Occipital and Cerebellar Theta Burst Stimulation for Mal De Debarquement Syndrome

Abstract

Background: Individuals with Mal de Debarquement syndrome (MdDS) experience persistent oscillating vertigo lasting for months or years. Transcranial magnetic stimulation (TMS) can modulate the motion perception of MdDS.

Materials and methods: Twenty-six TMS naive individuals received single administrations of continuous theta burst stimulation (cTBS) over the occipital cortex, cerebellar vermis, and lateral cerebellar hemisphere, in randomized order. A 0-100 point Visual Analogue Scale was used to assess acute changes in oscillating vertigo severity after each session. Repeated treatments were given over the target that led to the most acute reduction in symptoms. All treatments were performed with neuronavigation using the participant's own brain MRI. The Dizziness Handicap Inventory (DHI), MdDS Balance Rating Scale (MBRS), and Hospital Anxiety and Depression Scale (HADS) were assessed weekly at four pretreatment and six posttreatment time points.

Results: Twenty participants chose either the occipital cortex (11) or cerebellar vermis (9) targets as most effective in reducing the oscillating vertigo; one chose lateral cerebellar hemisphere; five chose none. After 10 to 12 sessions of 1,200 pulses over the target of choice, 19 of 25 treatment completers noted ≥ 25% reduction, 12 of 25 ≥50% reduction, and 8 of 25 ≥75% reduction in oscillating vertigo intensity. A one-way repeated measures ANOVA of DHI, MBRS, and HADS scores before and after treatment showed significant reductions in DHI, MBRS, and the HADS Anxiety subscore immediately after treatment with most improvement lasting through posttreatment week 6. There were no significant Depression subscore changes. Participants who had chosen vermis stimulation had comparatively worse balance at baseline than those who had chosen occipital cortex stimulation.

Conclusion: cTBS over either the occipital cortex or cerebellar vermis is effective in reducing the oscillating vertigo of MdDS acutely and may confer long-term benefits. Sustained improvement requires more frequent treatments.

Conflict of interest statement

Conflict of Interest Statement: The authors report no financial or ethical conflicts of interest in the execution of this study

Figures

Figure 1:. Neuronavigation targets

(A, D) Sagittal T1-structural image (A) and 3-D reconstruction (D) of visual association area target below the parieto-occipital sulcus. The path of stimulation was angled to pass between the midbrain-pontine junction, angled downward; (B, E) Sagittal T1-structural image (B) and 3-D reconstruction (E) cerebellar vermis target. The path of stimulation was angled to pass between the midbrain-pontine junction, angled upward (C, F) Axial T1-structural image (C) and 3-D reconstruction (F) of lateral cerebellar hemisphere. Twelve subjects received stimulation over the right horizontal fissure shown here; 12 received stimulation over lobule VIII just below (not shown).

Figure 2:. Change in VAS daily score pre to post TMS

Absolute changes on a 0-100 VAS scale (A) and percent changes (B) based on individual baselines in the total daily symptom score before and after treatment. Deflections to the left in blue represent a reduction of oscillating vertigo; deflections to the right in red represent a worsening of oscillating vertigo.

Figure 3:. mBESS sway baseline to post treatment

Baseline and post treatment changes in posture scores on the modified balance error scoring system (mBESS). Higher scores represent better balance. The best score is 100. Cbl Hem= Cerebellar Hemisphere.

Figure 4:. Longitudinal cTBS effects on DHI, MBRS, and HAD scores

Linear prediction model of repeated measures ANOVA with 95% confidence intervals presented for four baseline measurements, post TMS week, and six weeks post treatment for the DHI, MBRS, and the HADS Anxiety and Depression components. Pre= pre TMS scores, Pst= post TMS scores.