[Crossed cerebello-cerebral diaschisis in olivopontocerebellar atrophy]

We reported a case of crossed cerebello-cerebral diaschisis (CCCD) in olivopontocerebellar atrophy (OPCA). A 49-year-old male was admitted with complaints of titubation, dysarthria and tremor. Examination on admission revealed exaggerated triceps, patella and achilles tendon reflexes on both sides and rigidity in left wrist. Ocular movements were slightly saccadic and speech was scanning or explosive. Finger-nose and heel-knee coordination was poor on both sides (left dominant). Cardiovascular reflex tests showed abnormal findings, suggesting insidious autonomic dysfunction. Brain CT and magnetic resonance imaging (MRI) revealed mild atrophy of the pons and cerebellum. Brain single photon emission computed tomography (SPECT) showed reduced cerebellar N-isopropyl-P-(123I) iodoamphetamine (IMP) uptake more prominent on the left than on the right side. A reduction of 123I-IMP uptake was more striking in the right thalamus, basal ganglia and frontal lobe than on the left side. The cerebellar sign which was left dominant and the left extrapyramidal sign were consistent with the side where reduction of 123I-IMP uptake was more prominent. We suggest that CCCD in our case resulted from transneuronal deactivation in the classic anatomical (cerebello-thalamo-cortical) pathway and dopaminergic (cerebello-basal ganglia-cortical) pathway. There is a possibility that CCCD reflects the development of pathological changes in OPCA.