What Does It Take to Play the Piano? Cognito-Motor Functions Underlying Motor Learning in Older Adults.

The acquisition of skills, such as learning to play a musical instrument, involves various phases that make specific demands on the learner. Knowledge of the cognitive and motor contributions during learning phases can be helpful in developing effective and targeted interventions for healthy aging. Eighty-six healthy older participants underwent an extensive cognitive, motoric, and musical test battery. Within one session, one piano-related and one music-independent movement sequence were both learned. We tested the associations between skill performance and cognito-motor abilities with Bayesian mixed models accounting for individual learning rates. Results showed that performance was positively associated with all cognito-motor abilities. Learning a piano-related task was characterized by relatively strong initial associations between performance and abilities. These associations then weakened considerably before increasing exponentially from the second trial onwards, approaching a plateau. Similar performance-ability relationships were detected in the course of learning a music-unrelated motor task. Positive performance-ability associations emphasize the potential of learning new skills to produce positive cognitive and motor transfer effects. Consistent high-performance tasks that demand maximum effort from the participants could be very effective. However, interventions should be sufficiently long so that the transfer potential can be fully exploited.

Brain network flexibility as a predictor of skilled musical performance.

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.

Acute Neuromuscular Fatigability and Perceived Exertion in High-Level University Pianists: An Electromyography and Maximum Force Capacity Study.

PURPOSE: Musicians are labelled 'fine motor athletes' due to the significant demands of practice and performance. In response, sports medical concepts and expertise have been adapted and mobilized to address musicians' health considerations. However, understanding distinct differences between the sports and performing arts medical contexts is critical. Mismanagement of fatigue and acute fatigability are identified as key risk factors for deleterious symptoms and injuries in musicians. Acute fatigability in athletes and musicians have been assumed to occur similarly, although this has yet to be empirically demonstrated. This study aimed to evaluate acute muscular performance fatigability during piano performance of varied intensities. METHODS: Fourteen university pianists attended a single experimental session and performed three pieces of randomly ordered repertoire for 10 minutes each. Repertoire were self-selected to be physically easy (rating of perceived exertion [RPE] 9/20), somewhat hard (RPE 13/20), or hard (RPE 17/20). At baseline, after each repertoire performance, and following a concluding 10-minute silent sitting period, participants completed maximum voluntary contraction (MVC) grip and shoulder strength tests. Surface electromyographic (EMG) data were obtained from bilateral upper trapezius and forearm flexor and extensor muscles. Data were analyzed using uni- and multivariate repeated measures analyses of variance (ANOVAs). RESULTS: No evidence of muscular performance fatigability was found in study pianists at any intensity. Mean EMG amplitude and average median EMG frequency did not significantly vary during any repertoire performances or MVC tests (F≤1.72; p>0.09). Additionally, no changes in force or EMG parameters were found during any MVC tests (F≤1.19; p>0.31). CONCLUSIONS: The absence of muscular performance fatigability during even the most intense piano performances suggests substantially differing mechanisms of fatigability and perceived exertion in pianists versus those commonly seen in sport athletes. Further research is needed to understand the mechanisms of acute fatigability in musicians and develop musician-specific management strategies.

Sensorimotor Incoordination in Musicians' Dystonia.

To acquire and maintain outstanding sensorimotor skills for playing musical instruments inevitably requires extensive training from childhood. However, on the way toward musical excellence, musicians sometimes develop serious disorders, such as tendinitis, carpal tunnel syndrome, and task-specific focal dystonia. Particularly, task-specific focal dystonia in musicians, which is referred to as musician's dystonia (MD), has no perfect cure and therefore often terminates professional careers of musicians. To better understand its pathological and pathophysiological mechanisms, the present article focuses on malfunctions of the sensorimotor system at the behavioral and neurophysiological levels. Based on emerging empirical evidence, we propose that the aberrant sensorimotor integration, possibly which occurs in both cortical and subcortical systems, underlies not only movement incoordination between the fingers (i.e., maladaptive synergy) but also failure of long-term retention of intervention effects in the patients with MD.

Passive somatosensory training enhances piano skill in adolescent and adult pianists: A preliminary study.

Sensory afferent information, such as auditory and somatosensory feedback while moving, plays a crucial role in both control and learning of motor performance across the lifespan. Music performance requires skillful integration of multimodal sensory information for the production of dexterous movements. However, it has not been understood what roles somatosensory afferent information plays in the acquisition and sophistication of specialized motor skills of musicians across different stages of development. In the present preliminary study, we addressed this issue by using a novel technique with a hand exoskeleton robot that can externally move the fingers of pianists. Short-term exposure to fast and complex finger movements generated by the exoskeleton (i.e., passive movements) increased the maximum rate of repetitive piano keystrokes by the pianists. This indicates that somatosensory inputs derived from the externally generated motions enhanced the quickness of the sequential finger movements in piano performance, even though the pianists did not voluntarily move the fingers. The enhancement of motor skill through passive somatosensory training using the exoskeleton was more pronounced in adolescent pianists than adult pianists. These preliminary results implicate a sensitive period of neuroplasticity of the somatosensory-motor system of trained pianists, which emphasizes the importance of somatosensory-motor training in professional music education during adolescence.

