Brain study reveals hidden clues to a condition that masks dizziness and increases fall risk

A new study from Imperial College London provides the first detailed picture of how the brain's electrical activity responds to whole-body motion.  

 The research includes, for the first time, data from a person with no functioning vestibular nerves at all – offering early clues towards a long-missing diagnostic tool for "Vestibular Agnosia".  

A hidden condition 

When the inner ear's balance system is stimulated, it triggers automatic eye movements (called the vestibular-ocular reflex, or VOR) and creates a sense of movement, or 'vertigo'. While VOR responses are objectively measured via eye movements, no such objective measure exists for assessing the cortical vestibular processing of self-motion. 

In 2021 researchers at Imperial College London described a unique syndrome, "Vestibular Agnosia," in which people have a significantly reduced sense of body motion due to brain disconnection. The term was first coined and characterised by a team led by Dr Barry Seemungal, in a key publication. 

"Vestibular agnosia increases the risk of falls because it worsens balance but also because it hides the usual symptoms of dizziness, so people with the condition often don't report these issues, meaning they're less likely to get the right care and more likely to fall", said Dr Seemungal. 

For the wider research field, this study could help inform research into altered sensations of body motion – for example, dizziness, which can cause balance impairment and falls. It also improves our understanding of how the brain processes the body's motion.   Zaeem Hadi Research Postgraduate at the Department of Brain Sciences at Imperial College London

"Despite being common, as observed in a third of people with acute brain injury and a fifth of people above 65 years old, there are currently no easy clinical measures to identify people with vestibular agnosia," said Zaeem Hadi, Research Postgraduate at the Department of Brain Sciences at Imperial College London, who led this research. 

"Using EEG signals, we investigated how the brain responds to whole-body motion. We conducted this study to help develop easy-to-use clinical measures to identify people with vestibular agnosia," he added. 

Emerging patterns 

To investigate this, Hadi and his team recruited healthy volunteers and patients with bilateral vestibulopathy – a condition affecting the balance organs of the inner ear – and measured their brain activity using EEG while they were rotated in a special chair, in complete darkness, at varying speeds. 

"We provide the first-ever characterisation of the brain's EEG responses to whole-body motion in a single case with absent audio-vestibular nerves," said Hadi. 

By comparing how the brain responded to these movements across both groups, the researchers were able to identify distinct EEG patterns linked to the processing of self-motion – some of which were preserved in patients with residual vestibular function, and others that were notably absent in a patient with complete vestibular loss. 

"Surprisingly, we found that one marker of the brain's response to self-motion – alpha-wave desynchronisation – did not differ between people with partial or complete loss of vestibular function and healthy individuals. This challenges previous assumptions and opens up new questions about how the brain compensates for vestibular loss," said  Hadi. 

The team also examined how these EEG patterns changed across the five different rotational speeds tested. "Ours is also the only study to characterise how brain activity scales with the increasing speed of whole-body motion," said Hadi. 

Future impacts 

The EEG patterns represent some of the first candidate markers that could, in future, be used to objectively assess how well someone's brain is processing signals of body motion – something that currently cannot be measured directly in clinical practice. 

Identifying these markers is an important step towards developing simple diagnostic tools for vestibular agnosia, which could support earlier diagnosis, better clinical care, and a reduced risk of falls and balance-related injuries. 

"For the wider research field, this study could help inform research into altered sensations of body motion – for example, dizziness, which can cause balance impairment and falls. It also improves our understanding of how the brain processes the body's motion," summarised Hadi.  

More  

• Hadi Z, Du K, Suresh T, Bandrivska S, Seemungal BM. The cortical electrophysiological changes evoked by natural vestibular stimulation in healthy and bilateral vestibulopathy. J Neurophysiol. 2026 Jun 22;136(1):380-393. doi: 10.1152/jn.00115.2026.