Table.
GRADE Evaluation of interventions for Dystonia.
| Important outcomes | Neurological disability, Quality of life | ||||||||
| Studies (Participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| What are the effects of drug treatments for focal dystonia? | |||||||||
| at least 14 (at least 1029) | Neurological disability | Botulinum A toxin versus placebo in cervical dystonia in adults | 4 | 0 | 0 | –1 | 0 | Moderate | Directness point deducted for including only people who had previously responded to onabotulinumtoxinA in 1 RCT |
| 3 (308) | Neurological disability | Botulinum B toxin versus placebo in cervical dystonia in adults | 4 | 0 | 0 | 0 | 0 | High | |
| 3 (252) | Neurological disability | Botulinum A toxin versus botulinum B toxin in cervical dystonia in adults | 4 | 0 | 0 | –2 | 0 | Low | Directness points deducted for not reporting doses in 1 study and population differences between studies in previous experience with botulinum A toxin |
| 1 (31) | Neurological disability | Low-dose (100 U Botox/250 U Dysport) versus high-dose (>200 U Botox/960 U Dysport) botulinum A toxin in cervical dystonia in adults | 4 | –2 | 0 | –1 | 0 | Very low | Quality points deducted for sparse data and incomplete reporting of results; directness point deducted for no direct comparison between groups |
| 1 (92) | Neurological disability | Low-dose (2500–5000 U) versus high-dose (10,000 U) botulinum B toxin in cervical dystonia in adults | 4 | –1 | –1 | 0 | 0 | Low | Quality point deducted for sparse data; consistency point deducted for differing results with different outcome measures |
| 1 (66) | Neurological disability | Botulinum A toxin versus trihexyphenidyl in cervical dystonia in adults | 4 | –2 | 0 | –2 | 0 | Very low | Quality points deducted for sparse data and incomplete reporting; directness points deducted for differences in disease severity between groups and short cycle intervals between injections affecting generalisability of results |
| 1 (92) | Neurological disability | Botulinum B toxin in botulinum A toxin-resistant adults versus respondent adults | 4 | –2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data and incomplete reporting of results |
| 1 (40) | Neurological disability | Botulinum A toxin versus placebo in people with writer's cramp | 4 | –1 | –1 | 0 | 0 | Low | Quality point deducted for sparse data; consistency point deducted for differing results with different outcome measures |
| What are the effects of physical treatments for focal dystonia? | |||||||||
| 1 (40) | Neurological disability | Physiotherapy plus biofeedback plus drug treatment versus drug treatment alone | 4 | –2 | 0 | –1 | 0 | Very low | Quality points deducted for sparse data, results after crossover, and unequal observation periods; directness point deducted for including only people who had previously responded to botulinum A toxin |
| 1 (20) | Neurological disability | Physiotherapy plus relaxation versus no physiotherapy plus relaxation | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for sparse data; directness point deducted for including a subset of participants who were also receiving botulinum toxin |
| 1 (20) | Quality of life | Physiotherapy plus relaxation versus no physiotherapy plus relaxation | 4 | –1 | 0 | –1 | 0 | Low | Quality point deducted for sparse data; directness point deducted for including a subset of participants who were also receiving botulinum toxin |
| 1 (31) | Quality of life | Voice therapy plus botulinum A toxin versus sham voice therapy plus botulinum A toxin versus botulinum A toxin-only for laryngeal dystonia (adductor spasmodic dysphonia) | 4 | –3 | 0 | 0 | 0 | Very low | Quality points deducted for sparse data, incomplete reporting of results, selection bias, and botulinum toxin dose inconsistencies |
| What are the effects of surgical treatments for generalised dystonia? | |||||||||
| 1 (40) | Neurological disability | Deep brain stimulation versus sham treatment | 4 | –2 | 0 | –1 | 0 | Very low | Quality points deducted for sparse data and no long-term results; directness point deducted for inclusion of mixed population of people with focal and generalised dystonia |
| 1 (less than 40) | Quality of life | Deep brain stimulation versus sham treatment | 4 | –2 | –1 | –1 | 0 | Very low | Quality points deducted for sparse data and no long-term results; consistency point deducted for lack of consistent benefit in different elements of quality of life; directness point deducted for inclusion of people with focal dystonia, affecting generalisability of results |
We initially allocate 4 points to evidence from RCTs, and 2 points to evidence from observational studies. To attain the final GRADE score for a given comparison, points are deducted or added from this initial score based on preset criteria relating to the categories of quality, directness, consistency, and effect size. Quality: based on issues affecting methodological rigour (e.g., incomplete reporting of results, quasi-randomisation, sparse data [<200 people in the analysis]). Consistency: based on similarity of results across studies. Directness: based on generalisability of population or outcomes. Effect size: based on magnitude of effect as measured by statistics such as relative risk, odds ratio, or hazard ratio.