September 24, 2024 • 15 mins
Welcome to JAT Chat, presented by the Journal of Athletic Training, the official journal of the National Athletic Trainers' Association. In this episode, Dr. Shelby Baez is joined by Dr. Yuki Sugimoto, a postdoctoral research fellow at Northwestern University. Dr. Sugimoto discusses her recent publication on sensory reweighting system differences in individuals with and without chronic ankle instability.
Full article: https://tinyurl.com/yj27h68z
Guest Biography: Yūki Sugimoto is a postdoctoral research fellow in the Department of Physical Therapy and Human Movement Sciences at Northwestern University. She is currently exploring postural control and the sensory reweighting system in individuals with chronic ankle instability (CAI).
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
Music.
(00:14):
Welcome to JAT Chat, presented by the Journal of Athletic Training,
the official journal of the National Athletic Trainers Association.
I'm Dr. Shelby Baez, an assistant professor in the Department of Exercise and
Sports Science at UNC Chapel Hill, and the co-host of JAT Chat with Dr. Kara Radzak.
Today, I have the pleasure of being joined by Dr. Yuki Sugimoto. Dr.
(00:35):
Sugimoto is a postdoctoral research fellow in the Department of Physical Therapy
and Human Movement Sciences at Northwestern University.
She is the author of Sensory Rewaiting System Differences on Vestibular Feedback
with Increased Task Constraints in Individuals with and without Chronic Ankle
Instability, published in the Journal of Athletic Training.
Yuki, thank you so much for joining me today.
(00:58):
Thanks for having me. Very excited to be here. Wonderful. So starting off with
a very broad question for our listeners.
What do we currently know about outcomes in patients with chronic ankle instability?
Are they returning to sport? Are they engaging in physical activity, et cetera?
Yeah, so that's a very broad question. So individuals with chronic ankle instability
(01:19):
often display heterogeneous impairments, such as muscle mechanical impairments
and sensory motor dysfunctions.
They often experience repetitive relative perception of ankle giving way,
along with residual symptoms such as pain, muscle weakness,
reduced ankle dorsiflexion range motion, more adaptive gait,
(01:42):
impaired balance, and so on.
So defined chronic ankle instability patients could present in multiple combinations
of residual symptoms, and it is very individualized.
Those with chronic ankle instability often continue to experience recurrent
ankle sprains more than a year after their initial ankle sprain.
(02:03):
In terms of returning to sports or like engaging in physical activity,
first and foremost, like ankle sprain is often overlooked and considered as minor injuries.
So at least 50% of individuals do not seek any medical care after an initial ankle sprain.
(02:24):
But unfortunately, I can't blame them because I had multiple ankle sprains,
never sought any medical attention, and now I have chronic ankle instability as well.
So that being said, individuals with chronic ankle instability,
including athletes, often return to sports or engage in physical activities
despite ongoing digital symptoms.
(02:47):
The extent of their participation depends on their severity of those symptoms.
However, engaging in high-risk activities or collision sports may increase their
exposure to recurrence of ankle sprain.
Well, thank you for that comprehensive definition of who these patients are.
And as someone who also has chronic ankle instability, I'm really appreciative
(03:08):
of all the researchers who are doing this work.
Just a follow-up question when thinking about outcomes.
What are some of the long-term consequences of potentially not addressing chronic
ankle instability? stability?
Do these people go on to develop OA like we think about individuals with traumatic knee injuries?
I think so. I think one of the high risk factors for post-traumatic OA is chronic
(03:30):
ankle instability individuals.
I'm not too knowledgeable about this region in OA, but I know chronic ankle
instability is one of the risk factors for developing post-traumatic osteoarthritis.
Yeah, and just trying to think about this is more than just an ankle sprain
and thinking about the consequences of not addressing this across the lifespan.
(03:51):
So just curious a little bit about that.
You specifically examined this concept of sensory reweighting in this patient population.
Can you just provide our listeners of a definition of what sensory reweighting means?
Individuals' ability to distribute weight or their reliance on 3D primary sensory
(04:12):
systems that are somatosensory vision and vestibular to obtain relevant sensory
feedback from the environment that is constantly changing for them to coordinate
best suited motor behaviors.
So for example, like healthy individuals supposed to have flexible and adaptable
sensory weighting system to rely on different sensory feedback to obtain like
(04:37):
most relevant information on ever-changing environment to accomplish given tasks.
So in terms of like maintaining posture control, it has been suggested healthy
individuals rely on 70% of somatosensory feedback, 20% of vestibular feedback,
and 10% of visual feedback.
