Concussion and its neurobehavioural sequelae.

A concussion results from a force to the brain that results in a transient loss of connectivity within the brain. Sport psychiatrists are increasingly called to be part of the concussion team and need to be prepared to manage issues related to concussion and its behavioural sequelae. Objectively, the best evidence available suggests that deficits in attention and/or in balance are the most reliable objective findings that a concussion has occurred. Prognosis after a concussion is generally very good, although a sub-set of patients that are yet well defined seem pre-disposed to delayed recovery. Neither head CT nor MRI are sufficiently sensitive to diagnose the type of injuries that pre-dispose patients to the neurobehavioural sequelae that have been associated with a concussion; confounding this is the finding that many of these signs and symptoms associated with concussion occur in other types of non-head injuries. Brain biomarkers and functional MRI (fMRI) hold promise in both diagnosis and prognosis of concussion, but are still research tools without validated clinical utility at this time. Finally, neurocognitive testing holds promise as a diagnostic criterion to demonstrate injury but, unfortunately, these tests are also limited in their prognostic utility and are of limited value.