A clinical study from Lund University in Sweden has shown that long-term problems such as dizziness and difficulty focusing after a concussion originate in an injury to the vestibular nerve. The researchers published their findings in the Journal of Neurotrauma.
Concussion resulting from a blow to the head is a hazard in many sports. In American football, where players who have suffered from repeated concussions have developed dementia, severe depression and cognitive impairment.
Concussion usually has only temporary symptoms, 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 or impressions 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. We wanted to investigate this further to find out what really causes the symptoms,” said Professor Niklas Marklund, one of the study’s researchers.
The study included 21 healthy athletes without previous trauma to the head, and 21 athletes who all suffered from sports-related concussions and who had experienced persisting symptoms for more than six months. The researchers used a 7-Tesla MRI, to study the athletes’ brains to understand more about what caused the symptoms. They discovered 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.
“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,” said Anna Gard, doctoral student at Lund University and first author of the study.
Concussion often results from the head rotating too fast.
“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,” concluded Prof Marklund.
Source: Lund University
