Loss of balance encompasses very different clinical realities depending on whether it originates from the inner ear, the brain, or a peripheral toxic injury. Identifying the source of the disorder radically changes the management approach. What neurological mechanisms weigh most in the balance, and how can they be distinguished from pure vestibular causes?
Nitrous oxide and loss of balance: a toxic cause on the rise among young people
Articles addressing loss of balance focus on seniors, the inner ear, and neurodegenerative diseases. One angle remains absent: neurological injuries related to the recreational use of nitrous oxide, which has been rapidly expanding since 2023-2024 among 15-30 year-olds.
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Poison control centers and regional authorities in France report a marked increase in cases of balance disorders and spinal cord injuries due to functional vitamin B12 deficiency, caused by repeated inhalation of this gas. An official campaign in Auvergne-Rhône-Alpes reminds that nitrous oxide “can lead to severe neurological disorders, impair vigilance, and increase the risk of accidents,” including dizziness and imbalance.
The mechanism is well identified: nitrous oxide inactivates vitamin B12, an essential cofactor for maintaining the myelin sheath that surrounds nerves. Without functional myelin, nerve transmission deteriorates, causing paraparesis and gait disturbances. This cause is toxic, preventable, and affects a population rarely associated with balance problems.
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To delve deeper into frequent causes on Valbreon, it is essential to move beyond the reflex of only looking for an inner ear pathology.
Neurological causes and vestibular causes: a comparative table of mechanisms
Neurological loss of balance and vestibular loss of balance do not manifest in the same way. The table below contrasts the main clinical characteristics to help guide reasoning.
| Criterion | Vestibular origin (inner ear) | Neurological origin (brain, spinal cord, nerves) |
|---|---|---|
| Dominant sensation | Rotatory vertigo, feeling that the environment is spinning | Postural instability, imbalance while walking without rotation |
| Duration of episodes | Seconds to minutes (BPPV), hours (Meniere’s disease) | Continuous or progressive, rarely isolated episodic |
| Associated signs | Nausea, nystagmus, tinnitus, hearing loss | Muscle weakness, sensory disturbances, coordination difficulties |
| Examples of pathologies | BPPV, labyrinthitis, vestibular neuritis | Multiple sclerosis, cerebellar stroke, neuropathy (B12, nitrous oxide) |
| Typical trigger | Change in head position | No clear postural trigger, progressive worsening |
A brief positional vertigo triggered by a head movement points to the vestibular system. A permanent imbalance that progressively worsens points to a neurological injury.
Functional neurological disorders: when the brain malfunctions without visible lesions
Functional neurological disorders (FND) represent a recognized cause of loss of balance in neurology but are rarely mentioned in mainstream articles. The brain produces real, measurable motor or sensory symptoms, without any detectable structural lesion on imaging.
Among these disorders, we find:
- Walking difficulties with a constant sensation of instability, without identifiable vestibular or cerebellar anomalies
- Episodes of weakness in the lower limbs that mimic classic neurological injury
- Chronic dizziness associated with postural hypervigilance, sometimes labeled “persistent perceptual postural dizziness” (PPPD)
Recent reports from the National Assembly on the somatic consequences of trauma (violence, complex trauma) list these functional disorders among the documented sequelae. The diagnosis relies on positive criteria, not just on the exclusion of other pathologies.
The difficulty for the patient: a often lengthy medical journey, with normal tests that can give the impression that the symptom is “not real.” Management combines appropriate vestibular rehabilitation and a neuropsychological approach.
Common medications and imbalance: an underestimated factor
Some treatments prescribed for other conditions can themselves generate balance disorders. Antiepileptics, antihypertensives, anxiolytics, and certain antidepressants are among the classes most frequently associated with sensations of dizziness or postural instability.
The accumulation of multiple ototoxic or sedative medications multiplies the risk of falls, especially among polymedicated elderly individuals. A regular review of the prescription with the treating physician can sometimes reduce these effects without compromising the main treatment.
Loss of balance and climate change: an emerging neurological link
An even more recent angle concerns the impact of heat waves on the nervous system. Documented clinical cases in French neurology show that episodes of extreme heat exacerbate pre-existing neurological symptoms, particularly in patients with multiple sclerosis. Nerve conduction temporarily deteriorates when body temperature rises, a phenomenon known as Uhthoff’s sign.
This link between climate and balance disorders remains little explored in content aimed at the general public. However, it concerns an increasing number of patients as heatwave episodes become more frequent.
When to seek emergency care
Any sudden loss of balance accompanied by motor deficits (weakness on one side of the body), speech difficulties, or double vision warrants a call to 15. These signs point to a stroke, where every minute counts to limit sequelae.
- Sudden imbalance with facial paralysis or difficulty speaking: suspicion of stroke
- Progressive loss of balance with numbness in the limbs: look for neuropathy or spinal cord injury
- Brief and repeated positional vertigo: likely BPPV, to be confirmed by a simple clinical test
The distinction between neurological emergency and benign vestibular disorder relies on these associated signs. An isolated imbalance, without other neurological symptoms, rarely points to a serious cause, but always deserves medical evaluation if episodes recur or worsen.