Electrode Placement Sites Research Articles

Transcutaneous Spinal Cord Stimulation to Stabilize Seated Systolic Blood Pressure in Persons With Chronic Spinal Cord Injury: Protocol Development.

Transcutaneous spinal cord stimulation (tSCS) is an emerging therapeutic strategy to target spinal autonomic circuitry to normalize and stabilize blood pressure (BP) in hypotensive persons living with chronic spinal cord injury (SCI). Our aim is to describe our current methodological approach to identify individual tSCS parameters that result in the maintenance of seated systolic blood pressure (SBP) within a pre-defined target range. The parent study is a prospective, randomized clinical trial in which eligible participants will undergo multiple mapping sessions to optimize tSCS parameter settings to promote stable SBP within a target range of 110-120 mm Hg for males and 100-120 mm Hg for females. Parameter mapping includes cathode electrode placement site (T7/8, T9/10, T11/12, and L1/2), stimulation frequency (30, 60 Hz), current amplitudes (0-120 mA), waveform (mono- and biphasic), pulse width (1000 μs), and use of carrier frequency (0, 10 kHz). Each participant will undergo up to 10 mapping sessions involving different electrode placement sites and parameter settings. BP will be continuously monitored throughout each mapping session. Stimulation amplitude (mA) will be increased at intervals of between 2 and 10 mA until one of the following occurs: 1) seated SBP reaches the target range; 2) tSCS intensity reaches 120 mA; or 3) the participant requests to stop. Secondary outcomes recorded include 1) symptoms related to autonomic dysreflexia and orthostatic hypotension, 2) Likert pain scale, and 3) skin appearance after removal of the tSCS electrode. Clinical Trials Registration: NCT05180227.

287 Role and Efficacy of "Frequency-Modulated Electromagnetic Neural Stimulation" in Treatment for Painful Peripheral Neuropathy in Patients with Diabetes Mellitus: A Retrospective Cohort Study

Abstract Aim Evaluate the efficacy of frequency rhythmic electrical modulation system "FREMS" as a symptomatic treatment for painful peripheral neuropathy(PN) in patients with diabetes mellitus Method Retrospective cohort study on 75 patients with Painful PN , who had 10 FREMS sessions using APTIVA device (Lorenz Biotech, Italy), from January 2019 - February 2020. Patients’ data were collected through the Diabetic Foot Center digital database. Results 75 patients had APTIVA sessions; Pain assessment was done using Visual analog pain score 0 to 5: 0 = no pain / 5 = severe pain. 16 patients were excluded as they did not complete the 10 sessions and 59 patients were reviewed. No treatment-related adverse events were recorded during the study rather than very slight burning sensation at the site of electrode placement. Pain at the beginning 46/59(77.9%) of patients suffered from severe pain (grades 4 & 5), 10/59(16.9%) of patients suffered from moderate pain (grade 3,2) and 2/59 (5%) of patients suffered from mild pain (grades 1 &0). Pain at the last session : The percentage of patients that suffered from severe pain dropped from 77 % before treatment to 11% after treatment. From the 46 patients that suffered from severe pain, 12/46 patients (25%) of them improved to mild pain and 27/46 patients (58%) improved to moderate pain. By comparing the pain score in patients before and after APTIVA, there was a significant statistical difference between the 2 groups using “Paired t-test” with P<0.0001. Conclusions APTIVA proved to be a safe & effective treatment in reduction of Pain for painful PN.

Electroencephalogram (EEG) based prediction of attention deficit hyperactivity disorder (ADHD) using machine learning

“Attention-Deficit Hyperactivity Disorder (ADHD)” is a neuro-developmental disorder in children under 12 years old. Learning deficits, anxiety, depression, sensory processing disorder, and oppositional defiant disorder are the most frequent comorbidities of ADHD. This research focuses on ADHD in children, considering its common occurrence and frequent coexistence with other mental disorders. The study utilizes the resting-state open-eye “Electroencephalogram” (EEG) signals of 61 children with ADHD and 60 healthy children. Morphological and “Power Spectral Density” (PSD) features associated with ADHD are analysed and “Principal Component Analysis” (PCA) is employed to reduce data dimensionality. Classification algorithms including AdaBoost, “K-Nearest Neighbour” (KNN) classifier, Naive Bayes, and random forest are utilized, with the Bernoulli Naive Bayes classifier achieving the highest accuracy of 96%. This study found some relevant characteristics for classification at the frontal (F), central (C), and parietal (P) electrode placement sites. Finally, this reveals distinct EEG patterns in children with ADHD and the study provides a potential supplementary method for ADHD diagnosis.

