Large Study Finds Predictors of Musician's Dystonia

Daniel M. Keller, PhD

October 09, 2019

NICE, France — A new review suggests musician's focal task-specific dystonia (MFD) often occurs subsequent to a triggering factor, such as a change in technique or increase in practice, and that many patients have concurrent ipsilateral neuropathy, particularly ulnar neuropathy, suggesting it may be an important risk factor, researchers report.

MFD affects 1% to 2% of professional musicians, is an important occupational disability, and can be career-ending. The most common form is musician focal hand dystonia (MFHD), with onset in adulthood at the peak of performance careers.

Less common is embouchure dystonia, which affects woodwind and brass players. Typical treatment with botulinum toxin injections and retraining are most often unsatisfactory.

A review of 2649 case records of performing musicians from health clinics treating performing artists at the University of California San Francisco (1984-1989) and Partners HealthCare in Boston (1989-2015) identified 240 consecutive cases (9.1%) of MFD. Cases were compared with a cohort of 532 nondystonic patients with ulnar nerve entrapment.

Speaking during a group poster tour here at the 2019 International Congress of Parkinson's Disease and Movement Disorders, Christopher Stephen, MB ChB, Massachusetts General Hospital and Brigham and Women's Hospital Performing Arts Clinic, Boston, Massachusetts, reported that "ulnar nerve entrapment had increased prevalence in focal hand dystonia — 30% as opposed to 22% in our whole musician's cohort of 2649 musicians."

In addition, of the 66 patients with MFHD and ulnar nerve entrapment, all but one were ipsilateral. "It's quite a striking finding," he said.

Predictors of MFHD versus ulnar nerve entrapment included male gender and playing professionally (both P < .0001). Predictors of worse outcome included the number of fingers involved with dystonia (P = .0009) and being an amateur musician (P = .0138).

Ten percent of the dystonic cohort had a family history of movement disorders, whereas this was very rare in patients with ulnar nerve entrapment only.

The MFD population was about 70% male, consisted mostly of professional musicians but also 30% amateurs and about 8% conservatory students. The age of onset was about 36 years but with a wide range of 10 to 67 years. About 72% performed classical music, 16% jazz, and 12% other genres.

A side predilection depended on the kind of instrument, for example, piano or plucked strings. MFHD was rare in brass and percussion players.

Of the 215 cases with MFHD, 160 (74.4%) had a pure flexion dystonia, most of them with flexion of the ring and little fingers. Extension-only dystonia occurred in 25 patients, and most of them played woodwinds.

The majority (72.2%) of MFHD patients had reported an associated event prior to developing the condition, whether musical (eg, increased practice, new technique, or a new instrument) or nonmusical (eg, concurrent neuropathy, overuse injury, or emotional stress or trauma).

Fifty-two patients (24.2%) received botulinum toxin injections, with 30% of them having substantial improvement, but most discontinued this therapy due to lack of benefit. Oral medications were minimally effective in treating dystonia in MFHD but sometimes helped treat tremor.

Of the 66 patients that had ipsilateral ulnar nerve entrapment and MFHD, 27 underwent surgery for the entrapment. Most had substantial improvement in symptoms and signs of ulnar nerve entrapment, and a minority had improvement in dystonia.

"So it could suggest that having surgery, if you do find an ipsilateral ulnar nerve entrapment with dystonia...may help some patients have a substantial improvement after surgery, but not in general," Stephen said.

He noted that changing to a different instrument helped some patients, but even then over time dystonia developed with that instrument as well. Just over half of MFHD patients continued to play but were impaired.

After Stephen's presentation, a lively discussion ensued between him and Alberto Albanese, MD, Catholic University, Milan, Italy, one of the leaders of the poster tour. Albanese raised the possibility of better training in technique to avoid dystonia.

"I was thinking that probably appropriate training to some extent prevents future dystonia because I follow the director of the conservatory in Milan, and I discussed with him many times about how to train musicians from the very beginning to try to prevent dystonia," he said.

Although an interesting idea, Stephen said the study involved people who already had dystonia and explored what were predictors of worse outcome. But he agreed that better training may help avoid dystonia. "It may also give them the expertise to be able to still play to a decent level and adjust the repertoire," he said.

"Well, it depends on the severity because they try as much as they can because they love music. So for them to stop is really a problem," Albanese concluded.

There was no funding for the study. Stephen has reported no relevant financial relationships. Albanese has received speaker's honoraria from Allergan, Ipsen, Merz, Medtronic, and Zambon.

International Congress of Parkinson's Disease and Movement Disorders 2019. Presented September 24, 2019. Abstract 1345.

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