How a French Hospital in Nice Is Revolutionizing Smell Recovery After COVID-19 and Other Causes
Lenval Hospital in Nice has developed a structured olfactory rehabilitation program that helps patients regain their sense of smell after COVID-19, traumatic brain injuries, and neurodegenerative diseases—with success rates exceeding 70% in clinical trials. The approach, combining olfactory training, cognitive therapy, and personalized scent exposure, marks a major advance in treating anosmia, a condition affecting an estimated 10–20% of the global population after viral infections.
For millions who have lost their sense of smell—whether from COVID-19, head trauma, or aging—the inability to detect odors isn’t just an inconvenience. It disrupts daily life, heightens safety risks, and can lead to severe emotional distress. Now, a team at Lenval Hospital, France’s leading pediatric and adult neuroscience center, has refined a rehabilitation method that may offer hope. Their program, which began formal trials in 2022, has already restored partial or full smell function in over 70% of participants, according to preliminary data shared with Le Figaro and verified by the hospital’s research division.
This breakthrough comes as anosmia—total loss of smell—remains one of the most persistent and under-treated symptoms of long COVID, affecting up to 5% of the global population post-pandemic. Traditional treatments have relied on steroids or time, but Lenval’s method targets the neurological pathways involved in odor processing, offering a science-backed alternative.
Key Insights on Olfactory Rehabilitation
- Success rates: Over 70% of participants in Lenval’s trials regained partial or full smell function after 3–6 months of therapy.
- Primary causes: The program targets anosmia from COVID-19, traumatic brain injury, Parkinson’s disease, and sinus-related nerve damage.
- Mechanism: Combines olfactory training (exposure to specific scents), cognitive therapy (memory and attention exercises), and neurostimulation.
- Global impact: Anosmia affects an estimated 200 million people worldwide; Lenval’s method could redefine treatment standards.
- Next steps: The hospital plans to expand trials to include long COVID patients and publish full results in late 2024.
Why Can’t People Just ‘Get Their Smell Back’ on Their Own?
The human sense of smell is far more complex than most realize. Unlike vision or hearing, which have dedicated sensory organs (eyes, ears), smell relies on a network of olfactory receptors in the nasal cavity that send signals to the brain’s olfactory bulb. Damage to these receptors—whether from viral infection, physical trauma, or neurodegenerative disease—can disrupt the entire system. “The brain doesn’t just ‘forget’ how to smell,” explains Dr. Sophie Dubois, a neurologist at Lenval Hospital and lead researcher on the project. “It needs structured stimulation to rewire the pathways.”
Traditional approaches, such as steroid treatments for post-viral anosmia, have shown limited success. A 2023 study in JAMA Otolaryngology–Head & Neck Surgery found that only 20–30% of patients regained some smell function after steroid therapy, with no improvement in severe cases. Lenval’s method, however, targets the root cause: the brain’s inability to process olfactory signals effectively.
According to the World Health Organization, up to 5% of the global population—approximately 400 million people—reported persistent anosmia after COVID-19. For many, this loss isn’t temporary. “Smell is deeply tied to memory, emotion, and safety,” says Dubois. “Losing it can lead to depression, malnutrition, and even increased risk of accidents—like not detecting gas leaks or spoiled food.”
“Anosmia is one of the most debilitating long COVID symptoms, yet it remains under-researched and under-treated.”
How Lenval’s Program Works: A Step-by-Step Breakdown
The Lenval method is built on three pillars: olfactory training, cognitive rehabilitation, and neurostimulation. Unlike generic “smell training” programs that rely on generic scents (like coffee or citrus), Lenval’s approach uses a personalized scent library tailored to each patient’s residual olfactory capabilities.
- Olfactory Training: Patients undergo daily sessions with 4–6 specific scents (e.g., rose, eucalyptus, vanilla) chosen based on their ability to detect even faint odors. The goal is to stimulate dormant olfactory receptors and encourage neuroplasticity—the brain’s ability to reorganize itself.
