The dementia with Lewy bodies is very similar to Alzheimer’s dementia, but with specific characteristics that degenerative disease become a very particular dementia syndrome.
In fact, until a few years ago, it did not “exist”. That is, this type of disorder had not been discovered and the people who suffered it were diagnosed with Alzheimer’s disease (AD).
However, in the year 1980, the psychiatrist Kenji Kosaka coined the concept of “disease with Lewy bodies” when witnessing a type of dementia very similar to Alzheimer’s dementia, but with certain differences.
Lewy Bodies Dementia
In fact, this characteristic name (Lewy bodies) refers to the particles that were discovered in the neurons of patients with this type of disorder, which are responsible for producing the degeneration of the brain.
Thus, although Alzheimer’s dementia and DCL share many characteristics, in Alzheimer’s these particles are not present in neurons, so the cause of both types of dementia seems to be different.
However, currently many patients with dementia due to Lewy bodies are still “misdiagnosed” of Alzheimer’s.
To try to clarify a little the properties of the DCL, next we will comment all its characteristics and which of them make it different to the Alzheimer type dementia.
Characteristics of Dementia by Lewy Bodies
The main symptom of Lewy body dementia is cognitive impairment, which includes memory problems, problem solving, planning, abstract thinking, concentration, language, etc.
Also, another important feature of this disorder are cognitive fluctuations.
This refers to the fact that patients suffering from MCI do not always have the same cognitive performance. That is to say: sometimes they seem to have greater mental and intellectual capacities, and sometimes they seem to have a more advanced deterioration.
These variations in their performance are explained by the alterations in attention and concentration processes that people with this type of dementia present.
In the DCL, attention and concentration suffer unpredictable changes. There are days or times of the day in which the person can be attentive and focused, and there are other days in which their concentration can be totally deactivated.
In this way, when the person with MCI has greater attention and concentration, their cognitive performance increases, and performs more effectively mental activities, has a better functioning, speaks in a more fluid way, etc.
However, when attention and concentration are more deteriorated, their cognitive performance decreases sharply.
Another important symptom in dementia due to Lewy bodies are the motor signs: rigidity, muscle hardening, tremor and slowness of movement, which are presented in an almost identical way as in Parkinson’s disease.
Finally, the third main symptom of DCL is hallucinations, which are usually visual.
The elderly who suffer MCI usually hear and interpret voices that do not exist, and sometimes see elements in a hallucinatory way.
Thus, by way of summary, the 4 main characteristics of MCI are: cognitive deterioration, fluctuations in this deterioration, the presence of parkinsonian symptoms and the appearance of hallucinations.
However, in the DCL can also appear other symptoms such as:
Behavioral disorder of REM sleep : this disorder is characterized by living very intensely dreams, which can become violent actions and attitudes.
Significant changes in the autonomic nervous system: regulation of temperature, blood pressure, digestion, dizziness, fainting, sensitivity to heat and cold, sexual dysfunction, urinary incontinence, etc.
Excessive sleepiness during the day, possible changes in mood, loss of consciousness, apathy, anxiety or delusions.
The diagnosis of dementia by Lewy bodies is very controversial due to its multiple similarities with Alzheimer’s type dementia.
However, with the objective of delimiting the diagnosis as much as possible, the consortium on MCI held in 1996 established the following criteria:
The central feature is progressive cognitive deterioration of sufficient magnitude to interfere with normal social or work function. In early stages there may be no noticeable and persistent memory disorder, but it is usually evident as you progress. Attention defects can be especially accused.
Two of the following primary traits are necessary for the probable diagnosis of MCI and one for the possible diagnosis MCI:
Cognitive fluctuations with notable variations in attention and alertness.
Recurrent visual hallucinations, typically well structured and detailed.
Spontaneous motor Parkinson’s traits.
The following features support the diagnosis:
Loss of transient consciousness
Sensitivity to antipsychotics (bad reaction when taking these drugs).
The diagnosis of MCI is less likely in the presence of:
Cerebrovascular disease manifests as focal neurological signs.
Evidence in the physical or complementary examination of another general or cerebral disease capable of explaining the clinical picture.
Thus, the diagnosis of MCI is still not detailed today and it differs from Alzheimer’s disease by means of probability mechanisms.
Differences between Alzheimer’s disease and Dementia due to Lewy Bodies
Despite the multiple similarities, there are also divergent aspects between both diseases, therefore, in many cases it is possible to differentiate a DCL from an Alzheimer type dementia.
