Abstract
OBJECTIVE: 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. PATIENTS/INTERVENTION: 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). MAIN OUTCOME MEASURE: Reduction of rocking sensation reported on a visual analogue scale. RESULTS: 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. CONCLUSION: 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.