Different therapeutic techniques have been used for the treat-
ment of arm motor function in hemiplegia. Functional electrical
stimulation (FES) is one of these methods that use electrical
currents in stimulating the nerves connected to the paralyzed
muscles in precise sequence and magnitude so that the outcome
resembles functional tasks.
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In fact, FES aims to generate
movements or functions, which mimic normal voluntary move-
ments, and therefore to restore the functions served by those
movements.
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In the shoulder joint, FES is mainly used to stim-
ulate those muscles that are responsible to maintain the head of the
humerus in the glenoid fossa (especially the supraspinatus and
the posterior deltoid that counteract the inferior displacement of
the humerus
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) and can therefore prevent or restore subluxation,
reduce pain, and improve function. FES has some specific char-
acteristics that make it distinct from other forms of electrical
stimulation. The frequency range of FES falls between 10 and
50Hz,
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and it directly stimulates the nerves or their motor points,
not the muscle fibers. Moreover, compared with other forms of
electrical stimulation devices, FES can be used to elicit electrical
stimulation in a specific sequence and magnitude, which can be
used to create the muscle activity required for the performance of
a functional task.
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