Klinische Neurophysiologie 2010; 41 - ID136
DOI: 10.1055/s-0030-1250965

Diffusion Tensor Imaging (DTI) in idiopathic REM sleep behaviour disorder (iRBD)

M Belke 1, MM Unger 1, K Hattemer 1, JT Heverhagen 2, B Keil 2, K Stiasny-Kolster 1, F Rosenow 1, NJ Diederich 3, G Mayer 4, JC Möller 1, WH Oertel 1, S Knake 1
  • 1Philipps Universität Marburg, Neurologie, Marburg, Deutschland
  • 2Philipps-Universität Marburg, Department of Diagnostic Radiology, Marburg, Deutschland
  • 3Centre Hospitalier de Luxembourg, Department of Neurosciences, Luxembourg, Luxembourg
  • 4Hephata-Clinic for Neurology, Schwalmstadt, Deutschland

Introduction:

Idiopathic REM sleep behaviour disorder (iRBD) – a parasomnia characterized by dream enactments – is a risk factor for the development of Parkinson's disease (PD) and other alpha-synucleinopathies. The pathophysiology of iRBD is likely due to dysfunction of brainstem nuclei that regulate REM sleep.

Material and Methods:

Diffusion Tensor Imaging (DTI) of the brain is a method for studying the microstructural brain tissue integrity in vivo. We investigated whether DTI detects microstructural abnormalities in brains of patients with iRBD – compared with age-matched controls – as a potential in vivo indicator for changes related to „preclinical (premotor)“ PD neuropathology. Patients with iRBD (n=12) and age-matched healthy controls (n=12) were studied using a routine 1.5T MRI scanner. Whole-head DTI scans (measuring fractional anisotropy (FA), axial diffusivity (AD), a potential marker of neuronal loss and radial diffusivity (RD), a potential marker of myelin pathology) were analyzed without a priori hypthesis using tract-based spatial statistics (TBSS), a novel technique minimizing edge-related artifacts and alignment difficulties.

Fig.1

Results:

Using group analysis, we found significant microstructural brain tissue changes (p<0.0001). These changes were identified in the white matter of the brainstem, corona radiate, and in the right substantia nigra utilizing axial diffusivity maps. Using radial diffusivity data, we observed changes in the left temporal lobe, in the fornix, and the right visual stream. Furthermore, fractional anisotropy maps revealed microstructural changes in the olfactory region and the internal capsule.

Discussion:

These microstructural abnormalities were identified in regions known to either be involved in REM-sleep regulation (brainstem) and/or to exhibit neurodegenerative pathology in iRBD and/or early PD. The study suggests that iRBD-related microstructural abnormalities can be detected in vivo with DTI, a widely available MRI technique.