​​​​Dr. David Cassidy
An international team of clinician scientists, led by TWRI's Dr. David Cassidy, pictured here, has published an analysis of research focused on mild traumatic brain injury (MTBI). (Photo: UHN)​

In recent years, the effects of mild traumatic brain injury (MTBI) – also known as concussion – have become a major concern for the public and the focus of researchers. Many studies have been conducted but, what exactly do they tell us about the effects of concussion?

This month, the Archives of Physical Medicine and Rehabilitation published a supplement on this issue.

Guest edited by Dr. J. David Cassidy, Senior Scientist, Toronto Western Research Institute (TWRI) and his graduate students at the University Health Network, the supplement contains several original studies and systematic reviews of the best research available addressing prognosis for MTBIs.

A systematic review identifies, evaluates, and analyzes all studies relevant to a particular research question – in this case what people can expect after suffering a MTBI or concussion.

Cassidy was assisted by Dr. Carol Cancelliere, a PhD student in clinical epidemiology and Dr. James Donovan, a research associate with his lab.

The supplement includes 16 papers, including 10 systematic reviews and three original research papers. The findings provide many interesting points on a variety of issues linked to concussions.

Highlights include:

  • The majority of people with MTBI or concussion recover, but about 25% still have persistent symptoms a year after suffering the injury.
  • The main factors that influence a patient's recovery are: the severity of symptoms immediately after the injury, a person's expectations for recovery, and physical and mental health status prior to the injury.
  • There is a higher risk of epilepsy in children after concussion; however, the overall risk is low as it accounts for very few new cases.
  • Concussion can cause cognitive or "thinking" problems that can persist for months in some individuals.
  • People with other injuries also experience symptoms experienced by people with concussion, such as headache, dizziness, memory and concentration problems, an​d fatigue. Many symptoms associated with post-concussion syndrome are not specific to concussion.
  • Some small studies suggest that concussions are a possible risk factor for dementia. However, the larger studies don't show this. To date, there is no high-quality scientific evidence that concussions cause dementia or other neurodegenerative disorders.

This project was funded by the Ontario Neurotrauma Foundation. The funding allowed Cassidy to assemble an international team of clinician scientists from five countries and involved collaboration between UHN, the University of Alberta, the University of Southern Denmark, the University of Bordeaux, the Center for Disease Control in Atlanta and Karolinska Institute in Stockholm, Sweden.

The full issue can be viewed by clicking here

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