The effects of Functional Electrical Stimulation in Spinal Cord Injury on cardiovascular responses: A literature review

Background: Functional stimulation (FES) is considered to be an effective method to reduce the risk factors caused by spinal cord injury and enhance the cardiovascular responses. This study involved a systematic review of the current literature to investigate whether FES application has an effect on cardiovascular responses in both quadriplegic and paraplegic people. Methods: A systematic review of the literature identified 20 studies that met the inclusion criteria, including 51 quadriplegic and 121 paraplegic patients who received FES training. Methodological quality assessment was carried out by one researcher using the Cochrane’s Methodological Quality Scale. Large clinical heterogeneity, variety in outcome measures and low methodological quality of studies precluded a quantitative analysis of the data Results: Methodological quality scores ranged between 6-11 (out of 24), indicating poor study design. Evidence of clinical, methodological and statistical heterogeneity was present. FES tended to render positive effects, particularly for oxygen uptake and cardiac output. Paraplegic people tended to benefit more than quadriplegic persons, but this trend was not consistent. Also, interaction between cardiovascular variables made it difficult to interpret some of these results Conclusion: This study showed that there is a wide diversity in studies investigating the effects of FES in spinal cord injured individuals, pointing to the need for future well-designed study. It remains unclear how the above effects are best achieved in different subgroups.