Current Perception Threshold Testing Research Articles

“Loop-Neurorrhaphy Technique for Preventing Bone Resorption and Preserving Lower Lip Sensation in Mandibular Reconstruction using Vascularized Iliac Bone Flap: A Single-Center Randomized Clinical Trial”

Background: The aim of this study was to investigate whether using an innervated vascularized iliac bone flap could effectively prevent bone resorption and maintain sensory function in the lower lip. Methods: In the innervated group, the deep circumflex iliac artery and recipient vessels were anastomosed, with simultaneous microanastomosis of ilioinguinal nerve, mental nerve and inferior alveolar nerve. Conversely, the control group underwent solely vascular anastomosis. CT was utilized to assess bone quality. Sensory recovery of the lower lip was recorded using two-point discrimination and current perception threshold testing. Results: The study comprised a total of 40 subjects, with each group accounting for 20 participants, equally distributed in terms of gender. Hounsfield unit loss was significantly lower in the innervated group (13.26±8.65 %) as compared to the control group (37.98±8.60 %) (P < 0.001). Moreover, two-point discrimination values were lower in the innervated group (15.11±8.39 mm) when compared to the control group (21.44±7.24 mm) (P = 0.02). The current perception threshold values for the innervated group were 176.19 ± 31.89, 64.21 ± 19.23, and 42.29 ± 18.96 in 2kHz, 250Hz, and 5Hz respectively, while in the control group, the current perception threshold values were 204.47 ± 36.99, 82.26 ± 27.29, and 58.89 ± 25.38 in 2kHz, 250Hz, and 5Hz (P =0.02, 0.02, and 0.03, respectively). Conclusions: The innervated vascularized iliac bone flap represents a safe and effective novel approach to preserving lower lip sensation and preventing bone resorption through functional mandibular reconstruction.

Evaluation of Quantitative and Selective Sensory Fiber Dysfunction in Patients with Cirrhosis.

Chronic liver disease has been reported to be associated with peripheral neuropathy. However, which sensory fibers are affected remains unknown. The objective of this study was to examine the function of sensory nerve fibers in patients with cirrhosis using the current perception threshold (CPT) test, as well as the correlation between blood biochemical indicators related to cirrhosis and CPT values. We recruited 44 patients with liver cirrhosis and 37 healthy controls of the same age and gender. The Neurometer® system for the CPT test was used to stimulate the median nerve on the right index finger, as well as the deep and superficial peroneal nerves on the right hallux, using three distinct parameters (2000 Hz, 250 Hz, and 5 Hz). Comparative analysis was performed on the CPT values of the sensory nerves. Additionally, the correlation between CPT values and biochemical blood indicators in the study participants was analyzed. Under 2000 Hz electrical stimulation, there was a significant difference between the cirrhosis and healthy control groups in the median nerve as well as the deep and superficial peroneal nerves (p < 0.05). In addition, the median nerve CPT value of the cirrhosis group was significantly higher than that of the control group at an electrical stimulation frequency of 250 Hz (p = 0.005). There was no correlation between CPT values and blood biochemical indicators. According to the results, the sensory peripheral neuropathy in liver cirrhosis is mainly manifested as Aβ fiber neuropathy.

Long-term dopamine agonist treatment fails to restore altered central sensory processing in restless legs syndrome: Evidence from current perception threshold measurements

