Occipital Areas Research Articles

A CNN-Based Deep Learning Approach for SSVEP Detection Targeting Binaural Ear-EEG

This paper discusses a machine learning approach for detecting SSVEP at both ears with minimal channels. SSVEP is a robust EEG signal suitable for many BCI applications. It is strong at the visual cortex around the occipital area, but the SNR gets worse when detected from other areas of the head. To make use of SSVEP measured around the ears following the ear-EEG concept, especially for practical binaural implementation, we propose a CNN structure coupled with regressed softmax outputs to improve accuracy. Evaluating on a public dataset, we studied classification performance for both subject-dependent and subject-independent trainings. It was found that with the proposed structure using a group training approach, a 69.21% accuracy was achievable. An ITR of 6.42 bit/min given 63.49 % accuracy was recorded while only monitoring data from T7 and T8. This represents a 12.47% improvement from a single ear implementation and illustrates potential of the approach to enhance performance for practical implementation of wearable EEG.

Frontal-Temporal Triangle Area Hair for Eyebrow Restoration in Asians: A Comparative Study With Periauricular and Occipital Hair.

The frontal-temporal triangle area (FTTA) hair has a slow growth rate and thin caliber, which are similar to those of eyebrow hair. However, a comparison of cosmetic outcomes between FTTA and other scalp hair grafts in eyebrow transplantation has not been performed. To compare the cosmetic outcomes of FTTA hair and periauricular and occipital area (POA) hair in eyebrow restoration. A retrospective analysis of 155 patients with FTTA or POA hair transplants was performed. Comparative variables included patient characteristics, hair density, diameter, percentage of one-hair follicular units (FUs), number of transplanted FUs, harvesting time, transection rate, hair survival rate, frequency of eyebrow trimming, and patient satisfaction. There was a significant difference in hair density, diameter, percentage of one-hair FUs, and harvesting time between the FTTA and POA hair transplants. The FTTA hair grew significantly slower than the POA hair did. The patients in the FTTA group trimmed their postoperative eyebrows at a significantly longer interval than those in the POA group. The percentage of patients who were very satisfied with the surgery results was higher in the FTTA group. The FTTA hair grafts can provide aesthetically pleasing cosmetic results in eyebrow restoration.

Perceptual decision-making ‘in the wild’: How risk propensity and injury exposure experience influence the neural signatures of occupational hazard recognition

While previous studies have extensively explored the neural mechanisms of perceptual decision-making, most of them used paradigms with limited real-life consequences and largely neglected participants' individual differences. In this study, to resemble a perceptual decision-making scenario with real-life consequences, construction workers were recruited for an occupational hazard recognition task by categorizing construction site images as hazardous or safe with their EEG recorded. Event-related potential (ERP) analysis revealed distinct influences of perceptual decision-making by two dispositional factors of risk propensity and injury exposure experience. Risk propensity was positively correlated with the stimulus-locked difference waveforms (hazardous minus safe) at approximately 200 ms post-stimuli-onset over right-lateralized parietal–occipital areas. The difference waveforms showed reversed polarity between groups with high and low-risk propensity. Injury exposure experience was negatively correlated with the response-locked difference waveforms approximately 450 ms before motor response over right-lateralized parietal-occipital regions. To the best of our knowledge, this study is the first to report how individuals' injury exposure experience influenced the neural signatures of one's perceptual decision-making. These results extended previous findings for perceptual decision-making by setting up a scenario with high ecological validity and suggested possibly substantial different mechanisms for individual workers by the intrinsic factor of risk propensity and the extrinsic factor of injury exposure experience.

