Performance problems are often very subtle – they often go unnoticed at first and can have several different starting points which, oddly enough, are not in the fingers. We know that stressors such as overuse and incorrect technique can create problems, but often times the starting point is much more elusive, residing in the emotional or mental realm. The music world itself contains stressors such as the amount of self-generated pressure and the culture of silence surrounding technical problems both of which often result in pianists playing with pain and discomfort. In cases such as focal dystonia, the contributing factor can have a neurological basis. Regardless of the starting point, the “problem” becomes addressed by our entire being, physical, mental and emotional.

Many musicians are not aware of body and hand alignment as well as their levels of tension. Feedback-assisted retraining helps to bring about self-awareness and the skills to reduce tension in order to build healthy musicians.

Case Study

Gene is a 61 year old male who has suffered from dystonia-like symptoms in his right hand for over 30 years. The symptoms were curling of the 4^th, lifting of the 3^rd and 5^th, and a feeling that the 3^rd and the 4^th wanted to play at the same time. As he would say: "In moving from 3 to 4, it sometimes feels like I have to wait for a switch to go off. The finger doesn't always want to play."

From observations and case history, the initial hypothesis was that the main problem was in the 4th finger, with compensatory movement in the 3rd. However, after working with Disklavier recording, motion capture and sEMG, the problem seemed to be the interplay of the 2^nd, 3^rd and 4^th. The 2nd was often tense while 3 and 4 depressed the keys. On the sEMG readings, this was documented by the tension in the forearm commencing before and continuing to rise after the 3rd was depressed even though no finger movements followed. There was no release of the tension. This was heard as a louder attack of the 3^rd on the key and was documented by the MIDI velocity data. The video clips showed that the whole hand changed position in fast passages to 'help' the 3^rd play. When the 2^nd was relaxed, there was less movement because the 3rd finger was not working against the tension from 2. Gene had to relearn the movement of the finger without the assistance of the hand or other fingers.

MIDI recording coupled with music sequencing software display of a scrolling piano roll was the first form of feedback to be used in retraining Gene's technique. This was helpful in addressing the discrepancies between what Gene thought he was producing at the instrument and the sounds actually produced. He worried so much about his fingers while playing that he had become disengaged from the sound produced. In listening to the playback, he heard that his phrasing was very mechanical. The sequencing software's visual display of the performance as a piano roll also gave feedback on the executional onset and offset of notes played. He was able to see which fingers were overlapping while playing. Figure 1 is a piano roll showing Gene's overlap in a descending C Major scale:

Figure 1. Gene's overlap in a descending C Major scale

The note bars highlighted by arrows in the boxes are held over into the next note to be played. In the first box there is an overlap of the 5th to the 4^th, the 4^th into the 3^rd, and the 3^rd and the 2^nd played at the same time; the second box shows the thumb being held into the 3^rd. Figure 2 shows Gene's improvements after working with Disklavier playback and piano roll. There is only a slight overlap of the first three notes:

Figure 2. Gene's improved legato in descending C Major scale

Feedback through on-line digital video recording, motion analysis and sEMG was added to the Disklavier and piano roll feedback. While a pianist's hand may look relaxed on the surface, there is often a disturbance in the necessary tension-relaxation cycles in playing passages which the sEMG records in terms of mV. Initial work was done with Gene's large muscle groups. Through video and sEMG feedback he learned to relax his shoulders and elbows but his forearm readings of muscle tension were high.

The following figure is an example of how sEMG measurements of extensor carpi radialis (blue line) and flexor carpi radialis (red line) in the forearm synchronized with digital video recording can provide feedback regarding the efficacy of optimal technical movements. The time code was synchronized to the video clip. Gene was instructed to play an ascending and descending 5-finger exercise four times with rest periods in-between. Surface electrodes were attached to the skin on the forearm extensor and flexor. On the graphs in Figures 3 and 4, line numbers 1, 3, 5 and 7 mark the end of action phases; lines 2, 4, 6 and 8 mark rest phases.