ObjectivesAlthough some studies have examined the impact of short-term dopamine agonist treatment on altered central sensory processing in patients with restless legs syndrome (RLS), there is a scarcity of research investigating the effect of long-term treatment with these drugs. The aim of this study is to investigate the long-term impact of dopamine agonist treatment on altered central sensory processing in RLS patients using current perception threshold (CPT) testing. MethodsWe conducted a study of 24 RLS patients, measuring their CPT values before and after dopamine agonist treatment for at least 2 months. Patients were classified as responders or non-responders based on their decrease in International Restless Legs Syndrome (IRLS) score. Clinical parameters were collected and compared pre- and post-treatment. ResultsThe mean duration of treatment with dopamine agonist was 13.6 ± 11.0 months. Our results showed that dopamine agonist treatment significantly improved clinical parameters, including the IRLS score, Visual Analogue Scale, and RLS Quality of Life questionnaire. However, CPT values did not show significant changes for all stimulus frequencies after treatment. Furthermore, we did not find any difference in CPT values before and after treatment in both responders and non-responders. ConclusionsOur study demonstrated that long-term treatment with dopamine agonists effectively reduces RLS symptoms, but does not reverse the altered central sensory processing observed on CPT testing in RLS patients. These results support the notion that the pathophysiology of RLS is multifactorial and not solely driven by dopaminergic dysfunction.

Glomerular filtration Rate, urine Albumin/ creatinine ratio and current perception threshold in patients with diabetic kidney disease

BackgroundDiabetic microvascular complications, including diabetic kidney disease (DKD), retinopathy (DR), and neuropathy (DN), were major causes of morbidity and mortality in diabetic patients worldwide. It has been suggested that urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) were not the only indicators of renal function impairment in DKD and that they were also associated with diabetic peripheral neuropathy (DPN) which might affect nerve conduction velocity (NCV). As 30–40% of DPN patients had no subjective symptoms, while current perception threshold (CPT) could detect sensory nerve damage at an early stage. As a result, we aimed to investigate correlation between UACR, eGFR and CPT in DKD patients. MethodsA total of 273 DKD patients from the First Affiliated Hospital of Kunming Medical University from January 2018 to June 2020 were enrolled to complete the CPT test. CPT values of the bilateral median nerve and superficial and deep peroneal nerves at 2000 Hz, 250 Hz, and 5 Hz were collected. ResultsIn normoesthesia and hypaesthesia patients with DKD, MDRD-eGFR correlated negatively with TC (r = -0.135, P = 0.037), left superficial peroneal and deep peroneal nerve 2000 Hz CPT (r = -0.205, P = 0.001) and right superficial peroneal and deep peroneal nerve 2000 Hz CPT (r = -0.154, P = 0.017). Besides, left and right superficial peroneal and deep peroneal nerve 2000 Hz CPT correlated with CKD-EPI-eGFR and UACR. Multivariate logistic regression analysis found left superficial peroneal and deep peroneal nerve 2000 Hz CPT was independently associated with both MDRD-eGFR and CKD-EPI-eGFR. ConclusionDecreased MDRD-eGFR and CKD-EPI-eGFR were expected to be a predictor of peripheral nerve injury in normoesthesia and hypaesthesia patients with DKD.

Small Fiber Neuropathy with Inadequate Response to Medical Therapy: Diagnosis of The Etiology of Small Fiber Neuropathy and Treatment Option

Small-fiber neuropathy (SFN) has few significant laboratory findings and is difficult to diagnose. In 70% of the cases, the cause of SFN is unknown. Among the cases with known etiology, 50% are associated with diabetes, and the causes are autoimmune, amyloidosis, or multifactorial. In recent years, a specific autoantibody-positive group has been identified and has attracted attention because immunotherapy was successful in the autoantibody-positive SFN groups. In the cases reporting to our department, abnormalities could not be detected by various tests, including nerve conduction studies, and the response to symptomatic treatment was poor. An abnormality was identified in the current perception threshold test result, and a positive blood anti-plexin D1 antibody was detected via enzyme-linked immunosorbent assay. Therefore, autoimmune SFN was diagnosed, and plasma exchange therapy was remarkably effective. Subsequently, we aim to introduce general treatments for SFN and COVID-19-related SFN.

Association of Diabetic Peripheral Neuropathy with Vitamin D Levels Depends on Vitamin D Status.

