Opusmedica, PC&R Patient, Care & Research Network, Piacenza, Italy
The concept of neuromodulation is commonly referred to the chronic therapeutic electrical stimulation of the central nervous system or special nerves with an implanted stimulating device. In a more broad way INS (International Neuromodulation Society) defines neuromodulation as “the process of inhibition, stimulation, modification, regulation or therapeutic alteration of activity, electrically or chemically, in the central, peripheral or autonomic nervous systems. It is the science of how electrical, chemical, and mechanical interventions can modulate the nervous system function” (Krames, ES., et al. 2009). The use of electrical currents is the most common form of neuromodulation to interact with the brain, spinal cord, peripheral nerves, plexuses of nerves, the autonomic system, and muscles, while chemical neuromodulation uses direct placement of chemical agents to neural tissues through utilization of technology of implantation such as epidural or intrathecal delivery systems.
In this presentation we will not put attention on neuromodulation as described above rather than to a more basic science paradigm such as plasticity. Indeed any form of “modulation” is based on the specific property of the nervous system to be modified in both ways for bad and for good (Costigan, M., Scholz, J., & Woolf, C. J. 2009).
Spasticity for the motor system and chronic pain for the sensory system are examples of maladaptive response of the nervous system. In many cases they can be present and intermingled expression of this maladaptive plasticity (Finnerup, NB. 2017).
If we consider any therapy as the attempt to restore the homeostasis, pushing or pulling, blocking or activating, inhibiting or exciting any given “altered” function or activity within the body we have to enlarge the concept of neuromodulation to any form of physical, pharmacological as well as psychological intervention as a attempt to re-modulate a given function or neural activity.
This attempt is done in rehabilitation when the maladaptive motor and sensory responses are the effect of a lesion and therefore our ability to act on plasticity is limited by the lesion itself but also in more subtle and apparently inexistent malfunctioning of motor and sensory systems as we see in fibromyalgia.
Now we realised that fibromyalgia is the terminal of a sequence of inadequate responses to physical, psychological and social stressful events (May, A. 2011) without signs of lesion, leading to a more and more generalised maladaptive responses involving any aspect of the bio-psycho-social paradigm. Indeed there are no signs of anatomical lesion in nervous system of persons affected by fibromyalgia, however a consistent bulk of evidences are pinpointing the existence of functional dysregulation not only in the sensory system but also in motor cortical areas (Saavedra, L. C., Mendonca, M., & Fregni, F. 2014). This leads to the maintenance of a vicious circle involving sensory afferences, cortical sensory-motor coupling and non-adequate motor responses. Being fibromyalgia a severe form of maladaptive plasticity, any interventions should be tailored as also any form of therapy can be “interpret” in a maladaptive context. Although therapies such as the hyperbaric oxygen therapy (Casale et al 2019), transcranial magnetic stimulation (Macfarlane, G. J., et al. 2017) or other therapies are showing promising results “re-tuning” the metabolism -i.e the activity of different cortical areas- however factors such as resilience and the inner ability to overcome stressor events can be considered in the light of a still not acceptable percentage of persons affected by fibromyalgia non responding to any effort to re-tuning our brain.