Lewy body dementia

The dementia with Lewy bodies (DLB) is a type of progressive dementia that leads to a decline in thinking, reasoning and personal autonomy function due to abnormal microscopic deposits of a protein that is formed in brain cells. It is the second most common neurodegenerative dementia after Alzheimer’s disease . It is a complex disease with symptoms similar to Alzheimer’s and Parkinson’s disease.

Lewy body dementia mainly affects the parts of the brain associated with cognitive function and movement . It is distinguished from Alzheimer’s disease by a more rapid evolution. Like other neurodegenerative dementias, it mainly affects the health of the elderly.

This disease is named in honor of the medical doctor Heinrich Friederich Lewy, the first to describe these structures in the brain at the beginning of the 20th century.

Lewy bodies consist mainly of filaments of a protein called alpha-synuclein , which has an important role in learning. The abnormal accumulation of this protein in the nerve cells of the brain leads to deposits that interrupt the messages it transmits .

In patients with Parkinson’s disease, Lewy bodies are found in cells located in the brain stem, located at the base of the brain, and play a role in movement control. In MCI, Lewy bodies are also present in the outer layer of the brain called the cortex, which is responsible for mental functions.

Lewy bodies are also found in other brain disorders , including Alzheimer’s disease and Parkinson’s disease dementia. Many people with Parkinson’s sometimes develop problems with thinking and reasoning, and many people with MCI experience symptoms in their mobility, such as hunched posture, stiff muscles, random walking, and difficulty initiating movement.

This overlap of symptoms and other symptoms suggests that MCI, Parkinson’s disease, and Parkinson’s disease dementia may be related to the same underlying abnormalities in the way the brain processes alpha-synuclein protein. Many people with MCI and Parkinson’s dementia also have the brain changes associated with Alzheimer’s disease.

Symptoms of Lewy body dementia

• Changes in thinking and reasoning
• Confusion and alertness that varies significantly from hour to hour or day to day
• Parkinson’s symptoms, such as hunched posture, balance problems, and stiff muscles
• Visual hallucinations
• Delusions
• Problems interpreting visual information
• Disorders of the nervous system
• Memory loss that can be significant, but less prominent than in Alzheimer’s

Assessment of the disease

As with other types of dementia, there is no single test that can conclusively diagnose Lewy body dementia . A clinical diagnosis is needed. The only way to diagnose conclusively is through a post-mortem autopsy .

Many experts believe that MCI and Parkinson’s disease dementia are two different expressions of the same underlying problems with the brain’s processing of alpha-synuclein protein, although most experts recommend continuing to diagnose MCI and Parkinson’s dementia as separate disorders.

Accuracy in diagnosis

• The diagnosis turns out to be MCI when dementia symptoms and movement symptoms are present.
• When dementia symptoms appear within a year after movement symptoms.

Since Lewy bodies tend to coexist with Alzheimer’s brain changes, it can sometimes be difficult to distinguish MCI from Alzheimer’s disease , especially in the early stages.

The central feature for the diagnosis of Lewy body dementia is cognitive impairment of sufficient magnitude to interfere with social functioning .

Main clinical characteristics of this disease

• Development of a clinic close to Alzheimer’s dementia
• Spontaneous motor movements of Parkinson’s.
• Fluctuations in cognitive performance with pronounced variations in attention and alertness.
• Recurrent visual hallucinations, generally very precise and detailed. Other secondary manifestations also occur in their earliest stages.
• Sensitivity to antipsychotics.
• Frequent falls
• Syncope and / or temporary loss of consciousness.
• Systematic illusions, other than visual hallucinations.
• Sleep behavior disorders, accompanied by rapid eye movements during rest.
• Depression, anxiety.

The various manifestations of the symptoms of this disease are directly related to the distribution of Lewy bodies . Thus, while they are located in the hippocampus region, memory disorders are observed, while if they are located in the associative visual areas, located in the posterior part of the temporal lobe, patients suffer hallucinations. If the focus is in the right parietal region, responsible for spatial analysis, patients have difficulties in orientation.

Main differences between Alzheimer’s and MCI

1. Memory loss tends to be a more prominent symptom in early Alzheimer’s than early MCI, although advanced Lewy body dementia can cause memory problems , in addition to its more typical effects on judgment, planning, and judgment. visual perception .
2. The problems associated with the movement are the most important cause of early disability in Lewy body dementia in Alzheimer’s, although Alzheimer’s can cause problems to walk with external perception.
3. The hallucinations, delusions and misidentification of people known are significantly more common in the early stages of DCL in Alzheimer’s disease.
4. REM sleep disorder is more common in early MCI than Alzheimer’s.
5. The disruption of the autonomic nervous system , causing a drop in blood pressure that causes dizziness, falls and urinary incontinence is more common in early DLB than in Alzheimer.

Causes and risks

Researchers have not yet identified any specific cause of Lewy body dementia . Most people diagnosed with MCI have no family history of the disorder, and genes linked to this disease have not been conclusively identified.

Treatment and efficacy

There are currently no specific treatments that can slow or stop brain cell damage caused by Lewy body dementia. The treatment of this disease is symptomatic , that is, it is limited to the management of symptoms, in particular hallucinations, extrapyramidal syndrome (which affects the motor system) and cognitive impairment.

Therefore, MCI is a common and complex neurodegenerative disorder , shorter than the course of Alzheimer’s. Great advances have been made in the pathophysiology of imaging, allowing an earlier diagnosis of this disease. Although there are few double-blind clinical studies in drug therapy, L-dopa and newer antipsychotics are gradually being evaluated as treatment.

It is important to work closely with the doctor to identify the drugs that work best for the patient and the most effective doses to improve their health. Considerations when approaching treatments that include medications include these factors:

• The drugs that inhibit cholinesterase are the current mainstay for treating Alzheimer’s. They can also help with certain symptoms of MCI.
• The antipsychotic drugs should be used with extreme caution in the DCL. Although doctors sometimes prescribe these medications for the behavioral symptoms that can occur with Alzheimer’s, they can cause serious side effects. These may include sudden changes in consciousness, swallowing problems, acute confusion, episodes of delusions or hallucinations, or the appearance or worsening of Parkinson’s symptoms.

Antidepressants can be used to treat depression, which is common in Lewy body dementia, Parkinson’s disease dementia, and Alzheimer’s. The most commonly used antidepressants are selective serotonin reuptake inhibitors .

Clonazepam can be prescribed to treat sleep disorder.

Like other types of dementia that destroy brain cells, MCI worsens over time and shortens the patient’s life.

A geriatric and neurological opinion is needed for the treatment of the patient , especially psychometric tests, magnetic resonance imaging of the brain or at least perform a positron emission tomography scan to obtain brain images, using the technique called positron, in order to identify abnormal areas in some areas.

Depending on these results, and according to the advice of specialists in this field of medicine, regular care is needed by the therapist, physiotherapist or psychologist, in addition to the ophthalmologist, who can intervene to place well-adapted corrective lenses to minimize the risk of hallucinations. Support for caregivers and the contribution of human and technical resources at home, as well as legal protection for these people if necessary, are essential to ensure their health, in addition to other resources such as relaxation or music therapy .