Threshold Electrical Stimulation Research Articles

Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in panic disorder patients

Psychosocial stress-induced activation of salivary α-amylase (sAA) functions is as a marker of sympathoadrenal medullary system (SAM) activity. However, in contrast to salivary cortisol, sAA has been less extensively studied in panic disorder patients. The present study measured sAA and salivary cortisol levels in patients with panic disorder following electrical stimulation stress. The authors determined Profile of Mood State (POMS) scores and State-Trait anxiety Inventory (STAI) scores, heart rate variability (HRV), and levels of sAA and salivary cortisol in 34 patients with panic disorder and 41 healthy volunteers following the application of electrical stimulation stress. 34 alprazolam-treated patients with panic disorder were divided into non-responder and responder group. Vigor scores in patients with panic disorder were significantly decreased compared with healthy controls. Another score in POMS in patients with panic disorder were significantly increased compared with healthy controls. Trait and state anxiety of STAI in panic disorder patients were higher than healthy controls. There was no difference in either HRV or threshold of electrical stimulation applied between panic disorder patients and healthy controls. SAA levels in the responder group were significantly elevated compared with the non-responder group and controls both before and after electrical stimulation. In addition, there were no differences in salivary cortisol levels between responder and non-responder groups of patients with panic disorder and control. The sample may not be representative of the general population. These preliminary results suggest that sAA might be useful predictive biological markers of treatment responsiveness in patients with panic disorder.

Developmental and maladaptive plasticity in neonatal SCI

Babies and young children with early spinal cord injury (SCI) have evidence of an improved level of recovery over an extended time period. Enhanced neuroplasticity is well recognized in neonatal animal models. In the young human, developmental apraxia and learned early habitual movements mask expression of residual or recovered motor function. Techniques providing sensorimotor stimulation with threshold electrical stimulation (TES) and EMG triggered stimulation (ETS) act to increase awareness and useful function. Small cohort size and prolonged developmental maturation argue for the use of single subject research designs in this population.

Reliability of Static and Dynamic Quantitative Sensory Testing in Patients With Painful Chronic Pancreatitis

Quantitative sensory testing (QST) has proven to be an important instrument to characterize mechanisms underlying somatic and neuropathic pain disorders. However, its reliability has not previously been established in patients with visceral pain. We investigated the test-retest reliability of static and dynamic QST in patients with visceral pain due to chronic pancreatitis. Sixty-two patients (38 men, 53 [11] y) with painful chronic pancreatitis were included. Static QST comprised sensory thresholds for pressure and electrical stimulation performed in the ventral and dorsal T10 dermatomes (sharing spinal innervation with the pancreas, ie, pancreatic viscerotomes) and in 4 heterologous regions (control areas). Dynamic QST comprised conditioned pain modulation. Measurements were obtained from 2 subsequent test sessions separated by 1 week. The reliability of static QST was generally high, with the best test-retest performance seen for pressure pain thresholds (intraclass correlation coefficients [ICC], 0.74) and electrical sensation thresholds (ICC, 0.66). In contrast, the reliability of dynamic QST was poor (ICC, 0.01). For static QST measures, the reliability was higher for pain thresholds compared with suprapain thresholds (P < 0.01). No differences between assessments in the pancreatic viscerotomes compared with heterologous regions were seen (P = 0.6). Sensory thresholds in the pancreatic viscerotomes and control areas were reproducible over time. In contrast, dynamic QST measurements reflecting active central modulation of pain processing state (ie, conditioned pain modulation) were not stable over time and showed considerable variability. These factors should be taken into consideration in case QST is used to follow disease mechanisms, drug effects, or effects of pain intervention.

Comparison of Current Perception Threshold Electrical Testing to Clinical Sensory Testing for Lingual Nerve Injuries

