Lingering Symptoms of Brain Injury: Concussion Affects Nearly Half of the Individuals Six Months Later

Mild Concussion can cause long-term changes in the brain.


A concussion is a type of traumatic brain injury that results from a blow to the head or body, a fall, or any other injury that jars or shakes the brain inside the skull. While most concussions are mild and patients recover within a few days to a few weeks, some individuals experience symptoms that last much longer.

Mild traumatic brain injury, or concussion, can result from a blow to the head and is linked to persistent symptoms such as cognitive impairment, depression, headaches, and fatigue. Recent studies show that only half of the individuals with concussions recover fully after six months, indicating inadequate post-injury care. Predicting the recovery time for patients is challenging. Even with brain scans showing no structural damage, symptoms can persist.

Dr. Emmanuel Stamatakis from the Department of Clinical Neurosciences and Division of Anaesthesia at the University of Cambridge said: “Worldwide, we’re seeing an increase in the number of cases of mild traumatic brain injury, particularly from falls in our aging population and rising numbers of road traffic collisions in low- and middle-income countries. At present, we have no clear way of working out which of these patients will have a speedy recovery and which will take longer. The combination of over-optimistic and imprecise prognoses means that some patients risk not receiving adequate care for their symptoms.”

According to recent studies, almost half of people with concussions still show brain injury symptoms six months later. These symptoms can include headaches, dizziness, memory problems, trouble concentrating, and mood changes. In some cases, these symptoms can persist for a year or longer. They can significantly impact an individual’s quality of life.

It’s important to note that these symptoms are not always a direct result of ongoing brain damage. Sometimes, they may be related to other factors, such as stress or anxiety. However, ongoing symptoms of brain injury are a significant concern for healthcare professionals, as they can indicate more serious underlying issues.

Researchers studied fMRI brain scans from 108 patients with mild traumatic brain injury and compared them with scans from 76 healthy volunteers. They found that 45% of patients still had symptoms resulting from their brain injury, the most common being fatigue, poor concentration, and headaches.

The researchers found abnormalities in the thalamus region of the brain, which integrates sensory information and relays it around the brain. The thalamus was hyperconnected, trying to compensate for any anticipated damage, which is at the root of some long-lasting symptoms. The study suggests that drugs targeting these brain chemicals offer hope for treatment.

Mild traumatic brain injury (mTBI) is associated with persistent symptoms and incomplete recovery, but clinical care and prognostication are poor. Thalamic dysfunction has been implicated in post-concussive symptoms. 

The thalamus could be an essential region of interest in pathogenesis and prognosis following mTBI. However, signs of structural damage on CT or structural MRI are uncommon in the acute phase mTBI populations. 

Functional imaging provides a more sensitive means of investigating earlier thalamic damage and its relationship to the outcome, where resting state functional MRI (rs-fMRI) allows exploration of wider thalamic function and symptoms than specific cognitive domains in task-based fMRI. 

This manuscript reports on thalamic changes after mTBI, hypothesizing that nuclei-specific functional hyperconnectivity is present acutely after injury with relevance for persistent symptoms. Additionally, specific symptoms may show distinguishing profiles of acute connectivity change, with the exploratory hypothesis that potential underlying neurochemical relationships may guide future therapeutic opportunities.

Data from subjects recruited to the MRI sub-study of CENTER-TBI between December 2014 and December 2017 were analyzed. The inclusion criteria were 108 patients who had sustained mild traumatic brain injuries (mTBI) and matched healthy controls (n=76). Additionally, 31 patients were followed longitudinally for 6 and 12 months post-injury. Six-month outcomes were assessed using the Glasgow Outcome Scale-Extended (GOSE) and the Rivermead Postconcussion Symptom Questionnaire (RPQ). 

Imaging acquisition protocols for CENTER-TBI were used for structural (T1-weighted) and functional (rsfMRI) imaging during the acute phase after injury. Thalamic subdivisions and thalamic volume were analyzed using the probabilistic atlas defined by Najdenovska and colleagues.

The study “Acute thalamic connectivity precedes chronic post-concussive symptoms in mild traumatic brain injury” used functional MRI to investigate changes in brain connectivity after mild traumatic brain injury (mTBI) and their relation to chronic post-concussive symptoms (PCS). Patients with mTBI were assessed using fMRI to measure thalamic connectivity shortly after their injury and again after three months. 

Results showed that patients who developed chronic PCS had increased thalamic-frontal connectivity shortly after their injury, which was not seen in those who did not develop chronic PCS. Increased thalamic-frontal connectivity was also associated with worse PCS symptoms at the three-month follow-up. These findings suggest that thalamic-frontal connectivity shortly after mTBI may be an early marker for the development of chronic PCS.

Overall have important implications for identifying individuals at higher risk of developing chronic PCS and for developing interventions to prevent or mitigate the development of these symptoms. Further research is needed to validate these findings and to investigate potential interventions based on these results.

To reduce the risk of long-term complications from a concussion, it’s important to seek medical attention as soon as possible after a head injury. Even mild concussions should be evaluated by a medical professional, as they can have severe consequences if left untreated. In addition, it’s important to follow a doctor’s instructions for recovery, which may include rest, medication, and other treatments to manage symptoms and reduce the risk of long-term complications.

Journal Reference:

  1. Woodrow, R. E., Winzeck, S., Luppi, et al. A. Acute thalamic connectivity precedes chronic post-concussive symptoms in mild traumatic brain injury. Brain. DOI: 10.1093/brain/awad056
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