A number of medical conditions can cause dementia. Some are reversible while others can lead to more permanent states of dementia. Alzheimer's disease accounts for about 55 percent of all dementia cases. Dementia due to head injury is comparatively rare and accounts for less than 5 percent of cases.
Traumatic Brain Injuries (TBI's) affect an estimated two to three million people in the United States each year. Between 400,000 and 500,000 people are hospitalized. It is difficult to find accurate statistics on how many people with a TBI go on to develop significant dementia, but there are three areas that we need to consider. The first is the link between Alzheimer's disease and TBI; the second, post traumatic dementia affecting the elderly and thirdly dementia pugilistica, (also known as chronic traumatic encephalopathy).
Traumatic Brain Injury and Incidence of Alzheimer's Disease
There has been a lot of discussion about the association between a higher incidence of Alzheimer's disease following a serious TBI, but the link remains controversial. Both autopsy and experimental studies show apolipoprotein beta deposits and tau pathology following a head injury. This could support the link between traumatic brain injury and dementia. However, further studies are needed before more definite conclusions can be reached.
Dementia pugilistica, (also called chronic traumatic encephalopathy, punch drunk) is a dementia that occurs following cumulative and repetitive head trauma. It mostly affects career boxers, but can also be seen in people doing other contact sports. Symptoms begin around 16 years later and are characterized by Parkinsonism, poor coordination and slurred speech. Like Alzheimer's, the pathologic findings include neurofibrillary tangles and Beta-amyloid deposits
Dementia and Chronic Subdural Hematoma
A type of post TBI syndrome that affects the elderly is chronic subdural hematoma (SDH). This can occur immediately after an injury but can also be a chronic condition where symptoms of apathy, confusion, lethargy, memory impairment and problems with activities of daily living (executive functions) fluctuate. Those at greatest risk are people over the age of 60 years, have frequent falls, gait disturbances and are on anticoagulant therapy.
Traumatic brain injury is the leading cause of cognitive impairment (problems with thinking, memory, understanding, reasoning, and communicating) in young adults. Young adults are particularly affected because TBI is most commonly caused by falls and motor vehicle accidents. Males are most at risk because of more risky behavior in their youth. The elderly are most at risk of TBI from falls. Alcohol can also play a significant role in accidents leading to TBI in both groups.
Symptoms of Dementia Following Traumatic Brain Injury
Symptoms of Dementia following TBI include:
Poor concentration and difficulty in thinking clearly