Repetitive peripheral magnetic stimulation for improving upper limb function in post-stroke hemiparesis

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Repetitive peripheral magnetic stimulation for improving upper limb function in post-stroke hemiparesis

• Shereen Ismail Fawaz,
• Shin-Ichi Izumi,
• Amr Saeed Zaki,
• Shaimaa Elmetwally Eldiasty,
• Amr Saadawy,
• Heba Gamal eldin Saber,
• May Farouk Gadallah &
• Hossam Salaheldin Labib 

• Cite this article

Abstract

Background

Stroke is one of the leading causes of disability worldwide, with hand and arm weakness, affecting the patients’ daily activities and quality of life. Recently, repetitive peripheral magnetic stimulation (rPMS) was found to enhance neuroplasticity and motor recovery post-stroke hemiparesis via its deep proprioceptive stimulation and simulation of lost voluntary movement.

Objective

To determine the therapeutic effect of rPMS on the functional improvement of upper limb in patients with hemiparesis following cerebrovascular insult and to compare the effect of therapy in subacute and chronic cases.

Results

Post-rehabilitation program both the Fugl-Meyer-Upper Extremity scale (FM-UE) and Functional Independence Measures (FIM) scale showed highly significant improvement in the active group, compared to controls. Regarding active range of motion (AROM) of the shoulder abductors, triceps, wrist extensors and supinators, significant differences were also found in the active group in comparison to controls. Modified Ashworth scale showed also significant change in the active group. When dividing our patients according to the duration post-stroke, into subacute group (6 weeks to 6 months post-stroke) and chronic group (more than 6-month post-stroke), the subacute group showed significant improvements in the FM-UE scale, and in the AROM of wrist extensors and supinators but not in the chronic group. Ultrasonographic measurements showed a significant decrease in cross sectional area of the control group.

Conclusion

rPMS is potentially effective in improving motor recovery post-stroke, especially in the subacute stage.

Background

Stroke is one of the principal causes of disability worldwide. It is estimated that 25% to 75% of stroke survivors suffer from partial physical or cognitive disability. One of the most disabling post-stroke sequelae is hand and arm weakness, affecting the patient’s daily activities and quality of life [1].

As proven from previous researches, the timeline of recovery post-stroke is maximal in the subacute stage, and up to 6 months post-stroke. The earlier the initiation of effective rehabilitation, the better is the functional motor outcome. Any delay in initiation of effective rehabilitation requires more intensive protocols and longer durations of therapy in order to achieve the same functional improvements [2].

Over the past few decades, functional electric stimulation or neuromuscular stimulation (NMES) has proven to be a mean of augmenting neurological recovery, especially in the acute and subacute stages post-stroke [3]. However, its disadvantages include pain at high intensities, and relatively shallow penetration, causing insufficient stimulation of the deep, and/or the spastic muscles [4].

Several studies researched the effect of rPMS on motor recovery post-stroke [5,6,7,8] and is now considered as one of the most innovative therapeutic options in rehabilitation [9], causing selective stimulation of a nerve or a muscle as in NMES, but with a stronger, deeper and nearly painless penetration and, hence, more tolerable [10]. In many stroke cases, introducing repetitive transcranial magnetic stimulation (rTMS) in the acute and early subacute stages is potentially hazardous, especially cases of hemorrhagic strokes. This leaves rPMS and NMES as the best available options for reducing the possibility of learned non-use and maladaptive plasticity, which leads to long-term disability [2, 11,12,13,14].

Repetitive peripheral magnetic stimulation enhances proprioceptive afferent input by producing deep muscle stimulation which induces movement in muscles that have lost their central drive, simulating the lost voluntary action patterns. This results in cerebral activation and induction of plasticity [14]. This plastic cortical reorganization is considered the basis of motor relearning and adaptive plasticity [15, 16], contributing to the synergistic control of movements from different joints by integrating proprioception in motor drive [14]. In a study, Struppler et al. proved by positron emission tomography (PET) scan the influence of rPMS on upregulation of the ipsilesional sensorimotor and premotor areas, increasing cortical excitability and causing a symmetrical increase of cerebral blood flow. This increase was parallel to an increase in finger movement, in both amplitude and velocity [17]. In another study, Struppler et al., suggested that rPMS can reduce spasticity post-stroke, causing improvement in both the amplitude and velocity of movement and hence its dynamics [14]. Similar to NMES, it is proposed that rPMS can produce equivalent effects of preventing muscle atrophy [18].

Moreover, focal and deep stimulation are currently considered one of the merits of rPMS, when using the figure of eight coil. This study used it to stimulate the supinator muscle, which performs one of the distal forearm functions that is mostly missed in hemiplegic patients. This movement is crucial for object manipulation during ADLs [19].

The aim of this study was to determine the therapeutic effect of peripheral magnetic stimulation on functional improvement of the upper limb in patients with hemiparesis following cerebrovascular insult, and to compare the effect of therapy in subacute and chronic cases.

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