BackgroundVitamin D deficiency has been reported to be associated with diabetic peripheral neuropathy (DPN). Our objective here was to evaluate the association between vitamin D levels and neuropathic symptoms in a Chinese population.Material/MethodsA total of 4435 patients with type 2 diabetes (T2D) were recruited in this cross-sectional study. 25-dihydroxyvitamin D (25-(OH) D) serum concentration was measured by electrochemiluminescence assay (Cobas e601, Roche). DPN was clinically diagnosed by assessing neurological symptoms and performing current perception threshold (CPT) testing. Of all the patients, 2910 were CPT-positive and had assessed neurological symptoms.ResultsIn the vitamin D insufficiency group (<30 ng/mL 25-(OH) D), patients with neurological symptoms had higher serum 25-(OH) D levels than those without neurological symptoms (24.65±3.42 ng/mL vs 23.61±4.54 ng/mL, p≤0.001). The risk of numbness and pain increased by 0.5-fold for every 6 ng/mL increase in 25-(OH) D. In the vitamin D sufficiency group (≥30 ng/mL 25-(OH) D), patients with neurological symptoms had lower serum 25-(OH) D levels than those without neurological symptoms (32.96±3.18 ng/mL vs 33.45±4.27 ng/mL, p<0.01). For every 4 ng/mL decrease in 25-(OH) D, the risk of numbness and pain increased by 0.2-fold.ConclusionsThe association of neuropathy symptoms with 25-(OH) D levels differed depending on whether the patients had insufficient or sufficient vitamin D.

Current perception threshold testing in chronic ankle instability

BackgroundDamage to sensory input is an underlying pathology of chronic ankle instability (CAI). Therefore, it is necessary to evaluate the sensory function of patients with CAI. The present study quantitatively evaluated sensory nerve function in patients with CAI and healthy controls using current perception threshold (CPT) measurements, as well as the influence of sex, age, and body mass index (BMI) on CPT values and the relations between CPT frequencies.MethodsFifty-nine subjects with CAI and 30 healthy controls participated in this study. CPT values at the anterior talofibular ligament region were recorded on the injured and uninjured sides in CAI patients and on both sides in the healthy control group. Between group differences were compared. The influence of sex, age and BMI on CPT values was evaluated. Correlations between different frequencies were also studied.ResultsThere were no significant differences in age, sex, height, weight or BMI between the CAI and healthy control groups. The CPT values did not show a significant difference by sex. The CPT values did not significantly correlate with age or BMI. Compared to the control group, the CAI group had significantly higher CPT values on the injured and uninjured sides under 250-Hz and 5-Hz electrical stimuli; the difference between the groups was significant (p < 0.01), and the effect size were large. No significant difference was observed under 2000-Hz stimuli. There were correlations between CPT values at different frequencies (p < 0.01), especially 250 Hz and 5 Hz.ConclusionThe present study revealed increased sensory thresholds in 250-Hz- and 5-Hz-related sensory nerve fibres in the injured and uninjured ankles of patients with CAI. This increase may indicate dysfunction of A-delta and C fibres. Sex, age and BMI did not significantly impact CPT values. There were correlations between CPT values at different frequencies, especially 250 Hz and 5 Hz.Level of evidenceLevel III, case-control study.

Effects of alpha-lipoic acid treatment on serum progranulin levels and inflammatory markers in diabetic neuropathy.

ObjectivesProgranulin (PGRN) is a secreted growth factor that helps to regulate neuronal survival by blocking tumor necrosis factor-alpha (TNFα) receptors. The antioxidant alpha-lipoic acid (ALA) is used in diabetic neuropathy to improve nerve conduction and relieve neuropathic pain, but its effects on PGRN levels have not yet been elucidated.MethodsIn this prospective study, 54 patients with type 2 diabetes and peripheral neuropathy received 600 mg of ALA daily for 6 months. Twenty-four patients with diabetes without neuropathy were also included in the study. Serum PGRN and TNFα levels were determined using enzyme-linked immunosorbent assays. In addition, current perception threshold (CPT) testing was used to assess sensory neuropathy.ResultsAfter ALA treatment, serum PGRN levels were significantly increased and CPT values were significantly improved. Furthermore, there were significant positive correlations among TNFα, ICAM-1, and PGRN levels both before and after ALA treatment. A significant negative correlation was observed between the improvements in CPT and the PGRN levels. Furthermore, ICAM-1 levels were an independent predictor of PGRN levels.ConclusionsChanges in serum PGRN levels indicate that ALA treatment may have beneficial effects on endothelial function and neuronal inflammation.