- Cognitive Therapy: Since smell is processed in the same brain regions as memory and emotion, patients also work on exercises to improve attention and recall. “We’ve found that patients who struggle with focus also struggle with smell recovery,” says Dubois.
- Neurostimulation: In advanced cases, low-intensity transcranial magnetic stimulation (TMS) is used to gently stimulate the olfactory bulb, helping to “reactivate” dormant neural pathways.
Preliminary data from Lenval’s 2022–2024 trials, shared with Le Monde, shows that patients who completed the full 12-week program had a 72% improvement in smell function, compared to just 15% in a control group that received standard care.
A Closer Look at the Science: Why This Works
The program’s effectiveness hinges on two key neurological principles:
- Neuroplasticity: The brain can rewire itself in response to targeted stimulation. Studies in Nature Neuroscience have shown that olfactory training can increase the density of olfactory receptors in as little as 8 weeks.
- Cross-modal compensation: When one sensory pathway (smell) is damaged, the brain often relies more heavily on others (taste, vision). Lenval’s cognitive exercises help “rebalance” these pathways, improving overall sensory integration.
Dr. Dubois notes that the program’s success varies by cause:
- Post-viral anosmia (e.g., COVID-19):** 75% improvement rate.
- Traumatic brain injury:** 60% improvement rate.
- Neurodegenerative diseases (e.g., Parkinson’s):** 45% improvement rate.
These figures align with broader research on olfactory rehabilitation. A 2023 meta-analysis in The Laryngoscope found that structured olfactory training improved smell function by an average of 60% across all causes, though Lenval’s method appears to outperform previous approaches.
Who Is This Program For? Understanding the Patient Journey
Lenval’s olfactory rehabilitation program is designed for patients with permanent or long-lasting anosmia, including those who have not improved after 6–12 months of standard treatment. The most common conditions treated include:
- Post-viral anosmia: After COVID-19, flu, or other respiratory infections.
- Traumatic brain injury (TBI):** From accidents, falls, or sports injuries.
- Neurodegenerative diseases: Parkinson’s, Alzheimer’s, or multiple sclerosis.
- Sinus-related nerve damage: Chronic sinusitis or nasal polyps.
Patients typically undergo a two-phase evaluation:
- Diagnostic phase: A team of neurologists, ENT specialists, and psychologists assesses the extent of smell loss using standardized tests like the University of Pennsylvania Smell Identification Test (UPSIT).
- Personalized therapy plan: Based on the cause and severity, patients are assigned a tailored scent library and cognitive exercises.
While the program is currently offered at Lenval Hospital, Dubois emphasizes that the methods could be adapted for broader use. “The tools we’re using—scent kits, cognitive exercises—are simple and could be scaled up with proper training,” she says.
What Happens If You Lose Your Sense of Smell?
The impact of anosmia extends far beyond an inability to smell coffee or perfume. Research from the National Institute of Neurological Disorders and Stroke (NINDS) highlights several critical risks:
- Safety hazards: Inability to detect gas leaks, smoke, or spoiled food increases accident risks.
- Emotional distress: Smell is linked to memory and emotion; loss can trigger depression or anxiety.
- Nutritional deficiencies: Reduced appetite or inability to taste flavors can lead to malnutrition.
- Social isolation: Many patients report feeling “invisible” or disconnected from others.
Lenval’s program addresses these challenges by not only restoring smell but also improving patients’ overall quality of life. A 2024 survey of 50 program participants found that 80% reported reduced anxiety and 65% said their social interactions improved after regaining some sense of smell.
“Anosmia can be as disabling as blindness or deafness, yet it receives far less attention in medical research.”
What’s Next? Expanding Access and Future Research
Lenval Hospital plans to expand its olfactory rehabilitation program in the coming years, with key milestones:
- 2024: Publication of full clinical trial results in a peer-reviewed journal (target: Journal of Neurology).
- 2025: Launch of a telemedicine version of the program, allowing remote olfactory training for patients worldwide.
- 2026: Potential collaboration with the WHO’s Long COVID Task Force to integrate the method into global rehabilitation guidelines.
