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Perception disorder as a possible reason for dizziness
Dizziness is often a symptom of numerous illnesses. The causes for this can be of a diverse nature and have psychological or physical origins. The spectrum of dizziness causes ranges from harmless to serious illnesses. However, some of those affected have a type of dizziness, for which no cause can be determined. These patients have often had an unsuccessful medical odyssey and are just as clever afterwards. A German research team has now investigated the causes of functional vertigo.
A team from the Technical University of Munich (TUM) showed for the first time possible causes of dizziness that are not based on any physical findings. In various tests, the scientists showed that the cause of such complaints lies in the sensorimotor processing of the brain. The results were recently presented in the journal "Progress in Brain Research".
Some functional complaints are based on perceptual disorders
Among researchers who deal with functional complaints, the thesis was put forward that functional dizziness is based on incorrect processing of sensory stimuli in the brain. The team led by Professor Nadine Lehnen was able to support the thesis with her current work.
Course of the study
In a pilot study, eight people with functional dizziness and eleven healthy controls were individually placed in a dark room. Then points of light appeared on the left and right of the wall, to which the participants had to look. The test was then repeated with a special helmet that changed the inertia of the head. The subjects' eye and head movements were recorded and documented.
Dizziness patients could not compensate for indolence
The participants without functional dizziness were able to quickly adapt the head movements to the new conditions caused by the helmet. Wobble movements, which were initially caused by the increasing sluggishness, were quickly compensated for. The situation was very different for the participants with functional vertigo. These people struggled to compensate for the sluggishness and the head shook more and longer. "Our results make it impressively clear that functional dizziness expressed itself as serious physical illnesses, for example after a complete loss of the function of the equilibrium nerves," explains Nadine Lehnen from the research team. This shows how severely these people are restricted.
Prediction error in the brain
The researchers explain the background to this experiment. The brain stores learned models based on previous experience. Thanks to such models, people are able to predict sensory impressions that arise from movements. The brain then compares this expectation with the information that comes from the balance organs. If this information does not match, there is a contradiction between expectation and reality. In medical circles, this is known as a "prediction error".
Dizziness patients cannot compensate for prediction errors
"Healthy people can easily perceive this error, process it and adapt their movement," explains Lehnen. However, patients with functional dizziness do not seem to be able to process such senso-motor impressions correctly. As the research team reports, the brain of those affected by vertigo primarily relies on the stored models, which in certain situations then no longer match the real movement.
New therapy option opened
The tests also showed that those affected by vertigo have a limited ability to learn to balance such models. This opens up a new therapeutic approach that takes these newly discovered processing deficits into account. The team now wants to expand the findings in a larger study. (vb)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Graduate editor (FH) Volker Blasek
- Lehnen, Nadine / Schröder, Lena / Henningsen, Peter / u.a .: Deficient head motor control in functional dizziness: Experimental evidence of central sensory-motor dysfunction in persistent physical symptoms, Progress in Brain Research, 2019, sciencedirect.com
- Technical University of Munich (TUM): Perception disorder could upset those affected (retrieval date: 02.08.2019), tum.de