Sensory electrical stimulation and postural balance: a comprehensive review

Neuromuscular or Sensory Electrical Stimulation for Reconditioning Motor Output and Postural Balance in Older Subjects?

“…Indeed, the current intensity must be around the sensory threshold without exceeding it or only slightly, since a non-excito-motor current (low intensity) is already likely to lead to recruitment of type I muscle fibres from reflex pathways – mediated at spinal level, that is, homolateral monosynaptic connections of the Ia fibres with the α-motoneurons generate depolarisation of the latter and induce the contraction of the muscle fibres they innervate ( Zeronian et al, 2021 ). SES is painless (although there are possible sensations) and applied to a peripheral nerve, belly muscles (motor points) and/or joints at current intensities below, at or slightly above the sensory threshold ( Schröder et al, 2018 ; Paillard, 2021 ). In order to recondition the motor and postural functions in older subjects, SES should be applied with large pulses (e.g., 1 ms) and high frequencies (80–100 Hz) to facilitate potentiation and central integration of emitted signals ( Collins, 2007 ; Bergquist et al, 2011 ) for several tens of minutes in a uninterrupted way.…”

“…Evidence suggests that SES regularly applied to lower-limb muscle (motor points), peripheral nerve or joints in older subjects (>60 years old) improves sensorimotor function ( Park et al, 2014 ; Ng et al, 2016 ; Paillard, 2021 ). However, since SES generates no muscle deformation or contraction, it thus cannot stimulate synthesis of contractile proteins responsible for muscle structural adaptations ( Coffey and Hawley, 2007 ).…”

“…At the peripheral level (i.e., sensory sensors), SES would modify the sensitivity threshold of mechanoreceptors that result from altering the ion permeability of their membrane ( Gravelle et al, 2002 ; Ross et al, 2007 ). This sensory adaptation would optimise the potentiation and transmission of proprioceptive afferents and thus enhance the sensory contribution in the motor and postural regulation ( Ross et al, 2007 ; Severini and Delahunt, 2018 ; Paillard, 2021 ). At the spinal level, SES is likely to engender a reduction or increase in the amplitude of the induced H-reflex ( Goulet et al, 1997 ; Hardy et al, 2002 , respectively) that, in both cases, can improve motor and postural abilities ( Paillard, 2017a ).…”

“…At the cortical level, SES is likely to induce durable changes in motor cortex excitability that can be assimilated to enhance sensorimotor activity and connectivity ( Kaelin-Lang et al, 2002 ; Schröder et al, 2018 ; Insausti-Delgado et al, 2021 ). Enhanced sensorimotor activity could result from favourable impact of SES over postcentral and parietal cortices (primary somatosensory cortex and posterior parietal cortex) to precentral cortices (primary motor cortex) in the stimulated hemisphere ( Paillard, 2021 ).…”

“…paragraphs Application modalities and Motor and postural adaptations; Figure 1 ). Each stimulation induces specific physiological effects on the sensory, central and motor functions related to movement and postural balance with chronic applications ( Schröder et al, 2018 ; Paillard, 2020 , 2021 ). The choice of the stimulation should be based on the specific physiological needs of the older subjects under consideration.…”