The peripheral sensory system is critical to regulating motor plasticity and motor recovery. Peripheral electrical stimulation (ES) can generate constant and adequate sensory input to influence the ...excitability of the motor cortex. The aim of this proof of concept study was to assess whether ES prior to each hand function training session for eight weeks can better improve neuromuscular control and hand function in chronic stroke individuals and change electroencephalography-electromyography (EEG-EMG) coherence, as compared to the control (sham ES). We recruited twelve subjects and randomly assigned them into ES and control groups. Both groups received 20-minute hand function training twice a week, and the ES group received 40-minute ES on the median nerve of the affected side before each training session. The control group received sham ES. EEG, EMG and Fugl-Meyer Assessment (FMA) were collected at four different time points. The corticomuscular coherence (CMC) in the ES group at fourth weeks was significantly higher (p = 0.004) as compared to the control group. The notable increment of FMA at eight weeks and follow-up was found only in the ES group. The eight-week rehabilitation program that implemented peripheral ES sessions prior to function training has a potential to improve neuromuscular control and hand function in chronic stroke individuals.
This study was undertaken to investigate migraine glymphatic and meningeal lymphatic vessel (mLV) functions.
Migraine patients and healthy controls (HCs) were prospectively recruited between 2020 and ...2023. Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index for glymphatics and dynamic contrast-enhanced magnetic resonance imaging parameters (time to peak TTP/enhancement integral EI/mean time to enhance MTE) for para-superior sagittal (paraSSS)-mLV or paratransverse sinus (paraTS)-mLV in episodic migraine (EM), chronic migraine (CM), and CM with and without medication-overuse headache (MOH) were analyzed. DTI-ALPS correlations with clinical parameters (migraine severity numeric rating scale/disability Migraine Disability Assessment (MIDAS)/bodily pain Widespread Pain Index/sleep quality Pittsburgh Sleep Quality Index (PSQI)) were examined.
In total, 175 subjects (112 migraine + 63 HCs) were investigated. DTI-ALPS values were lower in CM (median interquartile range = 0.64 0.12) than in EM (0.71 0.13, p = 0.005) and HCs (0.71 0.09, p = 0.004). CM with MOH (0.63 0.07) had lower DTI-ALPS values than CM without MOH (0.73 0.12, p < 0.001). Furthermore, CM had longer TTP (paraSSS-mLV: 55.8 12.9 vs 40.0 7.6, p < 0.001; paraTS-mLV: 51.2 8.1 vs 44.0 3.3, p = 0.002), EI (paraSSS-mLV: 45.5 42.0 vs 16.1 9.2, p < 0.001), and MTE (paraSSS-mLV: 253.7 6.7 vs 248.4 13.8, p < 0.001; paraTS-mLV: 252.0 6.2 vs 249.7 1.2, p < 0.001) than EM patients. The MIDAS (p = 0.002) and PSQI (p = 0.002) were negatively correlated with DTI-ALPS index after Bonferroni corrections (p < q = 0.01).
CM patients, particularly those with MOH, have glymphatic and meningeal lymphatic dysfunctions, which are highly clinically relevant and may implicate pathogenesis for migraine chronification. ANN NEUROL 2024;95:583-595.
Objective
Quantitative sensory testing is widely used in clinical and research settings to assess the sensory functions of healthy subjects and patients. It is of importance to establish normative ...values in a healthy population to provide reference for studies involving patients. Given the absence of normative values for pain thresholds in Taiwan, the aim of this study was to report the normative values for future reference in the Taiwanese population and compare the differences between male and female participants.
Methods
Healthy adults without any chronic or acute pain condition were recruited. The pain thresholds were assessed over the cephalic (supraorbital area and masseter muscle) and extracephalic (medio‐volar forearm and thenar eminence) areas. The heat, cold, mechanical punctate, and pressure pain thresholds were measured with a standardized protocol. Comparisons between male and female participants were performed.