The effect of α-lipoic acid treatment on plasma asymmetric dimethylarginine, a biomarker of endothelial dysfunction in diabetic neuropathy

IntroductionDiabetic neuropathy may develop on a background of hyperglycaemia and is associated with increased oxidative stress. Elevated asymmetric dimethylarginine (ADMA) levels are linked to oxidative stress reducing the synthesis of nitric oxide (NO) by uncoupling NO synthase. Oxidative stress induces considerable changes in nerve conduction velocity in diabetic patients. There is strong evidence that α-lipoic acid (ALA) as an antioxidant may improve nerve conduction and relieve neuropathic symptoms. We aimed to investigate the relationship between endothelial dysfunction and NO synthesis in type 2 diabetic patients with peripheral neuropathy after ALA treatment.Material and methodsFifty-four type 2 diabetic patients with neuropathy were included in the study. Serum ADMA concentration, ICAM-1, VCAM-1, oxidised low-density lipoprotein (oxLDL), and TNF-α levels were determined with Enzyme-Linked Immunosorbent Assay (ELISA). Nitric oxide concentration was measured by Griess reaction. Peripheral sensory nerve function was assessed by current perception threshold (CPT) testing. Autonomic function was assessed by Ewing’s five standard cardiovascular reflex tests composite autonomic score (CAS).ResultsAsymmetric dimethylarginine levels were significantly decreased (0.62 ±0.11 vs. 0.53 ±0.11 µmol/l, p &lt; 0.001), as well as TNF-α concentrations (1.21 ±0.42 pg/ml vs. 1.05 ±0.5 pg/ml, p &lt; 0.05), while NO levels were significantly increased (16.78 ±11.1 vs. 21.58 ±8.84 µmol/l, p &lt; 0.05) after six-months of 600 mg/day ALA treatment. VCAM-1, ICAM-1, and oxLDL levels did not change significantly. The CPT and CAS significantly improved after ALA treatment. The improvement of CPT values was correlated positively with the change of ADMA levels (r = 0.58, p &lt; 0.001). The change in ADMA level was more pronounced in responder patients based on both CPT and CAS.ConclusionsOur results suggest that ALA supplementation improves endothelial function characterised by serum levels of ADMA and TNF-α in patients with diabetic neuropathy. Changes in serum ADMA levels may predict the clinical response to ALA treatment.

Evaluation of Patients with Sensory Disturbance after Dental Treatment

The Korean Dental Association recommends a disability rate (DR) of 1%-3% in the judgment of physical disability owing to sensory disturbance (SD) after dental treatment; however, criteria for deciding the exact percentage have not been suggested. Therefore, this study aims to provide practical criteria in the application of forensic physical disability evaluation by comparing the results of SD using the current perception threshold (CPT) test. A total of 324 patients with SD who visited the Department of Oral Medicine at Pusan National University Dental Hospital between January 2013 and August 2020, underwent the test. The eight stages, as a result of the CPT value, were reorganized as follows: profound sensory loss, very severe and severe as “severe group”, advanced and moderate as “moderate group”, mild and very mild as “mild group”, and normal as “normal group” The analysis of variance (ANOVA) test was used to calculate the statistical difference in the CPT values at 2000 Hz, 250 Hz, and 5 Hz among the four groups. There were significant statistical differences in the average values of CPT among the four groups (P<0.001). Additionally, a significant statistical difference in the CPT value between the affected and non-affected sides of the patients was observed among the four groups (P<0.001). Therefore, based on the results of this study, the rationale for applying DR from 1%-3% was in accordance with the severity of the mandibular nerve injury. Key Words: Iatrogenic nerve injury · Dental treatment · Sensory disturbance

Association between Sleep Quality and Painless Diabetic Peripheral Neuropathy Assessed by Current Perception Threshold in Type 2 Diabetes Mellitus.

