Stimulus Intensity Research Articles

Reference Standard of Median Nerve Conduction Study in Korea.

To establish the reference standard of the median nerve conduction study (NCS) in Korea. A total of 648 median motor and 602 median sensory NCSs from 349 Korean healthy volunteers were tested and analyzed prospectively. Equipment calibration, assessment of intraand inter-rater reliability, and the NCSs per se were conducted according to a predetermined protocol. A reference standard was established from uncertainty components for the following parameters: the onset and peak latencies; the baseline-to-peak and peak-to-peak amplitudes; the area and duration of the negative wave; and the nerve conduction velocity. The effects of sex, age and stimulation intensity were analyzed. Each measured value of 648 median motor and 602 median sensory nerves were obtained and presented with both mean and expanded uncertainties, as well as mean and standard deviations. The cut-off values with expanded uncertainty were determined for different age and sex groups. After adjusting for anthropometric covariates, all parameters except duration were affected by age, and sex appeared to influence both duration and area. While stimulation intensity significantly affected some parameters including latencies, the effect sizes were negligible. We propose the median NCS reference standard using the largest Korean dataset ever available. The use of the traceable and reliable reference standard is anticipated to promote more accurate and dependable diagnosis and appropriate management of median neuropathies in Korea.

Transcranial direct current stimulation over the right parietal cortex improves the depressive disorder: A preliminary study.

The right posterior parietal cortex is the core brain region of emotional processing and executive control network in the human brain, and the function of the right posterior parietal cortex is decreased in patients with major depressive disorder. This study aims to preliminarily investigate whether the excitation of the right posterior parietal cortex by transcranial direct current stimulation (tDCS) could improve their clinical symptoms. In this study, 12 patients with major depressive disorder were given tDCS treatment at Xuanwu Hospital of Capital Medical University and the First Hospital of Hebei Medical University. The stimulating electrode (anode) was placed on the patients' right parietal cortex, whereas the reference electrode (cathode) was placed on the patients' left mastoid. The stimulation intensity was set as 2.0mA. The patients with depressive disorder were treated for 20min at a time twice a day for 14 consecutive days. The severity of the clinical symptoms was evaluated using the Hamilton Depression Rating Scale-17 (HDRS-17) and the Hamilton Anxiety Rating Scale (HARS) at before and right after treatment. The HDRS-17 scores of patients with depressive disorder decreased significantly following the tDCS treatment compared with those before treatment (p<.001). Further analysis revealed that the patients' anxiety/somatization, cognitive deficit, retardation, and sleep disorder scores all decreased significantly after the tDCS treatment (p<.05), although there was no significant change in their weight. Moreover, the patients' HARS scores decreased significantly after the tDCS treatment when compared with those before treatment (p<.01). The right parietal cortex may be another key stimulation targets to improving the efficacy of tDCS treatment to the patients with major depressive disorder.

A phase 2a study investigating the effects of ritlecitinib on brainstem auditory evoked potentials and intraepidermal nerve fiber histology in adults with alopecia areata.

Reversible axonal swelling and brainstem auditory evoked potential (BAEP) changes were observed in standard chronic (9-month) toxicology studies in dogs treated with ritlecitinib, an oral Janus kinase 3/tyrosine kinase expressed in hepatocellular carcinoma family kinase inhibitor, at exposures higher than the approved 50-mg human dose. To evaluate the clinical relevance of the dog toxicity finding, this phase 2a, double-blind study assessed BAEP changes and intraepidermal nerve fiber (IENF) histology in adults with alopecia areata treated with ritlecitinib. Patients were randomized to receive oral ritlecitinib 50 mg once daily (QD) with a 4-week loading dose of 200 mg QD or placebo for 9 months (placebo-controlled phase); they then entered the active-therapy extension and received ritlecitinib 50 mg QD (with a 4-week loading dose of 200 mg in patients switching from placebo). Among the 71 patients, no notable mean differences in change from baseline (CFB) in Waves I-V interwave latency (primary outcome) or Wave V amplitude on BAEP at a stimulus intensity of 80 dB nHL were observed in the ritlecitinib or placebo group at Month 9, with no notable differences in interwave latency or Wave V amplitude between groups. The CFB in mean or median IENF density and in percentage of IENFs with axonal swellings was minimal and similar between groups at Month 9. Ritlecitinib treatment was also not associated with an imbalanced incidence of neurological and audiological adverse events. These results provide evidence that the BAEP and axonal swelling finding in dogs are not clinically relevant in humans.