(04:57):
However, obviously those ratios may change as constraints of organismic studies,
like individual state of health and task and environment.
So it sounds like traditionally it's more focused on that somatosensory feedback system.
In patients with chronic ankle instability, was there a shift?
(05:18):
I can't remember if you said specifically if there is a shift between reliance
on one system more than another.
Yeah, so if they have somatosensory dysfunction, based on the previous literature,
CAI individuals tend to heavily rely on visual feedback to compensate diminished
somatosensory feedback.
(05:40):
So a lot more reliance on visual feedback instead of this metal sensory feedback
that we see in those who don't have chronic ankle instability. Is that correct?
Right. So healthy individuals have more flexible adaptability,
so they are able to change their reliance on different sensory systems based
on like, you know, like task and environmental constraints.
(06:02):
But maybe like for chronic ankle instability individuals, because they may have
somatosensory dysfunction or impairment,
they have to rely on specific single either visual or vestibular feedback to
compensate somatosensory impairment.
So it sounds like because this injury potentially damages the somatosensory
(06:25):
feedback system, that there's this shift to more of this visual reliance in
this patient population.
Right. So with your specific study, what was your purpose and how did you examine
sensory reweighting in this patient population?
We had two primary purposes for our study.
So the primary purpose was to understand how sensory reweighting systems are
(06:49):
affected by sensory systems and task complexity,
while both individuals with and without chronic ankle instability was maintaining
posture under different environmental conditions.
And then the second purpose was to explore how task and environmental constraints
could impact postural control in both CAI and healthy groups.
(07:12):
So I don't know how everybody is familiar with Neurocom device,
but we use Neurocom postulography device to conduct sensory organization tests, which is known as SOT.
So the SOT comprises six conditions and was designed to manipulate and visual
feedback in combination with sway different support surface that is like standing
(07:38):
platform and then visual soundings with and without eyes closed.
My manuscript kind of like has the table summarizing all this but the SOT condition
1 to 3 has fixed support surface and condition 4 to 6 had sway different support surface.
(07:58):
So the platform was moving based on the individual's sway and vision was absent
during condition 2 and 5 with eyes closed and then condition 3 and 6 had sway
different surroundings.
So that by means individual standing and as they swayed, the surrounding wall
was moving based on their sway.
(08:21):
So all sensory feedback was intact during condition one.
So meaning like they were all three sensory feedback one manipulator, so they were available.
And reliance on somatosensory feedback was tested during conditions two and three.
And reliance on visual feedback was tested during condition four.
(08:42):
And vestibular reliance was tested during condition five and six.
So what sensory organization tests do is they compute equilibrium balance scores
by measuring how well the individual's center of gravity stays within expected
angular limits of stability.
They use those equilibrium scores from specific pairs of SOT conditions.
(09:07):
So, for example, like for somatosensory reliance, they compared the condition
2 to 1, where all sensory feedback was intact, available.
And for visual reliance, condition 4 was compared to condition 1.
And then for vestibular reliance, condition 5 was compared to condition 1.
They also have to compute it to the ratio, so they were all multiplied by 100.
(09:32):
So the sensory-duating ratio closer to 100% represented more reliance on each sensory feedback.
So, Yuki, what did you all hypothesize that you're going to see as it relates
to differences with these six sensory organization test conditions?
Based on the previous literature, the review indicated, you know,
(09:55):
chronic ankle instability individuals highly rely on visual feedback to compensate
diminished somatosensory feedback.
So our hypothesis was definitely, you know, those CAI group will upregulate
visual reliance to compare, say, somatosensory impairments.
However, that's not what we saw in our study, which was kind of surprising to us.
(10:20):
So tell us more. What did you all see? What were the results? odds?
Right. So the most unique findings of our study was that the CI group did not
downweight on vestibular feedback while maintaining on posture in the injured
leg, meaning they actually relied on vestibular feedback.
And both chronic ankle instability and healthy groups distributed weight differently
(10:43):
on each sensory feedback while maintaining posture in double and uninjured and in injured legs,
somatosensory feedback was obviously upgraded,
you know, the most while maintaining posture in double leg stance,
while both groups actually upgraded on visual feedback to maintain posture in
single leg stance, so both uninjured and injured leg stances.
(11:08):
And group differences in posture control were influenced by task and environmental constraints.
So surprisingly, we did not hypothesize for chronic ankle instabilities to perform
or maintain posture comparable to healthy individuals,
but our CAI group maintained posture very similar to or even sometimes better than healthy groups.
(11:32):
As you mentioned, this seems to be different than what you all hypothesized.
