There has been much discussion of Traumatic Brain Injury (TBI) and its association with Chronic Traumatic Encephalopathy (CTE), Post Traumatic Stress Disorder (PTSD), Alzheimer’s, and dementia. Most of this material has been covered in previous blogs.
The evidence on Parkinson’s Disease has been less clear but a recent study headed by researchers from U.C. San Francisco School of Medicine (my old medical school) of military veterans supports the relationship.
Parkinson’s disease is not a new neurologic condition. The disease often begins with mild tremors in the hands. It can progress to rigidity in body movement, can effect speech, and progress to total disability. The actor Micheal J. Fox has had Parkinson’s for many years and has been active in fund raising and creating awareness of the disease. Mohammad Ali, the famous heavy weight boxer, had Parkinson’s for years and recently died as a result of complications of his disease. Many believe his career as a pro boxer with many blows to the head were the main cause of his neurologic deterioration.
Parkinson’s Disease is caused by a loss of Dopamine (a neurotransmitter ) in the brain. The cells producing dopamine are lost. The etiology is partly genetic but appears to be multifactorial. Recent research in veterans demonstrate that those with even mild head injuries experienced during military service double or triple the risk of getting the disease. Now it is important to note the Parkinson’s, unlike PTSD, is still an uncommon condition. But as the population of veterans from Iraq and Afghanistan age, the incidence is likely to increase. Aging is a huge risk factor.
Treatment often involves giving forms of oral dopamine to replace lost internal production in the brain. As one can imagine, this produces modest improvement which often fades with time. Transplanting stems cells that produce dopamine deep into the brain has also been attempted but results have thus far been disappointing.
Parkinson’s disease, like other neurodegenerative disorders, is often associated with accumulation of abnormal proteins in the brain. This probably represents a common pathway for the association of many neurologic diseases.
Again, TBI is not an isolated neurologic condition and head injury does not need to be severe to increase long-term risk of brain disease. The initial traumatic events appears to activate a cascade of events that result in loss of precious brain cells. New treatments for Parkinson’s may also payoff in treating TBI. The relationship between the two conditions is only beginning to be realized.
