Pilot study on patients with Mal de Debarquement syndrome during pregnancy

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.

Mal de Debarquement Syndrome: A Matter of Loops?

Introduction: Mal de Debarquement Syndrome (MdDS) is a poorly understood neurological disorder affecting mostly perimenopausal women. MdDS has been hypothesized to be a maladaptation of the vestibulo-ocular reflex, a neuroplasticity disorder, and a consequence of neurochemical imbalances and hormonal changes. Our hypothesis considers elements from these theories, but presents a novel approach based on the analysis of functional loops, according to Systems and Control Theory.

Hypothesis: MdDS is characterized by a persistent sensation of self-motion, usually occurring after sea travels. We assume the existence of a neuronal mechanism acting as an oscillator, i.e., an adaptive internal model, that may be able to cancel a sinusoidal disturbance of posture experienced aboard, due to wave motion. Thereafter, we identify this mechanism as a multi-loop neural network that spans between vestibular nuclei and the flocculonodular lobe of the cerebellum. We demonstrate that this loop system has a tendency to oscillate, which increases with increasing strength of neuronal connections. Therefore, we hypothesize that synaptic plasticity, specifically long-term potentiation, may play a role in making these oscillations poorly damped. Finally, we assume that the neuromodulator Calcitonin Gene-Related Peptide, which is modulated in perimenopausal women, exacerbates this process thus rendering the transition irreversible and consequently leading to MdDS.

Conclusion and Validation: The concept of an oscillator that becomes noxiously permanent can be used as a model for MdDS, given a high correlation between patients with MdDS and sea travels involving undulating passive motion, and an alleviation of symptoms when patients are re-exposed to similar passive motion. The mechanism could be further investigated utilizing posturography tests to evaluate if subjective perception of motion matches with objective postural instability. Neurochemical imbalances that would render individuals more susceptible to developing MdDS could be investigated through hormonal profile screening. Alterations in the connections between vestibular nuclei and cerebellum, notably GABAergic fibers, could be explored by neuroimaging techniques as well as transcranial magnetic stimulation. If our hypothesis were tested and verified, optimal targets for MdDS treatment could be found within both the neural networks and biochemical factors that are deemed to play a fundamental role in loop functioning and synaptic plasticity.

The Interconnections of Mal de Débarquement Syndrome and Vestibular Migraine

OBJECTIVES/HYPOTHESIS

Mal de débarquement syndrome (MDDS) is characterized by a persistent rocking sensation, as though on a boat. It may occur following exposure to passive motion (motion-triggered MDDS [MT-MDDS]), or spontaneously (spontaneous-onset MDDS [SO-MDDS]). This study investigated the characteristics of MDDS patients with vestibular migraine (MDDS-VM) to those without (MDDS-O).

STUDY DESIGN

Retrospective review.

METHODS

Retrospective, single-center study of 62 patients with MDDS. Clinical characteristics, Dizziness Handicap Inventory (DHI), Migraine Disability Assessment Score (MIDAS), job impact, and optimal treatment(s) were studied.

RESULTS

There were 23 MDDS-O (19 women), and 39 MDDS-VM (35 women) patients. Comparisons between MDDS-VM and MDDS-O showed significant differences in age of onset (41 vs. 52 years, P = .005), interictal visually induced dizziness (89.7% vs. 30.4%, P < .001), interictal head motion-induced dizziness (87.2% vs. 47.8%, P = .001), other vestibular sensations (59% vs. 13%, P < .001), interictal aural symptoms (25.6% vs. 0%, P = .008), number of interictal symptoms (4.3 vs. 2.3, P < .001), total DHI score (54.9 vs. 38.1, P = .005), DHI-P (physical domain) score (16.1 vs. 10, P = .004), DHI-F (functional domain) score (20.9 vs. 15.7, P = .016 MIDAS (4.6 vs. 32, P = .002), and job resignations (23.2% vs. 5%, P = .016). On the other hand, between-group comparisons for MT-MDDS and SO-MDDS did not reveal any significant differences whatsoever. For optimal treatment, venlafaxine was the most used (27.3%) in all groups. For MDDS-VM, antiepileptic drugs and migraine preventive vitamins were also useful in relieving symptoms.

CONCLUSIONS

MDDS-VM patients appear to be more disabled than MDDS-O, in terms of severity of dizziness, job impact, and number of symptoms, but have good potential for improvement, particularly with migraine prophylactic treatment.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E1653-E1661, 2021.