We performed a retrospective study of lingual nerve injury assessment comparing the techniques of current perception threshold testing versus clinical sensory testing. We designed and implemented a cross-sectional study and enrolled a patient sample with lingual nerve injuries presenting for treatment to the principal investigator. The predictor variables were clinical sensory testing modalities (ie, temperature, nocioception, vibration, 2-point discrimination, brush stroke, and von Frey monofilament perception). The primary outcome variable was the electrical current perception thresholds of the tongue dorsum (neurometer measurements at 5, 250, and 2,000 Hz). Comparisons were established with the ipsilateral affected and contralateral unaffected lingual nerve distributions. The associations between the clinical sensory testing and current perception threshold measurements were assessed using correlation coefficients, with the level of statistical significance set at P < .05. A total of 40 patients (13 males and 27 females) were included in the present study. The average age of these patients was 34 years (range 13 to 66). Significant correlations were observed between the electrical stimulation thresholds at 2,000 Hz and the 2-point discrimination, reaction to brushing, reaction to vibration, and von Frey fiber thresholds, between the electrical stimulation thresholds at 250 Hz to the nociceptive and thermal thresholds, and between the electrical stimulation thresholds at 5 Hz to thermal stimuli. The significant correlations observed in the present study indicate that current perception threshold can be a complementary or alternative tool in the assessment and evaluation of lingual nerve injuries.

Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in major depressive disorder patients

Major depressive disorder (MDD) is often associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis by chronic stress. In comparison, psychosocial stress-induced activation of salivary α-amylase (sAA) functions as a marker of sympathoadrenal medullary system (SAM) activity. However, in contrast to salivary cortisol, sAA has been less extensively studied in MDD patients. The present study measured sAA and salivary cortisol levels in patients with MDD. The authors determined Profile of Mood State (POMS) and State-Trait anxiety Inventory (STAI) scores, Heart Rate Variability (HRV), and sAA and salivary cortisol levels in 88 patients with MDD and 41 healthy volunteers following the application of electrical stimulation stress. Patients with major depressive disorder were 8 points or more on Hamilton Depression Scale (HAM-D) scores. Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue, and Confusion scores in patients with major depressive disorder were significantly increased compared to healthy controls. In contrast, Vigor scores in patients with MDD were significantly decreased compared with healthy controls. There was no difference in heart rate variability measures between MDD patients and healthy controls. The threshold of electrical stimulation applied in MDD patients was lower than that in healthy controls. SAA levels in female MDD patients were significantly elevated relative to controls both before and after electrical stimulation. Finally, there were no differences in salivary cortisol levels between major depressive patients and controls. In the present study only three time points were explored. Furthermore, the increased secretion of sAA before and after stimulation could allude to an increased responsiveness of novel and uncontrollable situations in patients with MDD. These preliminary results suggest that sAA might be a useful biological marker of MDD.

Evaluation of noise reduction technologies in a contemporary cochlear implant system

Evaluation of noise reduction technologies in a contemporary cochlear implant system

The Variability of Stimulus Thresholds in Electrophysiologic Cortical Language Mapping

The aim of this study was to investigate the variability of electrical stimulation threshold in cortical language mapping in relationship to the lobar location of the mapped eloquent cortex and the distance between the latter and the location of the cortical lesion. A multivariate linear regression analysis was performed in a sample of 39 patients who underwent standardized successful language cortical mapping. Estimated stimulus threshold for temporal language cortex was 1.45 times higher than the estimated threshold for frontal language cortex, after adjusting for the other variables (P = 0.017). Stimulation of the mapped cortex in close proximity to the lesion or to the lesional edema increased the estimated threshold 2.6 or 1.8 times, respectively, compared with stimulation in other areas, after adjusting for the other variables (P < 0.0001, P = 0.0017). In concordance with prior findings, our results show that stimulus threshold in cortical language mapping is dependent on the lobar location of the mapped cortex. In addition, stimulus threshold is increased when the mapped cortex is in close proximity to the location of the lesion or perilesional edema.

Both electrical stimulation thresholds and SMI-32-immunoreactive retinal ganglion cell density correlate with age in S334ter line 3 rat retina

Electrical stimulation threshold and retinal ganglion cell density were measured in a rat model of retinal degeneration. We performed in vivo electrophysiology and morphometric analysis on normal and S334ter line 3 (RD) rats (ages 84-782 days). We stimulated the retina in anesthetized animals and recorded evoked responses in the superior colliculus. Current pulses were delivered with a platinum-iridium (Pt-Ir) electrode of 75-μm diameter positioned on the epiretinal surface. In the same animals used for electrophysiology, SMI-32 immunolabeling of the retina enabled ganglion cell counting. An increase in threshold currents positively correlated with age of RD rats. SMI-32-labeled retinal ganglion cell density negatively correlated with age of RD rats. ANOVA shows that RD postnatal day (P)100 and P300 rats have threshold and density similar to normal rats, but RD P500 and P700 rats have threshold and density statistically different from normal rats (P < 0.05). Threshold charge densities were within the safety limits of Pt for all groups and pulse configurations, except at RD P600 and RD P700, where pulses were only safe up to 1- and 0.2-ms duration, respectively. Preservation of ganglion cells may enhance the efficiency and safety of electronic retinal implants.