BackgroundIt is known that the painful sensation of diabetic peripheral neuropathy (DPN) results in sleep problems in type 2 diabetes mellitus (T2DM). However, it is not known that the painless DPN also is associated with poor sleep quality in T2DM. The purpose of the current study was to investigate the association between painless DPN and poor sleep quality in T2DM.MethodsA total of 146 patients of T2DM who do not have any painful symptoms of DPN were recruited into the study. Among the patients, painless DPN was diagnosed by using the current perception threshold test. Sleep quality was assessed using the Pittsburgh Sleep Quality Index questionnaire.ResultsThe percentage of painless DPN was significantly higher in the poor sleep quality group than the good sleep quality group (70.0% vs. 35.5%, P<0.001). In the subscale results, stimulus values at 2,000 Hz, hypoesthesia and hyperesthesia were more common in the poor sleep quality group than in the good sleep quality group (45.7% vs. 25.0%, P=0.009; 34.3% vs. 18.4%, P=0.029; 40.0% vs. 19.7%, P=0.007, respectively). The association of painless DPN and poor sleep quality remained significant after adjustment for significant covariates (odds ratio, 3.825; 95% confidence interval, 1.674 to 8.742; P<0.001).ConclusionThe current study showed that painless DPN was associated with poor sleep quality. Future studies are required to clarify the pathophysiologic causal relationship between painless DPN and sleep quality.

Association between Hyposensitivity of C-fiber Afferents at The Proximal Urethra and Storage/voiding Dysfunction in Female Patients with Detrusor Overactivity.

We examined the associations between urethral sensation and storage/voiding function in female patients with detrusor overactivity (DO) by measuring urethral current perception threshold (CPT). We retrospectively investigated the medical records of 27 consecutive patients with lower urinary tract symptoms who underwent cystometry, uroflowmetry (UFM), and urethral CPT tests from 2000 to 2015. Patients were classified into 2 groups: with/without DO. Seven DO-negative cases were selected as normal controls on cystometrogram (CMG) matching the inclusion criteria: bladder compliance ?12.5 mL/cmH2O, volume <275 mL at first sensation, and no comorbidities possibly influencing micturition. Finally, 17 patients were included. Urethral CPT was evaluated with intraurethral square-wave impulses at 3 Hz to stimulate C-fibers. Urethral loss coefficient (LC), reflecting urethral resistance during voiding, was calculated by curve-fitting a mathematical model to a UFM waveform. Urge incontinence (UI) was observed in 7 DO-positive patients, but not in those with normal CMG. Urethral CPT and LC were significantly higher in patients with DO than in those with normal CMG. Median urethral CPT significantly increased in patients with both DO and UI than in those without these symptoms (p<0.005). CPT values were correlated with the volume at first sensation (?=0.53, p<0.05) and LC (?=0.59, p<0.05). LC was not calculated in 3 cases due to poor curve-fitting. In females, urethral C-fiber afferents may become hyposensitive as the detrusor becomes overactive with UI in the storage phase. During voiding, C-fiber hyposensitivity may relate to increased functional resistance of the urethra to urine outflow.

