Pianists' expertise  

1. Motor control of finger/arm movements in piano playing

It has been a long-lasting mystery why expert pianist can maintain virtuosic performance throughout a two-hours of concert. To elucidate its underlying sensory-motor mechanism, I and my colleagues have studied biomechanics and motor control of piano performance.  

As a first step, we examined kinematics, kinetics, and muscular activity of the upper-extremity while expert pianists and novice piano players were striking keys at various tone loudness. To better understand the organization of movements at multiple joints and muscular coordination, we used motion-capturing system (high-speed cameras), electromyography (EMG), and force-sensor built on the key-surface. To assess all muscular and non-muscular forces acting on each joint of the upper-limb during piano keystroke, I developed non-linear equations of motion of human upper-extremity by means of state-of-art robotics technique (i.e. inverse dynamics and forward dynamics). 


These studies quantitatively determined pianists's skill to minimize muscular effort and improve movement accuracy during piano keystroke. For example, when striking a key, expert pianists effectively utilized non-muscular forces (e.g. inertial force and gravity), while the novices rather relied mostly on the muscular force. Experts also reduced finger muscular load to compensate for the key-reaction force by dexterously molding the hand posture. Consequently, the experts struck piano keys with reduced muscular work and its relevant signal-dependent noise, and thereby facilitated physiological efficiency 
(e.g. 33% smaller at the finger muscles than the novices) as well as  accuracy of movements. A part of these studies is introduced on YouTube shown below.

My research starts from 5:21 !!


As a next step, my current research focuses on virtuosic motor skill underlying extremely fast and complex keystrokes, such as "octave", "tremolo", and "arpeggio". In these studies, we carried out the 3D measurement and analysis of hand movements by using motion-capturing technique (high speed cameras) or data glove (CyberGlove). To characterize hand movements quantitatively, we developed some analytical techniques using multivariant analysis and machine learning techniques, such as PCA, EM algorithm, and K-means clustering. These studies successfully provided insights of neural control of sensorimotor skills such as independent control of movements across digits, and super-fast and accurate keystrokes in piano playing. 

   
        

           

Selected publication

  • Furuya S, Flanders M, Soechting J (2011) Hand kinematics of piano playing. Journal of Neurophysiology
  • Furuya S, Goda T, Katayose H, Miwa H, Nagata N (2011) Distinct interjoint coordination during fast alternate keystrokes in pianists with superior skill. Front Hum Neurosci
  • Furuya S, Osu R, Kinoshita H (2009) Effective utilization of gravity during arm downswing in keystroke by expert pianists. Neuroscience
  • Furuya S, Kinoshita H (2008) Expertise-dependent modulation of muscular and non-muscular torques in multi-joint arm movements during piano keystrokeNeuroscience

2. Prevention, biomechanics, & rehabilitation of pianists' injury

Playing-related neuromuscular disorders among pianists have been widely prevalent in the world. Nevertheless, their risk factors still remain unclear. I and my colleagues thus conducted a research to determine risk factors that are potentially harmful for pianists qualitatively and quantitatively.



We started with a questionnaire study that investigated about 200 pianists and piano teachers in Japan, and found that around 70 % of respondents had experienced playing-related physical problems within a few years, which ranges from mild pain to serious disorders such as tendonitis. A further non-parametric analysis indicated that prolonged daily practice (>4 hours), playing chords forcefully, eagerness about practice, and nervous traits contributed to the development of the injuries in these pianists. Hand size was, on the other hand, not a significant risk factor. 

We then attempted to determine biomechanical risk factors of pianists' injuries. We examined movements and muscular activity of the upper-extremity (from shoulder to finger) while 18 pianists were striking two keys simultaneously (octave) and repetitively at a variety of tempi and loudness levels. The obtained biomechanical data was subject to multiple-regression and K-means clustering analyses. The results showed that the pianists were categorized into three groups in terms of movement strategy to increase both tempo and loudness simultaneously(= the most physically demanding task). The muscular load also differed considerably across these three groups with distinct movement strategies. These results provide a basis of predicting biomechanical risk factors of individual pianists based on their movement pattern that is visually discernible.

Currently, my research focus is focal hand dystonia of pianists. The research goal is two-fold. The first one is to understand neural control mechanism behind dystonic finger movements in piano playing. We investigate hand kinematics and muscular activity of pianists with focal dystonia, with ambitious of developing novel and effective diagnosis techniques of pianists' dystonia. The second goal is to develop a novel neuro-rehabilitation technique to treat focal dystonia. These research are conducted in collaboration with Prof. Altenmüller.

Selected publication

  • Furuya S, Aoki T, Nakahara H, Kinoshita H (2012) Individual differences in the biomechanical effect of loudness and tempo on upper-limb movements during repetitive piano keystrokes. Hum Mov Sci
  • Furuya S, Nakahara H, Aoki T, Kinoshita H (2006) Prevalence and causal factors of playing-related musculoskeletal disorders of the upper extremity and trunk among Japanese pianists and piano students. Med Probl Perform Art

3. "Touch" manipulation in piano playing

Expressive music performance requires motor skill to elicit various timbres of tone. However, little has been known about how expert musicians manipulated the touch.  To understand it, we made a series of experiments that examined kinematics and kinetics of the upper-limb movements and key as well as sound waveforms when expert pianists performed a keystroke with different touches. 

We initially characterized the relation of sound waveform of piano tone to the finger-key contacting force in detail. Then, we determined the role of muscular and non-muscular forces generated at all joints in the upper-limb in production of various key-force waveforms in terms of a series of forward and inverse dynamics computations. This provided quantitative evidences demonstrating that touch-dependent control of the inter-segmental dynamics plays a key role in manipulating the touch. Finally, a psychoacoustic experiment revealed that the timbre of a tone produced by different touches were perceived differently. My further scope is to determine (1) a "sound-motion" map based on these methods and evidences, and (2) its underlying neural mechanism.

Selected publication

  • Furuya S, Altenmüller E, Katayose H, Kinoshita H (2010) Control of multi-joint arm movements for the manipulation of touch in keystroke by expert pianists. BMC Neuroscience
  • Kinoshita HFuruya SAoki TAltenmüller E (2007) Loudness control in pianists as exemplified in keystroke force measurements at different touches. J Acoust Soc Am

4. Role of auditory feedback in piano playing

Musical performance requires highly accurate spatiotemporal control of sequential movements. This involves monitoring and updating motor actions over time based on visual, auditory, and somatosensory information. How do pianists integrate these information into planning and executing keystrokes?

I recently developed a custom-made script to manipulate characteristic of piano tone (timing, pitch, loudness) during piano playing in a real-time manner (time resolution = 2 ms). Using this system, we investigated the effect of transient perturbation of auditory feedback on the control of successive keystroke motions while pianists were playing musical pieces. A similar approach has been extensively used in speech research for examining the role of auditory feedback  in vocal production and/or mechanism of stuttering, whereas its extension to piano playing was limited to studies that investigated the effect of persistently perturbing auditory feedback on piano playing. 

Our results showed a rapid compensatory action in response to a transient perturbation, illustrating that pianists accounted for auditory feedback from one single tone for accurate control of timing and intensity of successive keystrokes. We also found effects of perturbing auditory feedback from a keystroke with right hand on keystrokes with left hand. This emphasizes importance of auditory feedback for bimanual coordination of hand movements during piano playing.

Selected publication

  • Furuya S, Soechting J (2010) Role of auditory feedback in the control of successive keystrokes during piano playing. Exp Brain Res