Active Micro-Nano-Collaborative Bioelectronic Device for Advanced Electrophysiological Recording

The development of precise and sensitive electrophysiological recording platforms holds the utmost importance for research in the fields of cardiology and neuroscience.In recent years,active micro/nano-bioelectronic devices have undergone significant advancements,thereby facilitating the study of electrophysiology.The distinctive configuration and exceptional functionality of these active micro-nano-collaborative bioelectronic devices offer the potential for the recording of high-fidelity action potential signals on a large scale.In this paper,we review three-dimensional active nano-transistors and planar active micro-transistors in terms of their applications in electroexcitable cells,focusing on the evaluation of the effects of active micro/nano-bioelectronic devices on electrophysiological signals.Looking forward to the possibilities,challenges,and wide prospects of active micro-nano-devices,we expect to advance their progress to satisfy the demands of theoretical investigations and medical implementations within the domains of cardiology and neuroscience research.

Femoral Access with Ultrasound-Guided Puncture and Z-Stitch Hemostasis for Adults with Congenital Heart Diseases Undergoing Electrophysiological Procedures

Aims:Although the application of ultrasound-guided vascular puncture and Z-stitch hemostasis to manage femoral access has been widely utilized,there is limited data on this combined application in adult congenital heart disease(ACHD)patients undergoing electrophysiological(EP)procedures.We sought to evaluate the safety and efficacy of ultrasound-guided puncture and postprocedural Z-stitch hemostasis for ACHD patients under-going EP procedures.Methods and Results:The population of ACHD patients undergoing transfemoral EP pro-cedures at the University of Zurich Heart Center between January 2019 and December 2022 was observed and analyzed.During the study period,femoral access(left/right,arterial/venous)was performed under real-time ultrasound guidance.At the end of the procedure,a single Z-stitch was performed at the puncture site.We eval-uated the incidence of in-hospital complications associated with femoral access puncture in this population.Among 101 patients who had a total of 147 previous ipsilateral vascular punctures(mean 1.5 per person),100 patients underwent successful femoral vascular access for EP procedures.The median age of the patients was 47±15 years and 34(34%)were male.Z-stitches were performed after the procedure in 100 patients with 303 femoral vascular accesses(mean 3 punctures per person).No patient developed vascular puncture relevant inguinal hematoma,pseudo aneurysm,arteriovenousfistula,venous or arterial thrombosis.Conclusion:In ACHD patients undergoing EP procedures,optimal femoral access management can be achieved with ultra-sound-guided puncture and postprocedural Z-stitch hemostasis.

Superelastic Radiative Cooling Metafabric for Comfortable Epidermal Electrophysiological Monitoring

Epidermal electronics with superb passive-cooling capabilities are of great value for both daytime outdoor dressing comfort and low-carbon economy. Herein, a multifunctional and skinattachable electronic is rationally developed on a porous all-elastomer metafabric for efficient passive daytime radiative cooling(PDRC) and human electrophysiological monitoring. The cooling characteristics are realized through the homogeneous impregnation of polytetrafluoroethylene microparticles in the styrene–ethylene–butylene–styrene fibers, and the rational regulation of microporosity in SEBS/PTFE metafabrics, thus synergistically backscatter ultraviolet–visible–near-infrared light(maximum reflectance over 98.0%) to minimize heat absorption while efficiently emit human-body midinfrared radiation to the sky. As a result, the developed PDRC metafabric achieves approximately 17℃ cooling effects in an outdoor daytime environment and completely retains its passive cooling performance even under 50% stretching. Further, high-fidelity electrophysiological monitoring capability is also implemented in the breathable and skin-conformal metafabric through liquid metal printing, enabling the accurate acquisition of human electrocardiograph, surface electromyogram, and electroencephalograph signals for comfortable and lengthy health regulation. Hence, the fabricated superelastic PDRC metafabric opens a new avenue for the development of body-comfortable electronics and low-carbon wearing technologies.

