Why accelerometers?
Many techniques are used to assess gait and mobility in a clinical setting [32]. Some of these include observation, physical science techniques (footswitches, gait mats, force plates, optical motion analysis), diaries and questionnaires.
Observational techniques are an integral part of gait and balance analysis and as discussed accelerometers can provide a useful objective adjunct. Many of the other techniques have significant disadvantages for continuous analysis. The physical science techniques are laboratory based. Footswitches (pressure sensitive devices placed in the shoe) record temporal gait parameters (e.g. stride time, speed) but are extremely unreliable. Optical motion analysis involves video taping subjects wearing light reflective sensors. This is an expensive, impractical and time-consuming procedure. It is reasoned that accelerometers have significant advantages when compared with many of these techniques and can provide similar information in many instances.
Miniature accelerometers can be applied directly to the skin and are attached by cable to a portable recorder. Continuous recordings are stored on a memory card in the recorder and are then downloaded to a PC for analysis.