Definition and epidemiology of mild traumatic brain injury

Abstract

Background/objectives: The definition of mild traumatic brain injury (mTBI), also known as concussion, has been a matter of controversy, which makes comparison between studies difficult. Incidence varies greatly from one country to another. The present article reviews definitions and epidemiology.

Methods: Literature review.

Results: According to the Mild TBI Committee of the American Congress of Rehabilitation Medicine, revised by the World Health Organization (WHO), mTBI is defined by a Glasgow Coma Scale score between 13 and 15 at 30minutes post-injury, and one or more of the following symptoms: <30min loss of consciousness; <24hours post-traumatic amnesia (PTA); impaired mental state at time of accident (confusion, disorientation, etc.); and/or transient neurological deficit. If a focal lesion is found on computed tomography (CT) or magnetic resonance imaging (MRI), the term "complicated mild TBI" has been proposed. Incidence of mTBI is 200-300/100,000 persons per year for hospitalized patients and probably twice as high if non-hospitalized patients are included. However, a few recent population-based studies reported a much higher rate (>700/100,000). A changing pattern of epidemiology has been found in high-income countries, related to a decrease in road-accident injuries in young adults, while conversely the proportion of falls has increased with population aging.

Conclusion: Mild TBI is a major public health concern, the epidemiology of which has greatly changed in the last twenty years.

Keywords: Concussion; Epidemiology; Mild traumatic brain injury.