Performer Robin Williams had a common, but tricky to diagnose form of dementia when he died in August.
Autopsy results showed Williams had Lewy bodies dementia (sometimes called dementia with Lewy bodies or LBD), as well as Parkinson’s disease. LBD occurs when tiny clumps of proteins build up on brain cells. Like Alzheimer’s disease, a better-known form of dementia, it is progressive and fatal.
LBD affects an estimated 1.3 million Americans, but it’s not well-known and can be difficult to diagnose, according to the Lewy Bodies Dementia Association. It can be confused with Parkinson’s disease, another degenerative brain disease with which it shares several traits, or Alzheimer’s.
Differences between LBD and Alzheimer’s
But there are important differences between the disorders, said Dr. Keith Fargo, the director of scientific programs and outreach for the Alzheimer’s Association in Chicago. The Alzheimer’s Association supports scientific research and the development of new treatments for Alzheimer’s, LBD and other forms of dementia.
The initial symptoms of LBD and Alzheimer’s are noticeably different, Fargo said.
People with Alzheimer’s have lapses in memory, especially in the ability to remember newer information.
People with LBD will likely develop memory problems, but LBD starts with lapses in judgment, planning and attention span. Vivid and complex hallucinations and delusions that may include sounds and smells are also a hallmark symptom of LBD; they can happen with Alzheimer’s, but they’re rare, Fargo said.
Physical symptoms of LBD
LBD also includes physical symptoms that are similar to Parkinson’s disease ““ patients may develop muscle rigidity and have problems with balance and walking. They may develop muscle tics or tremors. The physical symptoms mean clinicians who aren’t familiar with brain orders or dementia might confuse LBD with Parkinson’s, Fargo said, though the two diseases have similar roots.
In LBD, abnormal proteins form clumps on cells in the brain’s cortex ““ the wrinkled outer layer of the brain that helps interpret sensory input, make and store memories, carry out executive functions, such as planning and generating new thoughts and ideas, and control voluntary muscle movements.
In Parkinson’s, the same types of protein clumps form, but they start in different areas of the brain, which explains the difference in initial symptoms, Fargo said. Both diseases result in brain cell death as the abnormal protein structures build up. “If you have LBD and live long enough, you’ll likely develop Parkinson’s,” he said. The reverse is also true.
LBD symptoms include:
- Progressive dementia, or deficits in attention and executive function, are typical; prominent memory impairment may not be evident in the early stages
- Fluctuating cognition with pronounced variations in attention and alertness
- Recurrent complex visual hallucinations, typically well-formed and detailed
- Spontaneous features of Parkinson’s disease, including muscle rigidity or tics or problems balancing or swallowing
- REM sleep behavior disorder, which can appear years before the onset of dementia and Parkinson’s-like symptoms
- Severe sensitivity to neuroleptics occurs in up to half of LBD patients who take them
- Low dopamine transporter uptake in the brain’s basal ganglia as seen on SPECT and PET imaging scans
- Repeated falls and fainting
- Transient, unexplained loss of consciousness
- Autonomic dysfunction
- Hallucinations of other senses, like touch or hearing
- Visuospatial abnormalities
- Other psychiatric disturbances
Whenever people begin showing signs of memory loss or cognitive problems, it’s important to see a clinician. Whether the issue turns out to be Alzheimer’s or LBD or something else, Fargo said, the sooner it’s identified, the sooner treatment can begin and families can begin planning for the future.
As with Alzheimer’s, available treatments for LBD can only alleviate the symptoms for the short term; no approved treatments are available that can stop or slow the progression of LBD. An accurate diagnosis is also important because some of the medications that can help ease Alzheimer’s symptoms can actually make LBD symptoms worse, Fargo said.
LBD treatments include cholinesterase inhibitors, levodopa to help reduce muscle problems and sleep aids.
