Inspired by a patient's mother
Mal de debarquement (MDD) is a rare and poorly understood disorder of the vestibular system that results in a phantom perception of self- motion typically described as rocking, bobbing or swaying. The symptoms tend to be exacerbated when a patient is not moving, for example, when sleeping or standing still. Studies have shown that a brief period of these symptoms is common in healthy individuals after prolonged episodes of passive motion, normally lasting seconds to three days. However, in MDD, significant balance impairment can persist for months to years. Symptoms may diminish in time or may reappear spontaneously or after another exposure. The most common triggers are water-based activities such as ocean cruising. Less common triggers include airplane travel, extended landing travel and sleeping on water beds. Other common complaints of patients with MDD include a sensation of uneven ground below their feet while walking, or feeling as if they are still on a boat. It is rare for MDD patients to have true rotational vertigo or motion sickness.
Signs & Symptoms
The primary symptom is the persistence of a sense of motion and rocking. Some patients may experience fatigue, mood changes and confusion. Imbalance is a common complaint. Symptoms often increase when exposed to fast movements, flickering lights and grocery store aisles. There may be transient improvement in symptoms with re-exposure to passive motion, for example, riding in cars or trains. After completion of the trip, however, the symptoms tend to recur.
Studies have shown that the length of time one is exposed to a motion experience does not determine the severity or duration of the syndrome, but most typical cases are triggered by day trips lasting several days.
The true cause behind MDD is still unknown. MDD likely results from the body’s balance system inadequately processing and adapting to multiple sensory inputs (visual, vestibular, proprioceptive and cognitive) from the environment once the stimulus (trigger) has ended. It is as yet undetermined as to the cause of the balance system’s inability to appropriately compensate and adapt. How or why this happens remains a mystery.
The majority of people affected are adult females, although there have been reports of males having the diagnosis. Patients with migraine may have any increased susceptibility through unknown mechanisms.
Benign paroxysmal positional vertigo (BPPV) is a common cause of dizziness, especially among the elderly. It comes about as a result of a movement of the head. Under normal conditions, calcium particles are attached to a specific location within the inner ear. As a result of injury or degeneration, these calcium particles clump together causing a sudden and brief episode of dizziness. (For more information on this disorder, choose “BPPV” as your search term in the Rare Disease Database.)
Meniere’s disease is a disorder characterized by periodic episodes of vertigo or dizziness; fluctuating, progressive hearing loss; tinnitus; and a sensation of fullness or pressure in the ear.
The diagnosis of MDD still remains mostly clinical. As such, the history is very important. Persistent “dizziness” after an ocean cruise, a sailing trip, a prolonged airplane flight or a cross-country road trip is highly suggestive of MDD. Vestibular function tests in patients with MDD have been normal or nonspecific in their abnormality. These tests are important in excluding other etiologies for the patient’s symptoms.
MDD is very difficult to treat, with little effectiveness of most treatments. Clonazepam at low doses once or twice a day has shown improvement in patients. Higher doses were not proven to be effective. Vestibular rehabilitation has shown effectiveness in a small number of patients.
A small study from Dai et, al. (see References below) reported that using a full-field visual stimulus while the head was rolled resulted in >50% improvement in both subjective and objective symptoms. These findings are encouraging but need to be reproduced. Patients who do recover may be susceptible to recurrences of increased duration.
Chen Y, Cha YH, Gleghorn D, Doudican BC, Shou G, Ding L, Yuan H. Brain network effects by continuous theta burst stimulation in Mal de Débarquement Syndrome: simultaneous EEG and fMRI study. J Neural Eng. 2021 Oct 20. doi: 10.1088/1741-2552/ac314b. Epub ahead of print. PMID: 34670201.
Objective: Heterogeneous clinical responses to treatment with non-invasive brain stimulation are commonly observed, making it necessary to determine personally optimized stimulation parameters. We investigated neuroimaging markers of effective brain targets of treatment with continuous theta burst stimulation (cTBS) in Mal de Débarquement Syndrome (MdDS), a balance disorder of persistent oscillating vertigo previously shown to exhibit abnormal intrinsic functional connectivity.
Approach: Twenty-four right-handed, cTBS-naive individuals with MdDS received single administrations of cTBS over one of three stimulation targets in randomized order. The optimal target was determined based on the assessment of acute changes after the administration of cTBS over each target. Repetitive cTBS sessions were delivered on three consecutive days with the optimal target chosen by the participant. EEG was recorded at single-administration test sessions of cTBS. Simultaneous EEG and fMRI data were acquired at baseline and after completion of 10-12 sessions. Network connectivity changes after single and repetitive stimulations of cTBS were analyzed.
