Long confused with Alzheimer’s or Parkinson’s, Lewy body disease nevertheless affects up to 250,000 people in France. Fluctuating symptoms, difficult diagnosis, imperfect treatments: insight into a pathology whose contours are still uncertain.
A disappearance which revives a disease that is still too invisible
French cinema is in mourning. Nathalie Baye, actress with four Césars, died at her Parisian home at the age of 77, as her family announced on April 18. For several months, she had withdrawn from public life, leaving concern over her state of health.
Born in Normandy, revealed by American Night by François Truffaut, it will have spanned half a century of cinema, moving with ease from auteur cinema to popular comedies. A dense career, marked by powerful roles, and a singular presence on screen.
But behind the emotion aroused by his disappearance, a question remains: what do we really know about this Lewy body disease, which is still too often unknown to the general public and professionals alike?
A confusing illness: between cognitive disorders, hallucinations and motor symptoms
Lewy body disease belongs to the family of neuroprogressive diseases. It is characterized by the abnormal accumulation of proteins in certain areas of the brain, disrupting the functioning of neurons.
Often confused with other pathologies, it confuses diagnostic benchmarks.
“Furthermore, one does not preclude the other. Research has shown that 40% of people with Alzheimer’s disease also suffered from Lewy body disease.“, underlined Professor Frédéric Blanc, geriatrician and neurologist at the Strasbourg University Hospitals, previously interviewed by True Medical.
This confusion is explained by the diversity of symptoms. Unlike Alzheimer’s, memory is not always the first sign.
“Unlike Alzheimer’s disease which manifests itself in 90% of patients through memory disorders, these are far from being the main signs by which patients develop Lewy body disease,” specifies the specialist (True Medical).
The clinical picture is often confusing, mixing:
- Attention and concentration problems;
- Fluctuations in cognitive state — the patient may be lucid one moment then confused the next;
- Sleep problems sometimes very early;
- Motor symptoms similar to Parkinson’s disease (stiffness, slowness, falls);
- And above all hallucinations, often visual, particularly characteristic.
Another striking sign, sometimes observed well before diagnosis: paradoxical sleep disorders.
“REM sleep, this phase during which we dream, is normally characterized by muscular atony which makes any movement impossible. However, people with Lewy body disease have intense nocturnal motor agitation.“, describes Professor Blanc.
This disease, still little known, also suffers from a lack of medical recognition.
“Lewy body disease is a disease that is still poorly understood. The first clinical criteria were described in 1992, their international recognition dates from 1996. As for the prodromal stages (…) they were only described in… 2020! Consequently, there are few doctors who know this disease well and are able to make its diagnosis.“, he insists.
Complex diagnosis, limited treatments: care still imperfect
One of the major challenges remains diagnosis. It is essentially based on the clinical observation of several key symptoms.
“The diagnosis is primarily clinical, it is based on examining the patient for 4 cardinal symptoms: visual hallucinations, one or more elements of parkinsonian syndrome, behavioral disorders during paradoxical sleep, and fluctuations in cognition and/or alertness.“, explains Professor Frédéric Blanc.
But the reality is more nuanced. “The specificity of the diagnosis thus made is very high, reaching 97%, however its sensitivity is low, only 31%: this means that more than 2/3 of patients are missed.“, he translates.
Result: a majority of patients are not diagnosed during their lifetime.
In terms of treatment, no medication can currently cure the disease. However, certain treatments can alleviate symptoms – notably cognitive disorders or hallucinations – but with caution.
Patients indeed present drug hypersensitivity.
“Patients with Lewy bodies are extremely sensitive to medications, particularly psychotropic drugs.“, warns the specialist.
Beyond medications, treatment is also based on non-pharmacological approaches: speech therapy, physiotherapy, psychological support.
As for the evolution, it remains progressive, often over ten years after the first marked signs.
“Patients frequently die from pulmonary infections resulting from aspiration, they also die from orthostatic hypotension (…) finally they die like the general population from cardiovascular diseases“, explains Professor Blanc.
Research that is still fragile, but brings hope
Despite its frequency – up to 250,000 people affected in France – Lewy body disease remains behind in research.
However, avenues are emerging. In Strasbourg, work is exploring biomarkers to improve diagnosis, while other teams are testing innovative techniques such as brain stimulation.
A crucial issue, because detecting the disease earlier could change the trajectory of patients.
“If we could identify patients at this stage in the development of the disease, we can imagine that we could prevent the development of more severe symptoms and slow down their progression.“, says Professor Blanc.
But obstacles remain, particularly financial. “The large pharmaceutical laboratories are far too cautious, they are very afraid of investing and of not having a return on investment. The only ones who put in the money are the small laboratories or the start-ups“, he regrets.
An illness behind the faces, a reality for families
The disappearance of Nathalie Baye is a powerful reminder that behind major public figures there are intimate, often silent battles at play. Lewy body disease, with its fluctuating symptoms and unpredictable course, upsets both patients and their loved ones. Knowing her better is already starting to support her better.
And, perhaps, to break the isolation of those who, in the shadows, face this disease which is still too little recognized every day.