Regaining Motor Control in Musician's Dystonia by Restoring Sensorimotor Organization

Abstract

Professional musicians are an excellent model of long-term motor learning effects on structure and function of the sensorimotor system. However, intensive motor skill training has been associated with task-specific deficiency in hand motor control, which has a higher prevalence among musicians (musician's dystonia) than in the general population. Using a transcranial magnetic stimulation paradigm, we previously found an expanded spatial integration of proprioceptive input into the hand motor cortex [sensorimotor organization (SMO)] in healthy musicians. In musician's dystonia, however, this expansion was even larger. Whereas motor skills of musicians are likely to be supported by a spatially expanded SMO, we hypothesized that in musician's dystonia this might have developed too far and now disrupts rather than assists task-specific motor control. If so, motor control should be regained by reversing the excessive reorganization in musician's dystonia. Here, we test this hypothesis and show that a 15 min intervention with proprioceptive input (proprioceptive training) restored SMO in pianists with musician's dystonia to the pattern seen in healthy pianists. Crucially, task-specific motor control improved significantly and objectively as measured with a MIDI (musical instrument digital interface) piano, and the amount of behavioral improvement was significantly correlated to the degree of sensorimotor reorganization. In healthy pianists and nonmusicians, the SMO and motor performance remained essentially unchanged. These findings suggest that the differentiation of SMO in the hand motor cortex and the degree of motor control of intensively practiced tasks are significantly linked and finely balanced. Proprioceptive training restored this balance in musician's dystonia to the behaviorally beneficial level of healthy musicians.

Illusory movements prevent cortical disruption caused by immobilization

“…Cortical rearrangement that encodes the kinematic parameters of a practiced movement has been observed after only 30 min of repetitive finger movements (Classen et al, 1998), or following long-lasting learning of skilled motor activities in musicians or blind Braille readers (Pascual-Leone et al, 2005). Functional remapping also appears as a consequence of sensory or motor restriction, following cortical or spinal cord injury (Topka et al, 1991), limb amputation (Chen et al, 1998;Giraux et al, 2001), hand dystonia (Rosenkranz et al, 2009) or peripheral deafferentation (Rossini et al, 1996;Tinazzi et al, 1998). Few studies have explored the cortical effects of transient enforced non-use of a limb caused by serious sprain or a fracture requiring a cast for several weeks.…”

Rating scales for musician's dystonia

“…Several versions of VAS have been used in MD, usually including ranges of 2100 to 100 when rating musical performance improvement while performing short symptom-evoking pieces, 43 but also ranges of 1 to 10, 44 and 0 to 6 and 23 to 3 after translating patient perceptions of impairment and change in performance, respectively. 26 The DES 27,28 is a rating of performance during movement exercises and symptom-evoking passages on an ordinal scale.…”

“…Figure 2B shows the number of studies using each type of scale. Few studies use more than one type of scale, and only one study 26 uses all 3 types. There is a broad distribution of use of the individual scales ( figure 2C).…”

A narrative review on haptic devices: relating the physiology and psychophysical properties of the hand to devices for rehabilitation in central nervous system disorders

“…It is also impaired by damage to the central and peripheral nervous systems. Kinaesthetic sense is trainable and is enhanced in athletes [16], dancers [17] and musicians [18].…”