Sex-related differences in corticospinal excitability outcomemeasures of the biceps brachii during a submaximal elbow flexor contraction.

The purpose of this study was to investigate the effects of sex, muscle thickness, and subcutaneous fat thickness (SFT) on corticospinal excitability outcome measures of the biceps brachii. Eighteen participants (10 males and 8 females) completed this study. Ultrasound was used to assess biceps brachii muscle thickness and the overlying SFT. Transcranial magnetic stimulation (TMS) was used to determine corticospinal excitability by inducing motor-evoked potentials (MEPs) at eight different TMS intensities from 90% to 160% of active motor threshold (AMT) from the biceps brachii during an isometric contraction of the elbow flexors at 10% of maximum voluntary contraction (MVC). Biceps brachii maximal compound muscle action potential (Mmax) was also recorded prior to and after TMS. Males had higher (p < 0.001) biceps brachii muscle thickness and lower SFT, produced higher levels of MVC force and had, on average, higher (p < 0.001) MEP amplitudes at lower (p < 0.05) percentages of maximal stimulator output than females during the 10% elbow flexion MVC. Multiple linear regression modeling revealed that sex was not associated with any of the neurophysiological parameters examined, while SFT showed a positive association with the stimulation intensity required at AMT (p = 0.035) and a negative association with biceps brachii pre-stimulus electromyography (EMG) activity (p = 0.021). Additionally, there was a small positive association between muscle thickness and biceps brachii pre-stimulus EMG activity (p = 0.049). Overall, this study suggests that some measures of corticospinal excitability may be different between the sexes and influenced by SFT and muscle thickness.

VR rehabilitation system evaluator: A fNIRS-based and LLM-enabled evaluation paradigm for Mild Cognitive Impairment

Virtual Reality (VR) has significant potential for Mild Cognitive Impairment (MCI) rehabilitation by offering dynamic and engaging tasks designed to stimulate various cognitive domains. However, how efficiently evaluating the VR tasks is always challenging. The current effectiveness evaluation methods for task evaluation and optimisation typically rely on post-training metrics like game performance or subjective questionnaires, which cannot directly reflect the comprehensiveness and intensity of cognitive stimulation. To bridge these gaps, we propose a novel approach integrating functional near-infrared spectroscopy (fNIRS) data and a Large Language Model (LLM) for VR rehabilitation task evaluation and optimisation. Firstly, we leverage fundamental cognitive theories to propose a systematic evaluation paradigm for assessing the scope of the cognitive domains stimulated by VR tasks. Secondly, we propose fNIRS-derived graph parameters to objectively evaluate the cognitive stimulation with high-time resolution. Finally, we develop a prompt-generating strategy to facilitate Large Language Model (LLM)-based analysis, which transforms fNIRS-derived metrics combined with the scope of stimulated cognitive domains into easy-to-understand evaluation reports and actionable recommendations for task optimisation. We demonstrate this approach with two VR rehabilitation tasks. Several experts evaluated the LLM-based task evaluation results and task optimisation recommendation and agreed that the LLM-generated results are meaningful and applicable. This approach offers a rapid, objective method to evaluate VR task effectiveness and improves their design, marking a significant step in developing more effective MCI interventions.

How to reduce fear in a snail: Take an aspirin, call me in the morning

Aspirin (Acetylsalicylic acid, ASA), one of the widely used non-steroid anti-inflammatory drugs can easily end up in sewage effluents and thus it becomes necessary to investigate the effects of aspirin on behaviour of aquatic organisms. Previous studies in mammals have shown ASA to alter fear and anxiety-like behaviours. In the great pond snail Lymnaea stagnalis, ASA has been shown to block a ‘sickness state’ induced by lipopolysaccharide injection which upregulates immune and stress-related genes thus altering behavioural responses. In Lymnaea, eliciting physiological stress may enhance memory formation or block its retrieval depending on the stimulus type and intensity. Here we examine whether ASA will alter two forms of associative-learning memory in crayfish predator-experienced Lymnaea when ASA exposure accompanies predator-cue-induced stress during the learning procedure. The two trainings procedures are: 1) operant conditioning of aerial respiration; and 2) a higher form of learning, called configural learning, which here is dependent on evoking a fear response. We show here that ASA alone does not alter homeostatic aerial respiration, feeding behaviour or long-term memory (LTM) formation of operantly conditioned aerial respiration. However, ASA blocked the enhancement of LTM formation normally elicited by training snails in predator cue. ASA also blocked configural learning, which makes use of the fear response elicited by the predator cue. Thus, ASA alters how Lymnaea responds cognitively to predator detection.

