Scans have shown loss of brain matter in two regions of the brain associated with pain regulation in Gulf War veterans, researchers from Georgetown University Medical Center reported in the journal PLoS One.
As background information, the authors informed that of the approximately 700,000 soldiers who served in Operation Desert Storm (1990-1991), nearly 30% developed Gulf War Illness (Gulf War Syndrome). Gulf War Illness presents itself with symptoms such as cognitive deficits, autonomic dysfunction, severe fatigue, and chronic widespread pain that implicate the CNS (central nervous system).
The majority of patients with Gulf War Illness experience post-exertional malaise, meaning their symptoms worsen considerably after physical and/or mental effort.
The scientists in this study had set out to determine what the causal relationship might be between exercise, the brain and alterations in symptoms. They recruited 38 volunteers – 28 Gulf War veterans and 10 controls (ten matched people who were not veterans). The participants underwent two exercise stress tests as well as two fMRI (functional magnetic resonance imaging) scans, one before and one after the tests – the aim was to see whether there were any serial changes in pain, *autonomic function and working memory.
*Autonomic function refers to how well the autonomic nervous system (ANS) is working. ANS is the part of the nervous system that acts as a control system and works largely below the level of consciousness. It affects digestion, heart rate, urination (micturition), sexual arousal, perspiration, pupillary dilation, salivation, and respiratory rate.
The scientists found that Gulf War illness appears to have two distinct forms, depending on which brain regions have deteriorated. Their findings may explain why doctors have consistently found that not all Gulf War veterans have the same symptoms and complaints.
After undergoing physical exercise tests, it became evident that there were subgroups with different symptoms among the veterans. In 18 of the veterans, pain levels rose after completing the exercise stress test. The fMRI scans revealed loss of brain matter in regions next to those associated with the regulation of pain.
When those veterans had to do cognitive (thinking, memory, judgment, intelligence) tasks, the scans showed that the basal ganglia part of the brain was used more – possibly a compensatory strategy used by the brain that is commonly found among Alzheimer’s disease patients as well as those with other neurodegenerative disorders.
After physical exercise, the affected veterans lost the ability to use their basal ganglia. The researchers suggest this was because of an adverse response to a physiological stressor.
Rayhan wrote that “a separate group of 10 veterans had a very different clinical alteration.” Their heart rates increased significantly. Atrophy (deterioration) was also observed in the brain stems of these ten veterans. The brain stem regulates heart rate.
Some patients with neurodegenerative disorders showed increased compensatory use of the cerebellum part of the brain when undergoing cognitive tasks. The authors reported that in this subgroup the same thing was observed – after exercise, they lost the ability to employ this compensatory area.
Dr. Baraniuk and team found no alterations in exercise-induced symptoms, brain structure or cognition in any of the 10 non-veterans (the control group).
“The use of other brain areas to compensate for a damaged area is seen in other disorders, such as Alzheimer’s disease, which is why we believe our data show that these veterans are suffering from central nervous system dysfunction.”
Just because these veterans have similar symptoms and atrophies to patients with neurodegenerative disorders does not mean that they will progress to Alzheimer’s disease or some other disorder, Rayhan added.
The scientist, who expressed surprised at their findings, wrote that their study follows another one published in March 2013 in PLoS ONE where abnormalities in the bundle of nerve fibers connecting brain areas that deal with the processing and perception of pain and fatigue were observed.
Roberta White, PhD, of Boston University School of Public Health and colleagues reported in 2007 that Gulf War veterans who returned with multiple symptoms and complaints were found to have significant differences in brain structures compared to their fellow returnees. Dr. White presented their findings at the American Academy of Neurology’s 59th Annual Meeting in Boston (2007).
The researchers had recruited 36 veterans from the 1990-1991 Gulf War (the first Gulf War). More than five of them had multiple symptoms, including difficulty concentrating, nausea, skin rash, headaches, forgetfulness, fatigue and joint pain. The rest had fewer than five symptoms.
Dr. White explained that two regions of the brain involved in thinking and memory were considerably smaller in those with more than five symptoms – the overall cortex was 5% smaller and the rostral anterior cingulated gyrus was 6% smaller. These participants had worse scores in the learning and memory test, compared to those with fewer than five symptoms.
Dr. White said “We don’t know the cause of these differences in the veterans’ brain volumes, but the hypothesis is that they are related to exposure to hazardous substances during the first Gulf War. Many troops were exposed to hazardous substances such as pesticides, and other studies have shown that exposures to these substances affect the central nervous system.”
Gulf War Illness, also known as Gulf War Syndrome is a long-term multi-symptom disorder that affects approximately one third of military personnel and civilian workers who were sent to the first Gulf War.
Several symptoms and complaints have been associated with Gulf War Illness, including:
- skin rashes
- cognitive problems
- physical pain
From 1995 to 2005, several studies reported on the worsening condition of combat veterans compared to non-deployed veterans. A significant number of combat veterans started suffering from new chronic diseases, chronic fatigue syndrome-like illness, PTSD (post traumatic stress disorder), greater persistence of adverse health events, functional impairment – there were also more repeated clinic visits and hospitalizations.
What are the causes of Gulf War Illness?
Nobody really knows. Initially, some health care professionals, military personnel and other “experts” wondered whether Gulf War Syndrome really existed. However, there have been so many study findings that the medical community now accepts it is real. Medical ailments linked to Gulf War syndrome are today recognized by the Department of Defense as well as the Department of Veterans Affairs This latest study is probably the best physical proof that Gulf War Illness exists.
Suggestions have been made that one or a combination of the following may have contributed to Gulf War Syndrome:
- Smoke form burning oil wells
- Depleted uranium
- Sarin gas
- Combat stress
- Pyridostigmine bromide – antitoxin for nerve agents
- Organophosphate pesticides
Written by Christian Nordqvist