Nausea as a complication of low-frequency repetitive transcranial magnetic stimulation of the posterior fossa

Background: Transcranial magnetic stimulation (TMS) can non-invasively investigate the function of human brain. However, it can induce a focal pain at the stimulated site on the scalp or seizures when applied with high frequency (>1 Hz). Here we report an induction of nausea as a complication of low-frequency repetitive TMS (rTMS) of the cerebellum. Subjects and methods: Eight right-handed normal volunteers underwent low-frequency (0.9 Hz) rTMS of the right cerebellum. The stimulus intensity was set at 90% of the resting motor threshold determined by TMS to motor cortex. Results: Nausea lasted as long as 10 min after the end of rTMS without apparent neurological deficit in two subjects. This symptom was replicated when the same protocol was applied on a different day in the same subjects. Conclusions: Low-frequency rTMS of cerebellum is still a safe procedure, but the experimenters should keep in mind the possibility of inducing nausea