Botulinum toxin type A versus anticholinergics for cervical dystonia

Botulinum toxin type A versus anticholinergics for cervical dystonia

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Cervical dystonia is the most common form of focal dystonia and is a highly disabling movement disorder, characterised by involuntary, usually painful, head posturing. Currently, botulinum toxin type A (BtA) is considered the first line therapy for this condition. Before BtA, anticholinergics were the most widely accepted treatment.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus anticholinergic drugs in adults with cervical dystonia.

SEARCH METHODS

We searched the Cochrane Movement Disorders' Trials Register to June 2003, screened reference lists of articles and conference proceedings to September 2018, and searched CENTRAL, MEDLINE, and Embase, with no language restrictions, to July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised trials (RCTs) of BtA versus anticholinergic drugs in adults with cervical dystonia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias and quality of the evidence. We resolved disagreements by consensus or by consulting a third review author. If enough data had been available, we were to perform meta-analyses using a random-effects model for the comparison of BtA versus anticholinergic drugs to estimate pooled effects and corresponding 95% confidence intervals (95% CI). The primary efficacy outcome was improvement in cervical dystonia-specific impairment. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included one RCT of moderate overall risk of bias (as multiple domains were at unclear risk of bias), which included 66 BtA-naive participants with cervical dystonia. Two doses of BtA (Dysport; week 0 and 8; mean dose 262 to 292 U) were compared with daily trihexyphenidyl (up to 24 mg daily). The trial was sponsored by the BtA producer. BtA reduced cervical dystonia severity by an average of 2.5 points (95% CI 0.68 to 4.32) on the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) severity subscale 12 weeks after injection, compared to trihexyphenidyl. More participants reported adverse events in the trihexyphenidyl treatment group (76 events), compared with the BtA group (31 events); however, the difference in dropouts due to adverse events was inconclusive between groups. There was a decreased risk of dry mouth, and memory problems with BtA, but the differences were inconclusive between groups for the other reported side effects (blurred vision, dizziness, depression, fatigue, pain at injection site, dysphagia, and neck weakness).

AUTHORS' CONCLUSIONS

We found very low-certainty evidence that BtA is more effective, better tolerated, and safer than trihexyphenidyl. We found no information on a dose-response relationship with BtA, differences between BtA formulations or different anticholinergics, the utility of electromyography-guided injections, or the duration of treatment effect.

Botulinum Toxin in Movement Disorders: An Update

Since its initial approval in 1989 by the US Food and Drug Administration for the treatment of blepharospasm and other facial spasms, botulinum toxin (BoNT) has evolved into a therapeutic modality for a variety of neurological and non-neurological disorders. With respect to neurologic movement disorders, BoNT has been reported to be effective for the treatment of dystonia, bruxism, tremors, tics, myoclonus, restless legs syndrome, tardive dyskinesia, and a variety of symptoms associated with Parkinson's disease. More recently, research with BoNT has expanded beyond its use as a powerful muscle relaxant and a peripherally active drug to its potential central nervous system applications in the treatment of neurodegenerative disorders. Although BoNT is the most potent biologic toxin, when it is administered by knowledgeable and experienced clinicians, it is one of the safest therapeutic agents in clinical use. The primary aim of this article is to provide an update on recent advances in BoNT research with a focus on novel applications in the treatment of movement disorders. This comprehensive review of the literature provides a critical review of evidence-based clinical trials and highlights recent innovative pilot studies.

Long-term quality of life in cervical dystonia after treatment with abobotulinum toxin A: a 2-year prospective study

BACKGROUND

The short-term quality of life (QoL) in cervical dystonia (CD) after treating with abobotulinum toxin A (Abo-BTX A) and neubotulinum toxin A (Neu-BTX A) have been studied in Thai CD patients. However; the long-term study has not been published.

OBJECTIVE

The aim of the present study was to determine long-term improvement of the health-related quality of life (HRQoL) after eight injections of Abo-BTX A over 2 years in CD patients.

PATIENTS AND METHODS

A 2-year prospective study on the QoL of CD patients, as measured by HRQoL, before and after receiving eight injections of Abo-BTX A at 3-month intervals over a 2-year treatment period was performed. The disease-specific HRQoL was assessed before and after the treatment by using the Cervical Dystonia Impact Profile-58 (CDIP-58) questionnaire. The general HRQoL was assessed by using the Medical Outcomes 36-Item Short Form Health Survey (SF-36), while depressive disorder screening was assessed by using the Center of Epidemiologic Studies-Depression (CES-D) questionnaire. The SF-36 and CES-D questionnaire were administered before treatment and every 3 months before the next injection for a 2-year period.

RESULTS

A total of 20 CD patients were enrolled from January 2013 to December 2015. CDIP-58 showed a significant improvement after long-term injections of Abo-BTX A in all domains (P < 0.001). However, only vitality domain of SF-36, which assessed general HRQoL, showed a significant improvement after long-term injections (P = 0.037). There was no prevalence of depressive disorder in all patients (CES-D score <20) in this study.

