Neuroselective measure of the current perception threshold of A‐delta and C‐fiber afferents in the lower urinary tract

Abstract

Sensory dysfunction could be involved in various pathogeneses in the lower urinary tract including neurogenic bladder, overactive bladder, painful bladder syndrome and neuropathy as a result of endocrine disorders. The ability to diagnose sensory function more objectively is of increasing interest to clinicians. Afferent innervations of the lower urinary tract involve myelinated (A-delta) and unmyelinated (C) fibers. The Neurometer (Neurotron, Baltimore, MD, USA) is the only reported commercially available device to evaluate afferent function by selectively depolarizing different subpopulations of afferent nerves, with 250 Hz activating A-delta fibers and 5 Hz activating C-fibers, to determine their current perception threshold (CPT) as a quantitative measure. Recently, increased evidence has suggested that measurement of CPT values of A-delta and C-fibers in the lower urinary tracts is feasible and shows significant correlation with clinical symptoms and conventional urodynamic variables, as well as the efficacy of various treatments. However, there are still controversial issues in the wider use of this technology in diagnosis and assessment of the therapeutic effectiveness of sensory dysfunction in the lower urinary tracts. In order to resolve the remaining challenges in the CPT test of the lower urinary tract, recent efforts include development of a new balloon-type electro-catheter with dual electrodes as an alternative sensory test for the bladder or urethra, which allows simultaneous performance of conventional urodynamic tests and urine collection, and future standardized techniques available for comparison with validated control values.

Does central sensitization help explain idiopathic overactive bladder?

“…Interestingly, no reports of QST specifically assessing temporal summation in patients with IC/BPS are currently available, even though this would be the most convincing evidence of central sensitization in patients with this disorder 28 . For OAB, a few investigators 103–107 have examined urethral electrical current perception thresholds that, in theory, can be used to assess firing thresholds of specific subtypes of afferent fibres. However, results of these studies have been inconsistent and difficult to interpret 103–107 .…”

“…For OAB, a few investigators 103–107 have examined urethral electrical current perception thresholds that, in theory, can be used to assess firing thresholds of specific subtypes of afferent fibres. However, results of these studies have been inconsistent and difficult to interpret 103–107 . Peripheral QST with either mechanical or heat stimuli in patients with OAB has not been reported; therefore, it remains unknown if patients with OAB have the more generalized hyperaesthesia, allodynia or hyperalgesia to evoked pain stimuli on psychophysical testing reported in some other patients with central sensitization-related disorders 44,47,49,50 .…”

Pudendal and median nerve sensory perception threshold: A comparison between normative studies

“…The Neurometer Õ is considered to be a useful tool in screening of sensory neurologic abnormalities, including peripheral neuropathy (Katims et al 1987). Current perception threshold (CPT) evaluation in the lower urinary tract (LUT) has proven to be important for diagnosis (De Laet et al 2005;De Wachter et al 2006;Fujihara et al 2011). A disturbed CPT in the LUT can indicate a possible neuropathic cause of bladder dysfunction (Kiesswetter 1977;Wyndaele 1993;Ukimura et al 2004;Van Meel et al 2010;Fujihara et al 2011;Van Meel and Wyndaele 2012).…”

Chest tube insertion is one important factor leading to intercostal nerve impairment in thoracic surgery

“…A marginal correlation was observed between CPT values at 2000 Hz during insertion of the chest tube and after removal and NRS score (p=0.058). Miyazaki 8 CPT testing using the Neurometer CPT/C ® has now seen wide use in various clinical setting associated with quantitative evaluation of sensory function, and its utility and objectivity have been confirmed [13,14]. However, use of CPT testing related to thoracic surgery has not been reported expect in our previous study [6].…”