Lingering concussion symptoms likely related to nerve damage, say researchers

Researchers in Sweden have found a link between damage to the vestibular nerve and lingering concussion-like problems.
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Damage to the vestibular nerve may be the cause of lingering concussion symptoms in some patients, researchers report.

Depression, dizziness, difficulty focusing the gaze and balance problems can linger in those affected by concussion.

A clinical study from Lund University in Sweden, reported in the Journal of Neurotrauma, indicates that such problems can originate from an injury to the vestibular nerve.

In most cases, symptoms after a concussion are temporary, but an increasing number of athletes experience long-term problems that make it difficult to work, go to school or play sports.

The symptoms are aggravated by activity and include headaches, depression, anxiety, nausea, difficulty focusing and problems with balance.

“It has been unclear what causes the symptoms, and it is difficult for healthcare professionals to help these athletes,” said one of the study authors, Niklas Marklund, professor of neurosurgery at Lund University and a consultant at Skåne University Hospital.

Marklund, who has a scientific interest in sports-related head injuries, continued: “We wanted to investigate this further to find out what really causes the symptoms.”

In all, 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 who had experienced persisting symptoms for more than six months.

All participants underwent various tests in which the researchers examined, among other things, their balance organs.

Using a so-called 7-Tesla MRI, the athletes’ brains were studied to understand more about what caused the symptoms. The researchers 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, three people had similar findings.

Anna Gard, a doctoral student at Lund University, resident in neurosurgery at Skåne University Hospital and first author of the study, said the test results show that the injury is 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.”

When individuals suffer a concussion, it is often because the head rotates too fast.

Marklund continues: “We have not examined athletes with short-term problems after blows to the head, so we cannot say anything about them. 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.”

Anna Gard, Ali Al-Husseini, Evgenios N. Kornaropoulos, Alessandro De Maio, Yelverton Tegner, Isabella Björkman-Burtscher, Karin Markenroth Bloch, Markus Nilsson, Måns Magnusson, and Niklas Marklund. Journal of Neurotrauma.ahead of print

The study, published under a Creative Commons License, can be read here

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