Okay, so we are here in Toronto, Canada, and I am talking to a very prestigious person from
Cape Town. He traveled a long time to get here to Toronto. Can you tell us your name and where
you work in Cape Town South Africa? Oh, yes, thank you for having me. My name is Katleho Limakatso,
from South Africa in Cape Town. Affiliated to the Department of Anesthesia and Perioperative
Medicine, at the University of Cape Town. Wow, and he traveled 24 hours,
many flights to get here to Canada. Yep!. So, Can you tell me about your special
interest in pain? A hundred percent yes. I have a special interest
in understanding the mechanisms that underlie post-surgical pain syndromes, particularly
Phantom limb pain, in people with amputations. So my interest as I've mentioned is understanding
the mechanisms that underline Phantom limb pain and also design treatments that may be effective
for phantom limb pain. So, phantom limb pain, for who don’t know, the person as an amputation. Yeah,
and it's missing a part but they continue having pain in the part that is missing.
That is missing. And you want to know what is the mechanism for this? so what did you find?
Quite interesting findings, really, so what we have seen, in fact it's a it's a theory that
has been tested at the moment, is that there is a stochastic entanglement of sensory motor
networks. In the brain? Yes, within the pain in the neural axis from the spinal cord level up,
so there is, what do you mean entanglement? They are kind of a short circuits that go in
the pathways? So entanglement in such a way that there is what we refer to as Hebb's law, meaning,
stating that neurons that fire together they wire together. Neurolasticity right? Absolutely yeah. I
already mentioned this in my channel, yeah, yep so neurons that fire together wire together, so when
you have an entanglement of sensory motor and pain Networks, when motor networks are activated then
pain networks are also activated, that's why we get to see patients when they imagine movements,
they also experience the perception of pain when they imagine movement, on. Or when they're
thinking about moving a part of the body that will be a short circuit, because the movement is not
painful. Yep. But then it will activate the other pathway, and they would interpret that as pain.
Absolutely. Because now, these networks have been entangled. So that seems to be a possible
theory for Phantom limb pain at this moment, so the treatments that work to reduce Phantom
limb pain, they work towards entangling suchness. Disentengling? Yes, disentenglin. Yeah? How do you
undo that thing? Because if neurons that fire that wire together or that fire together wire together,
that means that the inverse of that law would work in terms of reducing Phantom limb pain.
Meaning we need to provide treatments that fire motor networks below a certain threshold,
without activating pain networks. How do you do that as a physiotherapist? What exactly do
you do that in practice? What do you tell the person? So graded motor imagery is a
treatment that seems to be working very well. Can you explain what is graded motor imagery?
Yeah. so graded motor imagery is a sequence of strategies including Left-Right judgments,
imagined movements. The right hand and you have to see it's right, okay? Absolutely,
so during the Left Right judgments there is an app that we use, so if you are, if your arm has been
amputated then we will project photos of arms, left and right arms, quite equally and evenly,
so then the patient will get a chance to choose whether the shown arm represents the left or the
right. So this is retraining the pain system? I talk a lot in my Channel about retraining the pain
system. Yeah, absolutely, so what we have seen through the MRI studies that have been done is
that such laterality tasks they address changes in the primary sensory cortex. Okay, you're talking
too, a language that is too complicated, so you're saying that the right brain in the left side
they talk to each other, and this information going from one side to another one is important
to change, to undo those short circuits that happened? Not necessarily so, we're not at
that stage, so this is more of a preparatory stage, the first one, because what we have
seen is that patients with amputations, they have poor Left Right Judgment of the of the place that
was amputated, or like if they had an amputation of the leg, would they also have a poor Judgment
of the hands too? No no of the affected limb only. Only the affected limb. So, if you show,
if they had leg amputation and you show pictures of right and left foot,
they have difficulty identifying what is right, what is left? Absolutely, and then we have two
outcome measures that we look at in that instance. So the first one is accuracy, so what we have seen
is that they have poor accuracy in determining the sightedness of the affected limb. Okay, so let me
say for example, if they've been amputated on the left limb, they get it quite wrong,
so they have poor laterality, in that sense but also time that it takes for them to recognize
the affected limb. It takes longer for them to? Absolutely, it takes them longer to recognize the
affected limb relatively to the unaffected. Yeah. So, training them, showing them these pictures,
do you see benefits for the Phantom limb pain that they were having? Absolutely, so this as
I've mentioned, it's a preparatory stage, for us to get them performing Phantom Motor executions,
because the basis of the treatment is for them to move the Phantom limb, but it'll be
difficult for them to move the Phantom limb if they don't know what's left and what's right,,
so we'll retrain the left and right judgments, so that we can prepare them for movement,
which leads to the second stage of the treatment, so before they execute Movement,
we get them to imagine movements, thinking, just thinking about moving that part that is missing,
absolutely, so, this activates motor networks below a threshold that would usually trigger
a painful response. What if they are doing this exercise and they feel pain?