Acupuncture Effect on Thermal Tolerance and Electrical Pain Threshold: A Randomised Controlled Trial

The aim of this study was to test whether acupuncture could modify the threshold of tolerance to thermal and electrical stimuli. A randomised placebo-controlled single-blind trial was conducted in 36 healthy volunteers randomly distributed to control (no treatment), conventional acupuncture and sham acupuncture groups. The subjects were blind to the group allocation. The authors measured before and after treatment the pain threshold with the Painmatcher (Cefar Medical AB, Lund, Sweden) and the cold tolerance with the cold pressor test, together with the Visual Analogue Scale pain score. Electrical stimulation threshold and cold pressor tolerance both increased significantly in the control and the true acupuncture groups, but not the sham group. The changes in the true acupuncture group were highly statistically significant and amounted to 24% (pain threshold) and 44% (cold tolerance) increases in threshold. The changes in the true group were significantly greater than the control group but not significantly different from the sham group. The changes in the sham and control groups were not significantly different from each other. Acupuncture at true, appropriate points was more effective than no intervention in raising pain threshold and tolerance in volunteers, and acupuncture at inappropriate points had an intermediate effect which was not significantly different from either. Thus acupuncture analgesia may not be a point specific effect.

Does the Location of the Motor Point Identified with Electrical Stimulation Correspond to that Identified with the Gross Anatomical Method?

[Purpose] The purpose of this study was to determine whether the location of the motor point (MP) identified with the gross anatomical method corresponds with that identified with electrical stimulation in the tibialis anterior muscle (TA) in order to test the validity of adopting the nerve entry point as the target for electrical stimulation. [Subjects] We used 16 lower limbs from 12 cadavers and 26 lower limbs from 13 healthy adults. [Methods] We identified the location where the thickest motor nerve entered the muscle belly of TA in cadavers as the anatomical MP and where the surface electrical stimulation threshold of TA was lowest in healthy adults as the electrical MP. We defined the line connecting the fibular head and the lateral malleolus as the reference line and drew a line perpendicular to this that intersected the MP. We measured each MP as the length from the fibular head to the perpendicular line, and expressed this as a proportion of the reference line length. The distribution of each MP was compared. [Results] There was significant unequal variance between the two types of MP. The electrical MP was significantly more distal than the anatomical MP. [Conclusion] The anatomical MP does not appear to correspond to the electrical MP, hence adopting the nerve entry point as the target of electrical stimulation is inappropriate.

Does Threshold Nighttime Electrical Stimulation Benefit Children With Spina Bifida?: A Pilot Study

Electrical stimulation is an established treatment for muscle weakness. However, traditional tectonic stimulation is poorly tolerated in children as a result of discomfort. Threshold electrical stimulation performed at night reportedly increases muscle strength in a variety of neuromuscular conditions and has been well tolerated in children. We asked whether threshold electrical stimulation treatment at night would increase strength and function in children with myelomeningocele. In a pilot study we prospectively followed 15 treated children who served as his or her own control. The patients were provided with a stimulator and instructed to use it on areas of muscular weakness during sleep, six nights per week. Followup phone calls at 2 weeks and then monthly were performed by a physical therapist to address patient concerns. Assessments of muscle strength, monofilament sensation, and physical function using the Functional Independence Measure for Children were to be performed at 3-month intervals up to 12 months and compared with the pretreatment assessment. Only seven of the 15 subjects completed 9 months of treatment and none finished the 1-year study. The most frequent complaint was the treatment schedule was too intensive for the benefits received. We found small gains in muscle strength, gait, and bowel continence but no changes in physical function. Although threshold electrical stimulation made small improvements in muscle strength, the currently recommended treatment schedules are not practical for patients with myelomeningocele.