Do you have any insight into why this group maybe didn't downweight their vestibular
feedback system during the different tasks?
Both groups actually benefited from distorted vision to maintain posture,
but CAI group did not rely on distorted vision.
(11:54):
Vestibular feedback became dominant input with distorted somatosensory and visual
feedback during condition five and six.
I think that's why, because they have to identify their self-motion,
so they have to rely on vestibular feedback, which was most accurate for them
to retrieve relevant, you know, sensory information for them to maintain posture.
(12:19):
To clarify, what I'm hearing is that based off of the specific task that they
were almost forced to have to
do down weight and maintain and rely on that vestibular feedback. Right.
So for condition five and six, somatosensory and for condition five,
somatosensory is manipulated.
(12:40):
And then condition six, both somatosensory and vision are manipulated.
And during condition five, vision is absent because they are maintaining partial with eyes closed.
So they are kind of forced to rely on vestibular feedback.
So vestibular was only dominant feedback, which provided accuracy.
(13:00):
Sensory feedback. But because both groups somewhat benefited from distorted vision, so inaccurate,
you know, sensory feedback, so healthy individuals did not have to downregulate
on vestibular feedback.
So Yuki, those are very interesting results. Where should the next steps be
(13:22):
in this space from a clinical standpoint and from a research standpoint? Okay.
Yeah, so from BCH standpoint, even though our study focused on dynamic partial control,
it is probably important to note that sensory de-weighting system might work
differently for individuals with chronic ankle instability in actual world situations,
(13:44):
where like environment is constantly changing.
So I think the next step would be to explore whether this same sensory de-weighting
pattern process during more functional tasks,
such as walking and running, and maybe transitioning into more sports-specific movements.
(14:04):
Awesome. And the last question I have for you is, can you provide a take-home
point about your paper for our listeners?
Yeah. So because both healthy and SEI individuals rely on visual feedback,
as tasks became more difficult to maintain posture in the uninjured, injured legs,
(14:24):
And also, chronic ankle instability individuals typically rely on vestibular
feedback in addition to visual feedback to maintain postural control in their injured legs.
So I think taking a multi-sensory feedback approach by challenging both vestibular
feedback with and without vision or even with distorted vision may optimize
(14:47):
the rehabilitation intervention intervention for individuals with chronic ankle
instability to prevent any recurrence of ankle sprain.
Wonderful. Thank you so much for that feedback. And thank you so much for taking
the time to join us today.
This article is available free of charge by the Journal of Athletic Training.
And I highly recommend everyone go and download this manuscript in the Journal of Athletic Training.
(15:10):
Yuki, again, thank you so much. And we will see you all next time. Thank you.
Music.
Music.
(00:14):
Welcome to JAT Chat, presented by the Journal of Athletic Training,
the official journal of the National Athletic Trainers Association.
I'm Dr. Shelby Baez, an assistant professor in the Department of Exercise and
Sports Science at UNC Chapel Hill, and the co-host of JAT Chat with Dr. Kara Radzak.
Today, I have the pleasure of being joined by Dr. Yuki Sugimoto. Dr.
(00:35):
Sugimoto is a postdoctoral research fellow in the Department of Physical Therapy
and Human Movement Sciences at Northwestern University.
She is the author of Sensory Rewaiting System Differences on Vestibular Feedback
with Increased Task Constraints in Individuals with and without Chronic Ankle
Instability, published in the Journal of Athletic Training.
Yuki, thank you so much for joining me today.
(00:58):
Thanks for having me. Very excited to be here. Wonderful. So starting off with
a very broad question for our listeners.
What do we currently know about outcomes in patients with chronic ankle instability?
Are they returning to sport? Are they engaging in physical activity, et cetera?
Yeah, so that's a very broad question. So individuals with chronic ankle instability
(01:19):
often display heterogeneous impairments, such as muscle mechanical impairments
and sensory motor dysfunctions.
They often experience repetitive relative perception of ankle giving way,
along with residual symptoms such as pain, muscle weakness,
reduced ankle dorsiflexion range motion, more adaptive gait,
(01:42):
impaired balance, and so on.
So defined chronic ankle instability patients could present in multiple combinations
of residual symptoms, and it is very individualized.
Those with chronic ankle instability often continue to experience recurrent
ankle sprains more than a year after their initial ankle sprain.
(02:03):
In terms of returning to sports or like engaging in physical activity,
first and foremost, like ankle sprain is often overlooked and considered as minor injuries.
So at least 50% of individuals do not seek any medical care after an initial ankle sprain.