Smart epidermal electrophysiological electrodes:Materials,structures,and algorithms

Epidermal electrophysiological monitoring has garnered significant attention for its potential in medical diagnosis and healthcare,particularly in continuous signal recording.However,simultaneously satisfying skin compliance,mechanical properties,environmental adaptation,and biocompatibility to avoid signal attenuation and motion artifacts is challenging,and accurate physiological feature extraction necessitates effective signal-processing algorithms.This review presents the latest advancements in smart electrodes for epidermal electrophysiological monitoring,focusing on materials,structures,and algorithms.First,smart materials incorporating self-adhesion,self-healing,and self-sensing functions offer promising solutions for long-term monitoring.Second,smart meso-structures,together with micro/nanostructures endowed the electrodes with self-adaption and multifunctionality.Third,intelligent algorithms give smart electrodes a“soul,”facilitating faster and more-accurate identification of required information via automatic processing of collected electrical signals.Finally,the existing challenges and future opportunities for developing smart electrodes are discussed.Recognized as a crucial direction for next-generation epidermal electrodes,intelligence holds the potential for extensive,effective,and transformative applications in the future.

Adult adipose-derived stromal cells differentiate into neurons with normal electrophysiological functions

β-mercaptoethanol was used to induce in vitro neuronal differentiation of adipose-derived stromal cells. Within an 8-hour period post-differentiation, the induced cells exhibited typical neuronal morphology, and expression of microtubule-associated protein 2 and neuron-specific enolase, which are markers of mature neurons, reached a peak at 5 hours. Specific organelle Nissl bodies of neurons were observed under transmission electron microscopy. Results of membrane potential showed that fluorescence intensity of cells was greater after 5 hours than adipose-derived stromal cells prior to induction. In addition, following stimulation with high-concentration potassium solution, fluorescence intensity increased. These experimental findings suggested that neurons differentiated from adipose-derived stromal cells and expressed mature K^＋ channels. In addition, following stimulation with high potassium solution, the membrane potential depolarized and fired an action potential, confirming that the induced cells possessed electrophysiological functions.

Electrophysiological functional recovery in a rat model of spinal cord hemisection injury following bone marrow-derived mesenchymal stem cell transplantation under hypothermia

Following successful establishment of a rat model of spinal cord hemisection injury by resecting right spinal cord tissues, bone marrow stem cells were transplanted into the spinal cord lesions via the caudal vein while maintaining rectal temperature at 34 ± 0.5°C for 6 hours （mild hypothermia）. Hematoxylin-eosin staining showed that astrocytes gathered around the injury site and formed scars at 4 weeks post-transplantation. Compared with rats transplanted with bone marrow stem cells under normal temperature, rats transplanted with bone marrow stem cells under hypothermia showed increased numbers of proliferating cells （bromodeoxyuridine-positive cells）, better recovery of somatosensory-evoked and motor-evoked potentials, greater Basso, Beattie, and Bresnahan locomotor rating scores, and an increased degree of angle in the incline plate test. These findings suggested that hypothermia combined with bone marrow mesenchymal stem cells transplantation effectively promoted electrical conduction and nerve functional repair in a rat model of spinal cord hemisection injury.

Electrophysiologic testing guided risk stratification approach for sudden cardiac death beyond the left ventricular ejection fraction

Sudden cardiac death threats ischaemic and dilated cardiomyopathy patients. Anti- arrhythmic protection may be provided to these patients with implanted cardiac defibrillators(ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity meaning that a significant number of victims will remain undetectable by this risk stratification approach because they have a preserved left ventricular systolic function. Current risk stratification strategies focus on combinations of non invasive methods like T wave alternans, late potentials, heart rate turbulence, deceleration capacity and others, with invasive methods like the electrophysiologic study. In the presence of an electrically impaired substrate with formed post myocardial infarction fibrotic zones, programmed ventricular stimulation provides important prognostic information for the selection of the patients expected to benefit from an ICD implantation, while due to its high negative predictive value, patients at low risk level may also be detected. Clustering evidence from different research groups and electrophysiologic labs support an electrophysiologic testing guided risk stratification approach for sudden cardiac death.

