Mal de debarquement syndrome (MdDS) is a chronic disorder of imbalance characterized by a feeling of rocking and swaying. The disorder starts after prolonged exposure to passive motion such as from a boat or plane. All medical treatment is palliative and symptoms that persist beyond 6 months show low likelihood of remission. This pilot study explored the feasibility and tolerability of repetitive transcranial magnetic stimulation (rTMS) as potential treatment for MdDS.
Ten subjects (8 women) with persistent MdDS lasting from 10 to 91 months were given 1 session each of 4 counterbalanced protocols: left 10 Hz (high frequency), left 1 Hz (low frequency), right 10 Hz, and right 1 Hz rTMS over the dorsolateral prefrontal cortex (DLPFC).
Reduction of rocking sensation reported on a visual analogue scale.
1) Right-handers improved most with 10-Hz stimulation over the left DLPFC while left-handers improved most with 10 Hz stimulation over the right DLPFC; 2) low-frequency DLPFC stimulation was associated with symptom worsening in some subjects; 3) duration of symptoms was negatively correlated with treatment response; 4) rTMS was well tolerated in MdDS subjects, showing similar rates of headache (10 of 40 sessions) as for other studies; and 5) fatigue occurred after 6 sessions usually with low-frequency stimulation.
rTMS was well tolerated in subjects with MdDS with promising short-term symptom improvement. Future studies of rTMS in MdDS may consider sequential days of stimulation, longer post-rTMS observation periods, formal measurement of post-TMS fatigue, and randomization with a sham condition.