The plyometric activity as a conditioning to enhance strength and precision of the finger movements in pianists.

Stability of timing and force production in repetitive movements characterizes skillful motor behaviors such as surgery and playing musical instruments. However, even trained individuals such as musicians undergo further extensive training for the improvement of these skills. Previous studies that investigated the lower extremity movements such as jumping and sprinting demonstrated enhancement of the maximum force and rate of force development immediately after the plyometric exercises. However, it remains unknown whether the plyometric exercises enhance the stability of timing and force production of the dexterous finger movements in trained individuals. Here we address this issue by examining the effects of plyometric exercise specialized for finger movements on piano performance. We compared the training-related changes in the piano-key motion and several physiological features of the finger muscles (e.g., electromyography, rate of force development, and muscle temperature) by well-trained pianists. The conditioning demonstrated a decrease of the variation in timing and velocity of successive keystrokes, along with a concomitant increase in the rate of force development of the four fingers, but not the thumb, although there was no change in the finger muscular activities through the activity. By contrast, such a conditioning effect was not evident following a conventional repetitive piano practice. In addition, a significant increase in the forearm muscle temperature was observed specifically through performing the plyometric exercise with the fingers, implying its association with improved performance. These results indicate effectiveness of the plyometric exercises for improvement of strength, precision, and physiological efficiency of the finger movements even in expert pianists, which implicates that ways of practicing play a key role in enhancing experts' expertise.

Noncontact and High-Precision Sensing System for Piano Keys Identified Fingerprints of Virtuosity.

Dexterous tool use is typically characterized by fast and precise motions performed by multiple fingers. One representative task is piano playing, which involves fast performance of a sequence of complex motions with high spatiotemporal precision. However, for several decades, a lack of contactless sensing technologies that are capable of precision measurement of piano key motions has been a bottleneck for unveiling how such an outstanding skill is cultivated. Here, we developed a novel sensing system that can record the vertical position of all piano keys with a time resolution of 1 ms and a spatial resolution of 0.01 mm in a noncontact manner. Using this system, we recorded the piano key motions while 49 pianists played a complex sequence of tones that required both individuated and coordinated finger movements to be performed as fast and accurately as possible. Penalized regression using various feature variables of the key motions identified distinct characteristics of the key-depressing and key-releasing motions in relation to the speed and accuracy of the performance. For the maximum rate of the keystrokes, individual differences across the pianists were associated with the peak key descending velocity, the key depression duration, and key-lift timing. For the timing error of the keystrokes, the interindividual differences were associated with the peak ascending velocity of the key and the inter-strike variability of both the peak key descending velocity and the key depression duration. These results highlight the importance of dexterous control of the vertical motions of the keys for fast and accurate piano performance.

Back to feedback: aberrant sensorimotor control in music performance under pressure.

Precisely timed production of dexterous actions is often destabilized in anxiogenic situations. Previous studies demonstrated that cognitive functions such as attention and working memory as well as autonomic nervous functions are susceptible to psychological stress in skillful performance while playing sports or musical instruments. However, it is not known whether the degradation of sensorimotor functions underlies such a compromise of skillful performance due to psychophysiological distress. Here, we addressed this issue through a set of behavioral experiments. After artificially delaying the timing of tone production while playing the piano, the local tempo was abnormally disrupted only under pressure. The results suggest that psychological stress degraded the temporal stability of movement control due to an abnormal increase in feedback gain. A learning experiment further demonstrated that the temporal instability of auditory-motor control under pressure was alleviated after practicing piano while ignoring delayed auditory feedback but not after practicing while compensating for the delayed feedback. Together, these findings suggest an abnormal transition from feedforward to feedback control in expert piano performance with psychological stress, which can be mitigated through specialized sensorimotor training that involves piano practice while volitionally ignoring the artificially delayed provision of auditory feedback.

Aberrant Somatosensory-Motor Adaptation in Musicians' Dystonia.

