Post-Concussion Symptoms Linked to Vestibular Nerve Damage

A clinical study from Sweden’s Lund University has implicated injury to the vestibular nerve as the cause of lingering symptoms many professional athletes experience after sustaining head trauma.

The symptoms after a concussion are temporary in many cases, but an increasing number of athletes experience long-term problems that make it difficult to work, go to school or play sports. These symptoms can include depression, dizziness, anxiety, nausea, difficulty focusing gaze and balance problems. The issue has gained increased attention in recent years due to highly publicized cases of dementia, severe depression and cognitive impairment experienced by former American football players.

“It has been unclear what causes the symptoms, and it is difficult for healthcare professionals to help these athletes. We wanted to investigate this further to find out what really causes the symptoms,” says Niklas Marklund, professor of neurosurgery at Lund University and consultant at Skåne University Hospital.

A total of 42 people were included in the study. One group included 21 healthy athletes without previous trauma to the head, and the other 21 athletes who all suffered from sports-related concussions and experienced persisting symptoms for more than six months. All the participants underwent various tests in which the researchers examined, among other things, their balance organs. 7-Tesla MRI found impaired function of the balance organs in the inner ear of 13 athletes in the group with long-term problems. In the group of healthy athletes, 3 showed similar findings.

“The test results show that the injury is located to the vestibular nerve, which is connected to the semicircular canals in a cavity inside the skull, and which is directly adjacent to the cochlea in the ear. These injuries lead to the inward nerve impulses not working properly, and the brain therefore does not receive important information about body movements and sensory impressions required to maintain a good balance,” says Anna Gard, doctoral student at Lund University, resident in neurosurgery at Skåne University Hospital.

The study did not examine athletes with short-term problems after blows to the head. “This study applies to athletes with prolonged symptoms after concussion. The rotation of the head that occurs in connection with a concussion could lead to a stretch of the vestibular nerve, which then leads to impaired function. Now that we have more knowledge about where the problems are located, it is easier to find possible therapies that could help these athletes,” says Marklund.

The findings were published in Journal of Neurotrauma.