Electrode Montage Induced Changes in Air-Conducted Ocular Vestibular-Evoked Myogenic Potential.

Stimulus and recording parameters are pivotal for shaping the ocular vestibular-evoked myogenic potential (oVEMP). In the last decade, several attempts were made to identify the optimum electrode placement site to improve the oVEMP responses. A vast majority of these found larger response amplitudes for alternate electrode montages like belly-tendon (BT), chin-referenced (CR), and/or sternum-referenced montages than the clinically used infra-orbital montage. However, no study has yet compared all alternate electrode montages in a simultaneous recording paradigm to eliminate other confounding factors. Also, no study has compared all of them for their test-retest reliability, waveform morphology, and signal-to-noise ratio. Therefore, the decision on which among these electrode montages is best suited for oVEMP acquisition remains opaque. The present study aimed to investigate the effects of various electrode montages on oVEMP's response parameters and to determine the test-retest reliability of each of these in clinically healthy individuals using a simultaneous recording paradigm. This study had a within-subject experimental design. Fifty-five young healthy adults (age range: 20-30 years) underwent contralateral oVEMP recording using infra-orbital, BT, chin-referenced, and sternum-referenced electrode montages simultaneously using a four-channel evoked potential system. BT montage had a significantly shorter latency, larger amplitude, higher signal-to-noise ratio, and better morphology than other alternate montages ( p < 0.008). Further, all electrode montages of the current study showed fair/moderate to excellent test-retest reliability. By virtue of producing significantly better response parameters than the other electrode montages, BT montage seems better suited to the recording of oVEMP than the known electrode montages thus far.

High-Definition Transcranial Direct Current Stimulation Improves Decision-Making Ability: A Study Based on EEG

High-definition transcranial direct current stimulation (HD-tDCS) has been shown to modulate decision-making; however, the neurophysiological mechanisms underlying this effect remain unclear. To further explore the neurophysiological processes of decision-making modulated by HD-tDCS, health participants underwent ten anodal (n = 16)/sham (n = 17) HD-tDCS sessions targeting the left DLPFC. Iowa gambling task was performed simultaneously with electroencephalography (EEG) before and after HD-tDCS. Iowa gambling task performance, the P300 amplitude, and the power of theta oscillation as an index of decision-making were compared. Behavioral changes were found that showed anodal HD-tDCS could improve the decision-making function, in which participants could make more advantageous choices. The electrophysiological results showed that the P300 amplitude significantly increased in CZ, CPZ electrode placement site and theta oscillation power significantly activated in FCZ, CZ electrode placement site after anodal HD-tDCS. Significant positive correlations were observed between the changes in the percent use of negative feedback and the changes in theta oscillation power before and after anodal HD-tDCS. This study showed that HD-tDCS is a promising technology in improving decision-making and theta oscillation induced by may be a predictor of improved decision-making.

Semitendinosus muscle morphology in relation to surface electrode placement in anterior cruciate ligament reconstructed and contralateral legs.