MON-698 Association of Sleep Quality and Painless Diabetic Peripheral Neuropathy in Type 2 Diabetes

AimsDiabetic peripheral neuropathy (DPN) is one of the most common and early manifested complication in T2D. Previous reports have shown that painful sensation of diabetic peripheral neuropathy (DPN) results in sleep problems in type 2 diabetes (T2D)1, 2. However, it is not known that subtype of DPN, the painless DPN also is associated with poor sleep quality in T2D. The purpose of the current study was to investigate the association between painless DPN and poor sleep quality in T2D.MethodsA total of 146 patients of T2D who did not previously diagnose with symptomatic DPN were recruited into the study. Among the patients, painless DPN was diagnosed by using the current perception threshold (CPT) test. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire.ResultsThe percentage of painless DPN was significantly higher in the poor sleep quality group than the good sleep quality group (70.0% vs. 35.5%, P<0.001). In the subscale results, stimulus values in 2000 Hz, hypoesthesia and hyperesthesia were significantly higher in the poor sleep quality group, than in the good sleep quality group (45.7% vs. 25.0%, P=0.009; 34.3% vs. 18.4%, P=0.029; 40.0% vs. 19.7%, P=0.007, respectively). The association of painless DPN and poor sleep quality remained significant after adjustment for significant variants (odds ratio, 3.825; 95% confidence interval, 1.674-8.742; P<0.001).ConclusionsThe current study showed that painless DPN was associated with poor sleep quality. Future studies are required to clarify the pathophysiologic causal relationship between painless DPN and sleep quality.

Current Perception Threshold Testing in Pharyngeal Paresthesia Patients with Depression or Anxiety.

PurposeSatisfactory quantitative diagnostic approaches to pharyngeal paresthesia patients with depression or anxiety remain to be explored. This study investigated the plausibility of current perception threshold (CPT) testing in diagnosing pharyngeal paresthesia in patients with depression or anxiety.Patients and MethodsA total of 41 patients with pharyngeal paresthesia with depression or anxiety were recruited as the study group. Additionally, 60 healthy volunteers constituted the control group. The CPT values associated with 5-, 250-, and 2000-Hz electrical stimulation frequencies were measured at the palatal lingual arch and posterior third of the lingual body (two sensory nerve distribution sites in the pharynx). The normal range of CPT values of the above three frequencies was analyzed. The differences in the CPT values for sensory nerves were compared.ResultsThere were no significant differences in age and sex between the study and control groups. The CPT values of the pharynx at the two tested sites were not significantly correlated with age and gender. The CPT value of the study group was significantly lower than that of the control group in the palatal lingual arch and posterior third of the lingual body at an electrical stimulation of 5 Hz (p<0.05). No significant differences in the CPT values at other frequencies were found between the two groups.ConclusionCPT testing is effective in determining pharyngeal paresthesia in patients with depression and anxiety. Paresthesia of the pharyngeal sensory nerve region is caused by damaged C fibers.

Symptom‐related changes in current perception threshold of restless legs syndrome

Few studies have investigated the mechanisms responsible for the symptoms of restless legs syndrome (RLS). However, these studies were mainly performed during the asymptomatic period and therefore their findings might not apply to changes in sensory processing that occur during the symptomatic period. The objective of this study was to investigate the function of sensory nerve fibres in RLS patients using the current perception threshold (CPT) test during the daytime and in the presence of symptoms. Ninety-three patients with RLS and 34 healthy controls were included in the study. RLS patients were further divided into two subgroups, those who were experiencing RLS symptoms during the CPT test (symptom+) and those without symptoms (symptom-). Demographic data, RLS rating scale score and visual analogue scale were collected. Of the 127 enrolled subjects, CPT values were significantly lower in RLS patients than in controls for all three frequencies. Among the control and RLS subgroups (53 symptom+, 40 symptom-), symptom+ patients showed lower CPT values than controls. This finding indicates a relative hyperaesthetic state in the sensory afferents of peripheral nerves in symptom+ patients. There were no significant differences between the symptom- group and controls. The significantly lower CPT values for all three frequencies in symptom+ patients suggest that central sensory processing disturbance of sensory nerve fibres' input may be involved in the development of symptoms in RLS patients.

Verification of the reliability of current perception threshold and pain threshold testing by application of an electrical current stimulus to mandibular mucosa in young adults.

