Timing and motor control in drumming: Comparing players with and without focal dystonia.

The ability to keep a steady tempo is influenced by individual prerequisites as well as the
playing conditions at hand. Percussionists have to acquire playing techniques that allow them to
perform at the required tempi and dynamic levels.
For more extreme tempi and dynamic levels controlling the stick movement becomes
increasingly difficult, sometimes resulting in irregularities in timing and/or striking force.
Timing irregularities can also be a revealing sign of motor control problems, such as focal
dystonia (Jabusch, Vauth & Altenmüller, 2004). The "breakdown" in motor control can
therefore be expected to result in more pronounced changes in timing and movement pattern of
the affected arm for these patients.
This paper presents ongoing research utilizing movement analysis and perceptual ratings with
the objective to characterize performances of healthy percussionists and those suffering from
focal dystonia.
The arm, hand, and stick movements of four professional percussionists were recorded using a
motion capture system. Two of the players are focal dystonia patients with their left arm
affected. For each player and arm, 25 s of single strokes at different tempi (50, 120, 300 bpm)
and dynamic levels (p, mf, f) were recorded. The motion data was analyzed with respect to
general movement pattern, variability in timing and striking force.
Preliminary results confirm deterioration in movement patterns for the faster tempi, typically
displaying stiffened joints and lack of timing control. As expected, the patients' affected arms
displayed more disturbed movement patterns compared to the non-affected and the healthy
players. Detailed analysis and perceptual ratings of timing performance is under way and will
be reported.