Mal de debarquement
Mal de debarquement (or mal de débarquement) syndrome (MdDS, or common name disembarkment syndrome) is a rare neurological condition usually occurring after a cruise, aircraft flight, or other sustained motion event. The phrase "mal de débarquement" is French for "sickness from disembarkation". MdDS is typically diagnosed by a neurologist or an ear nose & throat specialist when a person reports a persistent rocking, swaying, or bobbing feeling (though they are not necessarily rocking). This usually follows a cruise or other motion experience. Because most vestibule testing proves to be negative, doctors may be baffled as they attempt to diagnose this rare neurological syndrome. A major diagnostic indicator is that most patients feel better while driving or riding in a car or while in passive motion. MdDS is unexplained by structural brain or inner ear pathology and most often corresponds with a motion trigger, although it can occur spontaneously. This differs from the very common condition of "land sickness" that most people feel for a short time after a motion event such as a boat cruise, aircraft ride, or even a treadmill routine which may only last minutes to a few hours. The syndrome has recently received increased attention due to the number of people presenting with the condition and more scientific research has commenced to determine what triggers MdDS and how to cure it.
|Mal de debarquement|
|Synonyms||Sickness of disembarkment|
|Classification and external resources|
Symptoms most frequently reported include a persistent sensation of motion usually described as rocking, swaying, or bobbing, disequilibrium; it is seldom accompanied by a true spinning vertigo, difficulty maintaining balance. Chronically fatigued, sufferers can become fatigued quickly with minimal exertion and experience back aches. Other common symptoms include visual disturbances such as seeing motion, blurred vision, difficulty concentrating or inability to focus, eye pain, headaches, ice pick headaches and/or migraine headaches, the feeling of pressure in the brain and confusion, tinnitus, ear pain and sensitivity to loud sounds. Colds, flu and/or virus infections may increase symptoms.
Fluctuations in temperature also affect suffers in particular heat, may have photo-sensitivity and find it more difficult to walk in the dark as well as other sensitivities to strong smells including chemical smells. Cognitive impairment ("brain fog") includes an inability to recall words, short term memory loss, an inability to multi-task, misspelling and mispronunciation of words. MdDS sufferers report they are unable to use a computer for any length of time due to the visual over stimulation, and some are even unable to watch television.
The condition is masked by a return to motion such as in a car, train, plane, or boat; however, once the motion ceases, the symptoms return often at much higher levels than when the journey first commenced. Symptoms can be increased by stress, lack of sleep, crowds, flickering lights, loud sounds, fast or sudden movements, enclosed areas or busy patterns.
MdDS sufferers can sleep up to 12 or more hours a day, depending on their symptom levels. Research reveals MdDS is not migraine related and many sufferers have never had migraine symptoms prior to the onset of the disorder. However, for some MdDS sufferers there maybe have been a correlation between migraine and some pathophysiological overlap or even some other sort of precipitating illness.
The symptoms of MdDS are extremely debilitating and fluctuate high and low on a daily basis, it greatly affects the working capacity of sufferers with many having to relinquish work, it also limits most other daily and social activities; sufferers can have low quality of life in both the physical and emotional realms, comparable to people who have multiple sclerosis.
In persistent MdDS, the symptoms continue for more than a month, possibly for many years, or indefinitely. The longer the disorder remains, there is a progressively lower likelihood of remission. All medical treatment is palliative for sufferers with "persistent MdDS" symptoms.
MdDS is diagnosed several ways, one being by the symptoms: in particular, the "constant rocking, swaying feeling" and the abatement of this feeling when in motion again and as a matter of exclusion. There are no definitive tests that confirm MdDS, only tests that rule out other conditions. Tests include hearing and balance, and MdDS is generally diagnosed by either a neurologist or an ear nose & throat specialist.
For most balance and gait disorders, some form of displacement exercise is thought helpful (for example walking, jogging, or bicycling but not on a treadmill or stationary bicycle). This has not been well-studied in MdDS. Medications that suppress the nerves and brain circuits involved in balance (for example, the benzodiazepine clonazepam) have been noted to help and can lower symptoms, but it is not a cure. It is not known whether medication that suppress symptoms prolongs symptom duration or not. Vestibular therapy has not proved to be effective in treating MdDS.
Additional research is being undertaken into the neurological nature of this syndrome through imaging studies. The disorder remains incurable and permanent if the symptoms do not remit in a short period of time.
The condition is thought to be under-reported in the medical literature. A study of 27 cases conducted by Timothy C Hain in 1999 noted all but one patient to be female. The average age in this series was 49 years. This apparent gender disparity, however, may be due in part to the fact that the questionnaire which formed the basis of the study was circulated in a publication with a predominantly female reader base.
Subsequent studies have produced conflicting results with regard to the gender distribution of MdDS. The trends in Hain's report have recently been supported by the MdDS Balance Disorder Foundation, in a study of over 100 individuals diagnosed with MdDS. The female:male ratio was approximately 9:1; the average age of onset was 43–45 years. However, another recent study found that 44% of subjects who had experienced MdDS for 2 years or more were male, suggesting a more even distribution.
It has been shown to occur in excursions of as little as 30 minutes though it has been unclear how long it takes for symptoms to occur. The most commonly reported inciting event was a prolonged ocean cruise (~45%); however, shorter boating excursions (~22%), aircraft travel (~15%), and automobile travel (~8%) have all been described.
Cases of MdDS have been reported in children as young as eight and in both genders. Men may have a more difficult time obtaining a diagnosis due to the disparity of women reported. When sailors and soldiers returned from World War II, the syndrome was reported at a higher rate in males.
Repetitive transcranial magnetic stimulationEdit
Despite MdDS causing significant disability, therapy for persistent MdDS remains virtually non existent. A pilot study has commenced utilizing repetitive transcranial magnetic stimulation (rTMS) this being a method of neuromodulation in which a local magnetic field is applied over the scalp to induce an electric current in the cortical structures underlying the coil. Low-frequency rTMS (e1 Hz) induces local inhibition, whereas high frequency rTMS (Q5 Hz) induces local excitation. The TMS studies have proved to help in lowering the symptoms of MdDS if the treatment is ongoing; however, it is not a cure.
Vestibulo-Ocular Reflex Research 2014Edit
At least one clinical trial on readaptation of the vestibulo-ocular reflex undertaken by Dr Mingjia Dai from Mount Sinai Hospital in New York City has produced results for a significant percentage of patients who have participated in the program.
Dai has developed a treatment that has provided either a cure or substantial improvement in symptoms for 70% of the patients in the clinical trial phase. The treatment involves a physical manipulation of the patient intended to readapt the vestibulo-ocular reflex. While the program is no longer in the research phase, Dai continues to accept patients for treatment. According to Dai, "success" is measured as a 50% reduction of symptoms.
Recent research reveals a very small percentage of MdDS cases may be related to optokinetic nystagmus (OKN).
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