Visual disorders and mal de debarquement syndrome: a potential comorbidity questionnaire-based study

Aim: Mal de debarquement syndrome (MdDS) is a neurological condition characterized by a constant sensation of self-motion; onset may be motion-triggered (MT) or non-motion-triggered/spontaneous (NMT/SO). People with MdDS experience similar symptoms to those with vertical heterophoria, a subset of binocular visual dysfunction. Hence, we aimed to explore potential visual symptom overlaps. Methods: MdDS patients (n = 196) and controls (n = 197) completed a visual health questionnaire. Results: Compared with controls, the MdDS group demonstrated higher visual disorder scores and visual complaints. NMT/SO participants reported unique visual symptoms and a higher prevalence of mild traumatic brain injury. Conclusion: Our findings suggest visual disorders may coexist with MdDS, particularly the NMT/SO subtype. The difference in visual dysfunction frequency and medical histories between subtypes, warrants further investigation into differing pathophysiological mechanisms. Plain language summary MdDS is a condition where patients feel like they are always on a boat. It is typically triggered by passive motion-events (cruises, flights, etc.), but can develop after non-motion events. People with MdDS can experience symptoms like those with certain visual disorders, therefore we wanted to see if there were overlaps between these conditions. This study surveyed people with MdDS and individuals from the general population about visual health and found that the MdDS group reported a higher frequency of visual dysfunction symptoms. Compared with motion-triggered patients, non-motion patients reported unique visual symptoms. This demonstrates that visual disorders may coexist in MdDS.