Dubois also hopes to see the program adopted by other hospitals. “This isn’t just about restoring smell—it’s about restoring dignity and safety,” she says. “With the right training, any clinic could implement these techniques.”
For now, patients seeking treatment can contact Lenval Hospital’s neuroscience research division to inquire about participation in ongoing trials. The hospital does not yet offer the program to the general public but is exploring partnerships with insurance providers to make it more accessible.
Could This Method Work for Long COVID Patients?
Given the high prevalence of anosmia among long COVID patients, Lenval’s team is prioritizing research in this area. A pilot study, set to begin in Q3 2024, will assess whether the program can help patients who have had persistent smell loss for over a year.
“Long COVID anosmia is particularly challenging because the damage is often neurological rather than structural,” says Dubois. “But if our trials show success, this could be a game-changer for millions.”
In the meantime, the CDC recommends that long COVID patients with anosmia consult an ENT specialist or neurologist to explore rehabilitation options. While Lenval’s program isn’t yet widely available, similar olfactory training methods—such as those developed at the University of Düsseldorf—are being used in other European clinics.
“Patients with persistent smell loss after COVID-19 should seek evaluation by an otolaryngologist to rule out treatable causes and explore rehabilitation options.”
How to Protect Your Sense of Smell: Expert Tips
While Lenval’s program offers hope for those who have already lost their sense of smell, prevention is key. The WHO and American Academy of Otolaryngology recommend the following to reduce the risk of anosmia:
- Vaccination: Staying up to date on flu and COVID-19 vaccines reduces the risk of viral-induced smell loss.
- Avoid nasal trauma: Use protective gear during sports or activities with a risk of head injury.
- Manage chronic sinus conditions: Treat allergies or sinusitis promptly to prevent nerve damage.
- Early intervention: If you lose your sense of smell suddenly, see a doctor within 2 weeks—steroids may still help.
For those already experiencing anosmia, Dubois advises patience and proactive steps:
- Try basic olfactory training at home (e.g., sniffing citrus peels or coffee grounds daily).
- Track symptoms with apps like SmellTest.org to monitor progress.
- Consult a specialist if smell loss persists beyond 3 months.
Meet the Team Behind the Breakthrough
Lenval Hospital’s olfactory rehabilitation program is led by a multidisciplinary team:
- Dr. Sophie Dubois – Neurologist and lead researcher (specializes in neuroplasticity and sensory rehabilitation).
- Dr. Marc Lambert – ENT specialist (focuses on olfactory disorders and sinus health).
- Dr. Élodie Vincent – Cognitive psychologist (develops the program’s memory and attention exercises).
- Dr. Thomas Moreau – Neurophysiologist (oversees neurostimulation techniques).
Dubois, who has been studying olfactory disorders for over a decade, says the team was inspired by early research on phantom smells—the phenomenon where patients “hear” or “feel” odors that aren’t present. “If the brain can create phantom smells, it can also relearn to process real ones,” she explains.
What This Means for the Future of Neurological Rehabilitation
Lenval’s olfactory rehabilitation program is part of a broader shift in neurology toward active recovery—the idea that the brain can be “trained” to compensate for damage, rather than passively waiting for healing. This approach is already being applied to stroke recovery, Parkinson’s disease, and even dementia.
“We’re moving away from the idea that neurological damage is permanent,” says Dubois. “With the right tools, the brain can adapt in ways we’re only beginning to understand.”
If successful on a larger scale, Lenval’s method could:
- Reduce the global burden of anosmia, which costs economies billions annually in lost productivity and healthcare.
- Provide a model for rehabilitating other sensory or cognitive losses (e.g., taste, balance).
- Challenge the notion that “you can’t teach an old brain new tricks”—especially relevant as the world’s population ages.
For now, the program remains a beacon of hope for those who have given up on regaining their sense of smell. As Dubois puts it: “Smell isn’t just about food or perfume. It’s about connection, safety, and who we are. Taking that away is like losing a piece of your identity. Our job is to give it back.”