Lewy Body Dementia
Lewy body dementia is an umbrella term that includes Parkinson’s disease dementia and dementia with Lewy bodies.
It is a form of progressive dementia identified by abnormal collections of alpha-synuclein protein, called Lewy bodies, in areas of the brain that regulate movement, cognition and behaviour. It appears to affect slightly more men than women.
- Parkinson’s disease (PD) dementia is dementia occurring in the context of an established diagnosis of Parkinson’s disease.
- Dementia with Lewy body refers to dementia associated with some combination of early and prominent deficits of inattention, thinking, memory, recurrent visual hallucinations, rapid eye movement (REM) sleep behaviour disorder and problems with movement (starting with or after dementia diagnosis).
- Advanced age is considered the greatest risk factor, with onset typically, but not always, between the ages of 50 and 85. Some cases have been reported much earlier.
What are the common symptoms of Lewy body dementia?
This condition impairs thinking, such as memory, executive function (planning, processing information), or the ability to understand visual information. People with LBD may have fluctuations in attention or alertness; problems with movement including tremors, stiffness, slowness and difficulty walking; hallucinations; and alterations in sleep and behaviour.
- Differentiating symptoms include early and recurrent visual hallucinations, fluctuating intellectual (cognitive) skills and development of a shuffling gait (parkinsonism-type symptoms)
- Fluctuations in cognition will be noticeable to those who are close to the person with LBD. At times, the person will be alert and suddenly have acute episodes of confusion. These may last hours or days. There is no specific time of day when confusion might occur.
- Hallucinations are usually, but not always, visual and often are more pronounced when the person is confused. They are not necessarily frightening to the person.
- Parkinsonism or Parkinson's Disease symptoms, take the form of changes in gait. The person may shuffle or walk stiffly and there may be frequent falls. Body stiffness in the arms or legs, or tremors, may also occur. Parkinson's mask (blank stare, emotionless look on face), stooped posture, drooling and runny nose may be present.
- REM Sleep Behaviour Disorder (RBD) is often noted in persons with Lewy body dementia. During periods of REM sleep, the person will move, gesture and/or speak. There may be more pronounced confusion between the dream and waking reality when the person awakens.
- RBD may actually be the earliest symptom of LBD in some people and is now considered a significant risk factor for developing LBD.
- Sensitivity to neuroleptic (anti-psychotic) drugs is another significant symptom that may occur. These medications can worsen the Parkinsonism and/or decrease the cognition and/or increase the hallucinations. Neuroleptic Malignancy Syndrome, a life-threatening illness, has been reported in persons with Lewy body dementia. For this reason, it is very important that the proper diagnosis is made and that healthcare providers are educated about the disease.
- Visuospatial difficulties, including depth perception, object orientation, directional sense and illusions may occur.
- Autonomic dysfunction includes blood pressure fluctuations (E.g., postural/orthostatic hypotension); heart rate variability (HRV); sexual disturbances/impotence; constipation; urinary problems; hyperhidrosis (excessive sweating); decreased sweating/heat intolerance; syncope (fainting); dry eyes/mouth; and difficulty swallowing (which may lead to aspiration pneumonia).
- Other psychiatric disturbances may include systematized delusions, aggression and depression. The onset of aggression in LBD may have a variety of causes, including infections (e.g., UTI), medications, misinterpretation of the environment or personal interactions and the natural progression of the disease.
How is Lewy body dementia diagnosed?
Dementia with Lewy bodies is often difficult to diagnose because its early symptoms may resemble those of Alzheimer’s, Parkinson’s disease or psychiatric illness. As a result, it is often misdiagnosed or missed altogether. As additional symptoms appear, it is often easier to make an accurate diagnosis.
The diagnosis of LBD is made on the basis of the symptoms − particularly persistent visual hallucinations, fluctuation in cognition with pronounced variations in attention and alertness and the presence of the stiffness and shuffling walk of Parkinson's.
The presence of supportive features such as postural instability, repeated falls, excessive daytime sleepiness and autonomic dysfunction such as blood pressure variation, constipation, urinary problems, and sweating abnormalities further support a diagnosis of LBD. Examining an individual with suspected LBD includes looking for orthostatic vital signs to investigate autonomic dysfunction.
Since cognitive features are an important aspect of diagnosis, cognitive screening is done using either the Montreal Cognitive Assessment Test (MoCA) or the Mini-Mental State Examination (MMSE). Evaluation for Parkinsonism includes observation for tremors, assessment of rigidity and gait.
New brain imaging tests can also help. Researchers are studying ways to diagnose LBD more accurately in the living brain. Certain types of neuroimaging— PET (positron emission tomography) and SPECT (single-photon emission computed tomography)—have shown promise in detecting differences between dementia with Lewy bodies and Alzheimer’s disease.
These methods may help diagnose certain features of the disorder, such as dopamine deficiencies. Researchers are also investigating the use of lumbar puncture (spinal tap) to measure proteins in cerebrospinal fluid that might distinguish dementia with Lewy bodies from Alzheimer’s disease and other brain disorders.
It is always important to get an accurate diagnosis of dementia, but a proper diagnosis is particularly important in cases of suspected LBD since people with LBD have been shown to react to certain types of medications (neuroleptics).
Is there a cure? How is Lewy body dementia treated?
Unfortunately, there is currently no known cure. Treatment for Lewy body dementia is currently focused on treating symptoms only.
The first step in treating an individual with LBD is to identify medications the person is taking that could contribute to symptoms or are best avoided in adults with dementia. This includes benzodiazepines, anticholinergic medications (for genitourinary symptoms), antipsychotic drugs and tricyclic antidepressants. Antipsychotic use is of particular concern in the treatment of dementia with Lewy bodies, given the risk of hypersensitive reactions. Anticholinergic medications used to treat tremors are associated with worsened cognition and psychosis.
Research suggests that cholinesterase inhibitor drugs used to treat Alzheimer’s Disease such as Aricept (Donepezil) or Exelon (Rivastigmine) could be helpful. Evidence suggests that these medications could improve behavioural such as psychosis, depression, anxiety and apathy for some people. Exelon (Rivastigmine) is the only cholinesterase inhibitor approved by the FDA for use in Parkinson’s Disease Dementia. Drugs used to treat Parkinson’s disease could be useful to control rigidity and spasticity but may aggravate confusion and hallucinations. Physiotherapy and mobility exercises may be tried.
A myriad of other symptoms in Lewy body dementia can benefit from pharmacologic treatment, including sleep behaviour disorder, constipation, etc. Melatonin is the first line of treatment for REM Sleep Behaviour Disorder (RBD) in the context of Lewy body dementia. Changes in blood pressure along with changes in posture are addressed by weaning contributing medications. Constipation is treated with increased water intake, dietary changes and various over-the-counter and prescription therapies not specific for Parkinson’s disease.
Nonpharmacologic approaches are an important aspect of treating people with Lewy body dementia. Exercise and physical activity have been shown to be extremely beneficial for individuals with Parkinson’s disease. Physical therapy, occupational therapy and speech-language pathology are also important considerations for care.
This content is provided for informational purposes only and is not to be used for diagnosis or treatment of any type of dementia or its symptoms. Any mention of pharmaceutical interventions or treatments is not an endorsement by the Alzheimer Society of Calgary. This information is apt to change at any time without notice. For medical advice, please contact your physician
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