Clinical trials have demonstrated that kilohertz-frequency transcutaneous spinal cord stimulation (TSCS) can be used to facilitate the recovery of sensory-motor function for patients with spinal cord injury, whereas the neural mechanism of TSCS is still undetermined so that the choice of stimulation parameters is largely dependent on the clinical experience. In this paper, a finite element model of transcutaneous spinal cord stimulation was used to calculate the electric field distribution of human spinal cord segments T ₁₂ to L ₂, whereas the activation thresholds of spinal fibers were determined by using a double-cable neuron model. Then the variation of activation thresholds was obtained by varying the carrier waveform, the interphase delay, the modulating frequency, and the modulating pulse width. Compared with the sinusoidal carrier, the usage of square carrier could significantly reduce the activation threshold of dorsal root (DR) fibers. Moreover, the variation of activation thresholds was no more than 1 V due to the varied modulating frequency and decreases with the increased modulating pulse width. For a square carrier at 10 kHz modulated by rectangular pulse with the frequency of 50 Hz and the pulse width of 1 ms, the lowest activation thresholds of DR fibers and dorsal column fibers were 27.6 V and 55.8 V, respectively. An interphase delay of 5 μs was able to reduce the activation thresholds of the DR fibers to 20.1 V. The simulation results can lay a theoretical foundation on the selection of TSCS parameters in clinical trials.
Humans ; Spinal Cord Stimulation/methods* ; Nerve Fibers/physiology* ; Finite Element Analysis ; Spinal Cord/physiology* ; Computer Simulation ; Spinal Cord Injuries/physiopathology* ; Lumbosacral Region ; Lumbar Vertebrae ; Transcutaneous Electric Nerve Stimulation/methods* ; Models, Neurological

OBJECTIVE: To provide useful information for selecting the most appropriate peripheral nerve injury model for different research purposes in nerve injury and repair studies, and to compare nerve regeneration capacity and characteristics between them. METHODS: Sixty adult SD rats were randomly divided into two groups and underwent crush injury alone (group A, n = 30) or transection injury followed by surgical repair (group B, n = 30) of the right hind paw. Each group was subjected to the CatWalk test, gastrocnemius muscle evaluation, pain threshold measurement, electrophysiological examination, retrograde neuronal labeling, and quantification of nerve regeneration before and 7, 14, 21, and 28 days after injury. RESULTS: Gait analysis showed that the recovery speed in group A was significantly faster than that in group B at 14 days. At 21 days, the compound muscle action potential of the gastrocnemius muscle in group A was significantly higher than that in group B, and the number of labeled motor neurons in group B was lower than that in group A. The number of new myelin sheaths and the g-ratio were higher in group A than in group B. There was a 7-day time difference in the regeneration rate between the two injury groups. CONCLUSION The regeneration of nerve fibers was rapid after crush nerve injury, whereas the transection injury was relatively slow, which provides some ideas for the selection of clinical research models.
Animals ; Rats ; Nerve Fibers ; Nerve Regeneration ; Rats, Sprague-Dawley ; Sciatic Nerve/injuries*

BACKGROUND: Corneal confocal microscopy (CCM) is a noninvasive technique to detect early nerve damage of diabetic sensorimotor polyneuropathy (DSPN). Time in range (TIR) is an emerging metric of glycemic control which was reported to be associated with diabetic complications. We sought to explore the relationship between TIR and corneal nerve parameters in asymptomatic patients with type 2 diabetes (T2DM). METHODS: In this cross-sectional study, 206 asymptomatic inpatients with T2DM were recruited. After 7 days of continuous glucose monitoring, the TIR was calculated as the percentage of time in the glucose range of 3.9 to 10.0 mmol/L. CCM was performed to determine corneal nerve fiber density, corneal nerve branch density, and corneal nerve fiber length (CNFL). Abnormal CNFL was defined as ≤15.30 mm/mm 2 . RESULTS: Abnormal CNFL was found in 30.6% (63/206) of asymptomatic subjects. Linear regression analyses revealed that TIR was positively correlated with CCM parameters both in the crude and adjusted models (all P   <  0.05). Each 10% increase in TIR was associated with a 28.2% (95% CI: 0.595-0.866, P  = 0.001) decreased risk of abnormal CNFL after adjusting for covariates. With the increase of TIR quartiles, corneal nerve fiber parameters increased significantly (all P for trend <0.01). The receiver operating characteristic curve indicated that the optimal cutoff point of TIR was 77.5% for predicting abnormal CNFL in asymptomatic patients. CONCLUSIONS There is a significant independent correlation between TIR and corneal nerve fiber loss in asymptomatic T2DM patients. TIR may be a useful surrogate marker for early diagnosis of DSPN.
Humans ; Diabetes Mellitus, Type 2/complications* ; Cross-Sectional Studies ; Blood Glucose Self-Monitoring ; Blood Glucose ; Nerve Fibers ; Diabetic Neuropathies ; Cornea ; Microscopy, Confocal/methods*