Postoperative outcomes and stimulation responses for sectioned nerve roots during selective dorsal rhizotomy in cerebral palsy

BackgroundCerebral palsy (CP) is the most cause of motor dysfunction in children. Selective dorsal rhizotomy (SDR) plays a major role in long term spasticity control. However, limited data exists on the effect of SDR on postoperative spasticity treatment requirements and supraspinal effects, and the stimulation responses of dorsal nerve roots in those with CP.MethodsThe current study included the outcome for 35 individuals undergoing SDR for motor functional outcome, spasticity, baclofen dose changes, botulinum toxin injection frequency, and spasticity related orthopedic procedures. We also report on the stimulation responses in 112 individuals who underwent SDR at our institution.ResultsThere was a significant difference in gross motor function measures (GMFM)-66 scores at last follow up that remained present when considering only ambulatory children but not with non-ambulatory children. Ashworth scores were significantly decreased for both upper and lower extremities after SDR at all follow up points. There was a significant decrease in Baclofen dose and botulinum toxin injections requirements after SDR, but no significant difference in the need for orthopedic intervention. A total of 5502 dorsal nerve roots were tested showing a decrease in stimulation intensity and increase in grade on the right side and for descending lumbosacral levels.ConclusionsSDR improves gross motor scores during short term follow up but has additional benefits in decreasing baclofen dosing and botulinum toxin injections requirements after surgery. They stimulation responses of sectioned dorsal nerve roots adds to the limited available data and our understanding of the pathological changes that occur in CP.

It's about the long game, not epic workouts: unpacking HIIT for endurance athletes.

High-intensity interval training (HIIT) prescriptions manipulate intensity, duration, and recovery variables in multiple combinations. Researchers often compare different HIIT variable combinations and treat HIIT prescription as a "maximization problem", seeking to identify the prescription(s) that induce the largest acute VO2/HR/RPE response. However, studies connecting the magnitude of specific acute HIIT response variables like work time>90% of VO2max and resulting cellular signalling and/or translation to protein upregulation and performance enhancement are lacking. This is also not how successful endurance athletes train. First, HIIT training cannot be seen in isolation. Successful endurance athletes perform most of their training volume below the first lactate turn point (<LT1), with "threshold training" and HIIT as integrated parts of a synergistic combination of training intensities and durations. Second, molecular signalling research reveals multiple, "overlapping" signalling pathways driving peripheral adaptations, with those pathways most sensitive to work intensity showing substantial feedback inhibition. This makes current training content and longer-term training history critical modulators of HIIT adaptive responses. Third, long term maximization of endurance capacity extends over years. Successful endurance athletes balance low-intensity and high-intensity, low systemic stress, and high systemic stress training sessions over time. The endurance training process is therefore an "optimization problem". Effective HIIT sessions generate both cellular signal and systemic stress that each individual athlete responds to and recovers from over weeks, months, and even years of training. It is not "epic" HIIT sessions but effective integration of intensity, duration, and frequency of all training stimuli over time that drives endurance performance success.

Evaluating phasic transcutaneous vagus nerve stimulation (taVNS) with pupil dilation: the importance of stimulation intensity and sensory perception.

The efficacy of transcutaneous auricular vagus nerve stimulation (taVNS) as a non-invasive method to modulate physiological markers of noradrenergic activity of the Locus Coeruleus (LC), such as pupil dilation, is increasingly more discussed. However, taVNS studies show high heterogeneity of stimulation effects. Therefore, a taVNS setup was established here to test different frequencies (10 Hz and 25 Hz) and intensities (3 mA and 5 mA) during phasic stimulation (3 s) with time-synchronous recording of pupil dilation in younger adults. Specifically, phasic real taVNS and higher intensity led to increased pupil dilation, which is consistent with phasic invasive VNS studies in animals. The results also suggest that the influence of intensity on pupil dilation may be stronger than that of frequency. However, there was an attenuation of taVNS-induced pupil dilation when differences in perception of sensations were considered. Specifically, pupil dilation during phasic stimulation increased with perceived stimulation intensity. The extent to which the effect of taVNS induces pupil dilation and the involvement of sensory perception in the stimulation process are discussed here and require more extensive research. Additionally, it is crucial to strive for comparable stimulation sensations during systematic parameter testing in order to investigate possible effects of phasic taVNS on pupil dilation in more detail.

