It happens that, after lying for a while in a way that puts pressure on a nerve in your arm, you do not feel the arm anymore, you cannot perceive its location and size, and it feels like it does not belong to your own body. If this condition lasts for years, the representation of the upper limb in the brain is chronically distorted. This body representation disorder is a neurological disorder and is one of the more prominent long-term consequences of stroke. It severely affects how people use their body in the environment to move, act and sense.
Stroke patients report a wide range of symptoms, like being unable to embody their own arm. They also report symptoms like being unable to control the muscles in their arms and hands, being unable to finely modulate grasp force while holding an object, and difficulty in perceiving their arms and hands in general.
If left untreated, sensory and body representation deficits may lead patients to perceive the affected limb as shorter, less sensitive, less responsive, and eventually even to 'forget` it.
In the EU, stroke is the leading cause of adult disability according to a 2020 study, and Covid has worsened the scenario. The number of patients with stroke requiring long term assistance and rehabilitation has dramatically increased since the outbreak of Covid-19, as well as flu-related strokes in young people. While some stroke survivors will recover, impairment of the upper limbs can become chronic and seriously affect the behaviour of the patient in up to 75% of stroke patients.
[...] Now, a consortium of neuroscientists, clinicians and neuroengineers, [...] has shown that carefully tuned electrical stimulation of the neuromuscular system, combined with current rehabilitation practices are promising for recovering upper limb control and embodiment in stroke patients with long-term disabilities. The details of their neuromuscular electrical stimulation (NMES) protocols tested on 45 chronic stroke patients are published today in MED, the new clinical and translational journal of the CELL editorial family. The project has been funded by CARIGEST and the CARIPLO foundation.
"Our approach has the potential to facilitate neurorehabilitative interventions that target multiple perceptual domains, including tactile acuity, perceived body size, distorted feelings of the arm, and consequently, restored use of the arm," explains first author Andrea Crema. He continues, "Our approach reduced the perceptual dissociation of the affected limb, that's why it's so important to pursue targeted electrical stimulation of the muscles in chronic stroke survivors, and to personalize the treatment to counter specific deficits."
[...] The scientists are currently working on a new system able to provide finer levels of motor and sensory stimulation, and with broader varieties of stimulation.
Andrea Crema, Michela Bassolino, Eleonora Guanziroli, et al. Neuromuscular electrical stimulation restores upper limb sensory-motor functions and body representations in chronic stroke survivors., (DOI: 10.1016/j.medj.2021.12.001)