OBJECTIVE: To observe the effect of moxibustion at "Zusanli" (ST 36) on distal, middle and proximal colonic mucosal injury and expression of calcitonin gene-related peptide (CGRP) positive nerve fibers of distal colonic mucosa in ulcerative colitis (UC) mice at different time points. METHODS: A total of 51 C57BL/6N mice were randomized into a 7-day control group ( RESULTS: Mucosal injury can be observed in mice after modeling, displaying epithelial layer disappearance, abnormal crypt structure or crypt disappearance. Compared with the 7-day control group, colon length was shortened ( CONCLUSION Moxibustion at "Zusanli" (ST 36) can reduce the expressions of positive nerve fibers of colonic mucosa and CGRP positive nerve fibers of distal colonic mucosa, thus, improve the colonic mucosal injury.
Animals ; Calcitonin ; Calcitonin Gene-Related Peptide/genetics* ; Colitis, Ulcerative/therapy* ; Intestinal Mucosa ; Mice ; Mice, Inbred C57BL ; Moxibustion ; Nerve Fibers

Objective: To study the oropharyngeal sensory function by Current Perception Threshold(CPT) detection, to explore the detection method of oropharyngeal sensory function in normal population, and to analyze the possible influencing factors. Methods: Fifty-eight normal subjects were included prospectively in this study. Age, gender, body mass index (BMI) were collected. The age of the subjects ranged from 20 to 76 (43.27±13.52) years old. There were 34 females with 17 in childbearing period and 17 in menopause; and 24 males were included.In all the cases, 6 cases were in low BMI, 39 cases were in normal BMI, 10 cases were overweight and 3 cases were suffering from obesity. The CPT system of Neurometer was used to stimulate bilateral palatoglossal arch and tongue base.The current used was 2000 Hz, 250 Hz and 5 Hz respectively.The function of type Aβ, Aδ and C sensory nerve fibers were tested and the CPT values were recorded.The values were inversely proportional to pharyngeal sensation function.To evaluate the oropharyngeal sensory function of the subjects, the CPT values of each frequency at each testing point were compared. SPSS 25.0 software was used for statistical analysis. Results: The CPT value of palatoglossal arch was significantly lower than that of tongue base (t=-2.58,-2.65,-2.54,-2.47,-2.37,-2.77,P<0.05), 2 000 Hz>250 Hz>5 Hz, and there was no significant difference between left and right sides(t=-0.03,-0.51,-0.49,0.06,-0.16,0.13,P>0.05). The CPT value of male was slightly higher than that of female (t=0.92,1.55,0.27,0.78,1.44,1.26,0.35,0.77,1.27,0.24,0.78,0.96,P>0.05). The CPT values of women in childbearing period were significantly less than those in menopausal women (t=-3.90,-3.64,-2.14,-4.20,-4.28,-4.28,-3.52,-4.46,-3.41,-3.63,-4.66,-2.86,P<0.05). The CPT value increased with age, and the values of all frequency of 20 to 30 years old group was significantly lower than those of subjects over 40 years old at each point (The t values of bilateral palatoglossal arch at 2 000 Hz were -5.57,-6.22,-10.18,-11.00;the t values of bilateral palatoglossal arch at 250 Hz were -6.39,-8.79,-6.39,-15.61;the t values of bilateral palatoglossal arch at 5 Hz were -7.09, -5.57, -9.26, -15.23;the t values of tongue base at 2 000 Hz were -3.11,-3.88,-7.60,-8.55;the t values of tongue base at 250 Hz were -6.31,-10.59,-8.52,-10.60;the t values of tongue baseat 5 Hz were -6.69,-5.09,-8.70,-7.07,P<0.05).The values at all frequencies and testing points of 30-40 years old group were significantly lower than those of all subjects over 60 years old (The t values of bilateral palatoglossal arch at 2 000 Hz were -10.91,-12.42;the t values of bilateral palatoglossal arch at 250 Hz were -6.25,-10.87;the t values of bilateral palatoglossal arch at 5 Hz were -5.53,-11.01;the t values of tongue base at 2 000 Hz were -8.62,-10.12;the t values of tongue base at 250 Hz were -6.89,-7.82;the t values of tongue base at 5 Hz were -6.13,-6.48,P<0.05). Conclusions: CPT can be used to evaluate oropharyngeal sensory function. The sensitivity of tongue base is lower than that of palatoglossal arch, there is no significant difference in oropharyngeal sensory function between male and female,between left and right sides. There are many factors influencing oropharyngeal sensory function. Age, hormone level changes may affect the sensitivity of oropharyngeal sensory function.
Adult ; Aged ; Electric Stimulation ; Female ; Humans ; Male ; Middle Aged ; Nerve Fibers ; Pharynx ; Sensation ; Sensory Thresholds ; Young Adult

