RT Journal Article SR Electronic T1 Cerebral Metabolic Changes Related to Freezing of Gait in Parkinson Disease JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 671 OP 676 DO 10.2967/jnumed.118.218248 VO 60 IS 5 A1 Trina Mitchell A1 Alexandra Potvin-Desrochers A1 Anne-Louise Lafontaine A1 Oury Monchi A1 Alexander Thiel A1 Caroline Paquette YR 2019 UL http://jnm.snmjournals.org/content/60/5/671.abstract AB Freezing of gait (FOG) in Parkinson disease (PD) often occurs during steering of gait (i.e., complex gait), which is thought to arise from executive dysfunction. Our aim was to test whether cognitive corticobasal ganglia-thalamocortical circuitry is impaired and whether alternate neural circuits are used for complex gait in PD with FOG. Methods: Eighteen individuals with idiopathic PD in the off-medication state, 9 with FOG (aged 68 ± 6 y) and 9 without FOG (aged 65 ± 5 y), were included. PET was used to measure cerebral glucose metabolism during 2 gait tasks, steering and straight walking, performed during the radiotracer uptake period. Results: During steering, there was a reduced change in cerebral glucose metabolism within the cognitive corticothalamic circuit. More specifically, those with FOG had less activation of the posterior parietal cortex, less deactivation of the dorsolateral prefrontal cortex and thalamus, and increased activation in the supplementary motor area. Interestingly, activity in the dorsolateral prefrontal cortex correlated with gait impairment (i.e., reduced stride length) in the FOG group. Conclusion: These results demonstrate decreased parietal control and an alternate control mechanism mediated by prefrontal and supplementary motor areas in PD with FOG.