The predictive power of balloon shape and change of sensory functions on outcome of percutaneous balloon compression for trigeminal neuralgia

Percutaneous balloon compression is a simple and effective treatment of trigeminal neuralgia. However, results between and within different series are varying. To further improve the results in terms of pain relief, the authors believe that a careful study of the surgical procedure is important. The object of this study was to analyze the impact of balloon shape, balloon position, balloon volume, and compression time on duration of the therapeutic effect following percutaneous balloon compression. Furthermore, they analyzed the sensory side effects associated with this treatment, and how these relate to surgical parameters. Medical records and intraoperative radiographs from 87 balloon compressions were reviewed, and different surgical parameters were categorized. Univariate and multivariate analyses were performed to correlate surgical parameters to pain relief. Sensory testing with a transcutaneous electrical stimulation technique and clinical examination data were reviewed to analyze changes in sensory function. The balloon shape had a significant impact on time to recurrence of pain. A pear-shaped balloon resulted in a far better surgical result than a non-pear-shaped balloon (p < 0.001). The difference between a distinct and a less distinct pear shape was not significant (p = 0.14). Statistical significance was not reached for any of the other parameters in relation to duration of therapeutic effect. A pear-shaped balloon was also significantly associated with increased thresholds for percutaneous electrical stimulation in the immediate postoperative period, but the perception thresholds were normalized at the late follow-up at 3-9 months. A similar outcome was found for clinical testing with light touch and pinprick. The authors have demonstrated that using a pear-shaped balloon when performing percutaneous balloon compression for trigeminal neuralgia results in longer pain relief than non-pear-shaped balloons. Other surgical parameters seemed less important with respect to pain relief. Balloon compression also, in many cases, results in hypesthesia.

MGluR2-Positive Allosteric Modulators: Therapeutic Potential for Treating Cocaine Abuse?

mGluR2-Positive Allosteric Modulators: Therapeutic Potential for Treating Cocaine Abuse?

Neurophysiological evaluation of convergent afferents innervating the human esophagus and area of referred pain on the anterior chest wall

Noxious stimuli in the esophagus cause pain that is referred to the anterior chest wall because of convergence of visceral and somatic afferents within the spinal cord. We sought to characterize the neurophysiological responses of these convergent spinal pain pathways in humans by studying 12 healthy subjects over three visits (V1, V2, and V3). Esophageal pain thresholds (Eso-PT) were assessed by electrical stimulation and anterior chest wall pain thresholds (ACW-PT) by use of a contact heat thermode. Esophageal evoked potentials (EEP) were recorded from the vertex following 200 electrical stimuli, and anterior chest wall evoked potentials (ACWEP) were recorded following 40 heat pulses. The fear of pain questionnaire (FPQ) was administered on V1. Statistical data are shown as point estimates of difference +/- 95% confidence interval. Pain thresholds increased between V1 and V3 [Eso-PT: V1-V3 = -17.9 mA (-27.9, -7.9) P < 0.001; ACW-PT: V1-V3 = -3.38 degrees C (-5.33, -1.42) P = 0.001]. The morphology of cortical responses from both sites was consistent and equivalent [P1, N1, P2, N2 complex, where P1 and P2 are is the first and second positive (downward) components of the CEP waveform, respectively, and N1 and N2 are the first and second negative (upward) components, respectively], indicating activation of similar cortical networks. For EEP, N1 and P2 latencies decreased between V1 and V3 [N1: V1-V3 = 13.7 (1.8, 25.4) P = 0.02; P2: V1-V3 = 32.5 (11.7, 53.2) P = 0.003], whereas amplitudes did not differ. For ACWEP, P2 latency increased between V1 and V3 [-35.9 (-60, -11.8) P = 0.005] and amplitudes decreased [P1-N1: V1-V3 = 5.4 (2.4, 8.4) P = 0.01; P2-N2: 6.8 (3.4, 10.3) P < 0.001]. The mean P1 latency of EEP over three visits was 126.6 ms and that of ACWEP was 101.6 ms, reflecting afferent transmission via Adelta fibers. There was a significant negative correlation between FPQ scores and Eso-PT on V1 (r = -0.57, P = 0.05). These data provide the first neurophysiological evidence of convergent esophageal and somatic pain pathways in humans.