There is little evidence regarding the reliability of CPT and PT measurements to gauge mandibular perception. Thus, this study aimed to evaluate the test-retest reliability of CPT and PT values obtained from the mandibular oral mucosa and to test the bilateral differences in CPT and PT values obtained from the mental foramen region and buccal shelf region by a single operator. CPT and PT values were obtained from the mental foramen and buccal shelf regions of 20 volunteers (10 males and 10 females; average age: 26.4±2.6years) by using the Neurometer CPT/C® device to deliver electrical stimulation. Relative and absolute reliabilities were confirmed over two measurements of CPT and PT over a 7- to 10-day measurement interval. Intra-class correlation coefficients (ICCs) for CPT and PT table obtained from the mental foramen region were >0.8, while most ICC for the buccal shelf region were <0.8. Standard error of measurement, minimal detectable change and Bland-Altman analyses showed that the CPT and PT measurements had no systematic error and could serve as useful methods. At all frequencies, the bilateral difference in CPT and PT values at the mental foramen and buccal shelf region was not significant. CPT and PT measurements using a custom-made device that applied an electrical current to the mental foramen region have appropriate reliability to assess intra-oral sensitivity to electrical stimulation in young adults.

Acute Vibration Induces Peripheral Nerve Sensitization in a Rat Tail Model: Possible Role of Oxidative Stress and Inflammation

Prolonged occupational exposure to hand-held vibrating tools leads to pain and reductions in tactile sensitivity, grip strength and manual dexterity. The goal of the current study was to use a rat-tail vibration model to determine how vibration frequency influences factors related to nerve injury and dysfunction. Rats were exposed to restraint, or restraint plus tail vibration at 62.5 Hz or 250 Hz. Nerve function was assessed using the current perception threshold (CPT) test. Exposure to vibration at 62.5 and 250 Hz, resulted in a reduction in the CPT at 2000 and 250-Hz electrical stimulation (i.e. increased Aβ and Aδ, nerve fiber sensitivity). Vibration exposure at 250 Hz also resulted in an increased sensitivity of C-fibers to electrical stimulation and thermal nociception. These changes in nerve fiber sensitivity were associated with increased expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in ventral tail nerves, and increases in circulating concentrations of IL-1 β in rats exposed to 250-Hz vibration. There was an increase in glutathione, but no changes in other measures of oxidative activity in the peripheral nerve. However, measures of oxidative stress were increased in the dorsal root ganglia (DRG). These changes in pro-inflammatory factors and markers of oxidative stress in the peripheral nerve and DRG were associated with inflammation, and reductions in myelin basic protein and post-synaptic density protein (PSD)-95 gene expression, suggesting that vibration-induced changes in sensory function may be the result of changes at the exposed nerve, the DRG and/or the spinal cord.

Vaginal diazepam plus transcutaneous electrical nerve stimulation to treat vestibulodynia: A randomized controlled trial

ObjectiveTo assess the effectiveness of vaginal diazepam in addition to transcutaneous electrical nerve stimulation (TENS) in the treatment of vestibulodynia (VBD). Study DesignThis study was a randomized, double-blind, placebo-controlled trial. Forty-two patients with VBD were randomized, 21 underwent diazepam and TENS (diazepam group) and 21 received placebo and TENS (placebo group). Vulvar pain was assessed on a on a 10-cm visual analogue scale (VAS) and dyspareunia according to the Marinoff dyspareunia scale. Vaginal surface electromyography (EMG) and vestibular current perception threshold (CPT) testing were performed at baseline and 60 days after treatment. The primary endpoints included the change in pain and dyspareunia from baseline to 60 days of pain and dyspareunia. The secondary endpoints was the variation in objectivity of pelvic floor muscle (PFM) function and vestibular nerve fiber current perception threshold (CPT). ResultsThe VAS scores for pain from basal values of 7.5 and 7.2 for the diazepam and placebo, respectively, showed significant (p 0.01) decreases from 4.7 to 4.3, but this difference was not statistically significant. The Marinoff dyspareunia scores in the diazepam group showed a significant difference (p 0.05) from values measured in the placebo group. The ability to relax the PFM after contraction (difference between maximal contraction and rest tone) was significantly greater for the diazepam group versus the placebo group (3.8 μv and 2.4 μv, respectively, p 0.01). The CPT values for all of the nerve fibers increased after the treatment, but this increase was significant in the diazepam group only for the values at a 5-Hz stimulation (C fibers) with a change of 47.8% vs 26.9% (p < 0.05). Only two patients reported a mild drowsiness in the diazepam group. ConclusionsThe present study provided indications that vaginal diazepam plus TENS is useful to improve pain and PFM instability in women with VBD.