Utility of electrophysiological studies to predict arrhythmic events

AIM:To evaluate the prognostic value of electrophysiological stimulation(EPS) in the risk stratification for tachyarrhythmic events and sudden cardiac death(SCD).METHODS:We conducted a prospective cohort study and analyzed the long-term follow-up of 265 consecutive patients who underwent programmed ventricular stimulation at the Luzerner Kantonsspital(Lucerne,Switzerland) between October 2003 and April 2012. Patients underwent EPS for SCD risk evaluation because of structural or functional heart disease and/or electrical conduction abnormality and/or after syncope/cardiac arrest. EPS was considered abnormal,if a sustained ventricular tachycardia(VT) was inducible. The primary endpoint of the study was SCD or,in implanted patients,adequate ICD-activation.RESULTS:During EPS,sustained VT was induced in 125 patients(47.2%) and non-sustained VT in 60 patients(22.6%); in 80 patients(30.2%) no arrhythmia could be induced. In our cohort,153 patients(57.7%) underwent ICD implantation after the EPS. During follow-up(mean duration 4.8 ± 2.3 years),a primary endpoint event occurred in 49 patients(18.5%). The area under the receiver operating characteristic curve(AUROC) was 0.593(95%CI:0.515-0.670) for a left ventricular ejection fraction(LVEF) < 35% and 0.636(95%CI:0.563-0.709) for inducible sustained VT during EPS. The AUROC of EPS was higher in the subgroup of patients with LVEF ≥ 35%(0.681,95%CI:0.578-0.785). Cox regression analysis showed that both,sustained VT during EPS(HR:2.26,95%CI:1.22-4.19,P = 0.009) and LVEF < 35%(HR:2.00,95%CI:1.13-3.54,P = 0.018) were independent predictors of primary endpoint events.CONCLUSION:EPS provides a benefit in risk stratificationfor future tachyarrhythmic events and SCD and should especially be considered in patients with LVEF ≥ 35%.

High‑Performance Flexible Microneedle Array as a Low‑Impedance Surface Biopotential Dry Electrode for Wearable Electrophysiological Recording and Polysomnography

Microneedle array(MNA)electrodes are an effective solution to achieve high-quality surface biopotential recording without the coordination of conductive gel and are thus very suitable for long-term wearable applications.Existing schemes are limited by flexibility,biosafety,and manufacturing costs,which create large barriers for wider applications.Here,we present a novel flexible MNA electrode that can simultaneously achieve flexibility of the substrate to fit a curved body surface,robustness of microneedles to penetrate the skin without fracture,and a simplified process to allow mass production.The compatibility with wearable wireless systems and the short preparation time of the electrodes significantly improves the comfort and convenience of electrophysiological recording.The normalized electrode–skin contact impedance reaches 0.98 kΩcm^(2)at 1 kHz and 1.50 kΩcm^(2)at 10 Hz,a record low value compared to previous reports and approximately 1/250 of the standard electrodes.The morphology,biosafety,and electrical/mechanical properties are fully characterized,and wearable recordings with a high signal-to-noise ratio and low motion artifacts are realized.The first reported clinical study of microneedle electrodes for surface electrophysiological monitoring was conducted in tens of healthy and sleep-disordered subjects with 44 nights of recording(over 8 h per night),providing substantial evidence that the electrodes can be leveraged to substitute for clinical standard electrodes.

Editor's Choice—Electrophysiological characteristics of epilepsy

Elect roencephalographic signals can act as an indicator of abnormal discharge during epileptic seizures, providing important evidence for diagnosing epilepsy. Abnormal electroencephalographic activity was detected during seizures, and high-amplitude epileptic discharge waveforms were observed during intermission in approximately 50% of patients.

