Impulses delivered by the electrodes are typically very small, such that orthodromic action potentials are generated to cause coordinated muscle contraction (Popovic, Masani, and Micera, 2015). The impulses are typically delivered in trains, usually as biphasic balanced pulses to reduce the discomfort associated with sensory nerve stimulation (ibid). In developing a protocol, trial and error is required to maximize benefit to the patient and reduce adverse effect. Devices are either current- or voltage-regulated, with voltage-regulated systems requiring greater manual adjustment because the charge delivered is not consistent between impulses. However, many systems can be operated largely via computational computing software. Major limitations of therapeutic FES have been the concurrent stimulation of sensory nerve alongside motoneurons, skin irritation from the electrodes, and the difficulty of stimulating deep nerve groups, such as those of the hip flexors (Triolo, Bieri, Uhlir, Kobetic, Scheiner, and Marsolais, 1996). Multiple-lead systems have been devised to target deep muscles and nerves, however. As a relatively new treatment, FES has not been studied in large, randomized controlled trials …show more content…
However, significant positive evidence points to improvements of hand dexterity, upper and lower extremity range of motion, and motor function of both upper and lower extremities, particularly if therapies are used for several months in patients with chronic issues. In general, FES appears to have more promise relative to traditional therapies in chronic populations, with a less noticeable effect in acute and subacute groups. However, this may partly be due to the general uncertainty of recovery in the acute period, with differences being more significant and lasting in groups have had longer periods to recover