Advanced analysis of auditory evoked potentials in hyperthyroid patients: the effect of filtering.

The purpose of the study is to evaluate Auditory Evoked Potentials (AEPs) in patients with hyperthyroidism and to compare their frequency components with those of healthy subjects. In this study the AEPs in hyperthyroidism were studied both in time and frequency domains rather than studying just in the time domain by peak scoring. This paper presents a method for filtering auditory oddball standard and target AEPs by using singular spectrum analysis (SSA) and feature extraction in the frequency domain via spectral analysis. AEPs were recorded during an auditory oddball paradigm in 25 newly diagnosed hyperthyroid patients and 15 healthy subjects. The signals are captured in the presence of ongoing background EEG activity so they are often contaminated by artifacts. This paper presents a method for filtering auditory odd-ball standard and target AEPs by using Singular spectrum analysis and feature extraction in frequency domain via spectral analysis. Information about the frequency composition of the signal is then used to compare normal and hyperthyroid states. While there was no significant difference either in the target or standard unfiltered signals between the hyperthyroid patients and the control group (p > 0.05), there was a significant difference in the filtered signals between the two groups (p < 0.01). In conclusion, our results revealed that SSA is an effective filtering method for AEPs. Thus, a much more objective and specific examination method was developed.

Investigation of dose-related effects of carnosine on anxiety with sympathetic skin response and T-maze.

Carnosine is a dipeptide formed of the amino acids ß-alanine and histidine. Only a limited number of studies have examined the effects of carnosine on sympathetic nerve activation and anxiety. The present study was undertaken to determine the dose-related effects of carnosine on anxiety in the elevated T-maze test (ETM) with electrodermal activity (EDA). Carnosine was injected in three groups of rats with doses of 10 (low dose), 100 (medium dose) and 1000 (high dose) mg/kg i.p. Physiological saline was injected in the sham group. The anxiety scores of the rats were measured with ETM 20 minutes after injection. Then, SCL was measured. The decreased number of entries into the open arm (NEOA), the percentage of time spent in the open arm (% TSOA) and higher EDA [shown by skin conductance level (SCL)] indicate higher anxiety. The NEOA and % TSOA were lower in the high-dose group than in the other groups. SCL was lower in the medium-dose carnosine group than in the high-dose carnosine and sham groups. SCL was higher in the high-dose group than in the medium-dose and sham groups. Our results suggest that high-dose carnosine produced anxiety-like effects as assessed in the SCL and ETM. Medium-dose carnosine acted as an anxiolytic. The anxiety-related responses of carnosine depend on its dose-related effect.

Multimodal analysis of cortical activation in young male adults with internet gaming disorder: A resting state EEG-fNIRS study.

BACKGROUND: Internet gaming disorder (IGD) has become increasingly prevalent worldwide and is recognized as a significant public health concern because of its negative consequences on individuals mental and physical health, social relationships, academic performance and overall well-being. While research on IGD has gained significant momentum in the past decade, the neural substrates underlying this disorder remains unclear. This study aims to investigate resting-state cortical activation in male subjects with IGD using a concurrent functional near infrared spectroscopy (fNIRS) and electroencephalography (EEG) hybrid system. METHODS: Twenty-two male individuals with IGD (18-23 years old) and twenty-two male healthy, age-matched healthy controls were included in the study. Mean oxygenation of the prefrontal cortex (PFC) and whole head neural activity were measured using fNIRS and EEG respectively, during eyes-open and eyes-closed conditions at the resting state. EEG signals were decomposed into distinct frequency sub-bands with wavelet transform, followed by the analysis of the power spectral density within each band. Mean oxygenation of PFC is measured using a multichannel fNIRS system. RESULTS: Results revealed that the individuals with IGD had significantly higher beta power in the frontal region compared to the control group. Individuals with IGD showed significantly increased PFC oxygenation compared to healthy controls. Additionally, both frontal beta power and PFC oxygenation were significantly correlated with IGD severity. However, there were no significant correlations observed between oxygenation and beta powers. CONCLUSION: This study is the first to examine resting-state cortical activation using multimodal EEG-fNIRS system in young adults with IGD. Moreover, it provides an important contribution to the understanding of the underlying neural mechanisms of IGD and offer new insights for the diagnosis and intervention of the disorder using multimodal EEG-fNIRS system. Further studies should aim to replicate the findings of this study using a larger and more culturally diverse sample to support the neurophysiological basis of IGD.