(02:24):
But unfortunately, I can't blame them because I had multiple ankle sprains,
never sought any medical attention, and now I have chronic ankle instability as well.
So that being said, individuals with chronic ankle instability,
including athletes, often return to sports or engage in physical activities
despite ongoing digital symptoms.
(02:47):
The extent of their participation depends on their severity of those symptoms.
However, engaging in high-risk activities or collision sports may increase their
exposure to recurrence of ankle sprain.
Well, thank you for that comprehensive definition of who these patients are.
And as someone who also has chronic ankle instability, I'm really appreciative
(03:08):
of all the researchers who are doing this work.
Just a follow-up question when thinking about outcomes.
What are some of the long-term consequences of potentially not addressing chronic
ankle instability? stability?
Do these people go on to develop OA like we think about individuals with traumatic knee injuries?
I think so. I think one of the high risk factors for post-traumatic OA is chronic
(03:30):
ankle instability individuals.
I'm not too knowledgeable about this region in OA, but I know chronic ankle
instability is one of the risk factors for developing post-traumatic osteoarthritis.
Yeah, and just trying to think about this is more than just an ankle sprain
and thinking about the consequences of not addressing this across the lifespan.
(03:51):
So just curious a little bit about that.
You specifically examined this concept of sensory reweighting in this patient population.
Can you just provide our listeners of a definition of what sensory reweighting means?
Individuals' ability to distribute weight or their reliance on 3D primary sensory
(04:12):
systems that are somatosensory vision and vestibular to obtain relevant sensory
feedback from the environment that is constantly changing for them to coordinate
best suited motor behaviors.
So for example, like healthy individuals supposed to have flexible and adaptable
sensory weighting system to rely on different sensory feedback to obtain like
(04:37):
most relevant information on ever-changing environment to accomplish given tasks.
So in terms of like maintaining posture control, it has been suggested healthy
individuals rely on 70% of somatosensory feedback, 20% of vestibular feedback,
and 10% of visual feedback.
(04:57):
However, obviously those ratios may change as constraints of organismic studies,
like individual state of health and task and environment.
So it sounds like traditionally it's more focused on that somatosensory feedback system.
In patients with chronic ankle instability, was there a shift?
(05:18):
I can't remember if you said specifically if there is a shift between reliance
on one system more than another.
Yeah, so if they have somatosensory dysfunction, based on the previous literature,
CAI individuals tend to heavily rely on visual feedback to compensate diminished
somatosensory feedback.
(05:40):
So a lot more reliance on visual feedback instead of this metal sensory feedback
that we see in those who don't have chronic ankle instability. Is that correct?
Right. So healthy individuals have more flexible adaptability,
so they are able to change their reliance on different sensory systems based
on like, you know, like task and environmental constraints.
(06:02):
But maybe like for chronic ankle instability individuals, because they may have
somatosensory dysfunction or impairment,
they have to rely on specific single either visual or vestibular feedback to
compensate somatosensory impairment.
So it sounds like because this injury potentially damages the somatosensory
(06:25):
feedback system, that there's this shift to more of this visual reliance in
this patient population.
Right. So with your specific study, what was your purpose and how did you examine
sensory reweighting in this patient population?
We had two primary purposes for our study.
So the primary purpose was to understand how sensory reweighting systems are
(06:49):
affected by sensory systems and task complexity,
while both individuals with and without chronic ankle instability was maintaining
posture under different environmental conditions.
And then the second purpose was to explore how task and environmental constraints
could impact postural control in both CAI and healthy groups.
(07:12):
So I don't know how everybody is familiar with Neurocom device,
but we use Neurocom postulography device to conduct sensory organization tests, which is known as SOT.
So the SOT comprises six conditions and was designed to manipulate and visual
feedback in combination with sway different support surface that is like standing
(07:38):
platform and then visual soundings with and without eyes closed.
My manuscript kind of like has the table summarizing all this but the SOT condition
1 to 3 has fixed support surface and condition 4 to 6 had sway different support surface.
(07:58):
So the platform was moving based on the individual's sway and vision was absent
during condition 2 and 5 with eyes closed and then condition 3 and 6 had sway
different surroundings.
So that by means individual standing and as they swayed, the surrounding wall
was moving based on their sway.
(08:21):
So all sensory feedback was intact during condition one.
So meaning like they were all three sensory feedback one manipulator, so they were available.
And reliance on somatosensory feedback was tested during conditions two and three.
And reliance on visual feedback was tested during condition four.
(08:42):
And vestibular reliance was tested during condition five and six.
So what sensory organization tests do is they compute equilibrium balance scores
by measuring how well the individual's center of gravity stays within expected
angular limits of stability.