Seldom happens, especially with imagined movements, its seldom happens, but sometimes
they do experience pain, and one of my, one of the things that I've seen in clinical practice is that
instead of imagining moving the Phantom limb, sometimes they are in fact moving the Phantom
limb, so let's be careful of the wording there. I don't know what you mean, so you were saying
that there is a difference between Imagining the movement and actually moving, but if they don't
have the foot anymore, how can they actually move it? Absolutely, so with you, and I if I was to
ask you to imagine extending your knee. Okay, I'm imagining now. You would imagine it. and
you are giving me feedback that you've imagined such movement. but nothing happened here, but if
I ask you to move your leg, you've moved it, and confirmation that you've moved it comes from your
visual feedback, you've seen that leg move so with people with amputations they can perform
both tasks of imagining movement, okay and then activate the muscle, also moving the Phantom limb,
but the problem with moving the Phantom limb is that there is no visual input, you can't see it
but there are several tests that I use in clinical practice to monitor that, so during the imagined
movement phase what I do you just patch them up with EMG feedback, so when they imagine, Feedback
means electrodes in the skin that measure how much muscle activation is in the stump area, so when
they imagine movement purely without moving the Phantom limb, they there won't be any activation
or reading on the EMG, so they are just imagining so there's no actually, absolutely, so when they
perform motor execution instead of Imagine a movement, then the reading will pop up, so
that's when you stop them to say we are not moving as yet, please imagine purely imagine moving your
Phantom limb instead of moving it, so to answer your question patients tend to experience pain
when they jump phases, when they execute movement instead of imagining moving, so you want them to
imagine first, and how long does it take for this training? so the current protocol that we have for
this treatment is about six weeks, so two weeks per phase, two weeks for Left Right judgments,
two weeks for Imagined movement exercises, and two weeks for Mirror therapy exercises.
The mirror means they're moving, and they and they mirror they see the side that they have
Both, absolutely, so with Mirror, exactly how you describe it the the amputated limb is hidden
behind the mirror, and then the intact limb is in front of the mirror, so you perform exercises both
with an intact Limb and the Phantom limb behind the mirror, and then while viewing the reflection
of the intact limb in the mirror, so the most important aspect of this treatment is movement
or the Phantom limb behind the mirror, because what we have seen is that initially we believed
that the visual feedback from the mirror was the therapeutic component, but Studies have shown
that compared mirror therapy and covered mirror therapy, the results were the same, which means
that it's more than sensation the proprioception what's coming from the brain the messages from
the muscles to the brain, absolutely, it's more of the Phantom motor execution that seems to be
a therapeutic component more than the vision, but vision is important in a sense that it helps you
to facilitate movement, the example that I usually used with my patients is that if you can walk with
your eyes closed? Yes, you can walk, but it's certainly easier to walk with your eyes open,
you see that so Vision facilitates movement, in there so fascinating because this shows that we
can revert this entanglement, the short circuits, right, absolutely. and tell me, is it better if we
do this therapy, this six weeks treatment right after they had the amputation, or do we wait
until they develop this chronic pain, and or how what if a person had this chronic pain for years,
do you think that would make a difference if we do this treatment many years after the amputation,
or is it better to do sooner after the amputation, do you have any data about that? Sooner,
we currently do not have any data, but I'm just going to from Clinical reasoning,
um sooner in fact there is data for conditions such as complex regional pain syndrome,
that graded motor imagery is more effective when applied sooner, so that's good because,
Complex regional pain syndrome I have a video about CRPS on my channel, yeah,
yeah, and so do you think that if we we could do the same three phases for treatment of CRPS, yeah
100 percent in fact, graded motor imagery view was primarily designed for the management of CRPS but
after comparing the mechanisms underlying CRPS and Phantom limb pain, that's when I conducted a
randomized control trial in addition to the study that Moseley conducted back in 2006 to determine
whether GMI would be effective for reducing Phantom limb pain, and the results were really
interesting, and fascinating so, in years to come in fact from next year we are going to conduct a
much bigger trial to investigate the effectiveness of this treatment a bit further, that's fantastic,
so thank you for talking to me today, and I was so lucky to meet you today at the conference,
the World Congress of pain, yeah, and talk to you about your very interesting research,
about phantom limb pain and explained to us, again the retraining of the pain system that
it is possible, and this is when treatment takes six weeks, it doesn't seem too complicated, and
we could be reducing pain medications, that they use, absolutely returning them to function, and if
it doesn't work could they repeat this, or because I guess it doesn't work for every single patient
that you try. could they repeat this six weeks, or try a little longer each phase? We don't have
any data in terms of trying it for a bit longer, we know that during that six weeks most of our
patients do recovery. They get a good benefit in 6 weeks? Absolutely, and even up to, we've monitored
their progress up to six months, so we know that even after six months, the patients are still
pretty well, but as a clinician in this case, if a patient doesn't benefit from this treatment
there are other promising treatments that could potentially help, so one of the treatments that my
colleagues in Sweden are working on is a surgical Intervention, which is really gaining popularity
mainly because of its Effectiveness, it's called targeted muscle re-innervation, TMR, so what they
do is to it can be used as a prophylaxis for the prevention of phantom limb pain,
but it can also be used as a treatment for Phantom limb pain, so the basis of that treatment is to
prevent the formation of a neuroma, so what they do is that they take a sensory nerve that has been
severed during an amputation and then they attach it to an already existing branch of a motor nerve,
so that way by touching this nerves together then. A neuroma is a little tumor of the nerve, because
when there is an amputation they cut the nerves and that nerve ending that just finished there,
can create this little tumor, it's a little like a growing of the the nerve, yeah, so you mean
instead of just leaving it there, hanging there, you connect to another nerve to give it purpose,
to give it function, to give a function, yeah, so if it functions it won't develop a neuroma,
which can be very painful because the neuroma is a pain in the stump, the part that has still
remaining, yeah and I have some patients that they, you touch, and you tap, and then it hurts,
or they try to use the prosthesis, and it hurts, yeah, so they try to move, and it hurt,s because
it it's pressing the neuroma, and they have those sharp, stabbing pain, and electrical shocks,
which is really hard to treat, absolutely absolutely, absolutely, you, you've said it
so well, that's fascinating, thank you so much for talking to me today! It was a pleasure, thank you.