P 123. CIPASS: Trial of a daily program of cerebral stimulation by TMS using a PAS paradigm in the recovery phase of stroke patients

Abstract

Introduction Paired Associative Stimulation (PAS) is a non-invasive brain stimulation technique allowing to modulate precisely brain plasticity. Effects on plasticity have been demonstrated in healthy subjects and stroke patients ( Stefan et al., 2000 , Castel-Lacanal et al., 2007 , Castel-Lacanal et al., 2009 ), translated by a motor-evoked potentiel (MEP) facilitation of the targeted muscle that was persistent (1 h), reversible and topographically specific. CIPASS (Chronic IPAS in Stroke) is a new neuromodulation protocol where a PAS session is performed during 5 days to hemiparetic patients with a stroke (less than 6 months). Objectives Our goals is to demonstrate a lasting increase (3 days) of motor cortical plasticity for extensor wrist muscles (Extensor Carpi Radialis, ECR), and an improvement of upper limb function. Our judgment criteria are electrophysiological and motors parameters. Materials and methods The intervention consists of a combination of two stimulations: an electrical and a magnetic stimulation (using TMS) with a frequency at 0,1 Hz over 30 min. This is a randomized, double-blind and placebo-controlled trial. 18 patients (13 men and 5 women, mean age: 47.3 ± 12.7 years) have been included (Fugl-Meyer Motor Scale: FMMS, upper limb section: 24.2/66 ± 13.1) divided into two groups (PAS: n = 10 and Placebo: n = 8). One session of PAS stimulation was applied to the ECR muscle on a daily basis during 5 days. The MEP surface of ECR muscle and FMMS variations have been analysed. Results Our trial will end in December 2012. Our first results have demonstrated, 3 days after the end of the last PAS session (J8), an important increase of MEP surfaces for group PAS (+168 ± 268%) compared to group Placebo (+0.1 ± 48%); with no significant difference between the 2 groups. Individual results show more important facilitation effects for patients of group PAS (5/10 patients: MEP facilitation > +100%) than group B (8/8 patients: MEP facilitation Fig. 1 ). FMMS improvement was slightly higher for group PAS (+6.1 ± 4.5 pts) than group Placebo (+4.6 ± 4.1 pts) at J8, also due to spontaneous recovery and rehabilitation. Individuals results show a more important improvement of FMMS for patients of group PAS (6/10 patients: ΔJ1–J8 > +4 pts) than group B (2/8 patients: Δ J1–J8 > +4 pts) ( Fig. 2 ). Conclusion A daily program of PAS session seems to induce long-term changes in the excitability of corticospinal projection to wrist muscles in group PAS up to 3 days following the end of the stimulation program; motor effects seem however less conclusive. These results have to be confirmed with a larger sample to allow us to draw reliable conclusions. This trial will help us to better understand brain plasticity processes and to prove the relevance of CIPASS use as a therapeutic adjunct in stroke rehabilitation.