The semitendinosus tendon is commonly harvested as graft tissue for anterior cruciate ligament reconstruction (ACLR). Although the semitendinosus tendon can regenerate following harvesting, ACLR results in substantial reductions in semitendinosus muscle size and length, potentially complicating electrode placement for electromyography. The purpose of this study was to assess whether the most commonly used electrode placement [recommended by the "Surface Electromyography for Non-Invasive Assessment of Muscles" (SENIAM) project] is appropriate for measuring semitendinosus electromyograms after ACLR. In nine participants (unilateral ACLR with a semitendinosus graft), B-mode ultrasonography was used to bilaterally determine (i) the semitendinosus muscle-tendon junction position and the state of tendon regeneration (latter for the ACLR leg only) and (ii) the anatomical cross-sectional area (ACSA) of the semitendinosus muscle at the SENIAM-recommended electrode placement site at rest and during isometric maximal voluntary contraction (MVC) at two knee joint angles. Depending on the contraction state and joint angle, the semitendinosus muscle had retracted past the recommended placement site in 33-78% of ACLR legs, but not in any contralateral legs. The ACSA of semitendinosus was smaller both at rest and MVC in the ACLR compared to contralateral leg. The ACSA for both legs decreased at MVC compared to rest and at deep compared to shallow knee flexion angles, likely due to sliding of the muscle under the skin. These results suggest SENIAM guidelines are likely unsuitable for recording surface electromyograms from the semitendinosus muscle after tendon harvesting for ACLR as the muscle of interest may not be within the electrode detection volume.

Examination of surface electrode placement site for suprahyoid muscle stimulation

Examination of surface electrode placement site for suprahyoid muscle stimulation

Enhancement of Processing Capabilities of Hippocampus Lobe: A P300 Based Event Related Potential Study.

Background and ObjectivesThe influence of music training on different areas of the brain has been extensively researched, but the underlying neurobehavioral mechanisms remain unknown. In the present study, the effects of training for more than three years in Carnatic music (an Indian form of music) on the discrimination ability of different areas of the brain were tested using P300 analysis at three electrode placement sites.Subjects and MethodsA total of 27 individuals, including 13 singers aged 16-30 years (mean±standard deviation, 23±3.2 years) and 14 non-singers aged 16-30 years (mean age, 24±2.9 years), participated in this study. The singers had 3-5 years of formal training experience in Carnatic music. Cortical activities in areas corresponding to attention, discrimination, and memory were tested using P300 analysis, and the tests were performed using the Intelligent Hearing System.ResultsThe mean P300 amplitude of the singers at the Fz electrode placement site (5.64±1.81) was significantly higher than that of the non-singers (3.85±1.60; t(25)=3.3, p<0.05). The amplitude at the Cz electrode placement site in singers (5.90±2.18) was significantly higher than that in non-singers (3.46±1.40; t(25)=3.3, p<0.05). The amplitude at the Pz electrode placement site in singers (4.94±1.89) was significantly higher than that in non-singers (3.57±1.50; t(25)=3.3, p<0.05). Among singers, the mean P300 amplitude was significantly higher in the Cz site than the other placement sites, and among non-singers, the mean P300 amplitude was significantly higher in the Fz site than the other placement sites, i.e., music training facilitated enhancement of the P300 amplitude at the Cz site.ConclusionsThe findings of this study suggest that more than three years of training in Carnatic singing can enhance neural coding to discriminate subtle differences, leading to enhanced discrimination abilities of the brain, mainly in the generation site corresponding to Cz electrode placement.

Effectiveness of Simulation Training on Graduate Audiology Students' Auditory Brainstem Response Testing Skills.

Purpose Simulation is a tool commonly used in the clinical training of students within the health professions fields, such as medicine and nursing. The effectiveness of simulation as a teaching technique has been extensively documented in numerous health care professions; however, little is known about the effectiveness of simulation techniques in audiology education. This study assesses the effectiveness of a simulation activity focused on auditory brainstem response (ABR) testing conducted with students of an applied doctoral program in audiology. Method Twelve 2nd year audiology graduate students enrolled in the auditory electrophysiology course at Towson University in Fall 2018 participated in this pre-post study. Over a 3-week period, each student (a) received didactic instruction in ABR testing, (b) underwent a presimulation exercise skills assessment, (c) participated in a simulation exercise, and (d) underwent a postsimulation exercise skills assessment. Results Significant improvements were observed in clinical skill level for the ABR tasks evaluated in terms of both accuracy and efficiency (time in seconds needed to complete the task). The tasks evaluated included skin preparation, identification of scalp electrode placement sites, and scalp electrode placement in a variety of configurations (single- and two-channel arrays, horizontal and vertical electrode montages). Benefits associated with simulation-based instruction varied by clinical skill as well as by student. Conclusions The data described in this study reinforce the need to incorporate simulation in audiology training programs, especially for complex clinical skills. It also emphasizes the need for additional research that can be useful in the design and implementation of simulation-based exercises.