Effect of Boron on Sympathetic Skin Response in Rats.

Background: Boron effects on reproduction and growth have been extensively studied in animals. Electrodermal activity (EDA) reflects the activity of eccrine sweat glands stimulated by the release of acetylcholine from sympathetic nerves. Aim: In the presen study, it was aimed to examine the effect of boron, which was turned into cream, on sweat glands. Methods: A cream form mixed with thyme oil was prepared for EDA recording. Our groups were formed as EDA recording gel (Group 1), cream with thyme oil (Group 2), cream containing 10% boron (Group 3) and cream containing 30% boron (Group 4). In each group, 3 months old, 10 male rats were used, and creams were applied to the soles of the hind extremities of the rats, EDA was recorded from this region after half an hour, and skin conductivity levels (SCL) were recorded as tonic (at rest) and phasic (with auditory sound stimulation). Results: EDA results recorded in the morning were analysed with tonic and phasic recordings. In the morning SCL measurements, tonic SCL value of Group 4 was higher than the other groups (P < 0.001). Although the phasic SCL value was measured, it was significantly higher in Group 4 than in all groups (P < 0.0s). Conclusion: EDA measurements showed that boron increased sweat gland activity by increasing sympathetic nerve activity.

Experimentally induced hyperthyroidism disrupts hippocampal long-term potentiation in adult rats.

BACKGROUND: Manipulating thyroid hormones has been shown to influence learning and memory. Although a large body of literature is available on the effects of thyroid hormone deficiency on learning and memory functions during developmental or adult-onset hypothyroidism, electrophysiological findings are limited. This limitation is especially notable with respect to thyroxine administration in adult, normothyroid animals. METHODS: Experiments were carried out on 12 adult male Wistar rats, each 9-10 months of age. Rats were randomly divided into hyperthyroid (0.2 mg/kg/day intraperitoneal thyroxine injection, for 21 days) and control groups (n = 6 animals in each group). Following spatial learning performance tests on hyperthyroid and control groups, rats were anesthetized with urethane and placed in a stereotaxic frame. A bipolar, tungsten electrode was used to stimulate the medial perforant path. A glass micropipette was inserted within the granule cell layer of the ipsilateral dentate gyrus to record field excitatory postsynaptic potentials (fEPSP). Following a 15-min baseline recording of fEPSPs, long-term potentiation (LTP) was induced by four sets of tetanic pulse trains. RESULTS: Thyroxine-treated rats showed significantly worse performance in the spatial memory task and attenuated input-output relationships in the electrophysiological analyses. Treated rats also showed a lower efficacy of LTP induction when compared with controls. CONCLUSION: The present study provides clear in vivo evidence for the action of L-thyroxine in the impairment of synaptic plasticity and in inducing spatial memory task deficits in adult rats. These findings may explain the complaints of cognitive function reductions in hyperthyroid patients.

A heritable profile of six miRNAs in autistic patients and mouse models.

Autism spectrum disorder (ASD) is a group of developmental pathologies that impair social communication and cause repetitive behaviors. The suggested roles of noncoding RNAs in pathology led us to perform a comparative analysis of the microRNAs expressed in the serum of human ASD patients. The analysis of a cohort of 45 children with ASD revealed that six microRNAs (miR-19a-3p, miR-361-5p, miR-3613-3p, miR-150-5p, miR-126-3p, and miR-499a-5p) were expressed at low to very low levels compared to those in healthy controls. A similar but less pronounced decrease was registered in the clinically unaffected parents of the sick children and in their siblings but never in any genetically unrelated control. Results consistent with these observations were obtained in the blood, hypothalamus and sperm of two of the established mouse models of ASD: valproic acid-treated animals and Cc2d1a+/- heterozygotes. In both instances, the same characteristic miRNA profile was evidenced in the affected individuals and inherited together with disease symptoms in the progeny of crosses with healthy animals. The consistent association of these genetic regulatory changes with the disease provides a starting point for evaluating the changes in the activity of the target genes and, thus, the underlying mechanism(s). From the applied societal and medical perspectives, once properly confirmed in large cohorts, these observations provide tools for the very early identification of affected children and progenitors.

