Mal de Debarquement Syndrome (MdDS): Clinical Guide

Definition and Classification

Mal de Debarquement Syndrome (MdDS) is characterized by a persistent sensation of motion, typically described as rocking, swaying, or bobbing, that continues after exposure to passive motion.

Types of MdDS:

• Classic MdDS: Occurs following prolonged exposure to passive motion (e.g., boat travel, long train rides, air travel)
• Spontaneous MdDS: Occurs without a clear motion trigger
• Transient MdDS: Symptoms resolve within one month
• Persistent MdDS: Symptoms continue for more than one month
• MdDS in Evolution: Symptoms present for less than one month, not yet classified as transient or persistent

Clinical Presentation

Primary Symptoms

• Persistent motion sensation: Continuous feeling of rocking, swaying, or bobbing
• Symptom modulation: Symptoms generally worsen during rest and improve with motion
• Onset timing: In classic MdDS, symptoms typically start within 48 hours after disembarking
• Duration: Symptoms must persist for more than 48 hours for diagnosis

Associated Symptoms

• Anxiety and panic attacks
• Depression
• Difficulty coping with stress
• Difficulty concentrating and brain fog
• Fatigue
• Unsteadiness and balance difficulties
• "Trampoline walking" sensation
• Intolerance to lights, noises, and crowds
• Blurry or fuzzy vision
• Head pressure
• Sensation of body heaviness

Key Diagnostic Features

• Absence of vertigo: Spinning sensations are NOT typically associated with MdDS
• Temporal relief: Symptoms often temporarily improve during car or plane rides
• Negative standard tests: Vestibular function tests typically normal
• Normal imaging: MRI and CT scans show no abnormalities

Clinical Assessment Tools

1. Simulator Sickness Questionnaire (SSQ)

• Purpose: Quantifies symptom severity before, during, and after treatment
• Administration: Before initial treatment, at the end of each treatment day, and at follow-up periods
• Interpretation: Lower scores indicate symptom improvement
• Clinical utility: Provides objective measurement of treatment progress
• Recommendation: Use as primary outcome measure for treatment efficacy

2. Postural Stability Assessment

• Methods:
  • Computerized Dynamic Posturography (CDP): Gold standard for measuring postural sway
  • Alternative: Modified Wii Balance Board for clinics without CDP access
• Parameters to measure:
  • Rocking frequency (typically around 0.2 Hz)
  • Postural stability scores (normal value approximately 70/100)
• Administration: Before treatment initiation and after completion of protocol
• Clinical significance: Average improvement of 11 points (approximately 15%) may be expected with successful treatment

3. Fukuda Stepping Test

• Purpose: Determines direction of optokinetic stimulus for treatment
• Procedure:
  • Patient stands with arms outstretched
  • Eyes closed, stepping in place for 30 seconds
  • Measure rotation angle and direction
• Interpretation: Direction of rotation guides selection of optokinetic stimulus direction
  • If rotation is clockwise, use leftward-moving optokinetic stimulus
  • If rotation is counterclockwise, use rightward-moving stimulus
• Clinical value: More reliable than nystagmus assessment for determining treatment parameters

4. Video-oculography (Optional)

• Purpose: Alternative method to determine optokinetic stimulus direction
• Assessment: Identify vertical nystagmus during head roll at patient's rocking frequency
• Interpretation: If slow-phase velocity is upward with head to right and downward with head to left, use leftward optokinetic stimulus; otherwise use rightward stimulus
• Clinical utility: May be technically challenging to detect and interpret correctly

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Treatment Protocols

1. Dai Protocol (Roll Adaptation with Optokinetic Stimulation)

Pre-Treatment Requirements:

• Discontinue benzodiazepines and vestibular suppressants at least 2 weeks before treatment
• Complete baseline assessments (SSQ, posturography, Fukuda test)
• Consider local accommodation during treatment week to minimize travel between sessions

Equipment Setup:

• Optokinetic stimulus array (full-field visual surround with vertical stripes)
• Metronome to pace head movements
• Chair positioned in front of visual display

Treatment Protocol:

1. Session frequency: 4-5 sessions per day for 5 consecutive days
2. Patient positioning: Seated in front of optokinetic array
3. Visual stimulus parameters:
   • Vertical stripes rotating horizontally at constant velocity
   • Initial velocity: 5 degrees/second
   • Direction determined by Fukuda test results
4. Head roll parameters:
   • Amplitude: ±20 degrees lateral head roll
   • Frequency: Matched to patient's rocking frequency (typically 0.25 Hz)
   • Timing: Use metronome (e.g., one click per second, with head gradually rolled right for 2 clicks, then left for 2 clicks)
5. Duration: Approximately 3-5 minutes per session, multiple sessions daily
6. Monitoring: Daily SSQ assessment to track symptoms
7. Protocol adjustment: If no improvement by day 3, consider reversing optokinetic stimulus direction

Post-Treatment Protocol:

• Repeat posturography to measure changes in body sway
• Provide home maintenance program
• For patients traveling by air or long distance by car after treatment:
  • Consider short-acting benzodiazepine (triazolam/Halcion, lowest dose) for travel
  • Advise against driving if medication is taken

