QUANTITATIVE ASSESSMENT OF BOTULINUM TOXIN TREATMENT IN 43 PATIENTS WITH HEAD TREMOR

We treated 43 patients who had head tremor as the major complaint with local botulinum toxin type A (Btx A) injections into neck muscles: 29 patients were classified as suffering from tremulous cervical dystoni a (TCD), and 14 had head tremor without dystonia (HT). All patients we re clinically assessed by means of the Tsui scale and a ii-point pain scale at baseline and follow-up visit. Quantitative recordings of head tremor with a bidirectional accelerometer system (horizontal and vert ical planes) placed on the forehead were obtained before and 2-3 weeks after Btu A injections. Muscle selection for an injection was based o n the visible and palpable tremor oscillation in the involved neck mus cles and on analysis of standardized simultaneous electromyographic re cordings of six cervical muscles. Patients with HT received mean total doses of 400 units (U) of Dysport (Btx A) (range, 160-560 U) distribu ted between the two splenius capitis muscles. Patients with TCD receiv ed a mean total dose of 500 U Dysport (range, 320-720 U) injected into a mean of 3 muscles (range, 2-4 muscles). The condition of all patien ts with HT and of 26 of the 29 patients with TCD improved subjectively . The total on the Tsui scale as well as pain scores decreased signifi cantly (p < 0.05) following treatment. Latency of onset, duration of i mprovement, and side effects showed no significant difference in HT an d TCD. Amplitude of HT decreased significantly for both groups followi ng treatment. The mean dominant peak frequency in TCD and HT was sligh tly less than 5 Hz and did not change significantly after treatment.