Debarkation Syndrome as a Technology-Induced Neurological Condition

Modern transport Debarkation Syndrome, or more properly Mal de Debarquement Syndrome (MdDS), is a neurological disorder that most commonly is associated with an ocean cruise or other type of water travel.  The hallmark symptom is “land legs,” a disorientation and sensation of the ground moving “like a ship,” with the symptoms becoming so severe that the person cannot walk or work, leading to depression and potentially suicide.   The basis for the condition is a form of disconnect between what the person sees and motion the person senses.  As it is a neurological condition, the common vertigo treatments associated with inner ear issues are ineffective.  Another hallmark is the symptoms are abated when the person is in a moving frame of reference, which in effect forces the visual and other sensory inputs into a stronger agreement.  Medicines such as benzodiazepines or even the use of alcohol can provide some relief, but their use is problematic. The official MdDS diagnosis is predominantly associated with middle aged women who report “permanent land legs” after a cruise ship vacation.    This is based on the intake of patients with a specific set of symptoms, how they reported developing the condition, then noting commonalities.  While the medical community tends to examine conditions based on intake data,  examining the physics attributed to MdDS onset bears striking resemblance to other types of travel-induced disorientation with cars, aircraft, spacecraft, and even Virtual Reality (VR) being associated with similar, if not identical, neurological conditions.  One of the poster’s authors has been diagnosed with MdDS caused by a submarine maneuver despite some researchers stating it cannot be MdDS as it was not caused by a surface ship.   In the course of seeking medical treatment, it was noted similar conditions were reported by older men who worked as sailors or other offshore workers.  These individuals report “feeling like on a ship in a storm” while ashore between work periods, with behavior fitting the stereotype of sailors abusing alcohol while ashore but being fine once underway.   This indicates number of ship-related potential patients is much larger than currently anticipated.  Coupled with the reports from other industries, such as aviation, as well as studies related to space travel and permanent disorientation through the use of Virtual Reality devices, the number of potential patients is even larger.     As a technology-induced medical condition, the study of MdDS has parallels to the early studies of another technology-induced condition, decompression sickness.  Decompression sickness was initially classified by how it was developed, such as construction (“Caissons Disease”) versus diving (“The Bends.)  As the medical understanding developed, engineers developed methods to prevent the conditions as well as treat them.  Understanding the physics and circumstances that creates the onset of a technology-based debilitating condition is an engineering issue as well as a medical one.  This poster summarizes the physics that is common to the various forms of similar conditions as well as how it related to decompression sickness.  The authors are members of the ASME Codes and Standards Committee for Pressure Vessels for Human Occupancy (PVHO), which publishes safety standards related to hyperbaric medical devices as well submarine and diving systems.