BACKGROUND: Some forms of movement disorders are characterized by task-specific manifestations of symptoms. However, its underlying mechanisms are poorly understood. Here we addressed this issue through a novel motor adaptation experimental paradigm. METHODS: Pianists with and without focal task-specific dystonia learned to play the piano with a key whose weight can be modified by a novel robot system. RESULTS: The result clearly demonstrated a significantly larger error between the target and produced keystroke velocities in the patients than the controls following a repetition of keystrokes of the weighted key. This adaptation failure was not correlated with the variability of timing and velocity of the keystroke when the patients were playing unloaded piano keys, which suggests distinct effects of focal task-specific dystonia on motor adaptation and fine motor control. Immediately after a repetition of the strikes of the heavy key with keeping the fingers adducted, the error of the keystroke velocity when striking the key with the fingers more abducted was maintained in both the patients and controls. This generalization of the adaptation across different hand postures suggests that motor memory of dynamics of the piano key is independent of biomechanical properties of the hand. Importantly, a lack of difference in the finger muscular strength between the groups indicated that the adaptation failure was not attributed to deficit of muscular strength in the patients. CONCLUSIONS: These findings suggest that task-specific manifestation of dystonic movements in focal task-specific dystonia is associated with malfunctions of internal representation of mechanical properties of a well-trained tool. © 2020 International Parkinson and Movement Disorder Society.

Neuromuscular and biomechanical functions subserving finger dexterity in musicians.

Exceptional finger dexterity enables skillful motor actions such as those required for musical performance. However, it has been not known whether and in what manner neuromuscular or biomechanical features of the fingers subserve the dexterity. We aimed to identify the features firstly differentiating the finger dexterity between trained and untrained individuals and secondly accounting for the individual differences in the dexterity across trained individuals. To this aim, two studies were conducted. The first study compared the finger dexterity and several neuromuscular and biomechanical characteristics of the fingers between pianists and non-musicians. As a measure of the dexterity, we used the maximum rate of repetitive finger movements. The results showed no differences in any biomechanical constraints of the fingers between the two groups (i.e. anatomical connectivity between the fingers and range of motion). However, the pianists exhibited faster finger movements and more independent control of movements between the fingers. These observations indicate expertise-dependent enhancement of the finger dexterity and reduction of neuromuscular constraints on movement independence between the fingers. The second study assessed individual differences in the finger dexterity between trained pianists. A penalized regression determined an association of the maximum movement speed of the fingers with both muscular strength and biomechanical characteristics of the fingers, but not with neuromuscular constraints of the fingers. None of these features covaried with measures of early and deliberate piano practice. These findings indicate that distinct biological factors of finger motor dexterity differentiate between the effects of piano practicing and individual differences across skilled pianists.

Neuromuscular incoordination in musician's dystonia.

INTRODUCTION: The present study aims to define patterns of muscular activities specific to focal task-specific dystonia (FTSD), and classify them according to their association with the degradation of fine motor control or compensation for it. METHODS: While thirteen pianists with FTSD and ten expert pianists played several melodies on the piano, the activity of eight intrinsic and extrinsic finger muscles and the key-striking movements were recorded. To exclude the confounding effects of expertise, twelve amateur pianists also participated. The muscular activities were analyzed with a non-negative matrix factorization, an unsupervised classification technique, and multiple regression analysis. RESULTS: Six different patterns of muscular coordination were identified, each of which was responsible for the keystroke with each of the five digits and co-contraction between an antagonistic pair of finger muscles. A comparison between the healthy pianists and pianists with FTSD found no evidence of FTSD-related elevation of the co-contraction. A regression analysis between the muscular coordination and the key-striking movements further identified 23.4% and 20.8% of the FTSD-related changes in the muscular activity as associated with the movement degradation (i.e. delayed transition of the finger motion from flexion to extension) and compensation for it, respectively. The former was associated not only with hyper-activation of the flexor, but also with reduced-activation of the extensor. CONCLUSIONS: The present study specified neuromuscular maladaptation relevant to the FTSD symptom, which suggests that muscular incoordination rather than muscular co-contraction characterizes pathological feature of FTSD in musicians.

Probing sensorimotor integration during musical performance.

An integration of afferent sensory information from the visual, auditory, and proprioceptive systems into execution and update of motor programs plays crucial roles in control and acquisition of skillful sequential movements in musical performance. However, conventional behavioral and neurophysiological techniques that have been applied to study simplistic motor behaviors limit elucidating online sensorimotor integration processes underlying skillful musical performance. Here, we propose two novel techniques that were developed to investigate the roles of auditory and proprioceptive feedback in piano performance. First, a closed-loop noninvasive brain stimulation system that consists of transcranial magnetic stimulation, a motion sensor, and a microcomputer enabled to assess time-varying cortical processes subserving auditory-motor integration during piano playing. Second, a force-field system capable of manipulating the weight of a piano key allowed for characterizing movement adaptation based on the feedback obtained, which can shed light on the formation of an internal representation of the piano. Results of neurophysiological and psychophysics experiments provided evidence validating these systems as effective means for disentangling computational and neural processes of sensorimotor integration in musical performance.

Skilful force control in expert pianists.