Stimulation threshold potentials of intraoperative cortical motor mapping using monopolar trains of five in pediatric epilepsy surgery

Direct cortical stimulation in commonly used for the accurate localization of the motor cortex but the electrical threshold stimulation parameters with this technique had not been fully established. A retrospective review of 15 cases of pediatric surgical cases were performed. The patients consisted of nine male patients and six female patients with age range from 2 to 18 years (mean: 10.8 years; median: 14 years). The most common pathology was cortical dysplasia (nine cases). Stimulation was performed with a train of five stimulations (range five-seven stimulations; <5% of stimulations required more than five stimulations) applied, each train of 50 micros pulse duration, with an interstimulus interval of 1.1 msec. Stimulation intensity commenced at 25 V and this was increased at 5-10 V increments until motor evoked potentials waveforms of sufficient duration and morphology were consistently generated. Monopolar electrical stimulation threshold for intraoperative motor cortical mapping were found to be more consistent in the upper limb compared to lower limb and facial muscles. Evoked responses from the extensor digitorium communis had the highest recorded rate (83.7%) and required the lowest stimulation voltage (36.0 V). The stimulation voltage was found to be statistically significant compared to threshold values for abductor hallucis, tibialis anterior, deltoid, and orbicularis oris with respective p values of 0.006, 0.021, 0,027, and 0.015. There was also a distinct trend that patients with cortical dysplasia/tuberous sclerosis have higher stimulation thresholds when compared to other pathology (p = 0.067). Monopolar electrical stimulation threshold for intraoperative motor cortical mapping were more consistent in the upper limb compared to lower limb and facial muscles. Evoked responses from the extensor digitorium communis had the highest recorded rate and required the lowest stimulation voltage. There was also a distinct trend that patients with cortical dysplasia/tuberous sclerosis have higher stimulation thresholds.

Computer-controlled electrical stimulation for quantitative mapping of human cortical function

Cortical mapping with electrical stimulation (ES) in neurosurgical patients typically involves the manually controlled delivery of suprathreshold electrical current to a discrete area of the brain. Limited numbers of trials and imprecise current delivery methods increase the variability of the behavioral response and make it difficult to collect quantitative mapping data, which is especially important in research studies of human cortical function. To overcome these limitations, the authors developed a method for computer-controlled delivery of defined electrical current to implanted intracranial electrodes. They demonstrate that stimulation can be time locked to a behavioral task to rapidly and systematically measure the detection threshold for ES in human visual cortex over many trials. Computer-controlled ES is well suited for the systematic and quantitative study of the function of virtually any region of cerebral cortex. It may be especially useful for studying human cortical regions that are not well characterized and for verifying the presence of stimulation-evoked percepts that are difficult to objectively confirm.

Current Threshold for Nerve Stimulation Depends on Electrical Impedance of the Tissue: A Study of Ultrasound-Guided Electrical Nerve Stimulation of the Median Nerve

Understanding the mechanisms causing variation in current thresholds for electrical nerve stimulation may improve the safety and success rate of peripheral nerve blocks. Electrical impedance of the tissue surrounding a nerve may affect the response to nerve stimulation. In this volunteer study, we investigated the relationship between impedance and current threshold needed to obtain a neuromuscular response. Electrical nerve stimulation and impedance measurements were performed for the median nerve in the axilla and at the elbow in 29 volunteers. The needletip was positioned at a distance of 5, 2.5, and 0 mm from the nerve as judged by ultrasound. Impulse widths of 0.1 and 0.3 ms were used for nerve stimulation. A significant inverse relationship between impedance and current threshold was found at the elbow, at nerve-to-needle distances of 5 and 2.5 mm (P = 0.001 and P = 0.036). Impedance values were significantly lower in the axilla (mean 21.1, sd 9.7 kohm) than at the elbow (mean 36.6, sd 13.4 kohm) (P < 0.001). Conversely, current thresholds for nerve stimulation were significantly higher in the axilla than at the elbow (P < 0.001, P < 0.001, P = 0.024). A mean ratio of 1.82 was found for the measurements of current thresholds with 0.1 versus 0.3 ms impulse duration. Our results demonstrate an inverse relationship between impedance measurements and current thresholds and suggest that current settings used for nerve stimulation may require adjustment based on the tissue type. Further studies should be performed to investigate the clinical impact of our findings.

