Lewy body dementia symptoms and diagnostic criteria
Every person with LBD is different and will manifest different degrees of the following symptoms. Some will show no signs of certain features, especially in the early stages of the disease. Symptoms may fluctuate as often as moment-to-moment, hour-to-hour or day-to-day. NOTE: Some patients meet the criteria for LBD yet score in the normal range of some cognitive assessment tools. The Mini-Mental State Examination (MMSE), for example, cannot be relied upon to distinguish LBD from other common syndromes.
LBD is a an umbrella term for two related clinical diagnoses, dementia with Lewy bodies and Parkinson's disease dementia.
The latest clinical diagnostic criteria for dementia with Lewy bodies (DLB) categorizes symptoms into three types, listed below. A diagnosis of Parkinsons' disease dementia (PDD) requires a well established diagnosis of Parkinson's disease that later progresses into dementia, along with very similar features to DLB. A rather arbirary time cutoff was established to differentiate between DLB and PDD. People whose dementia occurs before or within 1 year of Parkinson's symptoms are diagnosed with DLB. People who have an existing diagnosis of Parkinson's for more than a year and later develop dementia are diagnosed with PDD.
- Progressive dementia - 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 parkinsonism.
- REM sleep behavior disorder (RBD), which can appear years before the onset of dementia and parkinsonism.
- Severe sensitivity to neuroleptics occurs in up to 50% of LBD patients who take them.
- Low dopamine transporter uptake in the brain's basal ganglia as seen on SPECT and PET imaging scans. (These scans are not yet available outside of research settings.)
- Repeated falls and syncope (fainting).
- Transient, unexplained loss of consciousness.
- Autonomic dysfunction.
- Hallucinations of other modalities.
- Visuospatial abnormalities.
- Other psychiatric disturbances.
A clinical diagnosis of LBD can be probable or possible based on different symptom combinations.
A probable LBD diagnosis requires either:
- Dementia plus two or more core features, or
- Dementia plus one core feature and one or more suggestive features.
A possible LBD diagnosis requires:
- Dementia plus one core feature, or
- Dementia plus one or more suggestive features.
In this section we'll discuss each of the symptoms, starting with the key word: dementia. Dementia is a process whereby the person becomes progressively confused. The earliest signs are usually memory problems, changes in their way of speaking, such as forgetting words, and personality problems. Cognitive symptoms of dementia include poor problem solving, difficulty with learning new skills and impaired decision making.
Other causes of dementia should be ruled out first, such as alcoholism, overuse of medication, thyroid or metabolic problems. Strokes can also cause dementia. If these reasons are ruled out then the person is said to have a degenerative dementia. Lewy Body Dementia is second only to Alzheimer's disease as the most common form of dementia.
Fluctuations in cognition will be noticeable to those who are close to the person with LBD, such as their partner. At times the person will be alert and then suddenly have acute episodes of confusion. These may last hours or days. Because of these fluctuations, it is not uncommon for it to be thought that the person is "faking". This fluctuation is not related to the well-known "sundowning" of Alzheimer's. In other words, there is no specific time of day when confusion can be seen to occur.
Hallucinations are usually, but not always, visual and often are more pronounced when the person is most confused. They are not necessarily frightening to the person. Other modalities of hallucinations include sound, taste, smell, and touch.
Parkinsonism or Parkinson's Disease symptoms, take the form of changes in gait; the person may shuffle or walk stiffly. There may also 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 Behavior 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 patients, and is now considered a significant risk factor for developing LBD. (One recent study found that nearly two-thirds of patients diagnosed with RBD developed degenerative brain diseases, including Lewy body dementia, Parkinson’s disease, and multiple system atrophy, after an average of 11 years of receiving an RBD diagnosis. All three diseases are called synucleinopathies, due to the presence of a mis-folded protein in the brain called alpha-synuclein.)
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, including 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.