Expected Treatment Outcomes:

• Initial improvement often observed between days 1-2
• Progressive improvement typically continues through treatment week
• Average SSQ reduction from 14.4 to 8.9 (approximately 40% improvement)
• Posturography scores improve from average of 61.3 to 72.1 (to normal range)
• Benefits generally maintained at 2-week follow-up

2. Home-Based Virtual Reality Adaptations

Equipment Options:

• VR goggles with appropriate software
• Home projector systems
• Mobile applications (e.g., "Fushiki ETT OKN" iPhone app)

Protocol Implementation:

• Similar head roll parameters as clinic-based treatment
• Visual stimulus maintains horizontal orientation during head movements
• Regular daily practice as prescribed by clinician
• Patient self-monitoring of symptoms

Clinical Considerations:

• More cost-effective than in-clinic treatment
• May be used as maintenance therapy after formal treatment
• Emerging evidence suggests efficacy similar to in-clinic protocols
• Particularly valuable for patients with geographic or financial barriers to specialized clinics

3. Vestibular Rehabilitation Therapy

Core Components:

• Individually tailored exercise program based on specific presentation
• Balance and gait training adapted to MdDS symptoms
• Visual-vestibular interaction exercises
• Habituation exercises for motion sensitivity

Implementation Approach:

• Gradual progression of exercise difficulty
• Regular reassessment and program modification
• Extended treatment period (typically several months)
• Frequency: 3-5 times weekly for home program, with periodic clinical assessment

Clinical Management Recommendations

1. Patient Selection Criteria

• Confirmed MdDS diagnosis (classic or spontaneous)
• Symptoms present for at least 3 months
• No contraindications to vestibular adaptation exercises
• Ability to discontinue medications that may interfere with adaptation

2. Medication Management

• Discontinue prior to adaptation treatment:
  • Benzodiazepines (e.g., clonazepam, diazepam, alprazolam, lorazepam)
  • Vestibular suppressants (e.g., meclizine)
• Potential beneficial medications:
  • Migraine preventatives (e.g., nortriptyline, amitriptyline, gabapentin, venlafaxine, verapamil)
  • Short-acting benzodiazepines only for post-treatment travel when necessary

3. Treatment Progression

• Begin with intensive adaptation protocol if resources available
• Consider progression to different stimulation axes if plateau is reached
• Implement home program for maintenance after clinical improvement
• Address concurrent anxiety and related symptoms through appropriate referrals

4. Follow-up Recommendations

• Short-term: 2 weeks post-treatment
• Long-term: 3 months and 1 year post-treatment
• Monitor for symptom reversion, particularly in first 2 weeks
• Assess need for "booster" treatments if symptoms recur

Prognostic Factors

Factors Associated with Better Treatment Outcomes:

1. Duration of symptoms: Better results with symptoms present less than 1 year
2. Type of MdDS: Classic MdDS typically shows higher initial response rates than spontaneous MdDS
3. Age: Patients under 60 years maintain more consistent long-term improvement
4. Post-treatment stability: Avoiding symptom reversion in first 2 weeks improves long-term outcomes
5. Treatment adherence: Consistent participation in full protocol and home program
6. Proper medication management: Appropriate discontinuation of adaptation-blocking medications

Theoretical Mechanism of Treatment

The roll adaptation with optokinetic stimulation likely works through the "pseudocoriolis effect." The optokinetic stimulus builds a "bias" in the motion-sensing machinery in the brainstem (interpreted as rotation about earth vertical), while the roll head movement creates a sensory conflict because the visual surround does not tilt with the head. This conflict ultimately leads to readaptation of the vestibulo-ocular reflex and velocity storage mechanisms that are malfunctioning in MdDS.

References

1. Dai M, et al. (2014). "Readaptation of the vestibulo-ocular reflex relieves the mal de debarquement syndrome." Front Neurol 5: 124.
2. Dichgans J and Brandt T (1973). "Optokinetic motion sickness and pseudo-Coriolis effects induced by moving visual stimuli." Acta Otolaryngol 76(5): 339-348.
3. Fukuda T. Statokinetic reflexes in equilibrium and movement. U. Tokyo Press, 1984.
4. Graybiel A, et al. (1969). "Prevention of overt motion sickness by incremental exposure to otherwise highly stressful coriolis accelerations." Aerospace Medicine 40(2): 142-148.
5. Hain TC, et al. (1999). "Mal de debarquement." Arch Otolaryngol Head Neck Surg 125(6): 615-620.
6. Hain TC and Helminski JH. (2014). Mal de Debarquement. Vestibular Rehabilitation. S. Herdman (ed).
7. Hain TC and Cherchi M (2016). "Mal de debarquement syndrome." Handb Clin Neurol 137: 391-395.
8. Hoppes CW, et al. (2021). "Treatment of Mal de Debarquement Syndrome in a Computer-Assisted Rehabilitation Environment." Mil Med.
9. Yakushin SB, et al. (2020). "Readaptation Treatment of Mal de Debarquement Syndrome With a Virtual Reality App: A Pilot Study." Front Neurol 11: 814.

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