Focal Muscular Vibration to Treat Upper Limb Spasticity in Stroke

Spasticity following stroke is one of the most debilitating conditions and has a negative influence on the autonomy and quality of life, and greatly worsens the patient's degree of disability. Focal muscular vibration (FMV) is a non-invasive technique to treat spasticity. Has been showed the positive effects of FMV on spasticity in stroke subjects. FMV has been investigated on the antagonist muscle, as well as directly on the spastic muscle, showing in both cases a significant reduction in spasticity. However, isn't unclear which is the most effective in the treatment of spasticity.

The objective of the study is to evaluate the efficacy of FMV of the muscles of the upper limb in subjects with subacute stroke, comparing the effects obtained by treating the spastic muscles directly versus to those obtained by treating the respective antagonist muscles.

Stroke is the major cause of permanent disability with an incidence in Italy of 293 affected persons per 100,000 inhabitants. The onset of spasticity following stroke (20-46%) is one of the most disabling conditions and has a negative influence on the patient's autonomy and quality of life.

The development of spasticity during the rehabilitation process of these patients is a very limiting factor for the functional recovery of the affected side. The onset of spasticity considerably worsens the patient's degree of disability.

Focal muscular vibration (FMV) is a non-invasive technique to treat spasticity. Has been showed the positive effects of FMV on spasticity in stroke subjects.

Introduced by Hagbarth and Eklund at the end of the 1960s, it is based on the tonic-vibratory reflex. Based on this mechanism, some authors suggest that the FMV should be applied to the antagonist muscle in order to obtain a significant reduction in spasticity. However the literature shows a reduction in spasticity through the application of FMV directly on the spastic muscle. These effects seem to be related to the stimulation of cortical motor areas. Nevertheless, it remains unclear which approach is most effective in treating of spasticity.

Stroke is a very common pathology, as well as a rehabilitative and social problem which also affects welfare. Considering prevalence of spasticity in stroke patients and the effects on their functional recovery, it is important to identify the most effective treatment to guarantee a more suitable rehabilitation process. In addition to this, it is worth remembering that FMV is less invasive and has lower costs than botulinum toxin, the current gold standard in the treatment of spasticity.

The objective of the study is to evaluate the efficacy of FMV of the muscles of the upper limb in subjects with subacute stroke, comparing the effects obtained by treating the spastic muscles directly versus to those obtained by treating the respective antagonist muscles. Specifically, the two approaches will be compared on: (i) the reduction of the degree of spasticity, assessed by clinical scales and with an instrumental protocol; (ii) motor performance of the patient, using a robotic system; (iii) pain reduction.

Eligibility Criteria:
Inclusion Criteria:

* first cerebral stroke
* 2 weeks up to 12 months post the acute event (subacute patients)
* age between 35-80 years
* single cortical or subcortical event
* spastic paresis of the upper limb (Modified Ashworth Scale score ≥ 2)
* ability to give written consent
* compliance with the study procedures

Exclusion Criteria:

* comorbidities affecting the paretic upper limb (fractures, trauma or peripheral neuropathies)
* cognitive and/or communicative disability (e.g. due to brain injury): inability to understand the instructions required for the study
* treatment with focal or systemic antispastic drugs (i.e. baclofen, thiocolchicoside, tizanidine).