Author: Richard H. Adler

The possibility a traumatic brain/head injury with loss of consciousness presents a potential risk factor for Alzheimer's Disease (AD) has now been studied. It had previously been suggested traumatic brain injury created a heightened risk among carriers of a certain gene type for developing AD. That suggested casual link was affirmed by a study published in Neurology¹ that evaluated the relationship between head injury and Alzheimer's Disease. This paper is often referred to as the MIRAGE study (Multi-Institutional Research in Alzheimer Genetic Epidemiology).

The reachers evaluated 2,233 Alzheimer's patients meeting the AD criteria of the National Institute of Neurology and Communicative Disorders and Stroke/Alzheimer's Disease in Related Disorders Association between 1991 and 1996 at 13 centers in the United States, Canada, and Germany. The dementia status of 14,668 first degree family members of the study group (4,465 parents, 7,694 siblings, and 2,509 spouses) was collected by interview and review of medical records as well. Non-demented relatives and spouses served as control subjects for this study. The significant results of the MIRAGE study included:

"Our result showed that head injury with loss of consciousness and, to a lesser extent, head injury without loss of consciousness increased the risk of AD [Alzheimer's Disease]. We also found that the risk of developing AD was significantly higher among relatives with head injury than among relatives without head injury at all ages after 60. ... We did not find evidence for an interaction between family history and head injury, especially head injury with loss of consciousness. Our results indicate that head injury exerts a relatively greater effect on the risk of AD among persons lacking the APOE-E4 allele compared with those having one or two E4 alleles. ...
...
Our results suggest that severity of head injury is related to magnitude of AD risk. ...we found that the risk associated with head injury with loss of consciousness was approximately double that associated with head injury without loss of consciousness."

This seminal study provides several teaching points for health care providers and personal injury attorneys assisting traumatic brain injury survivors with their medical, insurance and legal needs:

1. Symptoms related to head injury must be fully evaluated to ascertain whether there is a concussion or traumatic brain injury.
2. It is also important to ascertain whether an individual has sustained a loss of consciousness following trauma. This is commonly accomplished by simply asking the patient basic questions. Often, however, the form of the question misses the mark. For example:
   

   Provider Question: "Did you loss consciousness?" Patient: "I don't think so."
   Provider's conclusion: There is no loss of consciousness.
   Critical Analysis: How would a patient know if they experienced a traumatic loss of consciousness if they were unconscious?

   If the form of the question is modified, one is more likely to obtain insightful information on loss of consciousness status. For example:
   

   Provider Question: "What is the last thing you remember before the traumatic event? What is the next thing you remember right after the traumatic event?"
   Patient: "I remember hearing screeching and then remember someone knocking on my driver's window asking if I was okay."
   Provider's conclusion: This patient obviously had a loss of consciousness since there is a gap of time between when the accident happened and when somebody came to their window. Critical Analysis: This patient may be at risk of developing AD later in life.

3. If a head injury is suspected, referral for an evaluation by a neurologist, neuropsychologist, or physiatrist well-versed in understanding and evaluating traumatic brain injury would be appropriate to help better assess, treat and provide a comprehensive prognosis for the patient's condition that includes a MIRAGE - based assessment on the risk of developing Alzheimer's Disease in the future.

Traumatic brain injury survivors face complex medical, insurance and legal issues for which a consultation with personal injury attorneys well versed in such matters is called for. The attorneys at Adler Giersch ps stand ready to assist your brain injury patients through their offices located in Seattle, Bellevue, Everett and Kent.

1. Neurology 2000; 54: 1316-1323