Old and new versions of the Molyneux question: A review of experimental answers

The ‘Molyneux problem’ is typically framed in terms of the crossmodal matching of shape information from touch to vision. Indeed, shape along with intensity have commonly been considered amodal stimulus properties/dimensions (at least by developmental researchers). However, it is important to note that what is common, if anything, to the senses differs in the two cases: It is the physical stimulus (and possibly also the associated phenomenology) that is thought to be the same in the case of crossmodal (or intermodal) shape matching between touch and vision, whereas it is the nature of the underlying neural encoding that is said to be similar in the case of crossmodal matching of auditory and visual stimulus intensity. While the first empirical data to have been published on these two forms of putatively amodal crossmodal matching appeared to suggest that they both emerge surprisingly early in the course of human development (i.e., within the first month of life), certain of these seminal findings have proved difficult to replicate. Ultimately, therefore, there is currently little convincing evidence to support the notion that such putatively innate crossmodal matching of amodal stimulus dimensions is actually different in kind from the various other crossmodal correspondences that are seemingly acquired at various points during the course of human development (typically as a result of the internalization of the crossmodal statistics of the environment). As such, there may be nothing particularly special about the type of crossmodal matching thought to underlie the ‘Molyneux problem’, and continued interest in the issue may inadvertently have helped to sustain a misguided account of the differences between different types of crossmodal correspondence.

Effect of Spatial and Temporal Prediction on Tactile Sensitivity.

The purpose of the present study was to examine whether spatial or temporal prediction of the tactile stimulus contributes to tactile sensitivity. To investigate the effect of spatial prediction on tactile sensitivity, electrical stimuli were provided for the digit nerve in one of five fingers, and advanced notice of the stimulating finger was provided before the stimulus in some trials but not in others. There was no significant effect of spatial prediction on the intensity at the perceptual threshold of the digit nerve stimulus. This indicates that spatial prediction of the tactile stimulus does not influence tactile sensitivity. To examine the effect of temporal prediction, an auditory warning cue was provided 0, 1, or 10 s before the electrical stimulus to the digit nerve. The stimulus intensity at the perceptual threshold in the trials with the 1 s warning cue was lower than those with the 0 s warning cue. This indicates that temporal prediction enhances tactile sensitivity. The stimulus intensity at the perceptual threshold in the trials with the 1 s warning cue was lower than those with the 10 s warning cue. This means that the contribution of temporal prediction to the tactile sensitivity is greater as the warning cue is closer to the time of the stimulus. This finding may be explained by a defense mechanism activated when humans predict that a tactile stimulus is coming soon.

Acute Response of Different High-Intensity Interval Training Protocols on Cardiac Auto-Regulation Using Wearable Device.

The purpose of this study was to compare different high-intensity interval training (HIIT) protocols with different lengths of work and rest times for a single session (all three had identical work-to-rest ratios and exercise intensities) for cardiac auto-regulation using a wearable device. With a randomized counter-balanced crossover, 13 physically active young male adults (age: 19.4 years, BMI: 21.9 kg/m2) were included. The HIIT included a warm-up of at least 5 min and three protocols of 10 s/50 s (20 sets), 20 s/100 s (10 sets), and 40 s/200 s (5 sets), with intensities ranging from 115 to 130% Wattmax. Cardiac auto-regulation was measured using a non-invasive method and a wearable device, including HRV and vascular function. Immediately after the HIIT session, the 40 s/200 s protocol produced the most intense stimulation in R-R interval (Δ-33.5%), ln low-frequency domain (Δ-42.6%), ln high-frequency domain (Δ-73.4%), and ln LF/HF ratio (Δ416.7%, all p < 0.05) compared to other protocols of 10 s/50 s and 20 s/100 s. The post-exercise hypotension in the bilateral ankle area was observed in the 40 s/200 s protocol only at 5 min after HIIT (right: Δ-12.2%, left: Δ-12.6%, all p < 0.05). This study confirmed that a longer work time might be more effective in stimulating cardiac auto-regulation using a wearable device, despite identical work-to-rest ratios and exercise intensity. Additional studies with 24 h measurements of cardiac autoregulation using wearable devices in response to various HIIT protocols are warranted.

