MIAMI BEACH — Early and aggressive treatment of dementia in people with Parkinson's disease could optimize outcomes and quality of life for patients and their caregivers, growing evidence suggests.
About one-third of people with Parkinson's disease experience dementia. “We know there is such high risk for dementia in this population. We need to be proactive,” Dr. David J. Burn said at the World Federation of Neurology World Congress on Parkinson's Disease and Related Disorders.
Hallucinations are a major concern. These can arise when mild cognitive impairment, common in people with Parkinson's disease, progresses to dementia.
How you deliver a dementia diagnosis to the patient and family members is important, said Dr. Burn, professor of movement disorder neurology at Newcastle University, Newcastle-Upon-Tyne, England. “There is some reluctance to give the diagnosis. You have to be sure [that] the dementia exists. But giving this in a reasonable way might reassure people with hallucinations they are not going mad.”
In addition, a definitive diagnosis can provide a sense of relief to caregivers.
Current patient age is the dominant risk factor for dementia in Parkinson's disease. Cognitive impairments (attention, executive functioning, visuospatial perception, and memory) and behavioral effects (apathy, mood) are clinical features often associated with this classic “dysexecutive visuoperceptual” dementia.
“There is a high psychiatric burden in that dementia, which is important in the management of the disease,” said Dr. Burn.
General and specific diagnostic instruments such as the Mini-Mental State Examination or the Mini-Mental Parkinson test can be helpful in this population. Dr. Burn recommended also using the Neuropsychiatric Inventory–4. “It is fairly quick to administer to the caregiver [together] with the Caregiver Distress Scale. It is a neat, compact way of assessing a lot quite quickly.”
Despite the usefulness of such scales, Dr. Burn advised that clinicians should not feel comfortable even if the resulting score is robust. “Always follow-up with an interview with the patient and the informant—that is essential.”
Fluctuation in symptoms presents one of the diagnostic challenges, Dr. Burn said. “These patients can have good hours or days versus bad hours or days, which can [yield] widely different values on neurologic testing. These fluctuations may be the biggest determinant of [the impact on] activities of daily living in the setting of Parkinson's disease dementia.”
Other confounding factors that can complicate diagnosis include an insidious onset, slow progression, motor effects of Parkinson's disease, and whether the impairment is the result of cognitive dysfunction, Dr. Burn said.
Multiple medications have been studied for efficacy in this comorbid population. These include clozapine (Clozaril); quetiapine (Seroquel); memantine (Namenda); rivastigmine (Exelon); and donepezil (Aricept). Dr. Burn disclosed that he was recently a member of the advisory board for Eisai Inc., the manufacturer of Aricept.
However, the level of evidence to support a particular agent varies in the literature, and many drugs have side effects that need to be considered.
Cholinesterase inhibitors can have effects on the heart, including reports of hospital visits for syncope and bradycardia, for example.
“Most of us, when we diagnose Parkinson's disease dementia, would reach for a cholinesterase inhibitor if patients are symptomatic,” Dr. Burn said. “You need to push the dose to the maximum.”
Keep in mind that patients do not always respond to the first agent, so a switch to a different agent in this class or to a different type of medication may be warranted for some patients, he added.
Evidence-based guidelines in the United Kingdom support the use of clozapine, but sedation and falls are possible, Dr. Burn said.
The choice of agent is unclear in part because randomized, controlled trials of antipsychotics in Parkinson's disease frequently exclude demented cases, he said.
In addition, there is a lack of randomized, controlled trials to support use of quetiapine.
“The jury is out on memantine, but for the moment … studies are favoring [its] use,” Dr. Burn said.
He added that he and his colleagues are planning a study in which they will randomize 500 patients with Parkinson's disease and dementia to either donepezil or placebo. Secondary measures will include caregiver distress, strain, and health economics.
Giving a diagnosis of dementia to patients with hallucinations might reassure them 'they are not going mad.'
Source DR. BURN