Meta-analysis of prevention and treatment methods for the occupational disease musicians dystonia (BK 2115)

Status:

completed 11/2021

Aims:

The so-called musicians dystonia, a task-specific focal dystonia, was listed as an occupational disease on August 1st, 2017 (BK 2115). Treatment success for patients suffering from this disorder is usually limited. Consequently, a professional music career is often terminated.

A meta-analysis should be created that allows a summary of all clinical studies on common forms of therapy. This should serve as a template for the derivation of concrete recommendations or improvement possibilities for the healing process. The knowledge gained should aim at a faster and more effective professional as well as social reintegration of the ill professional musicians.

Activities/Methods:

A meta-analysis is highly standardized and takes place in several steps. Publications and so-called gray literature from 1980 to the present (as of October 2021) were sought, primarily in English, but also in German, French, Dutch, and Italian. The research strategy was documented in detail. Specifically, the work steps were:

• study selection,
• coding and categorization,
• effect size calculation,
• reliability testing.

Results:

Because the data quality and data quantity did not meet the requirements of a methodologically sophisticated meta-analysis, a systematic review is currently being written (as of May 2022). A total of 42 studies were included in the systematic review. Sorted by level of evidence in descending order: IA: 0 studies; IB: 2 studies; IIA: 0 studies; IIB: 7 studies; IIIA: 5 studies; IIIB: 17 studies; IVB: 11 studies.

Treatment with botulinum toxin: Based on self-reports, a moderate to high number of patients may benefit from treatment with botulinum toxin. On average, this benefit is of moderate quality.

Pharmacotherapy for focal dystonia: Trihexyphenidyl shows low to moderate efficacy; patient and expert ratings agree. Primidone and propanolol are potentially effective agents for treating task-specific tremor in musicians.

Transcranial direct current stimulation (tDCS): positive effects only at the individual level, not at the group level.

Kinesiotaping: no effective treatment of the symptoms of musicians dystonia.

Invasive methods: one study (evidence level IVB, n = 1) investigated the effect of deep brain stimulation (DBS) → DBS is still in the early stages of research for FD in musicians, no conclusions possible yet.

Ergonomic modifications and sensory tricks: Five studies investigated the effect of ergonomic modifications and sensory tricks in the treatment of musicians dystonia. Three studies had level IIB evidence and two studies had level IIIA evidence. Two studies investigated the so-called "glove effect". Although it is an individual therapy strategy, there was no evidence at the group level that the glove effect improves fine motor skills. The use of different types of auditory feedback did not improve fine motor control. However, proprioceptive training with vibration significantly improved task-specific motor control. Individualized, nonstandard approaches such as position changes, splints, etc., resulted in selfreported improvement of up to 63%.

Nonspecific exercises: There were 3 studies identified that highlighted the effects of nonspecific exercises. One study had evidence level IIIA, the other 2 level IIIB. Jabusch et al (2005) reported 56% improvement in patients who performed nonspecific technical exercises. Butler et al. (2018) found that shoulder motion exercises and hand strengthening exercises were rated effective by 43% of patients. In a study by van Vugt et al. (2014), the mean effectiveness of hand therapy and relaxation exercises was rated medium and that of physical therapy was rated low. Similar to ergonomic modifications, these are individual approaches that are not standardized and for which no data from controlled studies are available.

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