Investigation of transcutaneous electrical nerve stimulation with a specific focus on the treatment of overactive bladder

This thesis investigates transcutaneous electrical nerve stimulation (TENS), and in particular its role in the treatment of overactive bladder (OAB), which has been of interest for several decades. A standardization and an evaluation of various TENS parameters of stimuli would be beneficial to optimize the techniques used and to achieve the maximal effectiveness. Previously, Hoffman reflex (H reflex) inhibition was interpreted as a surrogate measure of bladder afferent nerve activity, and thus showed a potential to be useful for such evaluations. However, an influence of other factors, such as pelvic floor muscle contraction on this H reflex inhibition makes this surrogate measure unsuitable. In general TENS techniques are usually implemented in the patient’s treatment pathway as secondary treatment options. This is presumably due to a lack of effectiveness. Therefore a thought was given to enhance the effectiveness of the stimuli by producing a larger sensory input with a spatial temporal pattern. This lead to a development of a novel ‘Sensory Barrage Stimulation’, as introduced in this thesis. The technique showed promising effectiveness in comparison to a conventional type of TENS in the patients with elbow spasticity. Other researcher groups have tried to enhance the effectiveness by stimulating deep nerve structures (usually only targetable by implanted devices) using non/invasive transcutaneous stimulation and a specific waveform. However the “Transdermal Amplitude Modulated Signal” waveform introduced for the treatment of OAB symptoms, which claimed to pass through the skin more easily did not appear to be any different to a conventional stimuli and thus it is not of benefit for the routine clinical practice. Specifically, on the treatment for OAB syndrome symptoms, the most promising seems to be the Posterior Tibial Nerve Stimulation (PTNS) applied near the ankle. A well-established form of PTNS, which uses a needle to stimulate the nerve have disadvantages of being invasive and expensive due to the patient’s clinical sessions. The transcutaneous form of PTNS was investigated here in a home based randomized pilot trial of idiopathic overactive bladder patients. A promising effect indicates that there might be patients who can benefit from this type of non-invasive and low cost approach of PTNS. Additionally a numerical modelling of both types of PTNS showed that both techniques achieve a stimulation comparable in a way of physiological effects. Thus suggesting the evidence of percutaneous form of PTNS is plausible to be present in the transcutaneous form.