The variability of electric pulp response thresholds in primary molars: a clinical study

The variability of the EPT response threshold is the most important part of accurate diagnosis of pulp status of caries-affected resorbing primary teeth. This study evaluated the mean EPT threshold values and appropriate electrode placement sites for primary molar teeth based on their physiological root resorption levels. This study was conducted with 100 primary second molars in 100 children ages 3-12 (mean age: 7.88years). Teeth were divided into 2 groups according to physiological root resorption levels. EPT response thresholds were recorded at the mesiobuccal cusp, occlusal third, middle third and cervical third of the crown. Data were analyzed according to resorption level using one-way analysis of variance and Duncan tests, with the level of significance set at 0.05. Mean threshold values at all placement sites were higher in the group with the higher level of physiological root resorption. In terms of placement, the lowest mean EPT threshold values were obtained at the mesiobuccal cusp regardless of resorption level. According to the study results, higher resorption levels were associated with higher physiologocial threshold values for EPT of primary second molars, with the mesiobuccal site identified as the most appropriate electrode placement site, regardless of resorption level.

Evaluation of variability of electric pulp response threshold in molars: an in vivo study

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Electric pulp testers are widely used diagnostic tools in endodontics. Several factors can affect the result of electric pulp test like thickness of enamel and dentin, concentration of sensory fibres (A delta fibres), direction of dentinal tubules, pulp chamber size, neural elements etc. There are very few studies available in the literature which evaluated the variability of electric pulp response in molar teeth, which are more susceptible to caries. Hence aim of current study was proposed to evaluate response threshold in molars with respect to age and sex using electric pulp tester.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Fifty volunteers aged between 20 to 69 years were recruited. The human subjects were divided into 5 groups of 10 each (5 males and 5 females) based on age. EPT was used with appropriate electrolyte as a conducting media. Seven sites on each molar crown were tested which includes mesiobuccal cusp tip, mesiobuccal cuspal surface, mesiobuccal gingival surface, centre of the supporting cusps (palatal of maxillary molar and buccal of mandibular molar), distobuccal cuspal surface, distobuccal gingival surface and centre of the guiding cusps (buccal of maxillary molar and lingual of mandibular molars). Statistical analysed using descriptive statistics and independent sample t test.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Mesiobuccal cusp tip showed lower response threshold values compared to other sites in all the groups. group 1 responded at lower threshold and group 5 at higher.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The optimum electrode placement site for electric pulp test in molars is the mesiobuccal cusp tip irrespective of age and sex.&lt;/p&gt;

Neuromuscular electrical stimulation for treatment of dysphagia in infants and young children with neurological impairment: a prospective pilot study

ObjectivesTo describe the acceptability, safety and effectiveness of neuromuscular electrical stimulation (NMES) in infants and young children with neurological impairment (NI) who have severe dysphagia.DesignA prospective pilot study using a...

Effects of noxious stimuli on the electroencephalogram of anaesthetised chickens (Gallus gallus domesticus)

