J Neurol (2004) 251 : 85–90 DOI 10.1007/s00415-004-0282-x ORIGINAL COMMUNICATION Michele Tinazzi Mirta Fiorio Laura Bertolasi Salvatore M. Aglioti Timing of tactile and visuo-tactile events is impaired in patients with cervical dystonia Introduction The term dystonia refers to a neurological disorder sup- posedly linked to a dysfunction of basal ganglia and characterized by sustained muscular contractions that cause repetitive movements and abnormal postures [4, 11, 21]. These motor disturbances may affect many body parts (generalized dystonia) or involve a single body re- gion (focal dystonia), mostly often the neck or the hand [5].Although symptoms in dystonia appear to be mainly motor in nature, marked somatosensory perceptual deficits are also present in this disease. Neurophysiolog- ical [13, 18, 20, 24, 34] and neuroimaging [23, 26, 29–32] studies have shown an abnormal somatosensory pro- cessing in several forms of primary dystonia, including JON 1282 Received: 12 June 2003 Received in revised form: 9 September 2003 Accepted: 24 September 2003 M. Tinazzi Unità Operativa di Neurologia Ospedale Civile Borgo Trento Piazzale Stefani 1 37100 Verona, Italy M. Fiorio Dipartimento di Scienze Neurologiche e della Visione Università di Verona Sezione di Fisiologia Umana Strada le Grazie 8 37134 Verona, Italy L. Bertolasi Clinica Neurologica Sezione di Neurofisiopatologia Policlinico GB Rossi Piazzale Scuro 37134 Verona, Italy Salvatore M. Aglioti () Dipartimento di Psicologia Università di Roma “La Sapienza” via dei Marsi 78 00185 Roma, Italy and IRCCS Fondazione Santa Lucia Roma, Italy Tel.: +39-064/9917526 Fax: +39-064/9917635 E-Mail: salvatoremaria.aglioti@uniroma1.it ■ Abstract Psychophysical studies show alterations of cross-modal in- tegration and timing processes in patients with generalized and focal hand dystonia. Here we assess the capability of 10 cervical dystonia patients, 5 patients with cervical pain but no dystonia, and 10 healthy controls to determine whether pairs of visual, tactile or visuo-tactile stimuli were simulta- neous or sequential (TD threshold) and which stimulus preceded the other (temporal order judgement, TOJ).Visual stimuli consisted of light emitting diodes and tactile stimuli of non-noxious electrical shocks delivered to the hands. In- tervals between stimuli were in- creased from 0 to 400 ms in steps of 10 ms. Cervical dystonia patients had a clear impairment of tactile and visuo-tactile temporal discrim- ination compared with patients with cervical pain but no dystonia who performed as well as healthy subjects. This suggests that deficits of temporal discrimination in cer- vical dystonia patients are not due to the possible distracting effect of unpleasant sensations or pain. Comparisons with previous studies show that deficits in cervical dysto- nia were more severe than in focal hand dystonia and less severe than in generalized dystonia. Thus, im- pairment of sensory timing may be a marker of disease, which varies along a continuum in the different forms of dystonia. ■ Key words cervical dystonia · temporal processing · cross-modal integration · sensory discrimination · basal ganglia