MILD TRAUMATIC BRAIN INJURY

Mild traumatic brain injury (MTBI) is presumptive diagnosis based primarily on the presence of head trauma associated with alterations in consciousness followed by the development of the post-concussion syndrome.  Although it is possible to document cognitive impairment on neuropsychological testing, it is not possible to directly demonstrate the presumed injury to the brain.  A cause, the head trauma, has been identified, and an effect, the post-concussion syndrome, has been clinically discovered.  The brain injury, the presumed mediator between cause and effect, remains unspecified.

The majority of the mild head injury cases I evaluate in my clinical and forensic practices meet the criteria for an MTBI diagnosis. The functional impairments that these patients experience in their daily lives and on testing range broadly from minimal, transient problems with word fluency and mental tracking to disabling problems that persist indefinitely. We can’t validate these differences with “objective” evidence from brain scans regarding the degree of brain injury. We have no basis for deciding that a patient has too much functional impairment for “this type of injury” and therefore must be malingering or exaggerating, and we ought to avoid facile psychological “reasons” for why these patients remain disabled.

We don’t know what has been injured inside the skull in an MTBI, and these unknowable injuries vary enormously. Within the MTBI diagnostic category, neuropsychological tests reveal a broad range of disability. I have evaluated several significantly impaired MTBI cases within a month of their injuries whose disability on cognitive testing is consistent with very significant brain dysfunction. These patients have great difficulty staying focused on cognitive testing, they lose track of what they are doing quickly, and their attempts to persist despite their difficulty leads to further deterioration in their performances. They are not easily able to return to work, they do not regain their pre-accident functioning and they never recover completely. Their disability is not mild even though their head injuries were. Although these patients initially strive to regain the lives they lost, they eventually accept a more limited role for themselves both personally and professionally.

This outcome is especially tragic for those who sustain vestibular system trauma and are diagnosed with a presumed MTBI.  Physicians have nothing other than the tincture of time to offer for patients with a post-concussion syndrome, but effective treatments exist for a vestibular trauma syndrome.  Proper evaluation begins with the specialized evaluation of the six semicircular canals in the inner ear.  Crystalline debris from trauma drifts into one or more of the canals causing them to transmit aberrant signals to the brain.  This condition, benign paroxysmal positional vertigo (BPPV), can cause all of the symptoms of the post-concussion syndrome without brain involvement, and it is treatable with the appropriate repositioning maneuvers. Even more central, brain-based vestibular syndromes can be treated with habituation and retraining exercises.