POSTTRAUMATIC SEGMENTAL MYOCLONUS ASSOCIATED WITH BILATERAL OLIVARY HYPERTROPHY

We present clinical and magnetic resonance (MR) findings in three pati ents with segmental myoclonia occurring 11-18 months after severe brai nstem injury. Palatal myoclonus and vertical ocular myorhythmia were p resent in all three patients and synchronous involuntary movements of the upper extremities (''wing beating'') in two patients. MR-imaging s howed multiple post-traumatic lesions within the dentato-rubro-olivary pathway (''myoclonic triangle''), associated with bilateral enlargeme nt and increased signal intensity of the inferior olives. The signal a bnormality was more prominent on proton density weighted images than o n T2-weighted images, suggesting underlying pathological changes diffe rent from typical gliosis.