Functional dizziness tied to physical perception disorders
Functional dizziness is often misdiagnosed and is not easily resolved. But, it may be better understood following research from the Technical University of Munich (TUM), Germany, which has identified problems with the processing of sensory-motor signals in the brain, resembling those associated with dizziness.
A pilot study with about 20 patients was conducted based on previous knowledge that functional disorders may be caused by faulty processing of sensory stimuli – study participants had either a dizziness complaint or were otherwise healthy.In the experiment, participants were tasked to note the points of light in a dark room (points of light were flashed in rapid succession on the wall left and right of gaze straight ahead). The experiment was performed with and without a weighted helmet, to alter the inertia of their head, and participants’ eye and head movements during the gaze shifts were recorded.
While the healthy subjects quickly adapted their movements to the added weight and managed to stop their head from wobbling, all the subjects with functional dizziness found it difficult – they surprisingly behaved like patients with dizziness due to severe physical disorders.
In short, most people have a certain expectation about the sensory impressions evoked by a movement, stored as a learned model in their subconscious. When the expectation is different from the information from vestibular organs, an imbalance or “prediction error” is created, which results in a dizzy episode.
Professor Nadine Lehnen, senior physician for psychosomatic medicine at the TUM University Hospital, has explained, “Healthy people easily perceive/process this error and adapt their movements accordingly. However, patients with functional dizziness do not appear to process sensory-motor impressions as such – they rely primarily on their stored model, but it no longer matches the new reality.”
Such patients would need therapeutic treatments that take into account this processing deficit, as these patients are still able to learn – albeit only to a limited degree.