Results
One hundred and thirty healthy participants (55 males: 30.4 ± 7.4 years; 75 females: 30.5 ± 8.1 years) finished the assessments. Male participants were less sensitive to mechanical stimuli, including pressure over masseter muscle (male vs. female: 178.5 ± 56.7 vs. 156.6 ± 58.4 kPa, p = .034) and punctate over medio‐volar forearm (male vs. female: 116.4 ± 45.2 vs. 98.7 ± 65.4 g, p = .011), compared to female participants. However, female participants were less sensitive to cold stimuli, indicated by lower cold pain thresholds over the supraorbital area (male vs. female: 18.6 ± 8.4 vs. 13.6 ± 9.3°C, p = .004), compared to male participants. No significant differences were found between sexes in other pain threshold parameters.
Conclusions
We provided the normative values of healthy male and female adults in Taiwan. This information is crucial for comparison in future pain‐related studies to identify potential hypoalgesia or hyperalgesia of tested subjects.
This is the first study that reports the normative values of pain thresholds following a standardized protocol of quantitative sensory testings among a large healthy cohort without any pain conditions in East Asia. These results are crucial as a comparison for future pain‐related research.
Objective
To determine whether multivariate pattern regression analysis based on gray matter (GM) images constrained to the sensorimotor network could accurately predict trigeminal heat pain ...sensitivity in healthy individuals.
Background
Prediction of individual pain sensitivity is of clinical relevance as high pain sensitivity is associated with increased risks of postoperative pain, pain chronification, and a poor treatment response. However, as pain is a subjective experience accurate identification of such individuals can be difficult. GM structure of sensorimotor regions have been shown to vary with pain sensitivity. It is unclear whether GM structure within these regions can be used to predict pain sensitivity.
Methods
In this cross‐sectional study, structural magnetic resonance images and pain thresholds in response to contact heat stimulation of the left supraorbital area were obtained from 79 healthy participants. Voxel‐based morphometry was used to extract segmented and normalized GM images. These were then constrained to a mask encompassing the functionally defined resting‐state sensorimotor network. The masked images and pain thresholds entered a multivariate relevance vector regression analysis for quantitative prediction of the individual pain thresholds. The correspondence between predicted and actual pain thresholds was indexed by the Pearson correlation coefficient (r) and the mean squared error (MSE). The generalizability of the model was assessed by 10‐fold and 5‐fold cross‐validation. Non‐parametric permutation tests were used to estimate significance levels.
Results
Trigeminal heat pain sensitivity could be predicted from GM structure within the sensorimotor network with significant accuracy (10‐fold: r = 0.53, p < 0.001, MSE = 10.32, p = 0.001; 5‐fold: r = 0.46, p = 0.001, MSE = 10.54, p < 0.001). The resulting multivariate weight maps revealed that accurate prediction relied on multiple widespread regions within the sensorimotor network.
Conclusion
A multivariate pattern of GM structure within the sensorimotor network could be used to make accurate predictions about trigeminal heat pain sensitivity at the individual level in healthy participants. Widespread regions within the sensorimotor network contributed to the predictive model.
Background
Half of the sufferers of reversible cerebral vasoconstriction syndrome (RCVS) exhibit imaging-proven blood-brain barrier disruption. The pathogenesis of blood-brain barrier disruption in ...RCVS remains unclear and mechanism-specific intervention is lacking. We speculated that cerebrovascular dysregulation might be associated with blood-brain barrier disruption in RCVS. Hence, we aimed to evaluate whether the dynamic cerebral autoregulation is altered in patients with RCVS and could be associated with blood-brain barrier disruption.
Methods
A cross-sectional study was conducted from 2019 to 2021 at headache clinics of a national tertiary medical center. Dynamic cerebral autoregulation was evaluated in all participants. The capacity of the dynamic cerebral autoregulation to damp the systemic hemodynamic changes, i.e., phase shift and gain between the cerebral blood flow and blood pressure waveforms in the very-low- and low-frequency bands were calculated by transfer function analysis. The mean flow correlation index was also calculated. Patients with RCVS received 3-dimensional isotropic contrast-enhanced T2 fluid-attenuated inversion recovery imaging to visualize blood-brain barrier disruption.
