Mild Traumatic Brain Injury & Concussion:  Historical Controversies and Recent Developments:

Difficulties with assessment and diagnosis

When the term “concussion” is used, there is a common understanding that this refers to a constellation of symptoms which occur following a blow to the head including dizziness, headache, fatigue, difficulty concentrating, being forgetful and problems with sleeping. However, diagnostically, none of these are specific to head injury. These symptoms are reported whether there has been an established loss of consciousness of not. Research has established that these symptoms are often reported in many groups of patients who have not had a blow to the head, for example, orthopaedic patients undergoing joint replacement surgery.

There is much misunderstanding regarding diagnosis, even amongst medical professionals. There are those who believe that for a concussion to have occurred, there must have been a loss of consciousness. This is not the case. The symptoms of concussion can occur even when there has not been a blow to the head, but where the body has been subjected to a forceful movement, such as a fall or being thrown from a horse as the mechanical forces involved can still result in shearing injuries within the brain.

There is a diagnostic category for concussion (and Post-Concussion Syndrome) within ICD-10 and DSM-V classification systems as well as a formal structured clinical interview which has been published in peer-reviewed journals (Rivermead Post Concussion Questionnaire). However, the lack of specificity of symptoms is of concern and can lead to much difference of opinion between clinicians when presented with the same patient.

Predisposing and maintaining factors which cannot be ignored

There is a significant published literature on the range of pre-disposing factors that are associated with the emergence of post-concussion symptoms: if you are female or over 40, if you have a lower than average IQ, if you have a history of psychiatric disorder or substance misuse, for example. There is also evidence that if you have previously experienced blows to the head, over time, it is more likely that your cognitive reserve will have been exploited and, as a result, the threshold for the emergence of troubling symptoms will be lowered. This is referred to as a “window of vulnerability” and can occur at any point in the period of months following the initial injury. In the late 1990s the commonly-held belief was that persisting symptoms following a concussion represented a somatic, or psychological, response and had no organic basis.

Post-concussion symptoms were referred to as having, “organic genesis and psychologically driven persistence” and there is some credibility to that view but recent thinking is that this is an over-simplification of the picture.

Unhelpful beliefs on the part of the person experiencing post-concussional symptoms, such as the “good old days hypothesis” where an individual presents an overly-rosy picture of their abilities and personality prior to the injury or “expectation as aetiology” where benign symptoms which emerge are incorrectly attributed to some underlying brain damage for which there is no evidence can also lead to perpetuation of symptoms which would, ordinarily, be expected to resolve.

Current thinking:

Diagnostic criteria and classification

However, in 2015, a new position paper by Sharp & Jenkins has crystallised the emerging view that the term “concussion” should no longer be used as it no longer has any useful clinical meaning. The term MTBI (Mild Traumatic Brain Injury) is more useful both in terms of explaining symptoms and predicting progression towards recovery. If this position is accepted, and it certainly looks that way, then concussive injuries will henceforth be considered as occurring on the same spectrum as moderate and severe head injuries rather than as a completely separate clinical entity.

Complete recovery or permanent brain changes

The vast majority of published literature, and as a result the received wisdom in this field of study and clinical practice, is that neuroimaging will not show any form of underlying brain injury in a concussional injury and it is this which underpins the current treatment approaches (see below)

However, there is an emerging literature on the topic of brain scans which now shows that even in what would be deemed mild concussions, there may be evidence of structural changes or confirmatory evidence in the form a blood deposits which follow a recognised pattern. This does away with the long-held belief that the absence of neurology on clinical examination, equates with an absence of neuropathology. The two main types of scan which are referred to are both types of MRI: Diffusion Tensor or Susceptibility Weighted imaging (DTI or SWI). Clearly, as the body of evidence becomes more weighty, clinical views will be directed to reconsider the possibility that some symptoms, for some patients, may become permanent for organic rather than psychological reasons.

Treatments which work

It is widely accepted that the earlier and more targeted the intervention, the better the prognosis for the individual who has had the concussional injury. Research indicates that up to two sessions of education around the symptoms along with reassurance of an expected full recovery is effective but needs to occur as soon as possible after the injury. The longer the period of time between injury and treatment, the more entrenched, and treatment-resistant, the symptoms and the beliefs about them become.

Psychological treatment needs to be provided by a qualified clinical neuropsychologist experienced in brain injury and familiar with the literature about MTBI. The focus is on education about the injury, reassurance about prognosis, structured anxiety management and encouragement to follow paced activity routines. Some individuals also benefit from pharmacotherapy in the form of antidepressant or anxiolytic medications.

Watch this space for developments in this exciting field of research and clinical practice!

[References available upon request from author]

expert witness neuropsychology

The Author: Dr. Tracey Ryan-Morgan is a Consultant Clinical Neuropsychologist  and Director of  Talis Consulting Limited, a company which specialises in the provision of Clinical and Neuropsychology services.

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