They use those equilibrium scores from specific pairs of SOT conditions.
(09:07):
So, for example, like for somatosensory reliance, they compared the condition
2 to 1, where all sensory feedback was intact, available.
And for visual reliance, condition 4 was compared to condition 1.
And then for vestibular reliance, condition 5 was compared to condition 1.
They also have to compute it to the ratio, so they were all multiplied by 100.
(09:32):
So the sensory-duating ratio closer to 100% represented more reliance on each sensory feedback.
So, Yuki, what did you all hypothesize that you're going to see as it relates
to differences with these six sensory organization test conditions?
Based on the previous literature, the review indicated, you know,
(09:55):
chronic ankle instability individuals highly rely on visual feedback to compensate
diminished somatosensory feedback.
So our hypothesis was definitely, you know, those CAI group will upregulate
visual reliance to compare, say, somatosensory impairments.
However, that's not what we saw in our study, which was kind of surprising to us.
(10:20):
So tell us more. What did you all see? What were the results? odds?
Right. So the most unique findings of our study was that the CI group did not
downweight on vestibular feedback while maintaining on posture in the injured
leg, meaning they actually relied on vestibular feedback.
And both chronic ankle instability and healthy groups distributed weight differently
(10:43):
on each sensory feedback while maintaining posture in double and uninjured and in injured legs,
somatosensory feedback was obviously upgraded,
you know, the most while maintaining posture in double leg stance,
while both groups actually upgraded on visual feedback to maintain posture in
single leg stance, so both uninjured and injured leg stances.
(11:08):
And group differences in posture control were influenced by task and environmental constraints.
So surprisingly, we did not hypothesize for chronic ankle instabilities to perform
or maintain posture comparable to healthy individuals,
but our CAI group maintained posture very similar to or even sometimes better than healthy groups.
(11:32):
As you mentioned, this seems to be different than what you all hypothesized.
Do you have any insight into why this group maybe didn't downweight their vestibular
feedback system during the different tasks?
Both groups actually benefited from distorted vision to maintain posture,
but CAI group did not rely on distorted vision.
(11:54):
Vestibular feedback became dominant input with distorted somatosensory and visual
feedback during condition five and six.
I think that's why, because they have to identify their self-motion,
so they have to rely on vestibular feedback, which was most accurate for them
to retrieve relevant, you know, sensory information for them to maintain posture.
(12:19):
To clarify, what I'm hearing is that based off of the specific task that they
were almost forced to have to
do down weight and maintain and rely on that vestibular feedback. Right.
So for condition five and six, somatosensory and for condition five,
somatosensory is manipulated.
(12:40):
And then condition six, both somatosensory and vision are manipulated.
And during condition five, vision is absent because they are maintaining partial with eyes closed.
So they are kind of forced to rely on vestibular feedback.
So vestibular was only dominant feedback, which provided accuracy.
(13:00):
Sensory feedback. But because both groups somewhat benefited from distorted vision, so inaccurate,
you know, sensory feedback, so healthy individuals did not have to downregulate
on vestibular feedback.
So Yuki, those are very interesting results. Where should the next steps be
(13:22):
in this space from a clinical standpoint and from a research standpoint? Okay.
Yeah, so from BCH standpoint, even though our study focused on dynamic partial control,
it is probably important to note that sensory de-weighting system might work
differently for individuals with chronic ankle instability in actual world situations,
(13:44):
where like environment is constantly changing.
So I think the next step would be to explore whether this same sensory de-weighting
pattern process during more functional tasks,
such as walking and running, and maybe transitioning into more sports-specific movements.
(14:04):
Awesome. And the last question I have for you is, can you provide a take-home
point about your paper for our listeners?
Yeah. So because both healthy and SEI individuals rely on visual feedback,
as tasks became more difficult to maintain posture in the uninjured, injured legs,
(14:24):
And also, chronic ankle instability individuals typically rely on vestibular
feedback in addition to visual feedback to maintain postural control in their injured legs.
So I think taking a multi-sensory feedback approach by challenging both vestibular
feedback with and without vision or even with distorted vision may optimize
(14:47):
the rehabilitation intervention intervention for individuals with chronic ankle
instability to prevent any recurrence of ankle sprain.
Wonderful. Thank you so much for that feedback. And thank you so much for taking
the time to join us today.
This article is available free of charge by the Journal of Athletic Training.
And I highly recommend everyone go and download this manuscript in the Journal of Athletic Training.
(15:10):
Yuki, again, thank you so much. And we will see you all next time. Thank you.
Music.
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