Dexterous object manipulation in skilful behaviours such as surgery, craft making, and musical performance involves fast, precise, and efficient control of force with the fingers. A challenge in playing musical instruments is the requirement of independent control of the magnitude and rate of force production, which typically vary in relation to loudness and tempo. However, it is unknown how expert musicians skilfully control finger force to elicit tones with a wide range of loudness and tempi. Here, we addressed this issue by comparing the variation of spatiotemporal characteristics of force during repetitive and simultaneous piano keystrokes in relation to the loudness and tempo between pianists and musically untrained individuals. While the peak key-descending velocity varied with loudness but not with tempo in both groups, the peak and impulse of the key-depressing force were smaller in pianists than in the non-musicians, specifically when eliciting loud tones, suggesting superior energetic efficiency in the trained individuals. The key-depressing force was more consistent across strikes in pianists than in the non-musicians at all loudness levels but only at slow tempi, confirming expertise-dependency of precise force control. A regression analysis demonstrated that individual differences in the keystroke rates when playing at the fastest tempo across the trained pianists were negatively associated with the force impulse during the key depression but not with the peak force only at the loudest tone. This suggests that rapid reductions of force following the key depression plays a role in considerably fast performance of repetitive piano keystrokes.

On the Origin of Muscle Synergies: Invariant Balance in the Co-activation of Agonist and Antagonist Muscle Pairs.

Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist-antagonist (AA) muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, we examined the AA concept using the following explanatory variables: the AA ratio, which is related to the equilibrium-joint angle, and the AA sum, which is associated with joint stiffness. We formulated muscle synergies as a function of AA sums, positing that muscle synergies are composite units of mechanical impedance. The AA concept can be regarded as another form of the equilibrium-point (EP) hypothesis, and it can be extended to the concept of EP-based synergies. We introduce, here, a novel tool for analyzing the neurological and motor functions underlying human movements and review some initial insights from our results about the relationships between muscle synergies, endpoint stiffness, and virtual trajectories (time series of EP). Our results suggest that (1) muscle synergies reflect an invariant balance in the co-activation of AA muscle pairs; (2) each synergy represents the basis for the radial, tangential, and null movements of the virtual trajectory in the polar coordinates centered on the specific joint at the base of the body; and (3) the alteration of muscle synergies (for example, due to spasticity or rigidity following neurological injury) results in significant distortion of endpoint stiffness and concomitant virtual trajectories. These results indicate that muscle synergies (i.e., the balance of muscle mechanical impedance) are essential for motor control.

Secrets of virtuoso: neuromuscular attributes of motor virtuosity in expert musicians.

Musical performance requires extremely fast and dexterous limb movements. The underlying biological mechanisms have been an object of interest among scientists and non-scientists for centuries. Numerous studies of musicians and non-musicians have demonstrated that neuroplastic adaptations through early and deliberate musical training endowed superior motor skill. However, little has been unveiled about what makes inter-individual differences in motor skills among musicians. Here we determined the attributes of inter-individual differences in the maximum rate of repetitive piano keystrokes in twenty-four pianists. Among various representative factors of neuromuscular functions, anatomical characteristics, and training history, a stepwise multiple regression analysis and generalized linear model identified two predominant predictors of the maximum rate of repetitive piano keystrokes; finger tapping rate and muscular strength of the elbow extensor. These results suggest a non-uniform role of individual limb muscles in the production of extremely fast repetitive multi-joint movements. Neither age of musical training initiation nor the amount of extensive musical training before age twenty was a predictor. Power grip strength was negatively related to the maximum rate of piano keystrokes only during the smallest tone production. These findings highlight the importance of innate biological nature and explicit training for motor virtuosity.

Pilot study on quantitative assessment of muscle imbalance: differences of muscle synergies, equilibrium-point trajectories, and endpoint stiffness in normal and pathological upper-limb movements.

This paper proposes a novel method for assessment of muscle imbalance based on muscle synergy hypothesis and equilibrium point (EP) hypothesis of motor control. We explain in detail the method for extracting muscle synergies under the concept of agonist-antagonist (AA) muscle pairs and for estimating EP trajectories and endpoint stiffness of human upper limbs in a horizontal plane using an electromyogram. The results of applying this method to the reaching movement of one normal subject and one hemiplegic subject suggest that (1) muscle synergies (the balance among coactivation of AA muscle pairs), particularly the synergies that contributes to the angular directional kinematics of EP and the limb stiffness, are quite different between the normal subject and the hemiplegic subject; (2) the concomitant EP trajectory is also different between the normal and hemiplegic subjects, corresponding to the difference of muscle synergies; and (3) the endpoint (hand) stiffness ellipse of the hemiplegic subject becomes more elongated and orientation of the major axis rotates clockwise more than that of the normal subject. The level of motor impairment would be expected to be assessed from a comparison of these differences of muscle synergies, EP trajectories, and endpoint stiffness among normal and pathological subjects using the method.