Lewy body dementia affects an estimated 1.4 million people and their families, and the disease can become aggressive and insidious as it progresses.
The condition is associated with the presence of Lewy bodies – abnormal deposits of a protein called alpha-synuclein – in the brain, according to the Lewy Body Dementia Association. An umbrella term, Lewy body dementia includes both Parkinson’s disease dementia and dementia with Lewy bodies (DLB).
“In dementia with Lewy bodies, the third most common dementia, patients usually experience visuospatial or executive dysfunction before they notice memory loss,” says Linda Hershey, a neurologist with OU Medicine in Oklahoma City. “They usually have signs of parkinsonism and may be confused with those who have Parkinson’s disease.”
Along with a buildup of Lewy bodies, about 75 percent of DLB patients have excessive amounts of tau and beta-amyloid, the same proteins that accumulate in the brains of Alzheimer’s patients.
“This is what we have learned from autopsy studies of DLB patients’ brains: the more Alzheimer’s disease changes in any given DLB brain, the more aggressive the clinical course and the shorter the patient’s survival,” Hershey says.
Kristin King, a movement disorders neurologist with Warren Clinic Neurology in Tulsa, says Lewy body dementia is diagnosed based on a patient’s history as well as mental and physical exams.
“Some features that point to this diagnosis include hallucinations and a history of dream enactment,” she says. “Motor symptoms classically include tremor, stiffness, slowing of movements and balance difficulties.
“Dementia with Lewy bodies and Parkinson’s disease dementia are differentiated from one another by determining the presenting features. If the thinking impairment occurs early, it is more likely dementia with Lewy bodies. If the thinking impairment occurs years after the onset of motor symptoms, it is more likely Parkinson’s disease dementia.”
Hershey says the quality of life of DLB patients varies widely upon symptoms and responses to medications.
“For example, one DLB patient may have visual hallucinations that respond to donepezil, while another has hallucinations that continue to be frightening regardless of medical intervention,” she says. “A second DLB patient may have parkinsonism that responds well to a low dose of levodopa, while another gains no benefit at all and only becomes more confused with the same drug.”
Both incurable, Lewy body dementia and dementia due to Alzheimer’s disease are treated similarly, King says.
“Certain medications are thought to slow the progression of the dementia; however, results are modest,” she says. “Some patients may notice improvement in thinking, behavior, anxiety and hallucinations. Many patients may not notice any difference at all. It is important to note that even for the patients who do not notice any difference, their rate of decline while on the medication is likely slower than it would be without the medication.”
King says dementia with Lewy bodies tends to be more aggressive than dementia associated with Alzheimer’s disease.
“Patients with Alzheimer’s dementia can have a similar prognosis, but may live much longer depending on their overall health at the onset of disease,” she says. “Parkinson’s disease dementia also tends to be more aggressive once it sets in because patients may already have substantial physical disability due to the underlying Parkinson’s disease.”