Visual electrophysiological examination in diagnosis of hepatic encephalopathy

Clinical observation of the neuropsychiatric condition, psychometric tests, and EEG recordings has been used to diagnose hepatic encephalopathy. However, no standardization for the diagnosis of minimal hepatic encephalopathy (MHE) has been achieved. According to the study in normal subjects, visual electrophysiology testing is a method of simple, objective record for the medical examination, which includes visual evoked potentials (VEP), electroretinograms (ERG), etc. 23 hepatic encephalopathy patients prospectively underwent visual electrophysiology testing and laboratory serum analysis, and it was found that 22 visual electrophysiology abnormalities which showed that the amplitudes were decreased and the implicit times were prolonged compared with the normal. The relationship between biochemical parameters and visual electrophysiology parameters showed that visual recording was related to the damage of the liver. On the basis of this preliminary study, we could conclude that this method can be as a way to predict for hepatic encephalopathy and it appears to be a method in the recognition of the MHE.

Objective electrophysiological contrast sensitivity with monofocal and multifocal intraocular lenses:a prospective clinical study

Background:To compare objective electrophysiological contrast sensitivity function(CSF)in patients implanted with either multifocal intraocular lenses(MIOLs)or monofocal intraocular lenses(IOLs)by pattern reversal visual evoked potentials(prVEP)measurements.Methods:Fourty-five cataract patients were randomly allocated to receive bilaterally:apodized diffractive-refractive Alcon Acrysof MIOL(A),full diffractive AMO Tecnis MIOL(B)or monofocal Alcon Acrysof IOL(C).Primary outcomes:1-year differences in objective binocular CSF measured by prVEP with sinusoid grating stimuli of 6 decreasing contrast levels at 6 spatial frequencies.Secondary outcomes:psychophysical CSF measured with VCTS-6500,photopic uncorrected distance(UDVA),and mesopic and photopic uncorrected near and intermediate visual acuities(UNVA and UIVA respectively).Results:Electrophysiological CSF curve had an inverted U-shaped morphology in all groups,with a biphasic pattern in Group B.Group A showed a lower CSF than group B at 4 and 8 cpd,and a lower value than group C at 8 cpd.Psychophysical CSF in group A exhibited a lower value at 12 cpd than group B.Mean photopic and mesopic UNVA and UIVA were worse in monofocal group compared to the multifocal groups.Mesopic UNVA and UIVA were better in group B.Conclusions:Electrophysiological CSF behaves differently depending on the types of multifocal or monofocal IOLs.This may be related to the visual acuity under certain conditions or to IOL characteristics.This objective method might be a potential new tool to investigate on MIOL differences and on subjective device-related quality of vision.

Electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure

Objective: To investigate the electrophysiological changes of autonomic cells in left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with chronic heart failure.Methods: Guinea pigs model of iron deficiency anemia complicated with chronic heart failure in 10 guinea pigs of the experimental group was made by feeding a low iron diet,pure water and subcutaneous injection of isoproterenol. The control group consisting of 11 guinea pigs was given normal food, normal water and injected with normal saline. The left ventricular outflow tract model specimen was also prepared. The standard microelectrode technique was used to observe electrophysiological changes of autonomic cells in the outflow tract of left ventricular heart failure complicated with iron deficiency anemia in guinea pig model. The indicators of observation were maximal diastolic potential, action potential amplitude, 0 phase maximal depolarization velocity, 4 phase automatic depolarization velocity, repolarization 50% and 90%, and spontaneous discharge frequency.Results: Compared with the control group, 4 phase automatic depolarization velocity,spontaneous discharge frequency and 0 phase maximal depolarization velocity decreased significantly(P < 0.01) and action potential amplitude reduced(P < 0.01) in model group. Moreover, repolarization 50% and 90% increased(P < 0.01).Conclusions: There are electrophysiological abnormalities of the left ventricular outflow tract in guinea pigs with iron deficiency anemia complicated with heart failure.

