G.P.130: Tracking the brain in myotonic dystrophy: A 5-year longitudinal neuroimaging and neuropsychological follow-up study

• Published in: Neuromuscular disorders : NMD Vol. 24; no. 9-10; pp. 839 - 840
• Main Authors: Merkel, C., Minnerop, M., Roeske, S., Gaertner, H., Schoene-Bake, J.C., Adler, S., Witt, J.A., Anspach, C., Schneider-Gold, C., Betz, R.C., Helmstaedter, C., Tittgemeyer, M., Amunts, K., Klockgether, T., Weber, B., Kornblum, C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2014
• ISSN: 0960-8966; 1873-2364
• DOI: 10.1016/j.nmd.2014.06.160

It is unknown whether brain affection in myotonic dystrophy type 1 (DM1) and 2 (DM2) is due to neurodevelopmental defects, neurodegeneration or both. Longitudinal imaging studies are missing to date. We performed a longitudinal study to compare changes in cognitive functioning and brain morphology including 16 DM1 (m/f: 6/10, age at baseline 42.48±6.46years/y, disease duration/DD 13.4±7.5 y), 16 DM2 patients (m/f: 9/7, age 48.49±8.36 y, DD 11.4±9.1 y), and 17 healthy controls (m/f: 9/8, age 50.54±9.78 y). At baseline and 5.45±0.41 y follow-up all subjects underwent neurological and neuropsychological (NP) examinations and 3T-brain magnetic resonance imaging using the identical hard- and software. Diffusion tensor imaging (DTI, Tract Based Spatial Statistics) was conducted to analyse white matter (WM) affection with respect to fractional anisotropy (FA), axial, radial, and mean diffusivity. We used 2-sample t-tests (TT) for group comparisons between patients and controls, and paired t-tests (PT) for longitudinal analyses within each group (p<0.05, corrected for multiple comparisons). DTI group comparisons (TT) showed almost identical FA reduction patterns at baseline and follow-up. In DM1 compared to controls, FA was reduced along the corpus callosum (CC), association (AF), and projection fibres. In DM2, we found mild affection of CC and forceps minor, and minor additional changes at follow-up. At follow-up, the number of voxels showing FA reduction was particularly increased in DM1 indicating progressive WM disintegrity. Analysing longitudinal differences within each group (PT), we found significant FA changes only in DM1 affecting frontal and posterior AF. These findings were accompanied by a decline in motor tasks in DM1, and a mild deterioration of NP performance in DM1 more than DM2 over time. Our data indicate a mild -however significant-progress of WM affection predominantly in DM1 which might point towards a neurodegenerative component of WM changes.