Prescribing wisely

Emerging therapies & future directions

The frontier is moving from blanket symptom suppression toward mechanism-based therapy — modulating central processing and neural plasticity, and delivering drugs precisely to the inner ear.

Neuromodulation

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique that modulates cortical excitability. In functional vestibular disorders such as PPPD and mal de débarquement syndrome — thought to involve maladaptive cortical processing and visual dependence — rTMS targeted at the posterior parietal and dorsolateral prefrontal cortex may help restore normal multisensory integration. A pilot trial found that low-frequency rTMS over the left dorsolateral prefrontal cortex reduced mal de débarquement symptoms for several weeks.1 Related techniques — transcranial direct-current stimulation and vestibular nerve stimulation — remain experimental but offer neuroplasticity-based, non-pharmacological options for refractory syndromes.2

NMDA antagonists and cannabinoids

The glutamatergic NMDA receptor is central to vestibular signal processing and plasticity. NMDA modulation can influence vestibular compensation and VOR-gain abnormalities after unilateral lesions in preclinical work, and agents such as memantine are under early investigation for balance disorders — though their clinical role is unsettled. Separately, cannabinoid (CB1/CB2) modulation is being explored for refractory vertigo and motion sickness via antiemetic, anxiolytic and anti-inflammatory pathways, but rigorous human trials are needed given cognitive and psychotropic concerns.

Vestibular-targeted drug delivery

The blood–labyrinth barrier limits systemic drug entry into the inner ear, which is why local delivery is advancing. Intratympaniccorticosteroids are already established in Ménière’s disease and autoimmune inner-ear disease. Newer nanocarriers — liposomes, hydrogels and microspheres — aim to prolong drug residence at the round-window niche for gradual diffusion, and biodegradable sustained-release implants are in preclinical and early-phase testing, promising better efficacy and compliance with less systemic burden.3

Outlook

The direction of travel is clear: from generalised suppression toward precise, mechanism-based therapy — corticosteroids in neuritis, betahistine in Ménière’s, SSRIs in PPPD — chosen on an accurate diagnosis and combined with rehabilitation. Neuromodulation, neurochemical modulation and inner-ear-targeted delivery point to a more personalised, multidisciplinary future for the complex and refractory cases.

Key points

  • rTMS and other neuromodulation are promising for functional disorders (PPPD, MdDS) but still experimental.
  • NMDA antagonists (e.g. memantine) and cannabinoids are under investigation, with unsettled roles.
  • Local inner-ear delivery — intratympanic steroids now, nanocarriers and implants next — bypasses the blood–labyrinth barrier.
  • The field is shifting from symptom suppression toward targeted, mechanism-based, personalised therapy.