This single-case study aims to evaluate the clinical effects of optokinetic stimulation (OKS) on dizziness perception and quality of life in a patient diagnosed with Mal de Débarquement Syndrome (MdDS). The intervention follows a standardized protocol in which the patient performs head roll movements synchronized with optokinetic visual stimulation at a frequency of 0.167 Hz (10 bpm). The study is conducted online using a digital application to provide full-field optokinetic stimulation. The patient's baseline motion sickness susceptibility was characterized using the Motion Sickness Susceptibility Questionnaire-Short Form (MSSQ-SF). Primary outcome measures assessed for change from baseline include the Dizziness Handicap Inventory (DHI), Visual Analog Scale (VAS), and the Istanbul MdDS Scale
Mal de Débarquement Syndrome (MdDS) is a rare neuro-otological disorder characterized by a persistent perception of self-motion, typically described as rocking, swaying, or bobbing sensations, following exposure to passive motion such as sea, air, or land travel. The syndrome can significantly impair balance, spatial orientation, and quality of life. Conventional therapeutic approaches are limited, and symptoms may persist for weeks, months, or even years. Recent studies have suggested that maladaptation of the vestibulo-ocular reflex (VOR) and velocity storage mechanisms may play a central role in the pathophysiology of MdDS. In this single-case study, a 28-year-old female patient with a clinical diagnosis of MdDS will undergo an online OKS-based rehabilitation program. The intervention will be conducted remotely via the Smart Optometry application, using the "OKN Stripes" module to deliver full-field optokinetic visual stimulation. The participant will sit close to the screen, ensuring that the optokinetic stripes occupy approximately 85-90% of the visual field. The researcher will guide each session online, ensuring the synchronization of head roll movements with the visual stimuli using a metronome (10 bpm). The intervention will be implemented for 3-5 consecutive days, with two sessions in the morning and two in the afternoon, each lasting 4 minutes. Assessment and Follow-up: Clinical outcomes are evaluated at multiple time points to monitor the progression and long-term sustainability of the treatment: Baseline (T0): Pre-treatment assessment. Post-treatment (T1): Immediately following the 5-day protocol. Short-term Follow-up (T2): 1 month after treatment. Long-term Follow-up (T3): 1 year after treatment to evaluate the durability of neuroplastic changes. Primary metrics include the Dizziness Handicap Inventory (DHI) for perceived disability, the Visual Analog Scale (VAS) for dizziness intensity, and the Istanbul MdDS Scale for syndrome-specific symptoms. To determine the patient's clinical profile and support differential diagnosis, the Motion Sickness Susceptibility Questionnaire - Short Form (MSSQ-SF) will be administered initially. This study aims to contribute to the limited clinical evidence on non-invasive, visual-vestibular rehabilitation strategies for MdDS and to explore the feasibility of delivering optokinetic therapy in an online, remote setting.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
1
The planned optokinetic stimulation (OKS) application will be implemented. The application will last for 5 consecutive days, with a total of 4 sessions, two in the morning and two in the afternoon. Each session will last 5 minutes, and head turns will be synchronized with a metronome at 10 beats per minute (10 bpm). Each beat will complete a full right-left cycle, achieving a frequency of approximately 0.167 Hz. This arrangement reflects the standardized protocol recommended in the literature. The application will be conducted online, and the participant will use the "Optokinetic nystagmus (OKN) lines" section within the "Smart Optometry" application on their computer. The direction of the lines will move in the direction opposite the patient's dominantly affected side. The participant was seated close to the screen, and approximately 85-90% of their visual field covered by the moving stimuli.
Istanbul Medipol University
Istanbul, Beykoz, Turkey (Türkiye)
Level of Disability
Dizziness Handicap Inventory: Provides information about disability and quality of life in individuals with vestibular disorders. The scale assesses the functional, physical, and emotional effects of dizziness on disability over the past month. It consists of 25 questions, 9 functional, 7 physical, and 9 emotional, with three answer options: yes (4 points), sometimes (2 points), and no (0 points). A total score is calculated along with the scores for each subsection. The total score ranges from 0 to 100, with higher scores indicating greater disability. According to the total score, the level of disability is classified as follows: 16-34 points as mild; 36-52 points as moderate; and 54 and above as severe. This scale, whose
Time frame: From enrollment (baseline) until the final follow-up, assessed at multiple time points: baseline, immediately post-treatment (day 5), 1 month, and 1 year.
Istanbul Mal de Debarquement Scale
The scale is composed of subfactors to better assess MdDS. The scale consists of four subfactors: "Diagnostic Criteria" (items 1-5), "Dizziness Character" (items 6-9), "Visual Movement Intolerance" (items 10-12), and "Quality of Life" (items 13-18). The scale was designed using a 5-point Likert-type scale, using the terms "Always," "Frequently," "Sometimes," "Rarely," and "Never." These statements were scored from 5 to 1, respectively. The total scale score was calculated as 100. Permission was obtained from the scale's author for use.
Time frame: From enrollment (baseline) until the final follow-up, assessed at multiple time points: baseline, immediately post-treatment (day 5), 1 month, and 1 year.
Dizziness Severity
Visual Analog Scale: The participant's dizziness intensity was assessed on a scale between 0 and 10-cm line, where 0 represents "no vertigo/dizziness," and 10 represents "extreme dizziness. Scores are categorized as mild (2-3), moderate (4-5), severe (6-7), quite severe (8-9), and extreme.
Time frame: From enrollment (baseline) until the final follow-up, assessed at multiple time points: baseline, immediately post-treatment (day 5), 1 month, and 1 year.
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