E Strijbos1, S Coenradie2, D J Touw3, Lam Aerden4. 1. Leids Universitair Medisch Centrum, the Netherlands. 2. Reinier de Graaf Gasthuis, the Netherlands. 3. Groningen University, the Netherlands. 4. Department of Neurology, Reinier de Graafgasthuis, the Netherlands Netherlands.aerden@rdgg.nl.