Experimental evaluation of three interaction channels for accessible digital musical instruments

Accessible Digital Musical instruments (ADMIs) dedicated to people with motor disabilities represent a relevant niche in accessibility research. The designer is often required to exploit unconventional physical interaction channels, different from hands and fingers. Although comprehensive evaluation methods for Digital Musical Instruments in general are found in literature, little has been done both in ADMIs evaluation and the analysis of suitable interaction channels from a Human-Computer Interaction perspective. In this work the performance of breath, gaze pointing and head movements is analyzed, in terms of movement speed and stability, through a simple experiment. These interaction channels could be exploited in the design of ADMIs dedicated to quadriplegic musicians. The proposed experiment has similarities with past Fitts Law evaluation tests. Results are discussed proposing possible mappings between channels and musical performance parameters. These results could also be useful to inform the design of different interface types.