Effective behavioral treatment of focal hand dystonia in musicians alters  somatosensory cortical organization

Candia, Victor; Wienbruch, Christian; Elbert, Thomas; Rockstroh, Brigitte; Ray, William J.

doi:10.1073/pnas.1231193100

Cited by 158 publications

(95 citation statements)

References 34 publications

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“…It may seem difficult to reconcile the observation that upper-limb immobilization may induce dystonia in some patients, while ameliorating dystonic symptoms in others. This point may be even more confusing, as some Authors reported that sensory training by learning to read Braille is an effective treatment for focal hand dystonia (Zeuner et al, 2002) and effective behavioral treatment for dystonia may reverse the abnormalities of cortical sensory maps (Candia et al, 2003). The effectiveness of two opposite behavioral strategies (i.e.…”

Section: Mechanisms Of Motor Cortex Hyperexcitabilitymentioning

confidence: 99%

Modulation of motor cortex excitability after upper limb immobilization

Zanette

Manganotti

Fiaschi

et al. 2004

Clinical Neurophysiology

102

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Objective: To examine the mechanisms of disuse-induced plasticity following long-term limb immobilization. Methods: We studied 9 subjects, who underwent left upper limb immobilization for unilateral wrist fractures. All subjects were examined immediately after splint removal. Cortical motor maps, resting motor threshold (RMT), motor evoked potential (MEP) latency and MEP recruitment curves were studied from abductor pollicis brevis (APB) and flexor carpi radialis (FCR) muscles with single pulse transcranial magnetic stimulation (TMS). Paired pulse TMS was used to study intracortical inhibition and facilitation. Compound muscle action potentials (CMAPs) and F waves were obtained after median nerve stimulation. In 4/9 subjects the recording was repeated after 35 -41 days.Results: CMAP amplitude and RMT were reduced in APB muscle on the immobilized sides in comparison to the non-immobilized sides and controls after splint removal. CMAP amplitude and RMT were unchanged in FCR muscle. MEP latency and F waves were unchanged. MEP recruitment was significantly greater on the immobilized side at rest, but the asymmetry disappeared during voluntary muscle contraction. Paired pulse TMS showed an imbalance between inhibitory and excitatory networks, with a prevalence of excitation on the immobilized sides. A slight, non-significant change in the strength of corticospinal projections to the non-immobilized sides was found. TMS parameters were not correlated with hand dexterity. These abnormalities were largely normalized at the time of retesting in the four patients who were followed-up.Conclusions: Hyperexcitability occurs within the representation of single muscles, associated with changes in RMT and with an imbalance between intracortical inhibition and facilitation. These findings may be related to changes in the sensory input from the immobilized upper limb and/or in the discharge properties of the motor units.Significance: Different mechanisms may contribute to the reversible neuroplastic changes, which occur in response to long-term immobilization of the upper-limbs.

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Section: Mechanisms Of Motor Cortex Hyperexcitabilitymentioning

confidence: 99%

Modulation of motor cortex excitability after upper limb immobilization

Zanette

Manganotti

Fiaschi

et al. 2004

Clinical Neurophysiology

102

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“…In this issue of PNAS, Candia et al (26) describe an orthotic-aided behavioral treatment for focal hand dystonia that apparently reverses the somatosensory map distortions associated with this motor disorder. Somatosensory map normalization is accompanied by a reduction in dystonic symptoms.…”

Section: The Cerebral Cortex Is Shaped Continuallymentioning

confidence: 99%

“…In focal hand dystonia, the boundaries between finger representations are degraded, resulting in cortical regions that represent large skin surfaces crossing multiple digits. In the article by Candia et al (26), sensory motor retuning was used to reduce dystonic symptoms. After the therapy, ''retuned'' maps appeared normalized.…”

Section: The Cerebral Cortex Is Shaped Continuallymentioning

confidence: 99%

Retuning the misfiring brain

Nudo

2003

Proc. Natl. Acad. Sci. U.S.A.

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“…There are a number of ways in which one can measure the positions and relative rotations of digit segments over time to get kinematic measures such as velocity and acceleration. Candia and colleagues developed a Dexterity Displacement Device 27,28,49,50 to measure velocity profiles of digit displacement during metronome-paced movements of 2 fingers on a device that looks like 2 keys on a keyboard. They then evaluated movement smoothness with the ratio of spectral power in frequency bands near vs outside of the metronome frequency.…”

Section: Resultsmentioning

confidence: 99%

Rating scales for musician's dystonia

et al. 2013

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Musician's dystonia (MD) is a focal adult-onset dystonia most commonly involving the hand. It has much greater relative prevalence than non-musician's focal hand dystonias, exhibits task specificity at the level of specific musical passages, and is a particularly difficult form of dystonia to treat. For most MD patients, the diagnosis confirms the end of their music performance careers. Research on treatments and pathophysiology is contingent upon measures of motor function abnormalities. In this review, we comprehensively survey the literature to identify the rating scales used in MD and the distribution of their use. We also summarize the extent to which the scales have been evaluated for their clinical utility, including reliability, validity, sensitivity, specificity to MD, and practicality for a clinical setting. Out of 135 publications, almost half (62) included no quantitative measures of motor function. The remaining 73 studies used a variety of choices from among 10 major rating scales. Most used subjective scales involving either patient or clinician ratings. Only 25% (18) of the studies used objective scales. None of the scales has been completely and rigorously evaluated for clinical utility. Whether studies involved treatments or pathophysiologic assays, there was a heterogeneous choice of rating scales used with no clear standard. As a result, the collective interpretive value of those studies is limited because the results are confounded by measurement effects. We suggest that the development and widespread adoption of a new clinically useful rating scale is critical for accelerating basic and clinical research in MD. Musician's dystonia (MD) is a focal task-specific movement disorder involving impaired voluntary motor control during extensively trained movements while a musician is playing the instrument.1 It has been documented for almost every instrument and in several body regions, including the embouchure.2 Yet the overwhelming majority of patients with MD have focal hand dystonia (FHD). MD is often described in conjunction with the writer's cramp form of FHD, and therefore sometimes is referred to as "musician's cramp." However, the term "cramp" can be misleading as MD rarely involves pain or the maximum intensity contractions associated with cramps.3,4 MD is the most common movement disorder affecting musicians. 5 Although prevalence estimates for FHD vary widely, depending on the study and geographic scope, 6 approximately 1% of musicians develop FHD, a rate about 10 times greater than for nonmusicians. 7MD is usually associated with loss of fine control and coordination, most commonly in heterogeneous subsets of digits 2-5. 5,[8][9][10] The relative amount of excessive finger flexion or extension, 8,11 as well as which hand is affected, depends on the type of instrument. 8 Among the focal dystonias, MD exhibits some of the most exquisite task specificity. In many cases, symptoms appear only while playing the instrument and only in specific passages of specific pieces. 12From the

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Effective behavioral treatment of focal hand dystonia in musicians alters somatosensory cortical organization

Cited by 158 publications

References 34 publications

Modulation of motor cortex excitability after upper limb immobilization

Modulation of motor cortex excitability after upper limb immobilization

Retuning the misfiring brain

Rating scales for musician's dystonia

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