Looking at Concussions in the Long Run

Alzheimers disease development may be related to head trauma in some individuals

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) As research continues to progress with Alzheimer's disease, scientists are looking for information about what might contribute to it. They recently found one possibility.

A recent study found that past concussions might be related to the development of Alzheimer's in patients who are already susceptible to cognitive problems.

The researchers compared brain scans of patients and found some differences only in those who already had mild cognitive impairment.

It's not clear what the finding means or whether a concussion poses any long-term risks to healthy individuals with normal brain function.

"See a neurologist for any possible head trauma."

The study, led by Michelle M. Mielke, PhD, of the Division of Epidemiology at the Mayo Clinic in Minnesota, looked at whether head trauma, such as a concussion, was linked to a gradual breakdown in the brain.

The researchers included in the study 488 participants who had normal brain function and 141 participants who had mild cognitive impairment.

The participants all underwent a head scan using magnetic resonance imaging (MRI), which uses a large magnet to create images of the brain.

The participants were also interviewed regarding whether they had ever suffered head trauma in which they lost consciousness or memory for even a moment.

Then the researchers compared differences in the brain scans among the participants, taking into account any differences that might have existed for their age and sex.

Among the 448 participants who had normal brain function, 17 percent reported having had a head trauma or concussion in their past.

However, the researchers found no differences in any of the diagnostic tests or imaging results among those who had past head trauma and those who didn't in this group.

Then, 18 percent of the 141 participants with mild cognitive impairment reported past head trauma.

Among these participants, the researchers found higher levels of a substance called amyloid in their brains, compared to those with mild cognitive impairment but no history of concussion.

Amyloid is a substance that can build up in the brain and has been linked to dementia and Alzheimer's disease.

The researchers therefore concluded that a past history of concussion increased the risk of having amyloid deposits in the brain among only those who have mild cognitive impairment (but not those with normal brain function).

They wrote that this finding suggests, "that head trauma may be associated with Alzheimer disease–related neuropathology."

In other words, it's possible that a past history of concussion or head trauma could be related to the development of Alzheimer's in some individuals.

According to Michelle M. Mielke, PHD, from the Mayo Clinic, “It does provide some additional link between traumatic brain injury and amyloid which is one of the pathologies of Alzheimer’s disease."

She continued with, "Clearly, we need to do a lot more work to understand this and more than anything, head trauma is likely to be a risk factor but it’s not going to determine specifically whether you’re going to develop Alzheimer’s disease."

However, the possible connection is not clear and requires more research to understand.

The study was published December 26 in the journal Neurology.

The research was funded by the National Institutes of Health, the Robert Wood Johnson Foundation, the Alexander Family Alzheimer's Disease Research Professorship, GE Healthcare, the Elsie and Marvin Dekelboum Family Foundation, the MN Partnership for Biotechnology and Medical Genomics and the Robert H. and Clarice Smith and Abigail van Buren Alzheimer's Disease Research Program.

Six authors reported some form of relationship with a range of pharmaceutical or industry companies, whether their relationship involved research funding, consulting, advising or serving on a board.

The companies included Eli Lilly, Lilly Pharmaceuticals, TauRx Pharmaceuticals, Baxter, Elan Pharmaceuticals, Forest Pharmaceuticals, Bayer Schering Pharma, GF Healthcare, Siemens Molecular Imaging, the MN Partnership for Biotechnology and Medical Genomics, the Leukemia & Lymphoma Society, Abbvie Health Economics and Outcomes Research, Pfizer, Janssen Alzheimer Immunotherapy and Siemens Healthcare.

Review Date: 
December 27, 2013
Last Updated:
January 29, 2014