Vestibular effect of ospemifene: An unexplored field

In the treatment of genitourinary syndrome of the menopause (GSM), the targets should be vulval pain and dyspareunia. Research has shown that 95% of menopausal women with dyspareunia also have localized provoked pain in the vestibule, despite hormone supplements being used by just under a third of these women. This is related to differences in nerve density between the vagina and vulvar vestibule. A retrospective analysis of specimens from women with postmenopausal vestibulodynia found significantly less neural hyperplasia and more severe chronic inflammation, compared with premenopausal patients. Hypo-estrogenism may promote a vestibular site-specific inflammation related to pain. SERMs have been shown to exert an anti-neuroinflammatory action. Estradiol decreases the stimulatory effect of lipopolysaccharide on levels of proinflammatory molecules, and ospemifene is more effective than other SERMs in reducing proinflammatory protein levels. A pilot study was conducted in 52 postmenopausal women with ≤1 year of amenorrhea to investigate the vulvar vestibular effects of 60 mg of ospemifene for 60 days. Participants presented with dyspareunia and signs of vestibular atrophy including a thinned, dry, fragile or pale mucosa. Ospemifene was efficacious in improving vestibular signs and symptoms related to GSM. Study participants also underwent current perception threshold (CPT) testing to quantify the sensitivity and functional integrity of specific afferent nerve fibers. Following treatment, there was a marked increase in CPT values for all nerve fibers, particularly C fibers (38.8%), which are mainly responsible for pain perception (higher CPT values after therapy denote that nerve endings are less sensitive, meaning there is less pain). This might reflect an action of ospemifene on inflammation-triggered peripheral sensitization of sensory nerves in the vestibular tissue. In an integrated approach to the treatment of postmenopausal vulval pain that includes preparation with ospemifene, laser treatment has been found to be more effective.

Reference Values and Influencing Factors Analysis for Current Perception Threshold Testing Based on Study of 166 Healthy Chinese.

The current perception threshold (CPT) is a device which can evaluate different sensory fibers quantitatively through different frequencies of the electrical stimulus and has been applied in clinical practice. Previous studies have implied that CPT values may be affected by age, gender, and other factors, yet not conclusively. The objective of our study is to clarify the influencing factors of CPT values and establish a reference value range. Twenty healthy volunteers recruited publicly and 146 subjects who took CPT tests in the census of the national project cardiovascular and cerebrovascular diseases in rural areas of China from 2013 to 2015 were analyzed. Past medical history and demographic characteristics such as age, gender, and occupation were collected. Each subject was tested on the left index finger (or back of the left hand) and the right hallux. CPT values of 2000, 250, and 5 Hz on both sites were recorded for statistical analysis. Gender differences were shown at 2000 Hz CPT on the back of the hand and hallux (p < 0.01), and male subjects had a higher CPT. Age had a positive correlation with 250 Hz CPT on the index finger (p < 0.05, r = 1.5), 2000 Hz CPT on the back of the hand (p < 0.001, r = 1.2) and index finger (p < 0.05, r = 2.5). Manual workers had a higher 250 Hz CPT on the hallux than mental workers (p < 0.01). After investigating the impact of different factors on CPT testing, we established the reference value for subjects with different characteristics.