Effects of carnosine on long-term plasticity of medial perforant pathway/dentate gyrus synapses in urethane-anesthetized rats: an in vivo model.

The objective of this study was to examine the effect of carnosine on the hippocampal-dependent learning in perforant pathway/dentate gyrus synapses. The experiments were carried out on adult rats. A bipolar stimulating electrode was placed to the medial perforant path and a double-barrel glass micropipette was placed in the dentate gyrus as the recording electrode. Artificial cerebrospinal fluid (to control group) or carnosine (0.1, 1 microg/microL) was infused into the dentate gyrus via one of the barrels of the glass electrode. Our results showed that the I/O curve of excitatory postsynaptic potential (EPSP) slope or population spike (PS) amplitude was not significantly shifted by carnosine. Although carnosine infused prior to high-frequency stimulation (HFS) decreased the slope of EPSP and amplitude of PS, when infused after HFS, no effect was observed. In the present study, we speculated that carnosine decreased LTP by inhibiting sGC activation. The present experiment provides the first evidence that carnosine may play a role in synaptic plasticity in dentate gyrus in vivo.

Evaluation of divided attention using different stimulation models in event-related potentials.

Divided attention is defined as focusing on different tasks at once, and this is described as one of the biggest problems of today's society. Default examinations for understanding attention are questionnaires or physiological signals, like evoked potentials and electroencephalography. Physiological records were obtained using visual, auditory, and auditory-visual stimuli combinations with 48 participants-18-25-year-old university students-to find differences between sustained and divided attention. A Fourier-based filter was used to get a 0.01-30-Hz frequency band. Fractal dimensions, entropy values, power spectral densities, and Hjorth parameters from electroencephalography and P300 components from evoked potentials were calculated as features. To decrease the size of the feature set, some features, which yield less detail level for data, were eliminated. The visual and auditory stimuli in selective attention were compared with the divided attention state, and the best accuracy was found to be 88.89% on a support vector machine with linear kernel. As a result, it was seen that divided attention could be more difficult to determine from selective attention, but successful classification could be obtained with appropriate methods. Contrary to literature, the study deals with the infrastructure of attention types by working on a completely healthy and attention-high group. Graphical abstract.

Effects of Methylphenidate on Reaction Time in Children with Attention Deficit / Hyperactivity Disorder.

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is associated with a broad range of neuropsychological impairments that are attenuated with methylphenidate (MPH) treatment. The aim of this study was to determine how MPH effects attentional functioning in terms of reaction time (RT) in ADHD. METHODS: Eighteen pre-medicated ADHD children (7 to 12 years old) and eighteen gender matched normal controls (7 to 12 years old) were included in the study. Participants performed an auditory attention task and the RT of participants to each target response was calculated automatically. The same test was repeated 3 months after OROS-MPH administration for ADHD group. RT, RT standard deviation (RTSD), and response errors (omission and commission errors) were compared between control and pre-MPH ADHD groups, and between Pre-MPH and post-MPH ADHD groups. RESULTS: Relative to control subjects, significantly longer RTs, higher RTSD and more errors of omission were observed in unmedicated ADHD children during auditory attention task. Analyses revealed significant effects of medication across all measures except commission errors. After treatment RTs were faster, RTSD values were lower, and errors of omission were attenuated compared to pre-medication condition in ADHD group. There were no significant differences in terms of commission errors between groups. CONCLUSION: In this study it was observed that MPH reduced RTs to stimuli, attenuated omission errors during the task in ADHD group and after 3 months of treatment ADHD children showed similar patterns in RT as compared to controls. Results suggest that when treating ADHD, it might help clinicians to evaluate objective and non-invasive cognitive outcomes such as RT, RTSD and response errors to evaluate the effects of treatment.

Dose-related anxiogenic effect of glycine in the elevated plus maze and in electrodermal activity.

We investigated effect of glycine on anxiety at different doses using electrodermal activity and an elevated-plus maze. A single dose of glycine was injected intraperitoneally into three different groups of mice at 250 mg/kg, 750 mg/kg, and 1250 mg/kg. The anxiety scores with the elevated-plus maze, consisting of two open arms and two enclosed arms, were measured 30 minutes after injection. Then skin conductance level was measured. Glycine significantly decreased the times spent on the open arms in middle-dose and high-dose groups compared with the control group. The skin conductance level was statistically lower in high dose group than control groups. Conclusion; glycine at a dose of 750 mg/kg induced a nearly maximal anxiogenic effect because a higher dose was not more effective.

