What is Lewy Body Dementia?

Lewy body dementia is a type of dementia, or cognitive impairment acquired in adulthood, that is characterized by the presence of clumps of protein in the neurons or nerve cells, called Lewy bodies. This physical feature of the disease is named after neurologist Frederic Lewy, who identified them in the early 20th century. Lewy bodies can only be detected in a post-mortem brain biopsy, though Lewy body dementia can be diagnosed according to its symptoms. This type of dementia is theorized to be the second most common form in the elderly, after Alzheimer's syndrome. The cause of the disease is unknown, but it is believed to have a genetic component.

In addition to loss of cognitive function, Lewy body dementia causes motor symptoms similar to those of Parkinson's disease. Since Parkinson's disease can also cause dementia, an accurate diagnosis can be complicated. Lewy body dementia is typically diagnosed when the onset of dementia is rapid and coincides with the onset of motor symptoms. Parkinson's disease-related dementia more commonly appears at least a year after the onset of motor symptoms.

There are three main symptoms of Lewy body dementia. The first is variable cognition, with the patient's alertness and mental clarity coming and going. The second symptom is visual hallucinations, often of animals or people. Third is motor dysfunction, similar to that seen in Parkinson's. Motor symptoms can take the form of stiff and shuffling movements, reduced facial expressions, and speech volume, drooling, and problems swallowing.

There is no cure for Lewy body dementia, but it can be managed through medication and caregiving. Pharmaceutical treatment must strike a balance between the medications used, as drugs used to treat the motor function problems can cause cognitive problems to worsen, and vice versa. Donepezil is often used to treat the cognitive symptoms of the disease, while a combination of carbidopa and levodopa can address motor function impairment. Patients with Lewy body dementia are hypersensitive to antipsychotic medications, such as haloperidol and thioridazine, which can induce coma and threaten the patient's life.

Caregiving is important because patients eventually become unable to care for themselves. It is important to monitor the patient for signs of injury and illness, as he or she may have difficulty communicating about them. In addition to looking after the patient's basic daily needs, treatment can include simplifying the patient's environment and activities, and encouraging regular exercise.