Reference Database for a Novel Binocular Visual Function Perimeter: A Randomized Clinical Trial

PurposeTo construct a comprehensive reference database for a novel binocular automated perimeter. DesignA four-site prospective randomized clinical trial. Subjects and controls356 healthy subjects without ocular conditions that might affect visual function were categorized into 7 age groups. MethodsSubjects underwent comprehensive ocular examination of both eyes before enrollment. Using the TEMPO/IMOvifa automated perimeter (Topcon Healthcare/CREWT Medical Systems, Tokyo, Japan), each subject completed four binocular threshold visual field (VF) tests during a single visit: First, practice 24-2 and 10-2 tests were obtained from both eyes. Next, study 24-2 and 10-2 tests were obtained from both eyes. Test order of each sequence was randomized, and the tests were conducted under Standard Automated Perimetry testing conditions (SAP): Goldmann stimulus size III, 3183 cd/m2 maximum stimulus intensity, and background intensity of 10 cd/m2, using AIZE-Rapid test strategy. Standard VF reliability indices were assessed. For each subject, 24-2 and 10-2 test results from one randomly selected eye were analyzed. Main Outcome MeasuresPerimetric threshold sensitivity and reference limits for each test analysis parameter. ResultsThe ages of the study cohort were widely distributed, with a mean age (SD) of 52.3 (18.5) years. Sex assignment was 44.0% male and 56.0% female. The majority of subjects self-identified as White (67.4%), followed by Black or African American (13.5%) and Asian (8.7%), with 14.6% self-identified as Hispanic or Latino ethnicity. Mean sensitivity (MS) (SD) was 29.1 (1.3) decibels (dB) for the 24-2 and 32.4 (1.0) dB for the 10-2 test. For the 24-2 and 10-2, MS (SD) age-related changes averaged -0.06 (0.01) dB and -0.05 (0.01) dB per year, respectively. The normal range of pointwise threshold sensitivity increased with eccentricity and showed asymmetry around the mean, particularly notable in the 24-2 test. Mean (SD) binocular test duration was 3.18 (0.38) minutes (1 minute 35 seconds per eye) for the 24-2 test and 3.58 (0.43) minutes (1minute 47 seconds per eye) for the 10-2 test. ConclusionsA reference database for the TEMPO/IMOvifa perimeter was established, highlighting the significance of considering both age and stimulus eccentricity in interpreting threshold visual field test results.

Placebo treatment affects brain systems related to affective and cognitive processes, but not nociceptive pain

Drug treatments for pain often do not outperform placebo, and a better understanding of placebo mechanisms is needed to improve treatment development and clinical practice. In a large-scale fMRI study (N = 392) with pre-registered analyses, we tested whether placebo analgesic treatment modulates nociceptive processes, and whether its effects generalize from conditioned to unconditioned pain modalities. Placebo treatment caused robust analgesia in conditioned thermal pain that generalized to unconditioned mechanical pain. However, placebo did not decrease pain-related fMRI activity in brain measures linked to nociceptive pain, including the Neurologic Pain Signature (NPS) and spinothalamic pathway regions, with strong support for null effects in Bayes Factor analyses. In addition, surprisingly, placebo increased activity in some spinothalamic regions for unconditioned mechanical pain. In contrast, placebo reduced activity in a neuromarker associated with higher-level contributions to pain, the Stimulus Intensity Independent Pain Signature (SIIPS), and affected activity in brain regions related to motivation and value, in both pain modalities. Individual differences in behavioral analgesia were correlated with neural changes in both modalities. Our results indicate that cognitive and affective processes primarily drive placebo analgesia, and show the potential of neuromarkers for separating treatment influences on nociception from influences on evaluative processes.

