Normal eyeblink classical conditioning in patients with fixed dystonia
Fixed dystonia without evidence of basal ganglia lesions or neurodegeneration typically affects young women following minor peripheral trauma. We use eyeblink classical conditioning (EBCC) to study whether cerebellar functioning is abnormal in patients with fixed dystonia, since this is part of the pathophysiology of primary dystonia. An auditory tone (conditioning stimulus) was paired with a supraorbital nerve stimulus (unconditioned stimulus) with a delay of 400 ms in order to yield conditioned responses. We recruited 11 fixed dystonia patients of whom six used medication and seven age-matched healthy controls. Non-medicated patients with fixed dystonia performed as well as healthy controls, while medicated patients showed fewer conditioned responses. We found an influence of medication and possibly extent of dystonic features and/or co-occurrence of complex regional pain syndrome (CRPS) on EBCC performance. Our study argues against abnormal cerebellar function in non-medicated, fixed dystonia patients without CRPS or spread of symptoms.
KeywordsDystonia/physiopathology Blinking Cerebellar diseases/physiopathology
we would like to acknowledge the support and funded by a grant from the Prinses Beatrix Fonds.
Conflict of interest
S. Janssen: none. L.C. Veugen: none. B.S. Hoffland: has received financial support from the Prinses Beatrix Fonds. P. Kassavetis: has received a grant from Parkinson’s UK. D.E. van Rooijen: none. D.F. Stegeman: none. M.J. Edwards: is senior Lecturer and Honorary Consultant Neurologist UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery. J.J. van Hilten: has been a consultant for GlaxoSmithKline; has received research grants from the government, the International Parkinson Disease Foundation and the National Parkinson Association. B.P. van de Warrenburg: has received grants from the Netherlands Brain Foundation, the Gossweiler Foundation, the Royal Dutch society for Physical Therapy, the Radboud University Nijmegen Medical Centre, the Prinses Beatrix Fonds, and BBMRI-NL.
- Merskey H, Bogduk N, International Association for the Study of Pain. Task Force on Taxonomy (1994) Classification of chronic pain: descriptions of chronic pain syndromes and definitions of pain terms, 2nd edn. IASP Press, SeattleGoogle Scholar