Results
Forty-five patients with RCVS (41.9 ± 9.8 years old, 29 females) and 45 matched healthy controls (41.4 ± 12.5 years old, 29 females) completed the study. Nineteen of the patients had blood-brain barrier disruption. Compared to healthy controls, patients with RCVS had poorer dynamic cerebral autoregulation, indicated by higher gain in very-low-frequency band (left: 1.6 ± 0.7,
p
= 0.001; right: 1.5 ± 0.7,
p
= 0.003; healthy controls: 1.1 ± 0.4) and higher mean flow correlation index (left: 0.39 ± 0.20,
p
= 0.040; right: 0.40 ± 0.18,
p
= 0.017; healthy controls: 0.31 ± 0.17). Moreover, patients with RCVS with blood-brain barrier disruption had worse dynamic cerebral autoregulation, as compared to those without blood-brain barrier disruption, by having less phase shift in very-low- and low-frequency bands, and higher mean flow correlation index.
Conclusions
Dysfunctional dynamic cerebral autoregulation was observed in patients with RCVS, particularly in those with blood-brain barrier disruption. These findings suggest that impaired cerebral autoregulation plays a pivotal role in RCVS pathophysiology and may be relevant to complications associated with blood-brain barrier disruption by impaired capacity of maintaining stable cerebral blood flow under fluctuating blood pressure.
Graphical Abstract
Purpose of Review
Studies on event-related evoked potentials have indicated that altered cortical processing of sensory stimuli is associated with migraine. However, the results depend on the ...experimental method and patients. Electrophysiology of resting state cortical activity has revealed compelling results regarding the pathophysiology of migraine. This review summarized the available information related to patients with episodic and chronic migraine to determine whether certain features can be used as signatures for migraine.
Recent Findings
A recent study examined differences in resting state functional connectivity among the pain-related regions and revealed that beta connectivity was attenuated in migraine and that altered connectivity in the anterior cingulate cortex was linked to migraine chronification. These findings suggested that chronification leads to neuroplasticity in the pain areas of higher-level processing rather than in areas involved in basic sensory discrimination (i.e., primary and secondary somatosensory areas). Another study discovered that the betweenness centrality of delta band in right precuneus was significantly lower in those with longer history of migraine. Electroencephalogram may also predict the treatment outcomes in patients with chronic migraine that those with lower pre-treatment occipital alpha power tend to show greater reduction in headache frequency.
Summary
Studies on resting state activity have yielded convincing findings regarding aberrant oscillatory power and functional connectivity in relation to migraine, thus contributing to identifying brain signatures for migraine. The role of such assessment in precision medicine should be further investigated.
Background
Migraine has complex pathophysiological characteristics and episodic attacks. To decipher the cyclic neurophysiological features of migraine attacks, in this study, we compared neuronal ...excitability in the brainstem and primary somatosensory (S1) region between migraine phases for 30 consecutive days in two patients with episodic migraine.
Methods
Both patients underwent EEG recording of event-related potentials with the somatosensory and paired-pulse paradigms for 30 consecutive days. The migraine cycle was divided into the following phases: 24–48 h before headache onset (
Pre2
), within 24 h before headache onset (
Pre1
), during the migraine attack (
Ictal
), within 24 h after headache offset (
Post1
), and the interval of ˃48 h between the last and next headache phase (
Interictal
). The normalised current intensity in the brainstem and S1 and gating ratio in the S1 were recorded and examined.
Results
Six migraine cycles (three for each patient) were analysed. In both patients, the somatosensory excitability in the brainstem (peaking at 12–14 ms after stimulation) and S1 (peaking at 18–19 ms after stimulation) peaked in the
Pre1
phase. The S1 inhibitory capability was higher in the
Ictal
phase than in the
Pre1
phase.
Conclusion
This study demonstrates that migraine is a cyclic excitatory disorder and that the neural substrates involved include the somatosensory system, starting in the brainstem and spanning subsequently to the S1 before the migraine occurs. Further investigations with larger sample sizes are warranted.
