Custom Search
|
|
|
|
An often repeated claim by mild traumatic brain injury (MTBI) advocates is that MTBI patients are suffering from “invisible injuries.” This article will explore the justification behind this claim as well as the serious problems inherent with it.
Many times, the term “invisible injury” is used to convey that the patient is suffering from symptoms that are not noticeable to others based on outward physical appearances alone. For example, while the patient may be subjectively reporting and/or experiencing headaches, fatigue, dizziness, memory problems, concentration difficulties, and depression, people who interact with the patient assume he/she is healthy because there is no way to readily detect this based on physical appearances. In other words, the person does not physically appear sick or disabled because they are not wheelchair-bound, have not lost their hair or significant weight like a patient on chemotherapy would be expected to, and do not have any obvious physical deformities such as a missing limb. Of course, a patent may grab his/her head and wince in pain or appear sleepy, but this term is typically used to refer to patients who do not have the traditional stereotypical outward appearances of one who has a significant physical illness.
While this argument certainly has merit to it since patients can indeed experience significant symptoms without outwardly appearing disabled or ill, anyone who regularly works with patients who have diverse neurological conditions will readily understand that this experience is in not unique to MTBI patients. Time and time again, I have heard from patients with other neurological conditions describe this same exact phenomenon to me. These patients have had brain tumors, strokes, multiple sclerosis, and moderate to severe brain injuries, just to name a few conditions. In fact, I have even had some patients describe this phenomenon when there technically were outward physical signs of something pathological, such as a skull depression from neurosurgery. Regardless, these patients still feel that such visible signs are overlooked and that they are considered to be healthy by others because they are able to communicate well and do not appear sickly or disabled.
The main difference between MTBI patients and those with the other diagnoses listed above is that those with the other diagnoses almost always have signs of brain injury or damage on conventional neuroimagining (brain CT/MRI) whereas MTBI patients often do not. It is for this reason (normal neuroimaging findings), that MTBI is also referred to as an “invisible injury.” However, not all MTBIs are invisible because in 10 to 15% of MTBI cases (potentially up to 21%), brain CT (computerized tomography) results show some signs of brain injury (Iverson et al., 2000). In addition, brain MRI (magnetic resonance imaging) is about 25-30% more sensitive than brain CT in detecting diffuse axonal injuries, in which part of the nerve cell that transmits information has been damaged (Mittl et al., 1994). For this reason, the prevalence of MRI abnormalities after MTBI ranges from 10% all the way up to 57% (12 of 21; Hofman et al., 2001). Another important point is that MRIs with greater magnet strength (i.e., 3 Tesla) will show more evidence of brain injury than MRIs with lower magnet strength (i.e., 1.5 Tesla; Frayne et al., 2003). Therefore, the notion that all MTBIs are all “invisible” is inaccurate. While one must be open minded to the idea that current neuroimaging techniques may not detect subtle areas of brain damage, the question then becomes whether or not such undetected brain damage would be enough to cause persisting symptoms more than three months post-injury. This must be evaluated on a case by case basis by a skilled clinician familiar with the evidence-based literature. As a general rule of thumb, the longer one is removed from the date of the MTBI, the less likely it is that brain injury is the explanation for persisting symptoms.
With all of this information kept in mind, one also needs to be aware of a serious problem with the “invisible injury” argument from a scientific perspective. That is, there are many cases where a mild injury to the head has been misdiagnosed by a well-meaning practitioner as a mild injury to the brain. Such diagnoses are often made in haste without consideration of formal diagnostic criteria. In some of these cases, patients become convinced they are brain injured and then begin to interpret common everyday experiences and/or unrecognized and undiagnosed comorbid psychiatric problems (e.g., depression, PTSD and panic attacks) as being caused by a non-existent brain injury.
In such cases, despite the fact that all neuroimaging and other diagnostic studies (e.g., neuropsychologial evaluation) are normal regarding the possibility of brain injury, the patient, health care provider, and other advocates may continue to assert that an “invisible” brain injury is present and explains all of the symptoms. This is an unscientific proposition because it is unfalsifiable. That is, to someone claiming that all symptoms are caused by an “invisible” brain injury, there is no amount of evidence that can ever be shown to disprove the claim because the injury is supposedly “invisible.” However, in some cases, the true state of affairs is that no brain injury is present. In science, a hypothesis must be falsifiable (capable of being proven wrong) to be valid. MTBIFacts.com presents this information so that patients and health care providers will be more open to begin shifting their conceptualization of what may be the root cause of persistent symptoms when overwhelming evidence shows that the cause does not appear to be a brain injury. As the poet, James Whitcom Riley stated sometime around 1833-1835, "When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck."
REFERENCES
Frayne et al. (2003). Magnetic Resonance Imaging at 3.0 Tesla: Challenges and
Advantages in Clinical Neurological Imaging. Investigative Radiology, 38, 385-402.
Hofman et al. (2001). MR Imaging, Single-photon Emission CT, and
Neurocognitive Performance after Mild Traumatic Brain Injury. American Journal of Neuroradiology, 22, 441–449.
Iverson, G. et al. (2000). Prevalence of abnormal CT-scans following mild head
Injury. Brain Injury, 14, 1057-61.
Mittl et al., (1994). Prevalence of MR evidence of diffuse axonal injury in patients with mild head injury and normal head CT findings American Journal of Neuroradiology, 15, 8, 1583-1589.
Dr. Carone offers paid lectures on MTBI, “post concussion syndrome,” and symptom validity testing upon request. He can be contacted at info@mtbifacts.com.
Copyright © 2009, MTBIFacts.com. All rights reserved. You may not reprint or redisplay this material for commercial use without the express written consent of MTBIFacts.com.
Use of MTBIFacts.com is subject to reading this disclaimer.
|