Arousal and continuous attention during Ramadan intermittent fasting.

During the month of Ramadan, practicing Muslims abstain from eating and drinking from sunrise to sunset. We aimed to investigate the effect of Ramadan fasting on arousal and continuous attention. The electrodermal activity and cancellation test of students were measured in fasting and non-fasting conditions after the conclusion of the Ramadan fast period. The skin conductance level of the fasting group was no different from the non-fasting group. In non-fasting group, the skin conductance response amplitude to an auditory stimulus was higher and the skin conductance response onset latency was lower than in the fasting group. Cancellation test results: the fasting group had a lower total number of marked targets (TNTM) but a higher total number of missed targets (TNMT) and length of time for the subject to complete the test (LTCT) than the non-fasting group. Ramadan fasting did not change arousal, but the reaction time to an auditory stimulus increased during the Ramadan intermittent fasting. Both reaction amplitude and continuous attention also decreased in the fasting condition.

Effect of PUVA therapy on electrodermal activity parameters in vitiligo patients.

UNLABELLED: Recent electrophysiological studies on autonomic dysfunction in vitiligo patients show an autonomic dysfunction as measured by absent sympathetic skin response (SSR). Nothing is known about the reversibility of these autonomic parameters with treatment. The present study examined how Electrodermal Activity (EDA) parameters were affected from vitiligo illness before PUVA therapy and whether any electrophysiological gains acquired from PUVA therapy would influence the progression of the condition itself. We studied in 14 healthy subjectS and 14 patients with generalized vitiligo before and after treatment. EDA was recorded with a skin conductance unit connected to a personal computer. Before treatment, skin conductance level (SCL) and habituation number (HN) was higher in vitiligo group than control groups. After treatment, SCL and HN were decreased nearly to normal value. Before and after treatment, prevalence of non-responsivity was higher in vitiligo group than controls. CONCLUSION: The sympathetic nervous system might have a particular role in the pathogenesis of vitiligo. Thus, patients with vitiligo may have changes to EDA parameters that are reversible to great extent with PUVA therapy. EDA is a useful method of studying the autonomic dysfunction in humans.

Effect of Vitamin E Administration on Learning of the Young Male Rats.

The effect of vitamin E intake on spatial learning and working memory performances of young rats has been investigated in the Morris water maze and locomotor activity has been assessed by an open-field test. A total of 45 young male Wistar albino rats aged two months were divided into three equal groups: control, olive oil, and vitamin E groups. These groups were treated for 30 days with a once daily intraperitoneal injection. The rats were then tested for their ability to find the location of the platform (spatial learning). The results revealed that there was no statistically significant difference between the time spent to find the platform and the time spent in half area of the tank, including the platform among the group, while the time spent to find the platform was found to have increased from the first day to the fourth day in all the groups. In the open-field test, the locomotor activity quite significantly increased in the peripheral area in the olive oil group. The supplementation with vitamin E for a short period had not improved the learning performance of the healthy young rats. It was concluded that the beneficial effect of vitamin E intake on learning is related to the beginning time and the duration of vitamin E intake.

Effects of cold exposure on behavioral and electrophysiological parameters related with hippocampal function in rats.

