Overview of human-machine interfaces for rehabilitation

As engineered devices and systems become more sophisticated and “intelligent” in their functionality, it is natural to apply them to the treatment of disabilities that arise through failure of their biological counterparts. It seems likely that one of the earliest tools fashioned by Homo sapiens would have been a walking stick or cane to compensate for an injured foot. The mechanical and materials science of the 18th and 19th centuries led to wheelchairs for invalids, cableoperated hooks for amputees and spectacles for myopes. These are all examples of interfaces that augment the otherwise reduced performance of a natural function.

The 20th century saw the rise of electronics, which can transduce energy between different forms, creating motion, light and sound where there was none. This led to attempts, mostly with limited success, to substitute one biological function for another (Marks, 1983; Kaczmarek et al., 1991), such as the Optacon tactile display of visual information (Hislop et al., 1983) and similar devices to represent sound (Reed et al., 1985; Tan et al., 1989; Waldstein and Boothroyd, 1995; Galvin et al., 1999), keyboard operated speech synthesizers (Carlson et al., 1981; Carlson, 1995; Flanagan, 1995; Liberman, 1995), voice-activated robots (Hammel et al., 1992; Van der Loos, 1995; Katevas et al., 1997; Burgar et al., 2000; Taylor et al., 2002) etc. Electronic communication systems use conversions from acoustic and light energy to electrical energy and back again.