Involvement of GABAergic mechanisms of the dorsal periaqueductal gray and inferior colliculus on unconditioned fear.

fact that the dorsal periaqueductal gray (dPAG) and inferior colliculus (IC), together with superior colliculus, medial hypothalamus and amygdala, constitute the brain aversion system has been well-established. Stepwise increases in the intensity of electrical stimulation of dPAG or IC cause freezing and escape responses, which are followed by a freezing behavior that lasts after the interruption of the stimulation. Freezing and escape are unconditioned defensive behaviors derived from the stimulation of the output centers for the defense reaction, whereas the post-stimulation freezing is the behavioral counterpart of the processing of aversive information. Although GABA-A mechanisms of the midbrain tectum exert a tonic inhibitory influence on the neural substrates of unconditioned fear, their influence on the processing of aversive information is not completely understood. Thus, the present study examines the effects of injections of the GABA-A receptor agonist muscimol (1 and 2 nmol/0.2 μL) or the glutamic acid decarboxylase blocker semicarbazide (5 and 7.5 µg/0.2 μL) into dPAG or IC of Wistar rats on freezing and escape thresholds determined by electrical stimulation of these same structures and on post-stimulation freezing. Intra-dPAG injections of muscimol increased and semicarbazide decreased the freezing and escape thresholds of electrical stimulation of the dPAG. Only semicarbazide enhanced the dPAG post-stimulation freezing. Intra-IC injections of muscimol significantly increased aversive thresholds, while having no effect on IC post-stimulation freezing. Intra-IC injections of semicarbazide had no significant effects. These findings suggest that GABAergic mechanisms are important regulators of the expression of unconditioned fear in dPAG and IC, whereas only in dPAG GABA appears to play a role on the sensory gating towards aversive information during post-stimulation freezing. Keywords: muscimol, semicarbazide, dorsal periaqueductal gray, inferior colliculus, aversive thresholds, post-stimulation freezing.

Treatment of atrial fibrillation by surgical epicardial ablation: Bipolar radiofrequency versus cryoablation

Atrial fibrillation is the most frequent form of cardiac arrhythmia. Its surgical management has improved in recent years with major advances in our knowledge of the underlying pathogenic mechanisms. This has led to simpler therapeutic strategies such as epicardial ablation. The aim of this comparative experimental study was to evaluate the efficacy of this treatment, achieved with either bipolar radiofrequency or cryoablation. Twelve sheep were used. After left thoracotomy, epicardial ablation of the junction between the left pulmonary veins and the left atrium was achieved by means of bipolar radiofrequency in group A (n=6) and by cryoablation in group B (n=6). Electrical stimulation thresholds were determined before and after ablation. Four weeks after ablation, sheep were killed for pathologic studies. The mean stimulation threshold was 3.5+/-0.6 mA before ablation and 15.6+/-5.6 mA after ablation. The difference was significant in both groups, showing that effective conduction blockade was obtained with the two ablation methods. Histologic studies after radiofrequency and cryoablation showed limited coagulation necrosis and cellular rarefaction, respecting the supportive tissue. Both methods of surgical ablation by the epicardial route yielded effective electrical isolation of the pulmonary vein junction with the left atrium. This conduction blockade was due to limited coagulation necrosis with myocyte rarefaction, of similar extents in the two procedures. Standardization and refinement of this technique could extend the treatment indications for atrial fibrillation associated with other cardiac disorders that require surgical treatment without opening the left atrium.

Assessment of impulse duration thresholds for electrical stimulation of muscles (chronaxy) in dogs

To determine the electrical impulse duration thresholds (chronaxy) for maximal motor contraction of various muscles without stimulation of pain fibers in dogs. 10 healthy adult Beagles. The dogs were used to assess the minimal intensity (rheobase) required to elicit motor contraction of 11 muscles (5 in the forelimb [supraspinatus, infraspinatus, deltoideus, lateral head of the triceps brachii, and extensor carpi radialis], 5 in the hind limb [gluteus medius, biceps femoris, semitendinosus, vastus lateralis, and tibialis cranialis], and the erector spinae). The rheobase was used to determine the chronaxy for each of the 11 muscles in the 10 dogs; chronaxy values were compared with those reported for the corresponding muscles in humans. Compared with values in humans, chronaxy values for stimulation of AA motor fibers in the biceps femoris and semitendinosus muscles and muscles of the more distal portions of limbs were lower in dogs. For the other muscles evaluated, chronaxy values did not differ between dogs and humans. Application of the dog-specific chronaxy values when performing electrical stimulation for strengthening muscles or providing pain relief is likely to minimize the pain perceived during treatment in dogs.