This article is about another example of chemo brain.  Published are articles a similar effect of statins and pump head (bypass surgery).  Add to this the anti-psychotic medication, so-called muscle relaxants, the opioids, antihistamines, to name some of the principle class.      

From Science Daily at http://www.sciencedaily.com/releases/2008/03/080319152426.htm

Mar 20, 2008

Possible Cause Of 'Chemo Brain' In Breast Cancer Patients Found

Thanks to early diagnosis and chemotherapy, more women survive breast cancer than ever before. However, following treatment, approximately 25 percent of survivors experience mild to moderate memory, concentration and cognitive problems known as “chemobrain”.

“Several studies have investigated chemotherapy’s cause and effect on memory problems, but until now scientists had no clue what changes in the brain lead to memory loss,” Jame Abraham, M.D., director of the Comprehensive Breast Cancer Program at West Virginia University’s Mary Babb Randolph Cancer Center, said.

Abraham and his research team conducted one of the first chemobrain studies of its kind. The study documented the extent of changes to the brain’s white matter in women who received chemotherapy for breast cancer.  The preliminary study involved ten breast cancer patients who had received chemotherapy and complained of cognitive changes. A control group of nine healthy women of similar age, education and IQ, who never received chemotherapy, was also studied.  All participants were screened for medical, neurologic and psychiatric conditions that could affect brain structure or function. Participants were tested for depression, anxiety and processing speed.  Each participant also participated in a diffusion tensor imaging (DTI) MRI scan. The DTI was used to assess changes in the white matter of the brain. 

“The images indicated differences in the white matter in the front part of the brain in women who had received chemotherapy,” said Marc Haut, Ph.D., of WVU’s departments of Behavioral Medicine and Psychiatry, Neurology and Radiology. “This difference in white matter correlated with how quickly the breast cancer patients could process information.” 

“Women who received chemotherapy performed significantly worse in speed of processing than their counterparts in the control group,” said Abraham. “Our preliminary findings suggest that chemotherapy may change the brain and those changes affect the patient’s cognitive skills.”

Morgantown resident Sharon Palmatory, a patient of Dr. Abraham, recently finished chemotherapy treatments. She had very few side effects during chemotherapy, but after treatment experienced trouble remembering names and numbers.  “I can’t multi-task anymore; I can only focus on one thing at a time. It’s frustrating because I am used to being in control,” Palmatory said.

In some patients chemobrain can have a significant and serious affect on their everyday life.

“I feel like I’m always lagging behind in processing information,” she said. “It’s good to know that Dr. Abraham and others are studying this problem; they can let women receiving chemo know that they may experience memory loss.”

WVU researchers also concluded that changes in the white matter of the brain do not appear to be caused by depression or anxiety.

Abraham and Haut are leading several chemobrain studies funded by the U.S. Department of Defense and the WVU Department of Radiology. Their article is published in Clinical Breast Cancer, Volume 8, Number 1, February 2008.  WVU co-authors include Maria Moran, Ph.D., Department of Behavioral Medicine and Psychiatry and Department of Radiology; Shannon Filburn, Clinical Trials Research Unit; and Susan Lemiuex, Center for Advanced Imaging and Department of Radiology. Hiroto Kuwabara, Ph.D., Department of Radiology at Johns Hopkins University, is also a co-author.

The issue is a complex.  First to eliminate other causes, testing should be done prior to all treatment, prior to surgery and the cessation of HRT.  Reduction in estrogen level has been shown to effect cognitive function. Cessation of HRT, use of drugs that block estrogen have been shown to effect cognitive function.  Given the variety of treatments risk varies.  Potential other mechanisms could be vascular injury and oxidative damage (its primary cause), inflammation (a risk factor for atherosclerosis), direct injury to neurons, autoimmune responses, chemotherapy induced anemia, and the presence of the apolipoprotein E (APOE, a genetic risk factor for atherosclerosis).  Other factors effecting cognitive performance would include depression and physical decline with its reduction in energy and alertness--jk.