Focal Muscular Vibration in Patients with Severe Acquired Brain Injury

Focal Muscular Vibration in the Intensive Treatment of Spasticity in Patients with Severe Acquired Brain Injury

Severe acquired brain injury (sABI) is a group of disorders that cause long-term disability. Rehabilitation is essential to counteract bed immobilization, muscle failure, pain, and sensory deficits that can affect the clinical and rehabilitation pathway of these patients.

Focal muscle vibration (FMV) is a tool that uses low-amplitude, high-frequency vibrations that when applied to muscle-tendon units. This technique, administered at specific frequencies, amplitudes and durations, can generate action potentials of the same frequency as the stimulus applied to the muscle or tendon. This makes it possible to activate selected afferent fibers and stimulate targeted brain areas with persistent effects over time (long-term potentiation).

Regarding the effect of counteracting vibration spasticity, FMV is able to inhibit the reflex arc and induce reciprocal inhibition of functional agonist muscle. In addition, the strong proprioceptive stimulus generated by vibration is able to reach the primary motor and somatosensory cortex, enhancing cortical mechanisms that regulate co-contraction between agonist and antagonist muscles, thereby reducing muscle tone and joint stiffness. In many studies, this technique has been shown to be effective in reducing pain and joint stiffness by improving muscle contraction and motor control.

The present study aims to analyze the effects of focal muscle vibration in patients with sABI. This study is innovative for the setting, as it will take place for the first time within a neurorehabilitation hospital ward, for the intensity of the treatment as patients will undergo daily treatment sessions, for longer periods than protocols so far in the scientific literature. Finally, the cortical effects of the vibratory stimulus will be analyzed through the analysis of cortical neurophysiological correlates

Inclusion Criteria:

• Age between 18-75 years
• Picture of subacute sABI (20 days to 6 months after the acute event), of any etiology (traumatic, vascular, metabolic)
• Presence of spasticity in the affected limb as assessed by the Modified Ashwort Scale (MAS) ≥ 1+

Exclusion Criteria:

• recent treatment with botulinum toxin (within 3 months);
• ongoing treatment with systemic muscle relaxant drugs (baclofen, tizanidine, benzodiazepines);
• deep vein thrombosis;
• central/peripheral accesses ipsilateral to the limb(s) to be treated;
• oncological diseases;
• epilepsy;
• open skin lesions or local infections.