PURPOSE: To report a case of non-glaucomatous retinal nerve fiber layer (RNFL) defect associated with paravascular inner retinal defect (PIRD) in a patient with idiopathic epiretinal membrane (ERM).CASE SUMMARY: A 70-year-old male who was diagnosed with ERM in his right eye and pseudoexfoliative glaucoma in his left eye visited our clinic. His intraocular pressure was 14 mmHg in both eyes while using topical hypotensive medications in both eyes. His right eye showed no glaucomatous change of the optic disc head, and also no glaucomatous visual field defect on standard automated perimetry. Red-free fundus photography and swept-source optical coherence tomography showed an ERM and wedge-shaped RNFL defect starting from the PIRD, not the optic disc head. He was diagnosed with non-glaucomatous RNFL defect in the right eye and was told to stop using topical hypotensive medication for the right eye. After 2 years of discontinuing the medication, the IOP was within the normal range, the RNFL defect showed no progression, and the visual field remained stationary.CONCLUSIONS: A non-glaucomatous RNFL defect can develop in association with PIRD in patients with idiopathic ERM. Examinations for PIRD as well as evaluation of the optic disc head are therefore necessary in patients with ERM and RNFL defect.
Aged ; Epiretinal Membrane ; Glaucoma ; Head ; Humans ; Intraocular Pressure ; Male ; Nerve Fibers ; Photography ; Reference Values ; Retinaldehyde ; Tomography, Optical Coherence ; Visual Field Tests ; Visual Fields

nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL).METHODS: One hundred sixty-four eyes with primary open-angle glaucoma were studied. The structural progression pattern evaluated by optical coherence tomography guided progression analysis was classified using hierarchical cluster analysis. The clinical parameters, patterns of structural progression, and visual field (VF) changes were compared among the groups.RESULTS: Three groups were included: stable, progressive peripapillary RNFL thinning without macular GCIPL involvement, and progressive thinning of both the peripapillary RNFL and macular GCIPL. The third group, those with progressive peripapillary RNFL and macular GCIPL thinning, showed more progressive peripapillary RNFL thinning in the inferotemporal area and VF progression in the parafoveal area. Conversely, the 12 and 6 o'clock areas were the most common locations of progressive peripapillary RNFL thinning in the group without macular GCIPL involvement.CONCLUSIONS: Structural progression patterns of glaucoma can be categorized into three groups. The location of progressive peripapillary RNFL thinning is associated with progressive macular GCIPL thinning and pattern of VF changes in the affected area. Our results indicate that the use of only macular GCIPL analysis is inadequate for analyzing the structural progression of glaucoma.]]>
Cluster Analysis ; Ganglion Cysts ; Glaucoma ; Glaucoma, Open-Angle ; Machine Learning ; Nerve Fibers ; Retinaldehyde ; Tomography, Optical Coherence ; Visual Fields

