the term "orthotic effect" can be used to describe the immediate improvement in function observed when the individual switches on their fes device compared to unassisted walking. this improvement disappears as soon as the person switches off their fes device. in contrast, a "training" or "therapeutic effect" is used to describe a long term improvement or restoration of function following a period of using the device which is still present even when the device is switched off. a further complication to measuring an orthotic effect and any long term training or therapeutic effects is the presence of a so-called "temporary carry over effect". liberson et al., 1961 was the first to observe that some stroke patients appeared to benefit from a temporary improvement in function and were able to dorsiflex their foot for up to an hour after the electrical stimulation had been turned off. it has been hypothesised that this temporary improvement in function may be linked to a long term training or therapeutic effect.