###### Abstract
Therefore, patterns of muscle spasticity of the ankle and foot and dropped foot are usually encountered. Walking is also strained to a considerable extent; as a result, patients depend on walking assistive devices or wheelchairs. The impairment in the functioning of the upper extremities is not as pronounced as in the lower ones; the patient basically preserves motor function of the upper limbs [13; 14; 15; 16]. Unlike post-stroke or SCI conditions, neuroplasticity in MS can manifest adaptively and improve motor motion performance, or manifest a maladaptive pattern, influenced by the localization of various injuries, inflammation, and the progressive nature of the disease. [17]. Therefore, the time-window of intervention from outside the central nervous system, through physiotherapy, is essential for the complete and complex rehabilitation [9]. Furthermore, rehabilitation techniques or devices are usually used in physical recovery to improve motor functions [18]. The beneficial role of physical exercise is well known regarding UMN disorders. However, besides performing physical training, the sensory-motor loss cannot always be fully restored, and recent research suggest that motor imagery of the movement seems to have a crucial role in brain plasticity. Therefore, any tool facilitating human body movement can play an essential role alongside motor imagery in increasing functional locomotor independence [19; 20]. Functional electrical stimulation (FES) is used as an adjunct therapy in stroke rehabilitation, but also for SCI patients, used either to assist in the voluntary rehabilitation of motor activity (early stages after stroke or incomplete SCI) or as a neuroprosthesis (when voluntary motor activity can no longer be restored) [21; 22; 23; 24]; it is also an assistive technology with a beneficial effect for patients with MS with leg involvement (presence of leg drop syndrome) [25]. Functional electrostimulation is divided into two categories: assistance FES for the complete replacement of the motor function, and therapy FES. Therapy FES helps rehabilitate patients with central motor neuron damage (stroke, SCI, MS); it also plays a vital role in preventing muscle atrophy and maintaining the health of the muscular system. Assistive FES aims to restore motor function in patients with upper motor neuron syndrome by completely replacing motor signals. Evidence shows that FES uses brain plasticity to restore the ability to perform voluntary movements after spinal cord injury and stroke [26; 27]. The parameters used to optimize FES effects are the duration, frequency and amplitude of electrical pulses. These parameters are precisely adjusted according to the patient's rehabilitation goals. The pulse duration of FES devices is typically between 300 and 600 microseconds, and these variations can have different effects on the targeted muscles. Electrical stimulation with a wide pulse width of 500-1000 microseconds associated with low frequency has been shown to cause additional muscle fatigue compared to a smaler pulse width. The frequency of the pulses varies between 20 and 50 Hz and is adjusted according to the goal pursued; the low frequency is used to achieve muscle contractions at a lower level of force, thus preventing the onset of early muscle fatigue. The intensity of the pulses varies between 0 and 100 mA; an amplitude value is selected according to the patient's needs and the targeted muscles. The selection of the amplitude interval is influenced by the pattern and the total simulation time [26]. When high-frequency ESF is applied, patients may experience a tingling sensation in addition to slow muscle contraction. In this view, this scoping review shall underline the effectiveness of FES in the rehabilitation of neurological patients, either as a single therapy or in combination with other therapies. Different stimulation devices and parameter settings will be approached, according to tailored rehabilitation interventions.