Clinical manifestations and MR imaging characteristics of hypertrophic olivary degeneration

Objective To analyze the clinical manifestations and MRI characteristics of hypertrophic olivary degeneration (HOD) to improve our knowledge for this disease and reduce misdiagnosis.Methods Twelve patients with HOD,admitted to our hospital from 2009 to 2012,were chosen in our study; their clinical data,including onset age,protopathy and other clinical manifestations,and imaging data,including SE sequence axial T1WI,T2WI and FLAIR fast spin-echo imaging,were analyzed.Results The protopathy in these 12 patients included pontine hemorrhage in 5,cerebellar infarction in 3,cerebral hemorrhage in 2,midbrain infarction in 1 and surgery for cerebellar tumor in 1.The main clinical symptoms included palatal myoclonus in 7,ataxia in 6,ocular myoclonus in 5,glossolalia in 3,diplopia in 2 and extremity tremor in 2.The region of inferior olivary nucleus (ION)presented high intensity on T2WI and iso-or mild hypointensity on T1WI in all 12 patients.Bilateral ION showed high signals in 5 in FLAIR; enlargement of the ION in 11 patients were noted.Conclusions HOD is a pathological phenomenon that occurs after injury to the dentato-olivary pathway.Its hallmarks include hypertrophy of the olive with increased T2 signal intensity on magnetic resonance imaging,and it often manifests with oculopalatal myoclonus clinically. Key words: Hypertrophic olivary degeneration;  Oculopalatal myoclonus;  Magnetic resonance imaging