad side effects. So, for example, remember how L-DOPA is kinda like a pendulum
that wants to bring our patient from too little movement to normal, but after a few years it can kinda overshoot and
cause too much movement. Well, we want to avoid that if we can, so with DBS, helping to manage the movement problems in the first place, the patient can often get away with taking less L-DOPA, which can maybe help our pendulum here from swinging a little too far and
causing too much movement. Good, that's surgical intervention. So, now we know that we have medications, and if needed later on,
surgery that can help manage some of the symptoms
of Parkinson's disease, but we have another category that we'll quickly touch on, and that's lifestyle management options. So, for example, exercise
and physiotherapy, well, they won't stop or slow
down the movement signs. They can help to alleviate
some of the associated muscle and joint pain that can result from things like rigidity,
and the postural changes that can happen over time
with Parkinson's disease. Another thing that can be really helpful is speech therapy, and that's because a lot of people with Parkinson's disease, they tend to develop a
really soft speaking voice due to a lack of coordination of muscles in the voice box, so speech therapy can help train them to
increase their speaking volume, and that allows them
to continue to converse with the people around them. One last example is emotional
and psychological support. This can be really important for someone with Parkinson's disease. This can be really helpful early on, when the person is kinda just learning about the disease and
starting to cope with it, and it can also be
really helpful later on, because remember that the disease can start to affect the person's mood. It can cause problems with depression and anxiety, so this support
can be really helpful if this happens for someone
with Parkinson's disease.