The main differences are:
In Alzheimer’s disease, memory deterioration is early and prominent, in DCL the memory losses are more variable and, in general, less important.
In DCL, visual motor skills (such as writing or picking up an object) are very deteriorated, while in Alzheimer’s this deficit is not usually very noticeable.
The same happens with visuoconstructive deficits (ability to plan and perform movements). They are very marked in the DCL and are less important in the EA.
In contrast, patients with MCI usually have a better verbal memory during the course of their disease than patients with Alzheimer’s.
The DCL has the unique characteristic of presenting fluctuations in the cognitive deterioration, this in the EA does not happen.
In DCL, hallucinations occur frequently, are very common and may already be present at the onset of the disease. In Alzheimer’s they are rare and usually appear only in very advanced stages.
The same happens with delusions, quite common in DCL, and rarely seen in Alzheimer’s type dementia.
Other main symptoms of MCI are stiffness, tremor, and signs typical of Parkinson’s. Patients with AD rarely present these symptoms and if they do, they present them in very advanced stages of the disease.
Sometimes demented patients have hallucinations, a fact that usually requires the use of antipsychotics. When a person with AD takes an antipsychotic drug usually has a good therapeutic response, when taken by a person with MCI usually has a very bad physical and psychological reaction .
In DCL, the famous Lewy bodies (cytoplasmic inclusions) are seen in the neurons, which cause neuronal death and cognitive deterioration. In Alzheimer’s disease this does not happen.
Dementia due to Lewy bodies is the third cause of dementia behind Alzheimer’s disease and vascular dementia.
In fact, Lewy bodies have been seen in the neurons of patients with dementia in approximately 20-30% of the autopsies performed.
There are studies that have found that the prevalence of MCI among people over 65 is 0.7%.
The onset of the disease varies between 50 and 90 years of age, and the prevalence of life of patients with this type of dementia is usually very short.
In people with MCI, it usually takes between 6 and 10 years between the onset of their illness and their death, thus being one of the dementias with worse prognosis.
The DCL originates when the famous Lewy bodies appear in the neurons of the person.
Lewy bodies are cytoplasmic inclusions that are formed through different proteins, especially alpha-synuclein.
That is to say, the brain of patients with MCI suffers an alteration in the synthesis of this protein, therefore, it joins the nucleus of the neurons, and thus constitutes the Lewy bodies.
Therefore, in the neurons of the patient, these bodies begin to appear, which collaborate in the death of the neuron itself and initiate cognitive deterioration.
Likewise, the Lewy body is distributed by neurons from different regions of the brain, producing a large number of alterations and causing cognitive deficits in many different areas.
The cause of MCI, that is, why they begin to “put together” Lewy bodies in neurons, is unknown today.
However, there seems to be some consensus that there is a genetic component in the development of this disease.
Genes such as the apolipoprotein gene or the cytochrome P450 gene seem to be involved in DCL. Likewise, the first one seems to be also related to Alzheimer’s and the second one to Parkinson’s, a fact that could explain the characteristic symptoms of AD and Parkinson’s that also appear in MCI.
However, these genetic patterns alone would not explain the development of the disorder.
Regarding the environment, there are no conclusive studies on what could be the risk factors for dementia due to Lewy bodies, however the following seem to have a certain relationship:
Age : as in most dementing syndromes, the longer one lives, the greater the likelihood of having MCI.
Cholesterol : although there are no studies that clearly demonstrate this, having cholesterol could be a risk factor.
Alcohol : high alcohol consumption could increase the risk of suffering from MCI, although moderate consumption could reduce it.
Diabetes : similarly, although there is no etiological evidence, there are authors who argue that diabetes can be a factor that contributes to the development of MCI.
The mild cognitive impairment: This condition greatly increases the risk of dementia as age increases. After 65 years, the risk can increase up to 40%.
How can it be treated?
The DCL presents a wide range of symptoms, which is why it is important to perform different therapeutic interventions.
With regard to cognitive impairment, it is important to perform cognitive stimulation activities to try to minimize the progress of the disease.
Working with the patient’s deficits such as attention, concentration, memory, language or visoconstruction, can favor the maintenance of their cognitive abilities.
As far as hallucinations are concerned, these should only be treated when they produce anxiety or agitation in the patient. Conventional antipsychotics such as haloperidol are contraindicated because of their strong side effects.
In those cases in which it is essential to treat hallucinations, atypical antipsychotics such as risperidone can be administered .
Finally, parkinsonian symptoms are also often difficult to treat as antiparkinson drugs are often ineffective and produce many side effects in patients with MCI.