Concussion is confusing us all

Abstract

It is time to stop using the term concussion as it has no clear definition and no pathological meaning. This confusion is increasingly problematic as the management of 'concussed' individuals is a pressing concern. Historically, it has been used to describe patients briefly disabled following a head injury, with the assumption that this was due to a transient disorder of brain function without long-term sequelae. However, the symptoms of concussion are highly variable in duration, and can persist for many years with no reliable early predictors of outcome. Using vague terminology for post-traumatic problems leads to misconceptions and biases in the diagnostic process, producing uninterpretable science, poor clinical guidelines and confused policy. We propose that the term concussion should be avoided. Instead neurologists and other healthcare professionals should classify the severity of traumatic brain injury and then attempt to precisely diagnose the underlying cause of post-traumatic symptoms.

Keywords: Concussion; Mild traumatic brain injury; Post-concussive; TBI; Traumatic brain injury.

Figure 1

The Persian physician Razes.

Figure 2

Two potential classification systems for traumatic brain injury and concussion.

Figure 3

A hierarchical approach to the management of mild traumatic brain injury.

Figure 4

A football player knocked unconscious at the World Cup 2014. He played on for a further 14 minutes before being substituted (see figure 5).

Figure 5

The football player from figure 4 is led off having played on for 14 minutes after being knocked unconscious.

Figure 6

A microbleed is clearly identified on susceptibility weighted MRI (marked with white arrow) but not clearly visible on standard T1 weighted nor fluid-attenuated inversion recovery MRI.

Figure 7

(A) Diffusion-tensor imaging assessment of white matter damage after traumatic brain injury (TBI). Axial images show a contrast between mild TBI and control groups. Normal white matter is shown in green, with red regions showing damaged areas (low fractional anisotropy). (B) and (C) A single case study of a 41-year-old man with a mild TBI following a road traffic collision (post-traumatic amnesia of <24 h, loss of consciousness <30 min). (B) Normal structural MRI (T1 and fluid-attenuated inversion recovery). (C) Diffusion-tensor imaging assessment of white matter structure. The graph shows Z-scores for the comparison of fractional anisotropy in each tract between the patient and controls. The central white area denotes the area of Z<1.64 (p>0.01) for the control group’s fractional anisotropy. Red bars indicate where that tract's fractional anisotropy value was >2.3 SDs from the control group mean. This provides evidence for extensive damage throughout this patient's white matter, despite normal standard structural imaging. (D) An illustration of diffusion-tensor imaging data, where the colour represents the predominant direction of water diffusion. L, left; R, right; CC, corpus callosum; SLF, superior longitudinal fasciculus; ILF, inferior longitudinal fasciculus; CST, corticospinal tract; Hipp, hippocampus.