The reliable assessment and management of avian pain is important in the context of animal welfare. Overtly expressed signs of pain vary substantially between and within species, strains and individuals, limiting the use of behaviour in pain studies. Similarly, physiological indices of pain can also vary and may be confounded by influence from non-painful stimuli. In mammals, changes in the frequency spectrum of the electroencephalogram (EEG) recorded under light anaesthesia (the minimal anaesthesia model; MAM) have been shown to reliably indicate cerebral responses to noxious stimuli in a range of species. The aim of the current study was to determine whether the MAM can be applied to the study of nociception in birds. Ten chickens were lightly anaesthetised with halothane and their EEG recorded using surface electrodes during the application of supramaximal mechanical, thermal and electrical noxious stimuli. Spectral analysis revealed no EEG responses to any of these stimuli. Given that birds possess the neural apparatus to detect and process pain, and that the applied noxious stimuli elicit behavioural signs of pain in conscious chickens, this lack of response probably relates to methodological limitations. Anatomical differences between the avian and mammalian brains, along with a paucity of knowledge regarding specific sites of pain processing in the avian brain, could mean that EEG recorded from the head surface is insensitive to changes in neural activity in the pain processing regions of the avian brain. Future investigations should examine alternative electrode placement sites, based on avian homologues of the mammalian brain regions involved in pain processing.

Ideal Electrode Placement Site of Electric Pulp Tester: A Clinical Study

Introduction: Endodontic diagnosis is the essential aid in deciding the treatment plan though it has limitations and shortcomings. Electric pulp testers are widely used for endodontic diagnosis. Such testing requires the tip of electrode to be in optimal position on the surface of the tooth. Aim: The aim of the study is to determine the ideal electrode placement site of electric pulp tester for the mandibular premolars. Material and Methods: Electric pulp tester was used to assess the response of the tooth. A sample size of 60mandibular premolar teeth were included in the study. The electrode tip of electric pulp tester was placed on different sites on the buccal aspect of the tooth. The response of the tooth was evaluated. Results: The lowest response for mandibular premolar was observed to be on the tip of the buccal cusp. The threshold level was said to increase from the buccal cusp tip to middle third and cervical third. It was also concluded that there was no significant difference found between male and female and also with respect to age in response to level of perception of threshold. Conclusion: It is necessary to place the electrode tip of the electric pulp tester at the appropriate site for the accurate diagnosis.

Influence of placement sites of the active recording electrode on CMAP configuration in the trapezius muscle

ObjectiveWe investigated how the active electrode placement site influences compound muscle action potential (CMAP) configuration of the upper trapezius muscle (TM). MethodsA nerve conduction study of the accessory nerve was performed, and the CMAPs obtained with two different placement sites, i.e., placement of the active recording electrode on the belly of the upper TM (CMAP-A) and placement of the electrode 2 cm behind the belly (CMAP-B), were compared. CMAPs were also obtained with the active recording electrode placed in the supraspinous fossa (CMAP-C). ResultsAll CMAPs were recorded from 21 healthy volunteers. The mean peak-to-peak amplitude of CMAP-B was 3.4 mV higher than that of CMAP-A (11.0 ± 4.0 mV vs. 14.4 ± 4.9 mV; P < 0.01). The mean peak-to-peak amplitude of CMAP-C was 10.3 ± 5.0 mV. ConclusionsCMAP of the upper TM was always higher when the active recording electrode was placed 2 cm behind the belly of the muscle. SignificanceWhen stimulating the accessory nerve, a current spread occurs to the C5 spinal nerve root and another CMAP originating from the supraspinatus muscle occurs in the supraspinous fossa. The volume conduction from the supraspinatus muscle affects the active recording electrode on the TM, resulting in an increase in CMAP amplitude.

Transcutaneous electrical nerve stimulation (TENS) for neuropathic pain in adults

Transcutaneous electrical nerve stimulation (TENS) for neuropathic pain in adults

Evaluation of threshold response and appropriate electrode placement site for electric pulp testing in fluorosed anterior teeth: An in vivo study.