Trace elements in diabetic cardiomyopathy:An electrophysiological overview

There is a growing body of evidence that Diabetes Mellitus leads to a specific cardiomyopathy apart from vascular disease and bring about high morbidity and mortality throughout the world.Recent clinical and experimental studies have extensively demonstrated that this cardiomyopathy causes impaired cardiac performance manifested by early diastolic and late systolic dysfunction.This impaired cardiac performance most probably have emerged upon the expression and activity of regulatory proteins such as Na+/Ca2+exchanger,sarcoplasmic reticulum Ca2+-ATPase,ryanodine receptor and phospholamban.Over years many therapeutic strategies have been recommended for treatment of diabetic cardiomyopathy.Lately,inorganic elements have been suggested to have anti-diabetic effects due to their suggested ability to regulate glucose homeostasis,reduce oxidative stress or suppress phosphatases.Recent findings have shown that trace elements exert many biological effects including insulin-mimetic or antioxidant activity and in this manner they have been recommended as potential candidates for treatment of diabetes-induced cardiac complications,an effect based on their modes of action.Some of these trace elements are known to play an essential role as component of enzymes and thus modulate the organ function in physiological and pathological conditions.Besides,they can also manipulate redox state of the channels via antioxidant properties and thus contribute to the regulation of [Ca2+]i homeostasis and cardiac ion channels.On account of little information about some trace elements,we discussed the effect of vanadium,selenium,zinc and tungstate on diabetic heart complications.

Effects of Calmodulin-dependent Protein Kinase Ⅱ Inhibitor,KN-93,on Electrophysiological Features of Rabbit Hypertrophic Cardiac Myocytes

Cardiac hypertrophy is an independent risk factor for sudden cardiac death in clinical settings and the incidence of sudden cardiac death and ventricular arrhythmias are closely related.The aim of this study was to determine the effects of the calmodulin-dependent protein kinase(CaMK) Ⅱ inhibitor,KN-93,on L-type calcium current(I Ca,L) and early after-depolarizations(EADs) in hypertrophic cardiomyocytes.A rabbit model of myocardial hypertrophy was constructed through abdominal aortic coarctation(LVH group).The control group(sham group) received a sham operation,in which the abdominal aortic was dissected but not coarcted.Eight weeks later,the degree of left ventricular hypertrophy(LVH) was evaluated using echocardiography.Individual cardiomyocyte was isolated through collagenase digestion.Action potentials(APs) and I Ca,L were recorded using the perforated patch clamp technique.APs were recorded under current clamp conditions and I Ca,L was recorded under voltage clamp conditions.The incidence of EADs and I ca,L in the hypertrophic cardiomyocytes were observed under the conditions of low potassium(2 mmol/L),low magnesium(0.25 mmol/L) Tyrode’s solution perfusion,and slow frequency(0.25-0.5 Hz) electrical stimulation.The incidence of EADs and I ca,L in the hypertrophic cardiomyocytes were also evaluated after treatment with different concentrations of KN-92(KN-92 group) and KN-93(KN-93 group).Eight weeks later,the model was successfully established.Under the conditions of low potassium,low magnesium Tyrode’s solution perfusion,and slow frequency electrical stimulation,the incidence of EADs was 0/12,11/12,10/12,and 5/12 in sham group,LVH group,KN-92 group(0.5 μmol/L),and KN-93 group(0.5 μmol/L),respectively.When the drug concentration was increased to 1 μmol/L in KN-92 group and KN-93 group,the incidence of EADs was 10/12 and 2/12,respectively.At 0 mV,the current density was 6.7±1.0 and 6.3±0.7 PA·PF-1 in LVH group and sham group,respectively(P>0.05,n=12).When the drug concentration was 0.5 μmol/L in KN-92 and KN-93 groups,the peak I Ca,L at 0 mV was decreased by(9.4±2.8)% and(10.5±3.0)% in the hypertrophic cardiomyocytes of the two groups,respectively(P>0.05,n=12).When the drug concentration was increased to 1 μmol/L,the peak I Ca,L values were lowered by(13.4±3.7)% and(40±4.9)%,respectively(P<0.01,n=12).KN-93,a specific inhibitor of CaMKII,can effectively inhibit the occurrence of EADs in hypertrophic cardiomyocytes partially by suppressing I Ca,L,which may be the main action mechanism of KN-93 antagonizing the occurrence of ventricular arrhythmias in hypertrophic myocardium.