CONCLUSION

The Abo-BTX A injections at 3-month intervals over a 2-year period improved the CDIP-58 scores, which assess disease-specific HRQoL, as well as an increased vitality domain of general HRQoL. No patient suffered from depression in this study.

Clinical Management of Dystonia in Childhood

Dystonia is one of the most frequent movement disorders in childhood. It can impede normal motor development and cause significant motor disability. The diagnostic evaluation of childhood dystonia is challenging due to the phenotypic variability and heterogeneous etiologies. Evidence to guide the diagnostic evaluation and treatment is limited. Assessment is primarily directed by clinical history and distinctive examination findings. Neuroimaging is typically necessary to evaluate for acquired or complex inherited dystonias. A trial of levodopa can be both diagnostic and therapeutic in children with dopa-responsive dystonia. However, for the majority of children with early-onset dystonia, treatment is symptomatic with varying efficacy. There is a paucity of therapeutic trials for childhood dystonia and most treatment recommendations are consensus or expert opinion driven. This review summarizes the available evidence and guidelines on the diagnostic evaluation and pharmacological treatment of childhood-onset dystonia and provides practical frameworks to approach both issues based on best evidence.

Quality of life in cervical dystonia after treatment with botulinum toxin A: a 24-week prospective study

OBJECTIVE

This study aimed to identify possible improvements in disease-specific health-related quality of life (HRQoL) after multiple injections of botulinum toxin A over 24 weeks in Thai cervical dystonia (CD) patients.

MATERIALS AND METHODS

A 24-week prospective study comparing HRQoL of Thai CD patients before and after multiple injections of botulinum toxin A at 3-month intervals was performed. Disease-specific HRQoL was assessed by using the Cervical Dystonia Impact Profile-58 questionnaire (CDIP-58) and the Craniocervical Dystonia Questionnaire-24 (CDQ-24). General HRQoL was assessed by using the Medical Outcomes' 36-Item Short Form Health Survey (SF-36) and the EuroQoL 5-dimension questionnaire (EQ-5D). All the assessments were performed before and after the 24-week treatment period.

RESULTS

A total of 20 CD patients were enrolled in this study from April to December 2011. CDIP-58 and CDQ-24 scores, which assess disease-specific HRQoL, showed a significant improvement after 24 weeks of treatment by botulinum toxin A (P<0.001). However, EQ-5D and SF-36 scores, which assess general HRQoL, showed no significant improvement after the treatment (P>0.05).

CONCLUSION

CD patients' disease-specific HRQoL improved after being treated with multiple botulinum toxin A injections. However, general HRQoL was not improved.

Patient considerations in the treatment of cervical dystonia: focus on botulinum toxin type A

Cervical dystonia is the most common form of focal dystonia characterized by involuntary muscle contractions causing abnormal movements and posturing of the head and neck and is associated with significant pain. Botulinum toxin is considered first-line therapy in the treatment of pain and abnormal head posturing associated with cervical dystonia. There are currently three botulinum toxin type A neurotoxins and one botulinum type B neurotoxin commercially available and US Food and Drug Administration (FDA) labeled for the treatment of cervical dystonia. This review will focus on the efficacy, safety, and therapeutic use of botulinum type A neurotoxins in the treatment of cervical dystonia. We conclude with a discussion of factors influencing toxin selection including therapeutic effect, duration of effect, side effect profile, cost, and physician preference.

Treatment of focal dystonia

OPINION STATEMENT

Dystonia is characterized by repetitive twisting movements or abnormal postures due to involuntary muscle activity. When limited to a single body region it is called focal dystonia. Examples of focal dystonia include cervical dystonia (neck), blepharospasm (eyes), oromandibular dystonia, focal limb dystonia, and spasmodic dysphonia, which are discussed here. Once the diagnosis is established, the therapeutic plan is discussed with the patients. They are informed that there is no cure for dystonia and treatment is symptomatic. The main therapeutic option for treating focal dystonias is botulinum toxin (BoNT). There have been several attempts to characterize the procedure, the type of toxin, dosage, techniques, and combination with physical measures in each of the focal dystonia forms. The general treatment principles are similar. The affected muscles are injected at muscle sites based on evidence and experience using standard dosages based on the type of toxin used. The injections are repeated after 3 to 6 months based on the individual response duration. In the uncommon event of nonresponse with BoNT, the dose and site are reassessed. Oral drug treatment could be considered as an additional option. Once the condition is thought to be medically refractory, the opinion from the deep brain stimulation (DBS) team for the suitability of the patient for DBS is taken. The successful use of DBS in cervical dystonia has led to increased acceptance for trial in other forms of focal dystonias. DBS surgery in focal dystonias other than cervical is, however, still experimental. The patients may be offered the surgery with adequate explanation of the risks and benefits. Patient education and directing the patients towards dystonia support groups and relevant websites that provide scientific information may be useful for long-term compliance and benefit.