Brainstem 1H-MR spectroscopy in patients with Parkinsonʹs disease with REM sleep behavior disorder and IPD patients without dream enactment behavior

Objectives The objective of our study was to evaluate brainstem involvement by 1H-MR spectroscopy (1H-MRS) method in patients with idiopathic Parkinsonʹs disease (IPD) with REM sleep behavior disorder (RBD) and IPD without dream enactment behavior. Patients and methods We prospectively studied 12 IPD (3 females, 9 males) with a clinically and electrophysiologically confirmed RBD and 12 IPD (3 females, 9 males) patients without dream enactment behavior followed in Outpatient Clinics for Movement Disorders of Department of Neurology, Haseki Hospital. Using long and short TE single voxel 1H-MRS directed at ventral and dorsal pons, long TE NAA/Cr, Ch/Cr and short TE NAA/Cr, Ch/Cr, MI/Cr values of both groups were compared. Results Although no difference was found between groups with RBD and IPD without dream enactment behavior in demographic characteristics, duration of disease, mean levodopa dosage and duration of levodopa use, all UPDRS scores (total, motor and cognitive) were worse in RBD group (p < 0.05). There was no statistically significant difference in long TE NAA/Cr, Ch/Cr and short TE NAA/Cr, Ch/Cr, MI/Cr values obtained in both groups (p > 0.05). Conclusion 1H-MRS does not detect marked metabolic differences in the pons in subjects with IPD with RBD and IPD without dream enactment behavior. This finding suggests either that present methodologies are not sensitive to detect subtle metabolic changes in the pons of subjects with RBD or that the primary lesion of RBD exists in other REM sleep-related brain regions beyond the pons such as the substantia nigra, the basal ganglia or the limbic system.