Propofol injection combined with bone marrow mesenchymal stem cell transplantation better improves electrophysiological function in the hindlimb of rats with spinal cord injury than monotherapy

The repair effects of bone marrow mesenchymal stem cell transplantation on nervous system damage are not satisfactory. Propofol has been shown to protect against spinal cord injury. Therefore, this study sought to explore the therapeutic effects of their combination on spinal cord injury. Rat models of spinal cord injury were established using the weight drop method. Rats were subjected to bone marrow mesenchymal stem cell transplantationvia tail vein injection and/or propofol injectionvia tail vein using an infusion pump. Four weeks after cell transplan-tation and/or propofol treatment, the cavity within the spinal cord was reduced. The numbers of PKH-26-positive cells and horseradish peroxidase-positive nerve ifbers apparently increased in the spinal cord. Latencies of somatosensory evoked potentials and motor evoked potentials in the hindlimb were noticeably shortened, amplitude was increased and hindlimb motor function was obviously improved. Moreover, the combined effects were better than cell transplantation or propofol injection alone. The above data suggest that the combination of propofol injection and bone marrow mesenchymal stem cell transplantation can effectively improve hindlimb electro-physiological function, promote the recovery of motor funtion, and play a neuroprotective role in spinal cord injury in rats.

Morphological and electrophysiological changes of retina after different light damage in three patients:Three case reports

BACKGROUND Light-induced retinal damage is a serious vision-threatening disease,resulting from unsuitable laser irradiation,high-power light and sustaining light exposure.Therefore,effectively evaluate the morphological and functional of retinal damage is urgently needed.Now,we mainly reported three patients suffered from typical light irradiations.CASE SUMMARY Patient 1 suffered from old laser pointer irradiation and followed with amblyopia treatment.Patient 2 suffered from acute high-energy light irradiation.Patient 3suffered from sustaining optical fiber irradiation.Detailed morphological and functional examinations of the retina revealed that the lesions of the three patients had many similar characteristics,such as macular morphological changes,patent pattern visual monitoring amplitude or peak time abnormalities,multi-fucus electroretinograms macular central amplitude density decreased.CONCLUSION In conclusion,light-induced retinopathy has many common features,which can help clinical medical staff to diagnose retinal photodamage diseases.

Effect of cyclosporine-A on electrophysiological properties of atria in tachycardia-induced atrial fibrillation

Objective To investigate the effects ofciyclosporine-A （CsA）,a calcineurin （CAN） inhibitor,on electrophysiological properties of atria in canine tachycardia-induced model of AF.Methods Eighteen healthy adult mongrel canines weighing 17.0 to 23.2 kg（ranged from 2 to 4 years old）were randomized to 3 groups,Sham group （no pacemaker was implanted）,atrial tachypacing group （ATP group） and CsA group (atrial tachypacing plus oral administration of CsA 10 mg·kg-1·d-1).Electrophysiological tests were performed on each group at baseline and after 8 weeks’ tachypacing.Measurements included atrial effective refractory period（AERP）,conduction velocity （CV）,wave length （WL）,atrial fibrillation load and rate-adaptability.Results After 8 weeks’ atrial tachypacing,ATP and CsA groups showed significant longer duration of the P wave,shorter AERP,decreased adaptation of AERP,slower CV,shorter WL and longer AF duration compared to the sham group （all P【0.05）.AERP of the CsA group was longer than that of ATP group （P【0.05）, but there were no differences in rate-adaptability,CV,incidence of induced AF and AF duration between CsA group and ATP group. Conclusions Our results suggest that calcineurin pathway intervention by CsA have a positive effect on tachycardia-induced electrical remodeling of atria,but can not prevent or reverse AF.

