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As was noted in the article on defining mild traumatic injury (MTBI), all national and international classification systems that provide operational definitions for MTBI either require the presence of an alteration of mental status or require the presence of an alternation of mental status if more strong indicators of brain injury are not observed (e.g., seizures). A loss of consciousness (LOC) is a significant alteration of mental status, which involves a complete or near-complete involuntary lack of responsiveness to environmental stimuli. Although LOC would meet definitional criteria for MTBI, it is important to consider the possibility of a psychologically-induced fainting spell upon exposure to a psychological trauma, which would not obviously equate to brain injury. The possible effects of illegal drug use and alcohol intoxication also need to taken into account since this can also alter one’s level of consciousness for reasons other than brain injury. This is particularly relevant in motor vehicle accidents and assaults, where drug and alcohol use sometimes play prominent roles.
The clinician can be more confident that LOC took place if this was documented and observed by medical providers. For example, if paramedics at the scene documented LOC, one can be very confident that LOC occurred. Assuming that the reliability of a non-medical collateral informant (e.g., family member or friend) is high, one can also be confident that LOC took place if this was observed. However, when there were no observers present, and the report of LOC is solely based on the patient, much greater caution is needed before drawing firm conclusions. The reason is because some patients experience a period of post-traumatic amnesia (PTA), which is a time period after trauma in which the person is unable to form clear and consistent memories for daily events. A patient may be conscious during this period of time, have no memory of it (or will report vague and spotty memories), and later report this as LOC when this may actually not be the case. Regardless, the presence of LOC and/or PTA would meet criteria for an alteration of mental status. It is crucial that clinicians make an attempt to obtain records from the first place where the patient was medically evaluated, which is usually an Emergency Room, Urgent Care Center, or physician’s office. This provides a way to cross-check information reported by the patient during interview. Sometimes, there are marked discrepancies between the various sources of information and having the records available allows one to explore this and attempt clarification. Unfortunately, many clinicians fail to request such records.
Contrary to popular belief, a loss of consciousness is not required for a diagnosis of mild traumatic brain injury, but it is a strong objective indicator when it is well-documented. Besides PTA, another example of a mental status change that does not require LOC is disorientation. Disorientation is when one experiences a loss of one’s bearings with regards to basic information about one’s environment. For example, if a hockey player is violently checked headfirst into the boards and subsequently does not know that he/she is at a hockey rink, this qualifies for disorientation to place. One can also be disoriented to time, situation, and self.
When less stringent criteria for an alteration of mental status change are used, the chance of a false positive brain injury diagnosis increases. This is most likely to occur when one solely relies on self-report of feeling “dazed” or “confused” because while these vague terms may indicate a brain injury induced mental status change, they may also reflect no brain injury. This is where a thorough clinical interview is needed. As an example, I once evaluated a patient who had an object drop on his head from above. He had been diagnosed with brain injury because he later reported feeling “dazed” at the time. Upon interview, it was revealed that when he stated he was “dazed” he did not mean that he was disoriented. What he meant was that he was “surprised” because he had not expected an object to hit him from above. This would of course be a totally normal experience when struck from behind unexpectedly. A natural feeling of surprise does not equate to brain injury.
What this anecdotal tale shows is that patients sometimes use terms in ways that are far different from how a medical professionals use them. Another example of this involves a patient I once evaluated who had told other providers he “blacked out” after the injury. This was used to support a brain injury diagnosis. However, detailed interview during a neuropsychological evaluation revealed that he could not state with any degree of certainty that he actually blacked out. What he was actually referring to was a one to two second period after he was struck from behind by a car (which pushed his car forwards) in which he could not state what happened between the time of impact and looking in his mirrors. He also stated it took him a few seconds to realize he was in an accident and where he was but that he figured this out very quickly. A period of a few seconds of a lack of clarity while one’s car has been smashed from behind and pushed forwards can be a totally normal experience given the situation that does not automatically equate to brain injury. For example, if you stood up and spun around 20 times it may take a few seconds to realize where you are, but that does not mean you suffered a brain injury.
While these stories are anecdotal, Lees-Haley et al (2001) provided data to show that subjective reports of feeling “dazed,” “confused,” and “disoriented” are quite common after experiencing traumatic events that do not involve brain injury. For example, about 67% of patients with MTBI claims in that study reported being “confused” and 71% reported feeling “dazed.” However, 52% of the non-brain injured sample also reported feeling “confused” and 65% reported feeling “dazed” after exposure to a traumatic event such as sexual harassment or exposure to horrific incidents. Forty-two percent of the non-brain injured group reported feeling “disoriented” whereas only 33% of the MTBI claimant group reported this symptom. Thirty-six percent of the non-brain injured group reported “memory loss” after the event whereas 42% of the MTBI claimant group reported this. None of these differences were statistically significant. The authors concluded that such subjective complaints are so non-specific that they offer little diagnostic specificity. As the authors state, “…failure to consider the prior probabilities of general stress symptoms when formulating diagnostic impressions may lead to misleading and erroneous diagnoses where no brain injury exists.” (p. 691). Therefore, clinicians should carefully evaluate subjective reports of altered mental status before equating them with brain injury.
REFERENCES
Lees-Haley et al. (2001). A comparison of complaints by mild brain injury claimants
and other claimants describing subjective experiences immediately following their injury. Archives of Clinical Neuropsychology,16, 689–695.
Dr. Carone offers paid lectures on MTBI, “post concussion syndrome,” and symptom validity testing upon request. He can be contacted at info@mtbifacts.com.
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