MR imaging of presumed olivary hypertrophy in palatal myoclonus.

Rhythmic palatal myoclonus is a neurologic sign with one of the most precise pathologic correlations. It almost always is associated with hypertrophic degeneration of the inferior olivary nucleus [1] ; however, such hypertrophic degeneration is not always accompanied by palatal myoclonus. The abnormality of the olivary nucleus is thought to be the result of a transsynaptic degeneration due to a lesion either in the ipsilateral central tegmental tract or in the contralateral dentate nucleus. We present a case that we think illustrates the MR detection of hypertrophic degeneration of the inferior olivary nucleus f2].