Beyond survival: How science is restoring lives after traumatic brain injuries

As a society, we love watching and cheering on our favorite sports team, especially during football season. Many recent rule changes aim to ensure that players are protected. However, far too often we hold our breath as an athlete fails to get up after an intense collision – we all know the risks that head injuries pose and we are immediately concerned for the injured player.

Some of the worst head injuries are called Traumatic Brain Injuries (TBIs) and they can have life-altering consequences. But did you know that the leading cause of TBIs is not contact sports?

According to the NIH, simple incidents such as falls and car accidents are the main cause of TBIs. For Gina Arata, a seemingly routine car ride altered the course of her life. In 2001, Gina was involved in a car crash that left her with a TBI, a turning point that she never saw coming. Many TBI survivors are faced with symptoms that could last a lifetime. For Gina, she suffered from a profound inability to focus, forcing her to drop out of college.

But how can such varied incidents – a football tackle or a car accident – cause similar brain injuries?

Generally, your brain is cushioned by the surrounding cerebrospinal fluid (CSF). This fluid serves several critical functions: providing nutrients to the brain, removing waste, and importantly for TBIs, acting as a shock absorber. However, when you experience rapid and drastic changes in head movement, like a jolt or blow to the head, the CSF fails to protect your brain, resulting in a TBI. Depending on the intensity of this injury, your brain cells may only be affected temporarily, or your brain tissue could bruise, tear or bleed. 

"For decades, the general consensus was that treating the immediate symptoms of a TBI is essential, but little can be done alleviate symptoms that persist longer than 12 months. But that paradigm may be about to change."

-- Annika Matthiesen

The cerebral cortex, the outermost layer of your brain that is important for controlling essential functions such as memory, thinking, learning and emotions, is the brain region most affected by a TBI. But stress and damage to the injured brain region can sometimes send signals to other parts of the brain, causing cells in that region to die. This is called a secondary brain injury and often affects deeper brain areas such as the hippocampus and striatum. Both brain regions have important roles in memory formation and retention.

Several studies have shown that TBIs are linked to disabilities that result from damage beyond the initial injury, such as mood disorders like anxiety and depression. Furthermore, TBIs challenge healthy aging, as patients with a history of TBIs are more likely to develop Alzheimer’s disease and chronic cardiovascular disease.

Because TBIs exhibit a wide range of disease symptoms, there is not a single standard of care. Treatment options range from pain killers, to anti-seizure drugs, to surgery to remove blood clots or repair skull fractures. For some patients, the only way to heal a TBI is to be placed into an induced coma. Many people also need significant physical rehabilitation and lifelong assistance.

For decades, the general consensus was that treating the immediate symptoms of a TBI is essential, but little can be done alleviate symptoms that persist longer than 12 months.

But that paradigm may be about to change.

Nicholas Schiff, M.D. and his colleagues from Weill Cornell Graduate School of Medical Sciences are challenging this medical consensus. Their groundbreaking study in TBI patients showed that they could reverse cognitive symptoms years after the initial incident. The group used deep brain stimulation (DBS) – a procedure that implants electrodes in the brain to alter brain signaling – to address TBI-induced brain dysfunction.

Generally, the brain communicates through both chemical and electrical signals which connect numerous brain areas, controlling how our body and mind function. After a TBI, communication between certain brain regions can be dramatically altered, resulting in shifts in behavior. DBS helps the brain to reprogram itself and restore brain function after a TBI.

This study concentrated on a specific connection from the front part of the brain to a deeper brain region, called the frontostriatal network. This network is critical in facilitating controlled movement, thinking and behavior. Lack of communication in this network, as seen in TBI patients like Gina, can result in a minimally conscious state, with severe cognitive and motor disabilities. 

Because TBI patients have a wide variety of neuronal changes, the research team screened patients carefully for this specific frontostriatal miscommunication. Initially, they implanted fine-tuned electrodes into both sides of the thalamus, a deep brain structure and important player in the frontostriatal communication, for DBS in one individual. The results were very promising. The research group followed up with five more patients, including Gina, and saw significant improvement of their TBI-associated symptoms.

All the participants underwent cognitive testing before and after electrode implantation and adjustment. They all showed significant recovery in their focus and memory after getting the implants, improving their quality-of-life months, and even years, after their initial injury.

While this study represents a significant advancement in TBI treatment, it's important to note that it will only benefit a subset of TBI survivors. Many others are still waiting for symptom relief, highlighting the ongoing challenges in treating this condition. Nonetheless, this study serves as a prime example of individualized medicine, where treatments are tailored to the specific needs of each patient.

The study discussed here represents a remarkable achievement in the field of translational science. It stands as a testament to the dedication of scientists like Schiff and his colleagues, who spent years conducting research and analyzing molecular and circuit changes in various animals to understand the effects of TBIs. Their perseverance has led to a groundbreaking approach that has now been successfully implemented in humans, bringing hope and transformative change to patients like Gina and many more.