Abdominal functional electrical stimulation training to improve peak cough flow

Introduction: There are fewer reports of the use of abdominal functional electrical stimulation (AFES) on paralyzed human abdominal muscles. However, little information is available on AFES effects in term of training. The purpose of this study was to identify the effects of the AFES training for normal subjects. Methods: The subjects were 3 healthy females who gave their informed consent to participate in this study. Electrical stimulation was delivered bilaterally by using 2 pairs of electrodes placed over the abdominal wall. The electricity used for stimulation had a pulse of 200μs on 50Hz. The stimulation time per session was 30 minutes, 3 times per week for 12 weeks. Measured in this study were the pulmonary function, respiratory muscle strength, voluntary cough parameters, and muscle thickness of the following muscles: external oblique muscle, internal oblique muscle, and transverses abdominal muscles. Results: The intensity of stimulation ranged in electric current from 40-60mA on all the subjects. The comparison of parameters 3 months after the training revealed that respiratory muscle strength and CPF had increased. However, there was no significant differences in all parameters. Conclusion: Under this protocol, some remarkable improvement was perceived on respiratory muscle strength and PCF. However, there was not much increase in all parameters owing to healthy subjects with a normal pulmonary function and cough function. Upon establishment of our new training protocol on the basis of these results, we are determined to continue this study, further progress of which is clinically applied to patients with spinal cord injury.