Local cochlear mechanical responses revealed through outer hair cell receptor potential measurements

Sensory hair cells, including the sensorimotor outer hair cells, which enable the sensitive, sharply tuned responses of the mammalian cochlea, are excited by radial shear between the organ of Corti and the overlying tectorial membrane. It is not currently possible to measure directly in vivo mechanical responses in the narrow cleft between the tectorial membrane and organ of Corti over a wide range of stimulus frequencies and intensities. The mechanical responses can, however, be derived by measuring hair cell receptor potentials. We demonstrate that the seemingly complex frequency- and intensity-dependent behavior of outer hair cell receptor potentials could be qualitatively explained by a two degrees of freedom system with local cochlear partition and tectorial membrane resonances strongly coupled by the outer hair cell stereocilia. A local minimum in the receptor potential below the characteristic frequency should always be observed at a frequency where the tectorial membrane mechanical impedance is minimal, i.e., at the presumed tectorial membrane resonance frequency. The tectorial membrane resonance frequency might, however, shift with stimulus intensity in accordance with a shift in the maximum of the tectorial membrane radial mechanical responses to lower frequencies, as observed in experiments.

Posttraumatic headache: pain related evoked potentials (PREP) and conditioned pain modulation (CPM) to assess the pain modulatory function

Posttraumatic headache (PTH) is common following traumatic brain injury and impacts quality of life. We investigated descending pain modulation as one possible mechanism for PTH and correlated it to clinical measures. Pain-related evoked potentials (PREP) were recorded in 26 PTH-patients and 20 controls after electrical stimulation at the right hand and forehead with concentric surface electrodes. Conditioned pain modulation (CPM) was assessed using painful cutaneous electric stimulation (PCES) on the right hand as test stimulus and immersion of the left hand into 10 °C-cold water bath as conditioning stimulus based on changes in pain intensity and in amplitudes of PCES-evoked potentials. All participants completed questionnaires assessing depression, anxiety, and pain catastrophising. PTH-patients reported significantly higher pain ratings during PREP-recording in both areas despite similar stimulus intensity at pain threshold. N1P1-amplitudes during PREP and CPM-assessment were lower in patients in both areas, but statistically significant only on the hand. Both, PREP-N1-latencies and CPM-effects (based on the N1P1-amplitudes and pain ratings) were similar in both groups. Patients showed significantly higher ratings for anxiety and depression, which did not correlate with the CPM-effect. Our results indicate generalized hyperalgesia for electrical stimuli in both hand and face in PTH. The lacking correlation between pain ratings and EEG parameters indicates different mechanisms of pain perception and nociception.

Addressing the sources of inter-subject variability in E-field parameters in anodal tDCS stimulation over motor cortical network

Objetive: . Although transcranial direct current stimulation constitutes a non-invasive neuromodulation technique with promising results in a great variety of applications, its clinical implementation is compromised by the high inter-subject variability reported. This study aims to analyze the inter-subject variability in electric fields (E-fields) over regions of the cortical motor network under two electrode montages: the classical C3Fp2 and an alternative P3F3, which confines more the E-field over this region. Approach. Computational models of the head of 98 healthy subjects were developed to simulate the E-field under both montages. E-field parameters such as magnitude, focality and orientation were calculated over three regions of interest (ROI): M1S1, supplementary motor area (SMA) and preSMA. The role of anatomical characteristics as a source of inter-subject variability on E-field parameters and individualized stimulation intensity were addressed using linear mixed-effect models.Main results. P3F3 showed a more confined E-field distribution over M1S1 than C3Fp2; the latter elicited higher E-fields over supplementary motor areas. Both montages showed high inter-subject variability, especially for the normal component over C3Fp2. Skin, bone and CSF ROI volumes showed a negative association with E-field magnitude irrespective of montage. Grey matter volume and montage were the main sources of variability for focality. The curvature of gyri was found to be significantly associated with the variability of normal E-fields.Significance. Computational modeling proves useful in the assessment of E-field variability. Our simulations predict significant differences in E-field magnitude and focality for C3Fp2 and P3F3. However, anatomical characteristics were also found to be significant sources of E-field variability irrespective of electrode montage. The normal E-field component better captured the individual variability and low rate of responder subjects observed in experimental studies.

F wave analysis based on the compound muscle action potential scan.

