Overview

Lewy body dementia is the second most common form of degenerative dementia after Alzheimer’s disease. Lewy body dementia refers to 2 different diseases, Parkinson’s disease dementia and dementia with Lewy bodies. Approximately 1.4 million individuals in United States are affected. Both diseases are characterized by the development of parkinsonism. In Parkinson’s disease dementia, the development of dementia occurs greater than one year after motor symptoms of Parkinson’s disease occur. In dementia with Lewy bodies, cognitive impairment occurs within 1 year of the development of motor symptoms of Parkinson’s disease. The brain pathology and clinical features of both dementia with Lewy bodies and Parkinson’s disease dementia are similar. After Alzheimer’s disease, Lewy body dementia is the most common cause of dementia. Lewy body dementia is commonly missed and is under diagnosed in the population. Patients with dementia with Lewy bodies often respond more poorly to antiparkinson medications such as levodopa compared to patients with Parkinson’s disease without dementia.

Symptoms

1. Cognitive impairment characterized by loss of executive function (planning and processing information), reduced ability to understand visual information, and short-term memory loss. Short-term memory impairment occurs is usually less severe than in Alzheimer’s disease. Patients may benefit from cues to help remember while patients with Alzheimer’s disease are less likely to benefit from cueing.

2. Cognitive fluctuations consisting of marked variability in attentiveness and sometimes consciousness. At times, patients may function cognitively fairly normally and at other times patients may be severely confused and having a decreased level of responsiveness. Such fluctuations may last minutes or hours. This is a somewhat specific feature of DLB compared to other forms of dementia such as Alzheimer’s disease.

3. REM behavior disorder which refers to a tendency to act out dreams usually with stereotypical violent dreams with the patient making fighting movements and sometimes screaming or shouting during sleep.

4. Parkinsonism which refers to the clinical features of bradykinesia (slowness of movement), tremor (usually of the hands at rest), rigidity (stiffness of the limbs when moved passively), and postural instability (poor balance). Patients may respond to antiparkinson medication such as levodopa, but often respond more poorly compared to patients with Parkinson’s disease without dementia.

5. Autonomic dysfunction may occur including orthostatic hypotension (lowering of blood pressure when arising from a lying or seated position often accompanied by lightheadedness or fainting), bladder dysfunction and constipation.

6. Visual hallucinations may occur early on in the disease and may be brought out or worsened with the administration of antiparkinson medication. Initially, the patient may have insight that the images seen are hallucinations. As hallucinations worsen, insight may be lost. Frank delusions may occur sometimes accompanied by paranoia.

7. DLB patients have a high degree of neuroleptic sensitivity. When administered antipsychotic medications which block dopamine they had may have profound and prolonged worsening of parkinsonism. DLB patients are often given antipsychotic medications because of the tendency to develop visual hallucinations and as the disease progresses frank delusions. Low affinity D2 receptor blocking medications or highly atypical antipsychotics such as pimavanserin and quetiapine and clozapine are preferred because of their efficacy and low tendency to worsen Parkinson motor symptoms.

8. Behavioral and mood problems including depression, apathy, anxiety, and agitation.

Diagnosis

An experienced clinician (usually a neurologist or a geriatrician) should evaluate the patient in detail. Detailed neurologic examination should be carried out including cognitive testing (neuropsychological testing which may be carried out by the initial examiner or by a separate neuropsychologist). Neuroimaging (brain CT or MRI scan) and certain blood tests should be performed to exclude other diagnoses. A dopamine transporter scan (DAT scan) can be helpful in verifying that there is a dopamine deficiency in patients with dementia when the presence of parkinsonism on physical examination is not clear.

Treatment

1. Cholinesterase inhibitors may be helpful in improving cognitive function and to a small extent behavior by inhibiting the breakdown of acetylcholine which is relatively deficient in the brain in patients with Lewy body dementia. Examples of these medications include rivastigmine (Exelon), donepezil (Aricept), and galantamine (Razadyne). Rivastigmine is specifically indicated by the FDA for treatment of both Alzheimer’s disease and Parkinson’s disease dementia while donepezil and galantamine are indicated for the treatment of Alzheimer disease only. Patients with Lewy a greater extent to these medications then to patients with Alzheimer’s disease.

2. Memantine (Namenda) is an NMDA receptor antagonist that is indicated for treatment of moderate to severe Alzheimer’s disease. Some studies have suggested mild cognitive benefit for patients with dementia with Lewy bodies.

3. Antiparkinson medication can improve parkinsonian symptoms such as slowness of movement, tremor, rigidity, and to a lesser extent, impaired balance. Levodopa/carbidopa (Sinemet) is the standard medication used. Other antiparkinson medications may also be used, but levodopa/carbidopa is a generally the mainstay of therapy since relative to its antiparkinson benefit, it has less tendency to produce cognitive adverse effects such as hallucinations.

4. Traditional antipsychotic medications are generally contraindicated (not appropriate) to treat symptoms of psychosis (hallucinations and delusions). Pimavanserin (Nuplazid), clozapine (Clozaril), and quetiapine (Seroquel) are the preferred medications due to their low tendency to worsen parkinsonism. Pimavanserin is specifically indicated by the FDA for treatment of Parkinson’s disease related psychosis.

5. Other behavioral symptoms such as depression and anxiety should be aggressively managed since treatment with antidepressants and/or psychotherapy may be of benefit in improving quality of life.

6. REM sleep behavior disorder can result in potential injury to the patient due to falling out of bed or to the bed partner who may be struck by the sleeping patient that is acting out his/her dreams. These symptoms can also significantly interfere with the sleep quality of the bed partner may be awoken by the dream enactment behavior and can reduce the restfulness of the patient’s sleep. Melatonin may be effective in up to 50% of patients usually at a dose of 3-12 mg nightly. Clonazepam (Klonopin) is the most effective medication for this problem and it is helpful in up to 90% of patients.

7. Physical therapy may be helpful to improve gait and balance and so reduce the likelihood of falls. Speech therapy may be helpful to improve softness of speech and swallowing difficulties. (UK) and rigidity in OT you also and then

Prognosis

Unfortunately, no treatment has been shown to slow the progression or cure Lewy body dementia. Despite our current treatments, disability including dementia continues to worsen over time. The disease has an average duration of about 7 years until death depending on the patient’s age and other health conditions.

Research

There are a number of clinical trials which are currently being conducted for treatment of various symptoms including cognitive impairment and REM sleep behavior disorder. Although current medications are somewhat helpful, patients’ symptoms and disability continue to progress substantially and are usually not adequately managed with currently available medications. Please consider applying to see if you or your loved one qualifies to participate in a clinical trial which may be able to significantly improve related symptoms.