The course of cervical dystonia with head tremor during botulinum toxin type A treatment

Abstract

Objective: to evaluate the efficacy and safety of botulinum toxin type A (BTA) injections into the neck muscles to reduce dystonic postures, head tremor, and pain syndrome in patients with cervical dystonia (CD) within the first 8 cycles of treatment.Patients and methods. The investigation included 76 patients (26 (34%) men and 50 (66%) women) with CD and dystonic head tremor, who were given BTA injections into the neck muscles for the first time. All the 76 patients received at least one cycle of BTA therapy. At the same type, 18 of these patients received 4 cycles of injections and 36 patients had 8 cycles. Injections were given when the symptoms of CD recurred or increased and the patient needed to be retreated. The interval between the injection cycles was arbitrary, but not less than 12 weeks. The doses of BTA agents per treatment cycle were as follows: Dysport was 400 to 1000 U, xeomin was 50 to 300 U, and Botox 200 to 300 U. The symptoms of CD were assessed using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Tsui scale before the first injection of BTA and injection cycles 4 and 8; the presence or absence of head tremor was recorded.Results. The TWSTRS severity of CD symptoms decreased from 38 [36; 41] to 30 [27; 33] scores by injection cycle 4 (p < 0.001) and to 26 [23; 27] scores by cycle 8 (p<0.01). The Tsui severity of CD reduced from 9.3 [9; 10] to 7.2 [7; 8] scores by injection cycle 4 (p<0.001) and to 6.7 [6; 7] scores by cycle 8. The Tsui tremor scores decreased from 1.9 [1.6; 2.1] to 1.4 [1.1; 1.6] scores by injection cycle 4 and to 1.1 [0.9;1.4] scores by cycle 8 (p<0.01). Tremor completely disappeared in 6 (11%) of patients by injection cycle 4 and in 6 (18%) patients by cycle 8. According to Section 3 of the TWSTRS, pain intensity was reduced from 9.9 [8.9; 11.0] to 5.0 [3.3; 6.6] scores by injection cycle 4 (p<0.001) and to 2.1 [0.7; 3.6] scores by cycle 8 (p < 0.01); pain regressed completely in 12 (41%) and 9 (64%) patients by cycles 4 and 8, respectively. Conclusion. BTA injections into the neck muscles are an effective treatment for CD symptoms, such as dystonic tremor, posture, and pain. Successive injection cycles have a cumulative effect that is more marked by injection cycle 8. It is appropriate to prescribe longer treatment cycles to patients with CD and head tremor. Dystonic head tremor, unlike dystonic postures, may regress fully after BTA injections

Keywords

• cervical dystonia
• botulinum toxin type a
• dystonic head tremor.