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Interactions between the body and the environment are dynamically modulated by upcoming sensory information and motor execution. To adapt to this behavioral state-shift, brain activity must also be flexible and possess a large repertoire of brain networks so as to switch them flexibly. Recently, flexible internal brain communications, i.e. brain network flexibility, have come to be recognized as playing a vital role in integrating various sensorimotor information. Therefore, brain network flexibility is one of the key factors that define sensorimotor skill. However, little is known about how flexible communications within the brain characterize the interindividual variation of sensorimotor skill and trial-by-trial variability within individuals. To address this, we recruited skilled musical performers and used a novel approach that combined multichannel-scalp electroencephalography, behavioral measurements of musical performance, and mathematical approaches to extract brain network flexibility. We found that brain network flexibility immediately before initiating the musical performance predicted interindividual differences in the precision of tone timbre when required for feedback control, but not for feedforward control. Furthermore, brain network flexibility in broad cortical regions predicted skilled musical performance. Our results provide novel evidence that brain network flexibility plays an important role in building skilled sensorimotor performance.

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OBJECTIVE: Embouchure dystonia (ED) is a task-specific movement disorder that leads to loss of fine motor control of the embouchure and tongue muscles in wind musicians. In contrast to musicians' hand dystonia, no validated severity rating for ED exists, posing a major obstacle for structured assessment in scientific and clinical settings. The aim of this study is to validate an ED severity rating scale (EDSRS) allowing for a standardized estimation of symptom severity in ED. METHODS: The EDSRS was set up as a composite score of six items evaluating audio-visual disease symptoms during the performance of three standardized musical tasks (sustained notes, scales, and fourths) separately for each body side. For validation, 17 musicians with ED underwent standardized audiovisual recordings during performance. Anonymized and randomized recordings were assessed by two experts in ED (raters). Statistical analysis included metrics of consistency, reliability, and construct validity with the fluctuation of the fundamental frequency of the acoustic signal (F0) (extracted in an audio analysis of the sustained notes). RESULTS: The EDSRS showed high internal consistency (Cronbach's α = 0.975-0.983, corrected item-total correlations r = 0.90-0.96), interrater reliability (intraclass correlation coefficient [ICC] for agreement/consistency = 0.94/0.96), intrarater reliability over time (ICC per rater = 0.93/0.87) and good precision (standard error of measurement = 2.19/2.65), and correlated significantly with F0 variability (r = 0.55-0.60, p = 0.011-0.023). CONCLUSION: The developed EDSRS is a valid and reliable tool for the assessment of ED severity in the hands of trained expert raters. Its easy applicability makes it suitable not only for routine clinical practice but also for scientific studies.

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Task-specific tremor in musicians is an involuntary oscillating muscular activity mostly of the hand or the embouchure, which predominantly occurs while playing the instrument. In contrast to arm or hand tremors, which have been examined and objectified based on movement kinematics and muscular activity, embouchure tremor has not yet been investigated. To quantify and describe embouchure tremor we analysed sound production and investigated the fluctuation of the time-varying fundamental frequency of sustained notes. A comparison between patients with embouchure tremor and healthy controls showed a significantly higher fluctuation of the fundamental frequency for the patients in the high pitch with a tremor frequency range between 3 and 8 Hz. The present findings firstly provide further information about a scarcely described movement disorder and secondly further evaluate a new quantification method for embouchure tremor, which has recently been established for embouchure dystonia.

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INTRODUCTION: Musician's dystonia is a task-specific loss of voluntary motor control of the fingers or the embouchure. In contrast to pianists' dystonia, which can be objectively assessed based on movement kinematics and muscular activities, no objective quantitative measure has been established for embouchure dystonia. METHODS: We focused on acoustic signals, and investigated, whether the fluctuation of the time-varying fundamental frequency of a note can provide an objective and reliable measure of embouchure dystonia. RESULTS: A comparison between patients with embouchure dystonia and healthy controls found a significantly higher variability of the fundamental frequency for the patients. CONCLUSION: The present findings propose a new quantification and objectivation method for embouchure dystonia.

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In Noh, a traditional performing art of Japan, extremely expressive voice quality is used to convey an emotional message. A periodicity of voice appears responsible for these special effects. Acoustic signals were recorded for selected portions of dramatic singing in order to study the acoustic effects of delicate voice control by a master of the Konparu school. Using a signal analysis-synthesis algorithm, TANDEM-STRAIGHT, to represent multiple candidates for pitch perception, signals deviating from the harmonic structure have been successfully displayed, corresponding to auditory impressions of pitch movements, even when narrow-band spectrograms failed to show the perceived events. Strong interaction between vocal tract resonance and vocal fold vibration seems to play a major role in producing these expressive voice qualities.

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