Read Full Text: Connectivity measures are robust biomarkers of cortical function and plasticity after stroke (Free to access)
Year Published: 2015
Ranked 19th on our 2014-2019 list of the 50 most influential articles
Article overview for OTs
This is a very technical article, and that means it’s not an easy read—but it does provide some important glimpses into future trends, and it also gives us a baseline vocabulary for what to be watching for.
The study followed 12 patients over 28 days, during which time intense therapy was provided to patients in the chronic stage of stroke recovery. Therapy interventions targeted upper extremity motor deficits.
EEG (electroencephalography) was also used to measure the “functional connectivity” between the primary motor cortex and premotor cortex sections of each patient’s brain. Note that these sections were examined on the side of the brain with the stroke lesion.
(The above image is licensed through Creative Commons and gives you a good visual of the primary motor cortex and premotor cortex.)
The connectivity measures were then compared with improvement in the patients’ motor skills (as measured by the Fugyl-Meyer).
Ultimately, the study showed that there was a correlation between the “functional connectivity” measures and motor improvement!
The EEG readings were also shown to be predictors of gains from therapy.
Terms worth noting
EEG: An electroencephalogram (EEG) is a test that detects electrical activity in your brain. This activity is measured by using small metal discs (electrodes) attached to your scalp. (Source: Mayo Clinic.) Examples of EEGs currently on the market are listed below!
Biomarker (also called bio-marker): A measurable substance in an organism whose presence is indicative of some phenomenon such as disease, infection, or environmental exposure. From cancer treatment, to measuring chemical exposure, to rehab, biomarkers are somewhat of a holy grail, because they make things objectively measurable.
Brain structure versus brain function: In the simplest sense, imaging such as an MRI gives you a snapshot of brain structure (in this case, the damage done by a stroke). On the other hand, an EEG shows you how the brain is functioning. These two measures appear to be most helpful when they are used together.
How was OT involved in this article?
Not gonna lie, the usage of OT in this article is a little unsettling. And I don’t think we should turn a blind eye to this issue.
The UE therapy does not seem to have been delivered by a rehab professional. Instead, the article states that the therapy included “slide show diagrams” of OT and PT exercises, along with virtual reality computer games.
The article does say that the therapy delivery was adjusted according to individual deficits, but it does not say by whom, nor does it discuss the clinical reasoning used to determine how to adjust the delivery. It also does not mention therapy intervention specifics, such as doseage.
What is actually on the market
(This section is all of my own research, as particular devices were not mentioned in the article.)
We recently talked about how virtual reality systems were now on the market at 1/1000th of the cost that they were 20 years ago. EEG is on a similar trajectory as it becomes more and more affordable. The most well-known consumer-facing EEG device is the Muse Headband, which retails for $199.
That being said, the Muse only has four leads, whereas the EEGs used in this study had 256. From what I can tell an EEG with around 256 leads is still in the $25,000+ range, which is significantly less expensive than an MRI, but still not super affordable.
One would anticipate the cost of these devices to continue to decrease. And perhaps we’ll also see EEG devices that are designed for more specific purposes (perhaps even ones for specifically tracking healing from stroke).
Takeaways for OT
Start imagining the ability to measure who is a good candidate for stroke rehab, and if rehab is working.
This article indicates that the technology exists to objectively measure improvements in upper extremity motor rehab following stroke—and that these measurements can be gleaned by directly measuring functional brain activity. It seems like it is only a matter of time before this technology becomes more affordable and accessible.
As therapists, we need to start wrapping our minds around how technology like this might impact our practices.
Rapidly decreasing technology costs are going to make rehab tech devices available to consumers in ways we never thought possible.
While this study has a very specific focus, the implications of more affordable EEG systems (especially ones that can collect even more targeted brain activity measurements in the future) are far reaching.
Imagine as a school OT using EEG to track whether students are achieving an optimal learning state.
Imaging using something like Muse for our mental health patients.
And, for therapists who work with patients recovering from strokes, imagine taking this one step further and having EEG impact your therapy in real time. Brain-computer interface (BCI) devices are in their infancy, but expect to see brain computer interface rehab devices like this coming to the market.
The quest for biomarkers is emerging as a trend in OT-related research.
We all know that most of the assessments we use in rehab are insufficient for our needs. That is why, across the medical field, there is a push to find biomarkers that give us objective ways to measure the presence, and advancement, of specific diseases.
Something that this article really drove home for me is that not only could biomarkers help you concretely measure whether rehab is working—they could also give you an unprecedented baseline for understanding the likelihood that your rehab treatments will be effective in the first place.
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