Electrophysiological evaluation in 4 patients with diabetic pseudotabes

BACKGROUND： Researches on diabetic nervous system lesion are mainly focus on peripheral nerve and vegetative nerve, so there are few investigations on diabetic pseudotabes. OBJECTIVE： To investigate the electrophysiological examinations on the diagnosis of diabetic pseudotabes. DESIGN： Case study. SETTING： Department of Electrophysiology and Department of Neurology, Zhongshan Hospital Affiliated to Xiamen University. PARTICIPANTS： A total of 4 patients with type 2 diabetes mellitus, including 3 males and 1 female aged from 50 to 72 years, were selected from Department of Neurology, Zhongshan Hospital Affiliated to Xiamen University from March 2002 to February 2005. All accepted subjects met the modified diagnostic criteria of diabetes mellitus, which was set by American Diabetes Mellitus Association （ADA） in 1997. Otherwise, the subjects had typical symptoms and physical signs of spinal posterior funiculus damage. However, patients with spinal cord lesion which was caused by other factors were excluded. All accepted subjects provided the confirmed consent. METHODS： Nicolet NT electromyography （EMG）/evoked potential meter （made in the USA） was used to detect spinal cord conduction velocity （SCCV）, somatosensory evoked potential （SEP） of lower limbs, motor nerve conduction velocity （MNCV） and sensory nerve conduction velocity （SNCV） of extremities. Determining criteria： Measurements were performed based on the laboratory standards. SCCV, which was less than lower limit of normal value （T2–12： 40–55 m/s, T12–L4： 20–41 m/s, T2–L4： 36–45 m/s）, was regarded as abnormal. SEP value of lower limbs： P40, P60 and PF, which were more than standard deviation of normal value （x — ＋2.5）, were regarded as the abnormality. Normal value of P40, P60 and PF latencies （x —±s） in this study： P40, P60 and PF in males were （37.6±1.9） ms, （59.8±3.9） ms and （7.6±0.9） ms, respectively; meanwhile, those in females were （35.5±1.7） ms, （55.2±2.7） ms and （6.3±0.7） ms, respectively. MNCV and SNCV, which were less than 50 m/s in upper limbs and 40 m/s in lower limbs, were regarded as the abnormality. MAIN OUTCOME MEASURES： Electrophysiological examinations. RESULTS： All 4 patients with type 2 diabetes mellitus were involved in the final analysis. ① SCCV： Among 4 patients, SCCV of three patients was decreased in T2–12, T12–L4 and T2–L4, and that of the other one was decreased in T2–12 and T2–L4; however, SCCV in T12–L4 was normal. There was significant difference as compared with normal value （P 〈 0.01）. ② SEP of lower limbs： SEP values of lower limbs were abnormal in all 4 patients. Among them, P40, P60 and PF latencies of two patients were delayed; P40 of one patient was delayed and PF was not drained out; P40 and P60 of the last one were delayed and PF was normal. ③ MNCV and SNCV： The MNCV and SNCV were normal in one patient and abnormal in three patients. The results demonstrated that MNCV and SNCV of extremities decreased; especially, sensory nerve action potential （SNAP） of both lower extremities of one patient were not drained out. CONCLUSION： Detections of SCCV, SEP of lower limbs, MNCV and SNCV of extremities are helpful to investigate whether peripheral nerve and deep sensory passage are damaged or not and determine whether deep sensory damage is caused by peripheral nerve and spinal posterior funiculus.