Free Communications 2Friday, October 04, 2013, 10:03 - 10:15
Changes in microarchitecture of white matter bundles after Wii balance board training in multiple sclerosisL. Prosperini, N. Petsas, F. Fanelli, E. Sbardella, E. Raz, F. Tona, C. Pozzilli, P. Pantano (Rome, IT)
Background: Rehabilitation of balance using the Nintendo® Wii Balance Board System (WBBS) has been reported as effective in patients with multiple sclerosis (MS) (Prosperini L et al. Neurorehabil Neural Repair 2013). However, the neurobiological basis of this training-related improvement is still unknown.
Purpose: To investigate the WBBS training-related changes in microstructural properties of white matter (WM) bundles, as evaluated by diffusion tensor imaging (DTI) tractography.
Methods: Before and after an intensive, home-based 12-week WBBS training period, patients with MS were tested by static posturography and scanned using a 3.0T magnet to obtain DTI brain images. A subgroup of them were scanned twice before WBBS training to test reliability of tractography-derived measures. A convenience sample of sex and age-matched healthy volunteers was also scanned once as control group.
Virtual dissection of specific WM bundles was done using a streamline deterministic tractography software (MedINRIA 1.9.0) by an operator unaware of clinical data. All images were aligned into a common space by non-linear registration. Tractography was carried out by outlining regions of interest around areas representing obligatory passages along the course of specific WM bundles. Values of DTI parameters were then obtained for each WM bundle.
Results: Full data were available for 21 (13 F, 8 M) patients with a mean (SD) age of 37.1 (8.1) years, mean MS duration of 11.6 (5.4) years, and median Expanded Disability Status Scale (EDSS) score of 3.0 (range: 2.0-5.0). The 12-week WBBS training was effective in reducing postural sway (primary endpoint of pilot study) by 17.5% respect to baseline assessment (p=0.001).
Mean total fractional anisotropy (FA) was lower in patients with MS than in 12 healthy controls (0.364 vs. 0.468, p<0.001). Reliability of tractography, based on scan/re-scan of 10 patients, was high (intraclass correlation coefficients from 0.80 to 0.97).
A significant increase of mean FA was found after WBBS training bilaterally along the dentato-thalamic tract (left:+4.1%, p=0.014; right: +2.5%, p=0.022). These findings were replicated even after correcting for intracranial volume and time spent for training (all p-values<0.05).
Conclusion: Our findings suggest that clinical improvement of standing balance after WBBS training might be mediated by enhanced microstructural properties of cerebellar efferences, thus reinforcing the role of cerebellum in adaptive mechanisms induced by high-intensity, task-oriented exercises.
This study was funded by FISM (Fondazione Italiana Sclerosi Multipla - Grant 2012/R/12).
LP received consulting fees from Merck Serono, Bayer Schering and Biogen Idec, and speaker honoraria from Biogen Idec, Teva and Novartis.
CP received consulting and lecture fees from Sanofi-Aventis, Biogen Idec, Bayer Schering, Merck Serono, and Novartis; he also received research funding from Sanofi-Aventis, Merck Serono, Bayer Schering and Novartis.
NP, FF, ES, ER, FT, PP: nothing to disclose.