Mal de Debarquement Syndrome (MdDS) is a French term that is utilized to describe a chronic vestibular disorder where individuals feel as if they are almost constantly rocking or swaying. Additional symptoms can include fatigue, spatial disorientation, visual motion intolerance, headache, and anxiety.
The name, when translated to English, means “sickness on dis-embarkment”. The condition is often triggered by traveling on a boat but can also be triggered by airline flights. MdDS can also occur spontaneously, although this is less common.
The condition is thought to be due to a central/neurologic maladaptation, more specifically, there are thought to be alterations to central velocity storage and with the cerebellar nodulus specifically being implicated. Essentially, these individuals have difficulty with accurate perception and integration of the vestibular and visual senses.
The population(s) most at risk for developing MdDS are middle aged females and those with a history of anxiety and/or migraine.
Assessment of MdDS
Most individuals with MdDS undergo extensive investigations with internal medicine/family medicine, neurology, otolaryngology, and/or cardiology to investigate for a potential source of the symptoms. However, there is no single test for MdDS and the diagnosis is often made based on the symptom description and the lack of other identifiable organic causes for the symptoms. The recommended symptom criteria from the Barany Society can be found below.
The Barany Society consensus document criterion
- Non-spinning vertigo, often described as a sensation of rocking, bobbing, or swaying, that is nearly constant.
- Onset should occur within 48 hours after exposure to passive motion.
- The symptoms should temporarily improve with re-exposure to passive motion.
- The symptoms persist for more than 48 hours.
It is also worth noting that MdDS can also have significant symptom overlap with another central/neurologic maladaptive process called persistent postural perceptual dizziness (PPPD). There is also a consensus document with criteria for diagnosing PPPD.
Treatments do differ slightly for PPPD and MdDS, as such correctly identifying the condition is important. One of the primary differentiating symptoms between these two conditions is that individuals with MdDS have symptoms that are initially triggered by passive motion and the symptoms improve with re-exposure to passive motion, while most individuals with PPPD report symptom exacerbation with exposure to passive motion. There is also not typically an initial passive motion trigger for PPPD.
Treatment for MdDS
There is currently no uniform treatment protocol for MdDS, but the condition is being studied further to better understand the most effective treatment(s). At present, treatments primarily consist of medications to calm and physical therapy to help recalibrate the central vestibular system.
Therapy
One of first novel treatments for MdDS was developed by the departments of Neurology and Otolaryngology at Mount Sinai Hospital in New York, USA in 2014. They developed a protocol that aimed to reverse the central vestibular maladaptive process by exposing individuals to a full field visual stimulus (optokinetic stimulus), while the individual tilted their head side to side in roll plane. They initially reported good success with 70% of the subjects noting a cure or substantial improvement in their symptoms.
A follow up to this initial study noted 78% of subjects with classic MdDS exhibited symptom improvement, while only 48% of those with spontaneous MdDS saw symptom improvement. This study also aimed to examine the long-term effects of the treatment with a 1 year follow up with he subjects. They noted 19-27% were completely cured of the symptoms and most of the other participants reported improvement but not complete resolution of the symptoms.
A more recent study aimed to replicate these findings with a similar treatment protocol and found an overall success rate of 64%. These data would suggest that VOR re-adaptation type therapy is beneficial for the MdDS patient, however, there seems to be a high risk for symptom recurrence and as such ongoing maintenance type therapy may be indicated. VOR re-adaptation therapy also seems to be most effective for classic cases of MdDS and less effective for spontaneous cases.
The ideal therapy protocols for MdDS have yet to be identified and it is currently unknown if additional maintenance type therapy could provide more lasting symptom improvement. Perhaps, even an at home therapy program on a maintenance basis could help sustain these effects.
Medication for MdDS
Medications are also sometimes utilized in the treatment of MdDS patients with varying levels of effectiveness. There is limited evidence to support that medications such as meclizine or promethazine provide symptom relief for MdDS patients. There is some data that benzodiazepines such as clonazepam and diazepam can be helpful in reducing MdDS symptoms, however, these medications aren’t without risk can potentially be addictive.
Selective serotonin reuptake inhibitors (SSRIs) may also be used in MdDS with an aim to provide an inhibitory or calming effect to the brain.
Many individuals suffering from MdDS also have a history of migraine and as such there has been some investigation in the use of medications that are traditionally utilized for migraine management for MdDS treatment. A 2017 study found that 73% of patients experienced significant quality of life improvement after being treated with lifestyle modification, as well as medications such as verapamil, nortriptyline, and topiramate.
A more recent study in 2021 echoed similar findings, noting patient symptom improvement when treated with migraine prophylaxis.
Neuromodulation for MdDS
The least utilized treatment option is a process called neuromodulation. Neuromodulation refers to utilizing electrical or chemical stimuli to alter neural firing patterns. One means of neuromodulation is by utilizing a process called transcranial magnetic stimulation (TMS), which uses a magnet to alter nerve cell function. TMS has been used successfully for management of depression and obsessive compulsive disorder, and it is now being studied for use in MdDS patients.
There is at least some emerging data that TMS may provide symptom improvement in MdDS patients, however, TMS treatment is not widely available or utilized for MdDS patients due to the lack of availability and standardized protocols.
Summary
There have been great strides in the past decade in our understanding of MdDS, however, the pathophysiology and ideal treatment(s) are still not fully understood. Additional research is needed to better understand the optimal treatment(s) that can provide lasting benefits for these patients.
I look forward to some of the research being done in this area to hopefully identify and provide more effective, long lasting treatment options for those suffering from MdDS.