Accurate diagnosis is key to success. Diagnosing the pulpal status in varied clinical situations poses a challenge to the clinician. Electric pulp test (EPT) is one of the valuable attempts in evaluating the sensibility of pulp tissue. The aim of this study was to find out and compare the threshold levels and optimal electrode placement site for EPT in fluorosed and nonfluorosed anterior teeth. Eighty volunteers recruited for this study were divided into two groups based on the incidence of dental fluorosis. Electric pulp testing was done on either of the central incisors in fluorosed and nonfluorosed group. Four sites on each crown were tested 4 times with digitest electric pulp tester, and the mean of the threshold responses was recorded. The data were analyzed with SPSS, version 11. Means of variables from each location were compared using one-way ANOVA and Tukey's post-hoc test while the critical level of significance was set at P < 0.05. The mean and standard deviation of threshold levels in fluorosed teeth were greater when compared to that of nonfluorosed teeth at all sites with incisal edge showing the least mean threshold levels for both the groups (P > 0.05). Within the limitations of this study, it can be concluded that fluorosed teeth respond to higher threshold levels than the non-fluorosed teeth, and incisal edge was the optimal electrode placement site.

Effect of interelectrode distance on surface electromyographic signals of vastus intermedius muscle in women and men

We previously developed a novel technique to record surface electromyography (EMG) of the vastus intermedius (VI) in men. The purpose of the present study was to assess whether this technique can be applied to women in the same way. We measured the subcutaneous fat thickness at the site of electrode placement on VI using ultrasonography. Nine men and ten women performed isometric knee extensions at 25%, 50%, 75%, and 100% of the maximal voluntary contraction. During the tasks, surface EMG signals were recorded from the superficial region of VI with interelectrode distances (IEDs) of 10mm (IED-10) and 20mm (IED-20). The subcutaneous fat thickness in women was significantly greater than in men (women: 8.7±2.1mm; men: 5.6±1.6mm, p<0.01). However, the amplitude and frequency of the EMG signal of VI at the different force levels were not affected by IEDs in either sex. These results suggest that surface EMG recording of VI with both IED-10 and IED-20 would be applicable to relatively lean women with a similar sensitivity to that in men.

Appropriate electrode placement site of electric pulp tester for the premolars: a clinical study.

Electric pulp testers (EPTs) are widely used as diagnostic aid in dentistry for dental pulp. This delivers enough current to overcome enamel and dentin resistance and to stimulate the myelinated sensory fibers at the junction of pulp and dentin. Such testing requires the electrode to be in contact with the surface of the tooth, with optimal positions identified for anterior teeth, premolars, and molars. To determine the best site position of EPT on premolars. The objective of electric pulp testing was to determine the sensibility of each premolar at the lowest sensory response threshold. Clinical study Materials and Methods: The premolars of 20 patients between 13 and 15 years accompanied with parents, free of restorations, and caries were selected. Five sites on the crown were tested with EPT for minimum of four times. One-way analysis of variance test and the Tukey's honestly significant difference test. The lowest threshold response was noted at the incisal edge of the tooth; the middle third had a higher threshold among all the different placement of electrode. Statistically significant difference was observed for occlusal surface in terms of region of placement of electrode. This experiment found the best electrode site for pulp testing in premolars. The appropriate EPT site was on the occlusal surface of maxillary and mandibular premolars.

Changes in muscle geometry during forearm pronation and supination and their relationships to EMG cross-correlation measures

Geometric artifact may alter the amplitude and frequency of the electromyography (EMG) signal. Artifacts include the changing geometry of muscles with respect to electrodes and potential crosstalk from adjacent muscles. This study addresses: (1) the geometrical relationships between common electrode placement sites for six forearm muscles, (2) the geometrical change of forearm muscles in pronation and supination, and (3) the relationships between EMG cross-correlation and muscle geometry. EMG and ultrasonography images were recorded during pronation, supination, and neutral forearm postures while exerting 20% maximum grip strength. Proportions of anatomical structures were then calculated for 15mm, 20mm, and 25mm radial pick-up zone distances, representing greater than 90% of observed myoelectrical signal energy. We found that guidelines for electrode placements were supported and no single posture maximized the proportion of the target muscle detected. Secondly, other muscles were present in the most conservative 15mm radius pick up zone; it is unlikely that surface EMG can completely differentiate between forearm muscle activities. Thirdly, forearm orientation did not appear to be an important factor in changing the geometrical relationships between surface electrodes and the muscles studied, and fourthly, certain muscles (e.g., FDS) may be more vulnerable to EMG crosstalk.