Ictal SPECT Imaging Findings in Parkinson's Disease with Rapid Eye Movement Sleep Behavior Disorder

Rapid eye movement sleep behavior disorder (RBD) is an established prodrome and symptom of synucleinopathies. The pathophysiology of this disorder has been well studied but there is a lack of functional imaging data to illustrate the dysfunction in vivo. We aimed to investigate the functional changes of RBD, by performing ictal REM sleep SPECT, comparing subjects with Parkinson's Disease (PD) and evidence of RBD to subjects with PD and no RBD. Participants underwent a targeted clinical assessment, followed by video polysomnography (vPSG). Ictal Tc-HMPAO SPECT was performed by injecting the tracer during vPSG confirmed REM sleep in seven cases (PD with RBD) and five controls (PD without RBD). Voxel-wise, whole brain regional relative perfusion changes between both groups were assessed using statistical parametric mapping. No difference in relative regional brain perfusion was demonstrated at a family wise error corrected p-value of 0.05 between the case and control groups. At an uncorrected P-value of