Isolated tongue tremor after removal of cerebellar pilocytic astrocytoma: Functional analysis with SPECT study

Tongue tremor is a rare form of focal tremor. Even though the dysfunction of the dentato-rubro-olivary circular pathway has been proposed as its mechanism, the origin of the rhythmic activities remains unknown. We experienced a case of isolated tongue tremor after the removal of a cerebellar pilocytic astrocytoma. To localize the activated structures corresponding to the isolated tongue tremor, we analyzed subtracted ictal SPECT coregistered to MRI (SISCOM). SISCOM demonstrated multiregional hyperperfusion including the Guillain-Mollaret triangular and extratriangular structures. The activation of the inferior olive and red nucleus and accompanying extratriangular structures might be related to the isolated tongue tremor.