Botulinum Toxin Effects on Sensorimotor Integration in Focal Dystonias

• Published in: Toxins Vol. 12; no. 5; p. 277
• Main Authors: De Bartolo, Maria Ilenia, Manzo, Nicoletta, Ferrazzano, Gina, Baione, Viola, Belvisi, Daniele, Fabbrini, Giovanni, Berardelli, Alfredo, Conte, Antonella
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.04.2020; MDPI
• Subjects: Abnormalities; Acetylcholine Release Inhibitors - adverse effects; Acetylcholine Release Inhibitors - therapeutic use; Adolescent; Adult; Aged; Biomechanical Phenomena; Blepharospasm - diagnosis; Blepharospasm - drug therapy; Blepharospasm - physiopathology; Botulinum toxin; botulinum toxin A; Botulinum Toxins, Type A - adverse effects; Botulinum Toxins, Type A - therapeutic use; Brain - drug effects; Brain - physiopathology; cervical dystonia; Dystonia; Dystonic Disorders - diagnosis; Dystonic Disorders - drug therapy; Dystonic Disorders - physiopathology; Female; focal dystonia; focal hand dystonia; Humans; Hypotheses; Kinematics; Male; Middle Aged; Motor Activity - drug effects; Muscles; Overflow; Patients; Proprioception; Proprioception - drug effects; Recovery of Function; Sensorimotor integration; somatosensory temporal discrimination threshold; Studies; Temporal perception; Thalamus; Time Factors; Torticollis - diagnosis; Torticollis - drug therapy; Torticollis - physiopathology; Toxins; Treatment Outcome; Young Adult; botulinum toxin A; focal dystonia; cervical dystonia; somatosensory temporal discrimination threshold; blepharospasm; focal hand dystonia; sensorimotor integration
• ISSN: 2072-6651; 2072-6651
• DOI: 10.3390/toxins12050277

(1) Background: In dystonia, the somatosensory temporal discrimination threshold (STDT) is abnormally increased at rest and higher and longer-lasting during movement execution in comparison with healthy subjects (HS), suggesting an abnormal sensorimotor integration. These abnormalities are thought to depend on abnormal proprioceptive input coming from dystonic muscles. Since Botulinum toxin-A (BT-A) reduces proprioceptive input in the injected muscles, our study investigated the effects of BT-A on STDT tested at rest and during voluntary movement execution in patients with focal dystonia. (2) Methods: We enrolled 35 patients with focal dystonia: 14 patients with cervical dystonia (CD), 11 patients with blepharospasm (BSP), and 10 patients with focal hand dystonia (FHD); and 12 age-matched HS. STDT tested by delivering paired stimuli was measured in all subjects at rest and during index finger abductions. (3) Results: Patients with dystonia had higher STDT values at rest and during movement execution than HS. While BT-A did not modify STDT at rest, it reduced the abnormal values of STDT during movement in CD and FHD patients, but not in BSP patients. (4) Conclusions: BT-A improved abnormal sensorimotor integration in CD and FHD, most likely by decreasing the overflow of proprioceptive signaling from muscle dystonic activity to the thalamus.