Main results: Using electrophysiological source imaging and a data-driven method, we identified network-level connectivity changes in EEG that correlated with symptom responses after completion of multiple sessions of cTBS. We further determined that connectivity changes demonstrated by EEG during test sessions of single administrations of cTBS were signatures that could predict optimal targets.
Significance: Our findings demonstrate the effect of cTBS on resting state brain networks and suggest an imaging-based, closed-loop stimulation paradigm that can identify optimal targets during short-term test sessions of stimulation.
Riley J, Gleghorn D, Doudican BC, Cha YH. Psychological assessment of individuals with Mal de Débarquement Syndrome. J Neurol. 2021 Sep 19. doi: 10.1007/s00415-021-10767-4. Epub ahead of print. PMID: 34541614.
Objective: To report on the psychological, personality, and behavioral profiles of individuals with persistent Mal de Débarquement Syndrome (MdDS).
Materials and methods: Individuals with MdDS who participated in neuromodulation clinical trials between May 2013 and June 2019 completed a series of standardized psychological questionnaires and underwent the Structural Clinical Interview for DSM-IV-TR (SCID) for specific psychiatric diagnoses. All data reported are from baseline assessments prior to any study interventions. Scores were compared to population norms for adult women.
Results: Complete datasets were available for 55 women. Mean age of onset of MdDS was 49.0 ± 11.9 years (range 22-69 years) and median duration of illness of 22 months (6 months-20 years). SCID results were as follows: healthy (48.1%), any lifetime Major Depressive Disorder (35.2%, 7.4% current); any lifetime history of anxiety disorder (11.1%); any lifetime substance use disorders (18.5%, 0% current). Compared to population norms, the MdDS group scored significantly higher on the Patient Health Questionnaire-9 depression scale and the Generalized Anxiety Disorder 7 (GAD-7) anxiety scale, but only the GAD-7 correlated with symptom severity. The NEO-Five Factor Inventory for personality, Positive and Negative Affect Schedule, Behavioral Inhibition System/Behavioral Activation System Scale, and the Empathy Quotient metrics did not correlate with duration of illness. Disability assessed by the 12-item World Health Organization Disability Assessment Schedule 2.0 was 25.7 ± 6.7, comparable to reports for concussion. Disability correlated with severity of depression, anxiety, neuroticism, and affect but not to severity of MdDS.
Conclusions: Psychological profiles of MdDS relate to disability but not to duration of illness.
Cha YH, Ding L, Yuan H. Neuroimaging Markers of Mal de Débarquement Syndrome. Front Neurol. 2021 Mar 4;12:636224. doi: 10.3389/fneur.2021.636224. PMID: 33746890; PMCID: PMC7970001.
Mal de débarquement syndrome (MdDS) is a motion-induced disorder of oscillating vertigo that persists after the motion has ceased. The neuroimaging characteristics of the MdDS brain state have been investigated with studies on brain metabolism, structure, functional connectivity, and measurements of synchronicity. Baseline metabolism and resting-state functional connectivity studies indicate that a limbic focus in the left entorhinal cortex and amygdala may be important in the pathology of MdDS, as these structures are hypermetabolic in MdDS and exhibit increased functional connectivity to posterior sensory processing areas and reduced connectivity to the frontal and temporal cortices. Both structures are tunable with periodic stimulation, with neurons in the entorhinal cortex required for spatial navigation, acting as a critical efferent pathway to the hippocampus, and sending and receiving projections from much of the neocortex. Voxel-based morphometry measurements have revealed volume differences between MdDS and healthy controls in hubs of multiple resting-state networks including the default mode, salience, and executive control networks. In particular, volume in the bilateral anterior cingulate cortices decreases and volume in the bilateral inferior frontal gyri/anterior insulas increases with longer duration of illness. Paired with noninvasive neuromodulation interventions, functional neuroimaging with functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and simultaneous fMRI-EEG have shown changes in resting-state functional connectivity that correlate with symptom modulation, particularly in the posterior default mode network. Reduced parieto-occipital connectivity with the entorhinal cortex and reduced long-range fronto-parieto-occipital connectivity correlate with symptom improvement. Though there is a general theme of desynchronization correlating with reduced MdDS symptoms, the prediction of optimal stimulation parameters for noninvasive brain stimulation in individuals with MdDS remains a challenge due to the large parameter space. However, the pairing of functional neuroimaging and noninvasive brain stimulation can serve as a probe into the biological underpinnings of MdDS and iteratively lead to optimal parameter space identification.
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