Did Robin Williams have dementia?

The Lewy Body Dementia Association (LBDA) provides information about what can -- and cannot -- be concluded from these reports.

The autopsy indicated the presence of 'diffuse Lewy body dementia' in the brain of Mr. Williams. This is more commonly called 'diffuse Lewy body disease' which reflects the biological disease process in the brain.

"The use of the term dementia in the neuropathology report should not be inferred to mean that dementia was observed during life," warns Dennis Dickson, M.D., Mayo Clinic in Jacksonville, Fla. and member of the LBDA Scientific Advisory Council.

Lewy bodies are misfolded protein deposits found in the brains of individuals with several different disorders including Parkinson's disease (PD) and dementia with Lewy bodies (DLB

According to his wife, Robin Williams was battling "the early stages of Parkinson's disease" before his death. In early PD, Lewy bodies are generally limited in distribution, but in DLB, the Lewy bodies are spread widely throughout the brain, as was the case with Robin Williams.

Dr. Dickson, who has reviewed the autopsy and coroner's report, further states, "Mr. Williams was given a clinical diagnosis of PD and treated for motor symptoms. The report confirms he experienced depression, anxiety and paranoia, which may occur in either Parkinson's disease or dementia with Lewy bodies."

Is it Dementia with Lewy Bodies or Parkinson's Disease?

Both Parkinson's disease with dementia and DLB are considered Lewy body dementias because of the presence of Lewy bodies in the brain. Collectively, Lewy body dementias are the second most common form of dementia and affect an estimated 1.4 million Americans.

To receive a diagnosis of dementia with Lewy bodies, a person must have significant problems with thinking and memory that interfere with everyday life. There is no mention in the media or in the autopsy report that Robin Williams exhibited these symptoms.

It is not uncommon, however, for early signs of dementia to go undetected. The Mini Mental Status Exam -- a common screening test for cognitive impairment and dementia used by many physicians -- is not able to detect cognitive impairment in early DLB.

"Further research is needed to better understand why some individuals with diffuse Lewy body disease do not show symptoms of dementia," according to Dr. Dickson. "In particular, we need to learn how dementia with Lewy bodies differs clinically from Parkinson's disease when they both share the same underlying disease process."

DLB and PD share many symptoms, but have different patterns of onset, progression and symptom severity. The most prominent and problematic clinical symptoms in early PD are related to movement, while in DLB they are more likely to be cognitive and psychiatric. However, over the course of both disorders, the symptoms become more and more alike.