Conventional F wave analysis involves a relatively uniform physiological environment induced by supramaximal stimulations. The F wave characteristics in a dynamic physiological condition, however, are rarely investigated. This study aimed to improve understanding of F wave properties in the more dynamic process by introducing a novel method to analyze F waves based on the compound muscle action potential (CMAP) scan technique. Twenty four healthy subjects participated in the study. The CMAP scan was applied to record muscle responses in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles, respectively. F wave characteristics including mean F wave amplitude and latency (F-M latency), persistence and activating threshold were quantified. An average of 200 F waves per muscle were obtained from the CMAP scan recording. Weak to moderate correlations between F wave amplitude and stimulating intensity were observed in most of the APB (19 muscles; r = 0.33 ± 0.14, all p < .05) and ADM (23 muscles, r = 0.46 ± 0.16, all p < .05) muscles. Significantly longer mean F latency and lower activating F-threshold were found in the ADM muscles (F-M latency: APB: 25.43 ± 2.39 ms, ADM: 26.15 ± 2.32 ms, p < .05; F-threshold: APB: 7.68 ± 8.96% CMAP, ADM: 2.35 ± 2.42% CMAP, p < .05). This study introduces new features of F waves using the CMAP scan technique and identifies differences of F wave characteristics between the hand muscles. The CMAP scan based F waves analysis can be combined with the motor unit number estimation to assess functional alterations in motor neurons in neurological disorders.

Risk factors for chloral hydrate sedation failure in pediatric patients: a retrospective analysis.

This study aimed to investigate the risk factors for chloral hydrate sedation failure and complications in a tertiary children's hospital in South Korea. A retrospective analysis of pediatric procedural sedation with chloral hydrate between January 1, 2021, and March 30, 2022, was performed. The collected data included patient characteristics, sedation history, and procedure. Multivariable regression analysis was performed to identify the risk factors for procedural sedation failure and complications. A total of 6,691 procedural sedation were included in the analysis; sedation failure following chloral hydrate (50 mg/kg) occurred in 1,457 patients (21.8%) and was associated with a higher rate of overall complications compared to those with successful sedation (17.5% [225/1457] vs. 6.2% [322/5234]; P < 0.001, odds ratio: 3.236). In the multivariable regression analysis, the following factors were associated with increased risk of sedation failure: general ward or intensive care unit inpatient (compared with outpatient); congenital syndrome; oxygen dependency; history of sedation failure or complications with chloral hydrate; procedure more than 60 min; and magnetic resonance imaging, radiotherapy, or procedures with painful or intense stimuli (all P values < 0.05). Factors contributing to the complications included general ward inpatient, congenital syndromes, congenital heart disease, preterm birth, oxygen dependency, history of complications with chloral hydrate, and current sedation failure with chloral hydrate (all P values < 0.05). To achieve successful sedation with chloral hydrate, the patient's sedation history, risk factors, and the type and duration of the procedure should be considered.

Effectiveness of cognitive reappraisal and distraction for induced acute pain: A laboratory study.

Cognitive reappraisal and distraction modulate pain; however, little is known about their effectiveness at different levels of pain intensity. Thus, the aim of this study has been to analyze the differential efficacy of both strategies to reduce perceived pain intensity and pain unpleasantness in low and moderate pain levels. 3 (emotion regulation strategy: cognitive reappraisal, distraction, and control) × 2 (intensity of the painful stimuli: low and moderate intensity) × 2 (time: pretest and posttest) mixed factorial design. Ninety healthy adults were randomly assigned to one of six experimental conditions. Pain-heat stimuli were administered with an advanced thermal stimulator. All participants completed the experimental pretest and posttest phases; in each phase, 12 pain stimuli were administered. Participants received brief training on how to apply cognitive reappraisal, distraction, and the control condition for the posttest phase. Data were collected from May 2022 to November 2022. Analyses of repeated-measure analysis of variance showed that at posttest cognitive reappraisal and distraction were equally effective in reducing perceived pain intensity in low pain levels, while distraction was more effective than cognitive reappraisal in decreasing perceived pain intensity in moderate pain levels. Both distraction and cognitive reappraisal were effective in decreasing pain unpleasantness regardless of the intensity of the painful stimuli. These findings highlighted the beneficial use of both strategies in the short term for pain relief, distraction being more effective in moderate pain levels. Applying both strategies to everyday situations that may cause short-term acute pain could be of great clinical relevance. (PsycInfo Database Record (c) 2024 APA, all rights reserved).