We delve deeper into what occurs inside the brain during a concussion, and how that relates to the work we're doing with Ocula AI.
We asked Brendan O’Brien, Senior Software engineer and researcher at Ocula AI to give us a rundown on what exactly goes on in the brain when someone is experiencing a concussion. Here’s what he had to say…
When we hit our head, be it during a car accident or sporting injury, whether we suffer what is diagnosed as concussion or not depends on a few factors. Inside your skull, your brain is actually suspended in a liquid known as cerebrospinal fluid (CSF).
The main purpose of CSF is not unlike the airbags in your car, it prevents the brain from crashing against the inside of your skull. With a serious enough impact, however, the CSF won’t be enough and the brain will still bounce off the inside of the skull. This leads to what is known clinically as a ‘minor Traumatic Brain Injury’ (mTBI) or what we know colloquially as concussion.
Just like the bruise that develops after you bang your shin, the parts of the brain that are impacted during a concussion will be damaged. This can mean loss of brain cells, breakage of the connections among brain cells or injury to the support cells that provide insulation for neural wires. Any and all of these will cause a reduced ability for the impacted brain areas to function.
Because brain functions are localised to different regions in our cerebral cortex, the brain functions that are lost depend upon where the impact occurred. For example, when you hit the back of your head, you will likely see illusory “stars” for a while because much of vision is carried out toward the back of the brain. Impacts to the front of your head will likely impact complex planning and decision making.
Damage also occurs away from the site of impact, as far away as the brainstem and spinal cord. Because the brain, brainstem and spinal cord are all one very large organ, when the brain moves inside the skull, the brainstem and spinal cord get flexed and stretched.
Like the brain, the brainstem and spinal cord are also protected by CSF, but there is much less space surrounding them. Any movement is likely to cause at least some damage. This is one reason that clinicians often use the pupillary light reflex (PLR) to assess whether a concussion has occurred.
As we discussed in a previous blog, the PLR is what contracts or relaxes the muscles in our iris to control the size of the pupil. When a light is shone in our eyes, the pupils are reduced in size by the reflex. When a concussion occurs, an abnormal PLR is often one of the first and most reliable signs.
Ocula works on the same principle. It uses an AI model running on a smartphone to quickly locate and measure the pupils of both eyes and how they react when stimulated with light from the phone’s own torch.
It then extracts many of the key metrics of the pupillary light reflex that are known to be impacted during concussion, such as the baseline pupil diameter and the latency of its response to light.
Some of these metrics can be subtle and difficult to detect clinically using just your own eyes and a pen torch. Ocula makes it possible for anyone, be they a physician, nurse, parent, coach, or paramedic to run an exam and get a rapid evaluation of key indicators of a concussion.