Definitions of the levels of the recommendations (A, B, C, U) and classification of the evidence (Class I through Class IV) are provided at the end of the "Major Recommendations" field.
Blepharospasm
Conclusions
For patients with blepharospasm, botulinum neurotoxin (BoNT) injection is probably effective with minimal side effects (two Class II studies). After dosage adjustment, Botox® and Xeomin® are probably equivalent (one Class I study), and Botox® and Dysport® are possibly equivalent (one Class II and one Class III study).
Recommendation
BoNT injection should be considered as a treatment option for blepharospasm (Level B).
Hemifacial Spasm
Conclusions
BoNT is possibly effective with minimal side effects for the treatment of hemifacial spasm (one Class II and one Class III study). Botox® and Dysport®, after dosage adjustment, are possibly equivalent in efficacy (one Class II study).
Recommendation
BoNT injection may be considered as a treatment option for hemifacial spasm (Level C).
Cervical Dystonia
Conclusion
BoNT is established as safe and effective for the treatment of CD (seven Class I studies).
Recommendations
- BoNT injection should be offered as a treatment option to patients with cervical dystonia (Level A).
- BoNT is probably more efficacious and better tolerated in patients with CD than treatment with trihexyphenidyl (Level B).
Focal Limb Dystonia
Conclusions
BoNT is probably effective for the treatment of focal upper extremity limb dystonia (one Class I and three Class II studies). While a few patients in one Class II study suggest that BoNT may be effective for lower extremity dystonia, the data are inadequate to provide a recommendation.
Recommendation
BoNT should be considered as a treatment option for focal upper extremity dystonia (Level B).
Laryngeal Dystonia
Conclusions
BoNT is probably effective for the treatment of adductor type spasmodic dysphonia (ADSD) (one Class I study). There is insufficient evidence to support a conclusion of effectiveness for BoNT in abductor type spasmodic dysphonia (ABSD).
Recommendations
- BoNT should be considered as a treatment option for adductor spasmodic dysphonia (Level B).
- There is insufficient evidence to support or refute the use of BoNT in abductor spasmodic dysphonia (Level U).
Tics
Conclusions
BoNT is possibly effective for the treatment of motor tics (one Class II study). There are insufficient data to determine the effectiveness of BoNT in phonic tics (one Class IV study).
Recommendation
BoNT may be considered as a treatment option for motor tics (Level C).
Tremor
Conclusions
BoNT injection of forearm muscles is probably effective in reducing the tremor amplitude in patients with essential hand tremor (two Class II studies). The benefits must be considered in conjunction with the common adverse effect of muscle weakness associated with BoNT injection. Existing data are insufficient to draw a conclusion on the use of BoNT in the treatment of head and voice tremor.
Recommendation
BoNT should be considered as a treatment option for essential hand tremor in those patients who fail treatment with oral agents (Level B).
Definitions:
Classification of Recommendations
Level A = Established as effective, ineffective or harmful (or established as useful/predictive or not useful/predictive) for the given condition in the specified population. (Level A rating requires at least two consistent Class I studies.*)
Level B = Probably effective, ineffective or harmful (or probably useful/predictive or not useful/predictive) for the given condition in the specified population. (Level B rating requires at least one Class I study or at least two consistent Class II studies.)
Level C = Possibly effective, ineffective or harmful (or possibly useful/predictive or not useful/predictive) for the given condition in the specified population. (Level C rating requires at least one Class II study or two consistent Class III studies)
Level U = Data inadequate or conflicting; given current knowledge, treatment (test, predictor) is unproven. (Studies not meeting criteria for Class I–Class III).
* In exceptional cases, one convincing Class I study may suffice for an "A" recommendation if 1) all criteria are met, 2) the magnitude of effect is large (relative rate improved outcome >5 and the lower limit of the confidence interval is >2).
Classification of Evidence for Therapeutic Intervention
Class I: Randomized, controlled clinical trial with masked or objective outcome assessment in a representative population. Relevant baseline characteristics are presented and substantially equivalent among treatment groups or there is appropriate statistical adjustment for differences. The following are required: a) concealed allocation, b) primary outcome(s) clearly defined, c) exclusion/inclusion criteria clearly defined, and d) adequate accounting for drop-outs (with at least 80% of enrolled subjects completing the study) and cross-overs with numbers sufficiently low to have minimal potential for bias.
Class II: Prospective matched group cohort study in a representative population with masked outcome assessment that meets b-d above OR a randomized controlled trial in a representative population that lacks one criteria a-d.
Class III: All other controlled trials (including well-defined natural history controls or patients serving as own controls) in a representative population, where outcome is independently assessed, or independently derived by objective outcome measurement.*
Class IV: Studies not meeting Class I, II, or III criteria, including consensus, expert opinion, or a case report.
*Objective outcome measurement: An outcome measure that is unlikely to be affected by an observer's (patient, treating physician, investigator) expectation or bias (e.g., blood tests, administrative outcome data).