RT Journal Article SR Electronic T1 Stimulation-induced cerebellar syndromes in VIM/DRT-DBS: An FDG PET activation study JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 15 OP 15 VO 61 IS supplement 1 A1 Ganna Blazhenets A1 Bastian Sajonz A1 Isabelle Walz A1 Marvin Frommer A1 Johannes Thurow A1 Lars Frings A1 Christoph Maurer A1 Michel Rijntjes A1 Volker Coenen A1 Philipp Meyer YR 2020 UL http://jnm.snmjournals.org/content/61/supplement_1/15.abstract AB 15Introduction: The ventral intermediate nucleus (VIM)/dentato-rubro-thalamic bundle (DRT) has been described as a relevant target for tremor control. However, up to 20% of patients with deep brain stimulation (DBS) of the VIM/DRT for essential tremor develop a stimulation-induced cerebellar syndrome, which is difficult to treat and has relevant effects on quality of life. While the exact cause is elusive, it is hypothesized that the (supratherapeutic) co-stimulation of cerebellar output pathways in addition to the DRT and antidromic stimulation of the cerebellum plays a crucial role. Methods: For this study, 8 patients who complained about recurrent tremor and symptoms of a cerebellar syndrome after DBS were enrolled. Cerebral FDG PET scans were performed with activated DBS (DBSON) and 72 hours after deactivation of DBS (DBSOFF) in each of the patients. Voxel-based changes of normalized glucose metabolism as a marker of regional neuronal activity between DBSON and DBSOFF conditions were assessed using a paired t-test and statistical parametric mapping (SPM). The correlation between regional uptake in thalamus (ROI) and voxel-wise cerebral uptake was analyzed by regression analysis. Tremor (accelerometer and electromyography) and gait analyses (video-based markerless motion capture system) were performed under both conditions. Results: We found a significantly increased metabolism of the thalamus and dentate nucleus and a decreased metabolism of the cerebellar hemispheres with DBSON compared to DBSOFF (p < 0.01). Across all patients and conditions, thalamic metabolism correlated positively with the metabolism of the dentate nucleus (p < 0.01). The coefficient of variation of step length (a marker of gait ataxia) with DBSON correlated negatively with the change (DBSON - DBSOFF) in the metabolism of the right cerebellar hemisphere (p < 0.01; i.e. the higher decrease of metabolism with DBSOFF, the higher the ataxia). Conclusions: We observed differential changes of neuronal activity in the dentate nucleus according to stimulation state. Increased neuronal activity of the thalamus with DBSON correlated positively with the increase of neuronal activity of the dentate nucleus, supporting the assumption that antidromic stimulation has a beneficial effect.