PURPOSE: To investigate the location of retinal nerve fiber layer defects (RNFLDs) in open-angle glaucoma and the differences in systemic and ocular factors between superotemporal and inferotemporal RNFLDs. METHODS: We performed a retrospective review of the 2008 to 2012 data from the Korea National Health and Nutrition Examination Survey. Subjects aged ≥19 years with an evaluable fundus photograph of at least one eye were enrolled, and open-angle glaucoma was diagnosed according to modified International Society of Geographical and Epidemiological Ophthalmology criteria. In subjects with open-angle glaucoma, locations of RNFLDs were evaluated, and systemic and ocular factors were compared between the bilateral superotemporal RNFLD group and bilateral inferotemporal RNFLD group. RESULTS: A total of 534 subjects had open-angle glaucoma with RNFLDs. The unilateral inferotemporal region (25.8%) was the most common location for RNFLDs, followed by the unilateral superotemporal region (24.4%). Multivariate analysis revealed that hypertension was more significantly associated (p = 0.048) with the bilateral superotemporal RNFLD group than with the bilateral inferotemporal RNFLD group. CONCLUSIONS: Superotemporal RNFLDs are more related to hypertension than are inferotemporal RNFLDs.
Glaucoma, Open-Angle ; Hypertension ; Korea ; Multivariate Analysis ; Nerve Fibers ; Nutrition Surveys ; Ophthalmology ; Retinaldehyde ; Retrospective Studies

PURPOSE: This study compared the glaucoma diagnostic abilities of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). In addition, the possibility of enhancing diagnostic capability by combining the two modalities was investigated. METHODS: A total of 131 healthy eyes and 113 glaucomatous eyes were imaged by both OCT and OCTA. In OCT, glaucoma was defined as when the color of the superior or inferior quadrant of the peripapillary retinal nerve fiber layer thickness map was yellow (borderline, <5%) or red (outside normal limits, <1%). In OCTA, glaucoma was determined using the cut-off value of the superior or inferior peripapillary vessel density, calculated after receiver operating characteristic curve analysis. Sensitivity and specificity were determined by OCT alone, by OCTA alone, or by OCT and OCTA combined. RESULTS: The sensitivity of OCT (86.7%) was better than that of OCTA (74.3%), whereas the specificity of OCTA (87.0%) was better than that of OCT (67.9%). When these two modalities were combined, both sensitivity and specificity were enhanced (90.3% and 92.4%, respectively). Among the 131 eyes, 32 were misdiagnosed as glaucomatous by OCT but accurately diagnosed as normal by OCTA. These eyes were myopic, with a longer axial length and a thinner and temporally displaced peak of peripapillary retinal nerve fiber layer thickness, causing the false positive result in OCT. CONCLUSIONS: When OCTA was combined with OCT, the specificity of glaucoma diagnoses were enhanced. OCTA may compensate for the shortcomings of OCT in the diagnosis of glaucoma.
Angiography ; Diagnosis ; Diagnostic Techniques and Procedures ; Glaucoma ; Nerve Fibers ; Retinaldehyde ; ROC Curve ; Sensitivity and Specificity ; Tomography, Optical Coherence

PURPOSE: We sought to investigate the effects of Graves' orbitopathy (GO) and orbital decompression on lamina cribrosa depth (LCD) using spectral-domain optical coherence tomography. METHODS: Forty eyes that underwent orbital decompression to relieve compressive optic neuropathy or correct disfiguring exophthalmos in the context of GO were included. Subjects were imaged with spectral-domain optical coherence tomography before surgery and at 1 and 3 months after surgery, at which the examiner measured the LCD (distance from the anterior surface of the lamina cribrosa to the Bruch membrane opening line) and peripapillary retinal nerve fiber layer thickness. Subjects were divided into two groups—a muscle-dominant group composed of patients who had extraocular muscle enlargement on preoperative orbital computed tomography scan and a fat-dominant group composed of patients who did not show extraocular muscle enlargement on preoperative orbital computed tomography scan—and subgroup analysis was performed. Preoperative and postoperative intraocular pressure, exophthalmos, LCD, and retinal nerve fiber layer thickness were evaluated. RESULTS: At baseline, LCD was remarkably shallower in the muscle-dominant group than in the fat-dominant group (95% confidence interval, p = 0.007). In the muscle-dominant group, LCD showed no definite change after surgery. However, the fat-dominant group showed temporary posterior displacement of the lamina cribrosa at 1-month postoperation that was reversed to baseline at 3 months postoperation (95% confidence interval, p < 0.01). CONCLUSIONS: The lamina cribrosa was anteriorly displaced preoperatively, and its position was nearly unchanged after the surgery, especially in association with extraocular muscle enlargement. An enlarged extraocular muscle could reduce the pressure-relieving effect of orbital decompression around the scleral canal in patients with GO.
Bruch Membrane ; Decompression ; Exophthalmos ; Graves Ophthalmopathy ; Humans ; Intraocular Pressure ; Nerve Fibers ; Optic Nerve ; Optic Nerve Diseases ; Orbit ; Retinaldehyde ; Tomography, Optical Coherence