# Focal Muscle Vibration for Stroke Rehabilitation: A Review of Vibration Parameters and Protocols
## 4 Discussion  
To our knowledge, this is the first review aimed to investigate FMV devices, parameters, protocols, and outcome measures in post-stroke rehabilitation. The only other review of FMV for stroke rehabilitation was a systematic review focused on the effectiveness of FMV on hemiplegic upper extremity spasticity in individuals with stroke [28]. Our review agreed with the findings that FMV therapy may reduce spasticity in both upper and lower extremities and improve function in individuals with stroke [28; 29]. The positive effect of FMV in inhibiting hemiplegic upper and lower extremity spasticity in patients with strokes was confirmed with other reviews [25; 28; 29]. Included studies were primarily quasi-experimental design and RCTs. Most studies did not justify the choice of target muscles for vibration or provide the rationale behind the vibration protocols. Blinding of participants and therapists was poor, although the assignment of control and experimental groups was randomized. There was overall a lack of follow-up post FMV intervention to determine how long the improvements would last. [PERSON] et al. (2011) and [PERSON] et al. (2017) examined the effects of FMV therapy after two weeks of intervention and reported that, even though the changes on the main outcome measures were less than observed immediately post interventions, patients were still better than baseline [47; 59]. This finding indicates that the benefit of FMV therapy might last for two weeks. [PERSON] et al. (2012) and [PERSON] et al. (2017) checked the participants one month after the FMV therapy, and there were no significant differences on the outcome measures [50; 57]. In addition, the included studies did not compare FMV therapy with other interventions, except for  
Figure 4: Outcome measures used and number of studies using each outcome measure. traditional physical therapy (PT). There was agreement with our review and others that a wide variety of FMV devices with different vibration frequencies, amplitude, targeted muscles, vibration protocol, and outcome measures were used [25; 28; 29]. Seven different vibration devices were used in the 19 studies that reported the vibration devices. The technical details of those devices were ambitiously described, but their availability for clinical and home use were not clear. In the 22 included studies, participants visited the clinics for the vibration interventions, which could lead to poor compliance for sustainable usage of the FMV therapy. Recently, newer wearable FMV technologies were developed, including the Equistasi(r) Equistasi S.R.L. Via C.Porta, 16 20064 Gorgonzola, Italy), VibraCool(r) (Pain Care Labs, 195 Arizona Ave LW08, Atlanta, GA 30307, USA), and Myovolt (Myovolt Limited 146a Litchfield Street, Christchurch 8011, New Zealand). Equistasi(r) uses nanotechnology fibers to deliver frequency as high as 9000 Hz with very low amplitude less than 0.002 mm. It has been used to treat Parkinson's disease [63; 64; 65], multiple sclerosis [66], and ataxia [67; 68]. However, due to the much higher frequency and the lower amplitude, the mechanism of Equistasi(r) might not be the same as that of the FMV discussed in this study. In addition, Equistasi(r) has not been used for patients with stroke to our knowledge. VibraCool(r) uses proprietary high-speed vibration frequencies and intense cold for pain relief and to treat muscle tension and myofascal trigger points. Research evidence on VibraCool(r) appears unavailable, and its technical specifications were not reported on their website. Myovolt combines therapeutic vibration together with a gentle warming effect to massage and relieve muscle soreness and stiffness. Studies conducted using Myovolt reported improvement in muscular power performance [69] and alleviation of muscle soreness in healthy adults [70] and improved muscle function in patients with peripheral artery disease [71]. All of these wearable FMV technologies showed promise but with limited application or evidence in stroke rehabilitation.