Figure 3. Raised wrist position and sEMG graph of 5-finger exercise performed
Extensor reading is on the top line, flexsor is on the bottom

Figure 4. Statistics on 5 finger exercise with raised wrist

In figure 3, Gene's wrist is raised high with the hand hanging down toward the keys. In figure 4, the readings for the 5 finger exercise with high wrist show a high extensor in resting phase as well as in the action phase. There is no significant difference between the resting and action phases. This indicates that he did not relax his arm during the resting phases. He was unaware of how high his wrist was positioned and not aware of holding any tension in his arms during the resting phase.

After receiving feedback from motion analysis and sEMG measurements of muscle tension, Gene was instructed to repeat the 5-finger exercise, lowering his wrist and concentrating on relaxing during the resting phase.

Figure 5. Lowered wrist position and sEMG graph of 5-finger exercise performed
Extensor reading is on the top line, flexor is on the bottom.

Figure 6. Statistics on 5 finger exercise with corrected wrist

Figure 5 shows the wrist height lowered to the height of the hand. Readings for the lowered wrist (Figure 6) show a significant change in the extensor in the resting phase. This change in position also affected the minimum reading in the active phase: .95 compared to 31.56 with the raised wrist as shown in Figure 7. These changes indicate a more controlled tension-relaxation cycle during performance. Gene was able to feel the difference in his arm and replicate the wrist position in subsequent exercises.

Once the wrist position was corrected, problems with finger movement were addressed with motion capture. By moving frame by frame, forwards and backwards, through a selected video clip, minute changes in finger and hand position can be tracked that might have been invisible to the eye during performance. Gene found the process helpful and has become more aware of tension in his forearm, especially what he calls "preset" tensions. He noticed that he has little or no tension when working the fingers with no preconceived pattern. For example, if the instructor called out each succeeding finger number to be played in an exercise, he was able to maintain a relaxed hand position. However, if he knew a pattern ahead of time, he "worried" about what his 3^rd and 4^th digits would do. When this happened he becomes disengaged from the musical phrase and concerned with the mechanics. Disklavier playback was helpful here in bringing his awareness to the sounds produced. When he began to focus on the sound, his fingers relaxed and he had better technical control.

The following video clips in Figure 7 show a collapsed 4^th finger in the ascending passage and the 5^th rose as the 3^rd was depressed.

Figure 7. 5 finger passage ascending

In the descending passage the 5th rose and the 3^rd extended forward as the 4^th depressed the key in a collapsed position; the 5^th also rose as the 3^rd depressed the key.

Figure 8. 5 finger passage descending

After analyzing the data from the sEMG in figure 5 with the corrected wrist and the finger movements through motion analysis, it was decided that attention needed to be given to the 5^th in retraining. Figures 9 and 10 depict Gene's on-line feedback work. He was instructed to relax the 5th and try not to lift it as the 4^th and 3^rd depressed the keys. This exercise was repeated 10 times and worked on in three sessions. In figure 9, the 3rd still extended forward when the 4^th depressed the key, but the 4^th depressed the key without collapsing.

Figure 9. Pianist A with instructor; D5, D4, D3 descending

With instruction to concentrate on relaxing the 5^th, it did not lift as the 4^th and 3^rd depressed the keys (Figure 10).

Figure 10. Online feedback retraining

In figures 11 and 12 we can see Gene's finger position after having received three sessions of online feedback retraining. In Figure 11 the 4^th did not collapse and the 5^th stayed on the key. In Figure 12, the 5^th did not lift and the 4th depressed and released the key without collapsing. Gene commented that he did not feel any tension in the fingers.

Figure 11. Ascending 5 finger passage after feedback

Figure 12. Descending 5 finger passage after feedback

Conclusion

SEMG and video feedback and analysis provides a tool for teachers and therapists to discover compensatory relationships between fingers and muscles that, to the naked eye, might otherwise go undiscovered. This process takes time and patience on the part of the pianist and instructor/therapist. Gene has been pleased with the results. He states: "I have much more awareness of what is going on between my fingers and I feel more in control of each movement. The sEMG graphs have helped me become aware of the amount of tension I was holding in my arms, hands and fingers at all times. Sometimes I was not aware of it until I started working with the EMG. The video of my hand from different angles than I can see while playing has been extremely helpful, especially when taken frame by frame in playback. By looking at my hand on the computer screen, it’s easier for my brain to get 'inside my hand.' Disklavier playback is always helpful as to the evenness of the sounds I am playing. I am able to do more technically at the instrument than I was able to do for 30 years."