Provision of adequate task-oriented training can be difficult for stroke survivors with limited hand movement. The current passive devices are mainly intended for gross grasp and release training. ...Additional assistive devices are required to improve functional opposition. This paper investigated the functional recovery of chronic stroke patients after using a three-dimensional (3D) printed dynamic hand device (3D-DHD) as an adjunct to conducting a task-oriented approach (TOA). Ten participants were randomly assigned to either the 3D-DHD group (n = 5) or the control group (n = 5). The TOA was used for the 3D-DHD group by using the 3D-DHD twice a week for four weeks, followed by a two-week home program. Only the TOA was used for the control group. The outcome measures, including the box and blocks test (BBT) of manual dexterity and prehensile strength, were conducted at baseline and at follow-up at four and six weeks later. The 3D-DHD group exhibited significantly superior improvements to the control group in the BBT and the palmar pinch force test. Both the groups had significant within-group improvements in the BBT and in all strength measures compared with baseline measurements. The use of 3D-DHD could position stroke-affected hands in coordinated functional opposition and had the potential to facilitate manual dexterity and advanced prehensile movement.
Abstract
Pain disorders are associated with aberrant oscillations in the pain-related cortical regions; however, few studies have investigated the relationship between the functional cortical network ...and migraine chronification through direct neural signals. Magnetoencephalography was used to record the resting-state brain activity of healthy controls as well as patients with episodic migraine (EM) and chronic migraine (CM). The source-based oscillatory dynamics of the pain-related cortical regions, which comprises 10 node regions (the bilateral primary SI and secondary somatosensory cortices, insula, medial frontal cortex, and anterior cingulate cortex ACC), were calculated to determine the intrinsic connectivity and node strength at 1 to 40 Hz. The total node strength within the pain-related cortical regions was smaller in the beta band in patients with migraine (70 EM and 80 CM) than in controls (n = 65). In the beta band, the node strength and functional connectivity values of patients with CM and patients with EM differed from those of controls in specific cortical areas, notably the left SI (EM < control) and bilateral ACC (CM < control); moreover, the node strength was lower in patients with CM than in those with EM. In all patients with migraine, negative correlations were observed between headache frequency and node strength in the bilateral ACC. In conclusion, migraine is characterized by reduced beta oscillatory connectivity within the pain-related cortical regions. Reduced beta connectivity in the ACC is linked to migraine chronification. Longitudinal studies should verify whether this oscillation change is a brain signature and a potential neuromodulation target for migraine.
Objective
Previous studies regarding the quantitative sensory testing are inconsistent in migraine. We hypothesized that the quantitative sensory testing results were influenced by headache frequency ...or migraine phase.
Methods
This study recruited chronic and episodic migraine patients as well as healthy controls. Participants underwent quantitative sensory testing, including heat, cold, and mechanical punctate pain thresholds at the supraorbital area (V1 dermatome) and the forearm (T1 dermatome). Prospective headache diaries were used for headache frequency and migraine phase when quantitative sensory testing was performed.
Results
Twenty-eight chronic migraine, 64 episodic migraine and 32 healthy controls completed the study. Significant higher mechanical punctate pain thresholds were found in episodic migraine but not chronic migraine when compared with healthy controls. The mechanical punctate pain thresholds decreased as headache frequency increased then nadired. In episodic migraine, mechanical punctate pain thresholds were highest (p < 0.05) in those in the interictal phase and declined when approaching the ictal phase in both V1 and T1 dermatomes. Linear regression analyses showed that in those with episodic migraine, headache frequency and phase were independently associated with mechanical punctate pain thresholds and accounted for 29.7% and 38.9% of the variance in V1 (p = 0.003) and T1 (p < 0.001) respectively. Of note, unlike mechanical punctate pain thresholds, our study did not demonstrate similar findings for heat pain thresholds and cold pain thresholds in migraine.
Conclusion
Our study provides new insights into the dynamic changes of quantitative sensory testing, especially mechanical punctate pain thresholds in patients with migraine. Mechanical punctate pain thresholds vary depending on headache frequency and migraine phase, providing an explanation for the inconsistency across studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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