AIM: Behavioral and mental changes may occur in people exposed to cold stress by decreasing their work efficiency and their mental capacity while increasing the number of accidents on the job site. The goal of this study was to explore the effect of cold stress in spatial learning performance excitability and LTP. MATERIALS AND METHODS: Three to four month old rats were randomly divided into four groups to form a control group and a cold stress group for each sex. The groups of cold stressed animals were placed in a cold room ambient temperature of 4°C for 2 h day. Adrenal glands and body weight (g) were recorded in control and stressed rats during the cold exposure. Spatial learning (acquisition phase) and memory (probe trial) were tested in the Morris water maze (MWM) immediately after daily exposure. Latency to locate the hidden platform, distance moved (DM), mean distance to platform, swim speed (SS) and time spent in the platform quadrant were compared between genders and treatments. Field potential recordings were made, under urethane anesthesia, from the dentate gyrus (DG) granule-cell layer, with stimulation of the medial perforant pathway 2 h after the probe trial. This study examined spatial memory as measured by MWM performance and hippocampal long-term potentiation (LTP) in the DG after exposure to cold in a repeated stress condition for 2 h/day for 5 days. RESULTS: The cold-exposed female rats needed less time to find the hidden platform on day 1 (43.0 ± 13.9 s vs. 63.2 ± 13.2 s), day 2 (18.2 ± 8.4 s vs. 40.9 ± 12.2 s) and on day 4 (8.0 ± 2.1 s vs. 17.2 ± 7.0 s) while cold-exposed male rats showed a decreased escape latency (EL) on day 1 only (37.3 ± 12.5 s vs. 75.4 ± 13.1 s). Cold-exposed male rats spent less time in the target quadrant (30.08 ± 6.11%) than the control male rats (37.33 ± 8.89%). Two hour cold exposure decreased population spike (PS) potentiation during both induction (218.3 ± 21.6 vs. 304.5 ± 18.8%) and maintenance intervals (193.9 ± 24.5 vs. 276.6 ± 25.4%) in male rats. Meanwhile cold exposure did not affect the body weight (C: 221 ± 2.5 vs. S: 222 ± 1.7) but it impacts the adrenal gland relative weight (S: 27.1 ± 1.8 mg vs. C: 26.2 ± 1.4 mg). CONCLUSION: Overall, the results show that repeated cold exposure can selectively improve spatial learning in adult female rats, but impaired retention memory for platform location in male rats. It is possible that impaired LTP underlies some of the impaired retention memory caused by cold exposure in the male rats.

Examination of Attention Level in Nurses Working Night Shifts in terms of the Relationship between Electrodermal Activity and Sex Hormones.

INTRODUCTION: Electrodermal activity (EDA) is an electrical activity of eccrine sweat gland stimulated by the sympathetic nervous system. Skin conductance level (SCL) is measured with EDA. SCL and sweat gland activity increase in emotional situations, such as high activation, attention or stress. In this study, we investigated whether working in shifts affects attention level of nurses with EDA and explored the relationship between EDA and sex hormones. METHOD: The study was carried out on nurses working night shifts (16.00-08.00 h) (n=22) and nurses working without a shift (08.00-16.00 h) (n=20). Firstly, The Epworth Sleepiness Scale which evaluates a person's daytime sleepiness was applied to the subjects. For EDA measurement, Ag/AgCl electrodes were put on two fingers of their dominant hand. SCL was measured via MP30 system and GSR connection. The blood samples were analyzed for cortisol and ACTH hormone levels to investigate the changes in sleep and circadian rhythm. RESULT: It was found that there was no statistically significant difference in skin conductance levels between the groups. Moreover, in the comparison of hormone values between the groups, the cortisol levels in night shift nurses were higher than in those working without a shift. CONCLUSION: Night shift had no significant effect on the attention levels in the nurses. This situation is thought to be related to the fact that the nurses responsible for the night service raise their attention level to the highest point. The reason for higher level of cortisol in nurses working shifts may reflect that cortisol has no effect on the breadth of attention but reflects a high level of stress.

Maternal intake of Omega-3 essential fatty acids improves long term potentiation in the dentate gyrus and Morris water maze performance in rats.

Omega-3 fatty acid deprivation during development reduces performance in learning tasks, and dietary DHA supplementation improves learning ability and enhances long term memory in both young and old animals. However, little attention has been paid to the effect of maternal intake of Omega-3 fatty acids on hippocampal function in their pups. Randomly some of the pregnant dams were supplemented with Omega-3 essential fatty acid, others with tap-water, during pregnancy and breast-feeding by gavage daily. Spatial learning and memory was tested in Morris water maze. Field potentials from the dentate gyrus were recorded in response to medial perforant pathway in urethane-anesthetized pups. Omega-3-treated rats found the platform less traveled and closer to platform than control animals. However the pups from both groups show the same performance in retrieval task. No differences were found between corresponding animal groups in the input-output curves of the field potential slopes, suggesting no effect of Omega-3 supplementation on basal synaptic efficacy. Potentiation of population spike amplitude was much higher in pups of Omega-3 treated dams than control. Up to now Omega 3 fatty acid has been shown to be beneficial on the synaptic plasticity only under some pathological conditions. For the first time, we showed improved dentate gyrus-LTP and enhanced Morris water maze performance in healthy pups from healthy dams treated with Omega-3 fatty acids during pregnancy and breast-feeding period. Molecular studies are needed to explain Omega-3 effect on hippocampal synaptic plasticity.

