Francesca Morgante1,2, Angela Matinella3, Elisa Andrenelli4, Lucia Ricciardi2, Cosimo Allegra1, Carmen Terranova1, Paolo Girlanda1, Michele Tinazzi3. 1. Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy. 2. Neurosciences Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, United Kingdom. 3. Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy. 4. Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy.
Abstract
BACKGROUND: Pain is often experienced by patients with functional dystonia and idiopathic cervical dystonia and is likely to be determined by different neural mechanisms. OBJECTIVE: In this exploratory study, we tested the sensory-discriminative and cognitive-emotional component of pain in patients with functional and idiopathic dystonia. METHODS: Ten patients with idiopathic cervical dystonia, 12 patients with functional dystonia, and 16 age- and sex-matched healthy controls underwent psychophysical testing of tactile and pain thresholds and pain tolerance. We delivered electrical pulses of increasing intensity to the index finger of each hand and the halluces of each foot. Pain threshold and pain tolerance were respectively defined as the (1) intensity at which sensation changed from unpainful to faintly painful and (2) intensity at which painful sensation was intolerable. RESULTS: No differences were found between the three groups for tactile and pain thresholds assessed in hands and feet. Pain tolerance was significantly increased in all body regions only in functional dystonia. Patients with continuous functional dystonia had higher pain tolerance compared to subjects with paroxysmal functional dystonia and idiopathic cervical dystonia. There was no correlation between pain tolerance and pain scores, depression, anxiety, disease duration, and motor disability in both groups. CONCLUSIONS: Patients with functional dystonia have a dissociation between the sensory-discriminative and cognitive-emotional components of pain, as revealed by normal pain thresholds and increased pain tolerance. Abnormal connectivity between the motor and limbic systems might account for abnormal pain processing in functional dystonia.
BACKGROUND:Pain is often experienced by patients with functional dystonia and idiopathic cervical dystonia and is likely to be determined by different neural mechanisms. OBJECTIVE: In this exploratory study, we tested the sensory-discriminative and cognitive-emotional component of pain in patients with functional and idiopathic dystonia. METHODS: Ten patients with idiopathic cervical dystonia, 12 patients with functional dystonia, and 16 age- and sex-matched healthy controls underwent psychophysical testing of tactile and pain thresholds and pain tolerance. We delivered electrical pulses of increasing intensity to the index finger of each hand and the halluces of each foot. Pain threshold and pain tolerance were respectively defined as the (1) intensity at which sensation changed from unpainful to faintly painful and (2) intensity at which painful sensation was intolerable. RESULTS: No differences were found between the three groups for tactile and pain thresholds assessed in hands and feet. Pain tolerance was significantly increased in all body regions only in functional dystonia. Patients with continuous functional dystonia had higher pain tolerance compared to subjects with paroxysmal functional dystonia and idiopathic cervical dystonia. There was no correlation between pain tolerance and pain scores, depression, anxiety, disease duration, and motor disability in both groups. CONCLUSIONS:Patients with functional dystonia have a dissociation between the sensory-discriminative and cognitive-emotional components of pain, as revealed by normal pain thresholds and increased pain tolerance. Abnormal connectivity between the motor and limbic systems might account for abnormal pain processing in functional dystonia.
Authors: Mark Hallett; Selma Aybek; Barbara A Dworetzky; Laura McWhirter; Jeffrey P Staab; Jon Stone Journal: Lancet Neurol Date: 2022-04-14 Impact factor: 59.935