Botulinum Toxin Injection

Adductor spasmod.ic dysphonia is a vocal disorder of uncertain etiology with no satisfactory long-term treatment-result. Recently injecrton of Botulinum toxin (BOTOX) into the thyroarytenoid muscle has been used as an effective temporary treatment. In this experiment, 9 partents with adductor spasmodic dysphonia (SPD) were studicd and injected percutaneously the Bonlinum toxin with dose of injection ranges from 1.25 to 5 units totally. Post teatment results were monitored acoustically for objective voice analysis and auditorily for perceptual judgment. Temporary satisfactory results were obtained after the average of 2 months post-iniection, and lasted for at least 5 months of average. The test ofvocal controllability derived from several acoustic parameters exftaction, e.g. the pitch pernrbation quotient (PPQ), amptinde perturbation quotient (APQ), the Fo overallvariability (FoV), energy of slow andfast Fo perturbation (FoS and FoF), showed improvement on post-BOTOX injection, and illustrate the fficacy of the analysis system used. Abstrak Disfonia addulctor spasmodik adalah kelainan suara yang etiologinya belwn jelas, dengan hasil terapi jangla panjang yang tidak memuaskan. Dewasa ini injetcsi toksin Botulinwn (BOTOX) læ muskulus tiroaritenoi.d banyak diteraplcan. Pada pmelitian ini dilalatkan sndi pada 9 kasus disfonia ad.duktor spasmodik dengan menyuntikkan 1.25 sampai 5 unit BOTOX melalui kulit ke dalam otot I'aring. Hasil terapi dimonitor secara akustik untuk menganalisis suara secara objektif dan perseptual. Keberhasilan semmtara didapatkan setelah kurang lcbih 2 bulan pasca terapi, dan berlanjut sampai kurang-lebih 5 bulan. Tes kontrol suorayang dihimpun dari hasil beberapa parameter yang dihiung yaitu: pitch perturbation quotient (PPQ), amplinde perturbation quotient (APQ), Fo overall variability(loV), energy of slow andTastperturbation(FoS andFoF) menunjukkanperbaikanyangbermaknapada gruppasca-BOTOX. Hal ini juga menggambarlcan kinerja yang berdaya-guna dari sistem analisis suara yang dipakai. Keyw or ds : sp as tic dy s phonia, v o ice analy sis, v o cal c ontro llab ility. Spasmodic dysphonia (SPD) is a central nervous system phenomenon of unknown etiology characteized by c€ tremor with erratic patterns of lar The uncertainty of the SPD etiology arose researchers to conduct experiments and options in the treatment of SPD patients to try to eliminate the disruptive voice resection of a Portion on one side,2 Côz laser 3 anterior laryngoplasty, voice therapy, pharmacotherapy, and the most promising one is Botulinum toxin injection. Eventhough most of opinions declared that adductor SPD was a vocal disorder with no satisfactory longterm treatment-result, many experiments had been Department of Otorhinolarytgology, Facuhy of Medicine, Llniversity of Indonesia/Dr. Cipn Mangunkusumo Hospital, Jakarta, Indonesia conducted. Woodson et al4 reported a study on the effects of Botulinum toxin therapy in patients with adductor SPD in term of acoustic, aerodynamic and videoendoscopy findings, and concluded a successful result on post-therapy condition. Adams et al'reported a study concerning unilateral versus bilateral Botulinum toxin injections in SPD for acoustic and perceptual results and concluded that unilateral BOTOX injections may provide both superior and longer lasting begefits than bilateral BOTOX injections. Green et al6 reported his method of point-touch technique of Botulinum toxin injection for the treatment of SPD by means of flexible nasopharyngeal endoscopy guidance. Kobayasi et al/ also reported his successful method for percutaneus insertion technique of the needle for injecting the Botulinum toxin into the thyroarytenoid muscle of SPD patients. Botulinum toxin is produced by the anaerobic bacterium Clostridium botulinum, and causes temporary paralysis by blocking the presynaptic release ofacetylVoI 6, No 3, July September 1997 choline at the neuromuscular junction. This action is clinically used to alleviate muscle spasm by injecting the toxin directly into the overactive muscle. Despite so many experiments and researches has been done concerning SPD, there are still many unanswered questions, and the field for investigations and researches in SPD remains widely open. In this study, experiment was conducted upon adductor SPD patients, and injection of Botulinum toxin was performed using percutaneus technique of needle insertion into the thyroarytenoid muscle. Auditory perceptual were done subjectively by the patients themselves and objectively by the doctor. Besides, acoustical analysis were also performed before and after treatment, to monitor the results as a follow up mean. MATERIALS AND METHOD This study was conducted in the Research Institute of Logopedics and Phoniatrics (RILP), Tokyo University, from 1995 through 1996. The subjecrs for this experiment were 9 patients of adductor SPD, consisted of 2 males and 7 females with ages ranged from 20 to 71 years, who had been suffering from the disease for more than six months. The control group voice samples were obtained from 15 normal speakers aged26 to 67 years. The normaVhealthy voices were the modal voice samples produced at most comfortable level and pitch by healthy speakers, without any history of pathology affecting phonation. BOTOX injection were performed using percutaneus procedure, and the technique is identical to electromyography of the vocal folds. A 23-gauge hypodermic needle, coated with Teflon except for its tip, was used both as a monopolar electrode to locate the vocal folds and as an injection channel. The needle was inserted percutaneusly through the crycothyroid membrane, and correct positioning of the needle was confirmed by EMG display or audiomonitoring on phonation. Voice samples collection were performed by recording sustained vowel /a/ produced by subjects as long as they were able to, at their most comfortable level and pitch. SPD voice samples were obtained before (preBOTOX) and about 2 months after (post-BOTOX) BOTOX injection. Recordings were made using DAT tape-recorder, with a constant distance of 15 cm, between microphone and Vocal Assessmmt on SPD 159 mouth, following repeated patient's practice, and recordings were made in sound attenuated room. Voice samples of sustained vowel lal were then digitalized through a 16-bit A/D converter at a sampling rate of 40 kHz and stored on a disk controlled by computer. The acoustic feature of a voice sample was analyzed using the "SONG" computer aided program. Using waveform matching and peak picking method, the method proposed by Imaizumi et al,8'e local maximum points which could correspond to vocal excitation epochs were detected successively and then two time series of Fo(i) and A(i), the fundamental frequency and the maximum amplitude of i-th glottal period were determined. Cycle-by-cycle perturbation quotient were calculated, pitch perturbation quotient (PPO and amplitude perturbation quotient (APQ) and several voice properties were extracted such as the overall variability of Fo (FoV), the additive noise level (Noise Level), and the energy of slow and fast Fo perturbations (FoS and FoF). Two kinds of scoring were applied to assess the voice condition auditorily: appraisement by the patients themselves depending on their feeling, called as "subjective scaling". The scores ranged between 0 (for no complaints on phonation, no difficulty, smooth, the voice seemed regular and not disruptive), up to 3 [for difficult feeling on phonation, straining, and no change compared to before injection (pre-BOTOX)1. In between there were better conditions of voices, score 1 (much better than before injection) and 2 (better than before). The "perceptual objective scaling" was a scoring method performed by the doctor using 25 morae. The score depends upon how many morae could be well pronounced by the patients. Scaling ranged betw een25 for bad condition with no mora pronounced clearly, smoothly, regularly and without voice stops, up to 0 for normal condition, the whole 25 morae were pronounced smoothly, effortless and without voice stops. For statistical calculation, an analysis of variance (ANOVA) with one factor, the group, was performed to determined significance.