The effects of long-term sleep deprivation on the long-term potentiation in the dentate gyrus and brain oxidation status in rats.

Some evidence suggests that sleep deprivation might impair synaptic plasticity and produce oxidative stress in the hippocampus. However it is not clear whether impairment of long-term potentiation depends on the oxidative stress evoked by sleep deprivation protocol. In this study we aimed to investigate the effects of a 21-day sleep deprivation period on long-term plasticity taking into account the stressful effect of sleep deprivation. Sleep deprivation was carried out using the multiple platforms method on adult male Wistar rats. Long-term potentiation was studied in the medial perforant pathway-dentate gyrus synapses. Elevated T test was applied, and blood corticosterone levels were measured. Lipid peroxidation products in whole brain and hippocampus were determined. No significant difference was found between the sleep deprived, pedestal and cage control groups at the end of the 21-day period when corticosterone levels were compared. The results of the elevated T test indicated that sleep deprivation did not change the anxiety-like behavior of the animals. When compared with cage or pedestal control groups, sleep deprived rats displayed elevated malondialdehyde levels, and decreased superoxide dismutase and glutathione peroxidase activities together with impaired long-term potentiation maintenance. It can be argued that 21-day SD may impair the maintenance of long-term potentiation evoked in the dentate gyrus, and the balance between oxidant and antioxidant defenses of the hippocampus.

Electrophysiological evidence of biphasic action of carnosine on long-term potentiation in urethane-anesthetized rats.

Carnosine is a dipeptide synthesized by the carnosine synthetase from ß-alanine and l-histidine. The well-known effects of carnosine may be related with mechanisms producing long-term potentiation which is one of the electrophysiological signs of memory. In the present study we aimed to investigate the effect of four different doses of carnosine on long-term potentiation in urethane-anesthetized rat. A bipolar stimulating electrode was placed in the medial perforant path and a double-barrel glass micropipette was placed in the dentate gyrus as the recording electrode. Artificial cerebrospinal fluid (in the control group) or carnosine (0.1, 1, 10, and 100µg/µL) was infused into the dentate gyrus. Our results showed that the I/O curve of the excitatory postsynaptic potential slope or population spike amplitude was not significantly shifted by carnosine. We found that population spike amplitude increased to 244% and 287% at the dose of 100µg/µL in the post-tetanic and induction phases, respectively, but decreased to 163% and 186% at the dose of 0.1µg/µL and to 145% and 162% at the dose of 1µg/µL when compared with 203% and 232% of the control values. However, there were no significant differences for the slope of excitatory postsynaptic potential. Carnosine had no effect on the EPSP slope or PS amplitude recorded from the dentate gyrus in response to test stimuli when high-frequency stimulation was not delivered. In the present study, we speculated that the effects of carnosine in lower or higher doses could be explained by its effect on different processes, such as soluble guanylyl cyclase inhibition or the conversion of carnosine into histamine.

Effect of hyperglycemia on electrodermal activity in diabetic rats.

This study investigated the relationship between hyperglycemia and electrodermal activity (EDA) parameters in streptozotocin (STZ) induced diabetic rats. The article evaluates the course of development of neurophysiological alterations in the peripheral nervous system in diabetic rats through EDA. Rats were made diabetic using a moderate dose of STZ (DI) and high dose (DII). The placebo group (P) was injected with physiological saline. EDA was recorded 1 h before the injection (beginning, 0, day), 1st day (one day after the injection) and 10th day. Skin conductance level (SCL) was lower in DII than P on the 1st and the 10th days. The SCL and SC fluctuation rate (SCFr) of DI were significantly lower on the 10th day compared to their first record. SC response rate (SCRr) was lower on the 10th day compared to the 1st day, in the DI. In the DI, SCL, SC fluctuation rate (SCFr) and SC response rate (SCRr) were lower on the 10th day compared to the 1st day. The DII was statistically higher in electrodermal non-responsiveness compared to other groups on the 1st day. The results obtained show that hyperglycemia affects the peripheral nervous system, and EDA parameters are affected by blood glucose level. It is suggested that EDA is a simple and non-invasive electrophysiological method in early diagnosis of diabetic neuropathy.