Effectiveness of Transcranial Direct Current Stimulation and Monoclonal Antibodies Acting on the CGRP as a Combined Treatment for Migraine (TACTIC): Protocol for a Randomized, Double-Blind, Sham-Controlled Trial

BackgroundMigraine is a recurrent headache disorder that has a still unclear pathophysiology, involving several circuits of both the central and peripheral nervous system. Monoclonal antibodies acting on the calcitonin gene-related (CGRP) pathway (CGRP-MAbs) are the first drugs specifically designed for migraine; those drugs act peripherally on the trigeminal ganglion without entering the blood-brain barrier. Conversely, neuromodulation techniques such as transcranial direct current stimulation (tDCS) act centrally by increasing or decreasing the neuronal firing rate of brain cortical areas. The aim of the study will be to evaluate whether tDCS, in addition to CGRP-MAbs, is an effective add-on treatment in reducing headache frequency, intensity and acute medication use in patients with migraine. To demonstrate the biological effects of tDCS, the electroencephalographic (EEG) power changes after tDCS will be assessed.MethodsWe will include patients with migraine on treatment with CGRP-MAbs and reporting ≥8 monthly migraine days. During a prospective 28-day baseline period, patients will fill in a headache diary and questionnaires to evaluate migraine-related disability, anxiety and depressive symptoms, sleep quality, and health-related quality of life. Subjects will be randomly assigned in a 1:1 ratio to active or sham tDCS. The stimulation protocol will consist in five daily sessions, the cathodes will be applied bilaterally above the occipital areas, with the reference anode electrodes positioned above the primary motor areas. Before the first, and immediately after the last stimulation session, patients will perform a 10-min resting EEG recording. During a 28-day follow-up period following tDCS, patients will have to fill in a headache diary and questionnaires identical to those of the baseline period.DiscussionThis trial will evaluate the efficacy of an add-on treatment acting on the brain in patients with migraine, who are already treated with peripherally acting drugs, showing how tDCS acts in restoring the dysfunctional brain networks typical of the migraine patient.Clinical Trial RegistrationNCT05161871.

Comparison Between Trichoscopic and Histopathological Evaluations of Hair Parameters.

BackgroundCollecting data on hair counts helps dermatologists diagnose hair diseases more accurately. Quantitative trichoscopy analysis and pathologic examination are two common ways to evaluate hair parameters.PurposeThe study aims to compare the effect of quantitative trichoscopy analysis and pathologic examination in hair counting and quantify the hair density of average Chinese people.MethodsTrichoscopy was performed in four scalp regions with a total of twenty-three volunteers without alopecia: frontal, vertex, occipital, and parietal. Hair density parameters were recorded. A 4-mm punch biopsy was performed in the occipital area, and all specimens were transversely sectioned serially and observed to calculate the hair densities.ResultsThe average hair density, hairs per follicle unit, and vellus hair ratio from quantitative trichoscopy analysis in the occipital region were 163.07±28.17/cm2, 1.87±0.25 and 6.60±3.95%, lower than those from biopsy significantly (214.97±48.73/cm2, 2.24±0.30 and 10.48±6.43%). The hair shaft diameter measured by quantitative trichoscopy analysis was 74.52±8.02μm, higher than that by histopathologic examination (68.65±8.00μm) (p<0.05).ConclusionQuantitative trichoscopy is a noninvasive, quick, and convenient way to evaluate hair density. Histopathologic examination is an invasive way but provides more accurate data. The data obtained from trichoscopy and pathological examination are different to some extent, which cannot be substituted entirely for each other. This study established the reference for hair density in the adult Chinese population.

Modeling the Hemodynamic Response Function Using EEG-fMRI Data During Eyes-Open Resting-State Conditions and Motor Task Execution

Being able to accurately quantify the hemodynamic response function (HRF) that links the blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) signal to the underlying neural activity is important both for elucidating neurovascular coupling mechanisms and improving the accuracy of fMRI-based functional connectivity analyses. In particular, HRF estimation using BOLD-fMRI is challenging particularly in the case of resting-state data, due to the absence of information about the underlying neuronal dynamics. To this end, using simultaneously recorded electroencephalography (EEG) and fMRI data is a promising approach, as EEG provides a more direct measure of neural activations. In the present work, we employ simultaneous EEG-fMRI to investigate the regional characteristics of the HRF using measurements acquired during resting conditions. We propose a novel methodological approach based on combining distributed EEG source space reconstruction, which improves the spatial resolution of HRF estimation and using block-structured linear and nonlinear models, which enables us to simultaneously obtain HRF estimates and the contribution of different EEG frequency bands. Our results suggest that the dynamics of the resting-state BOLD signal can be sufficiently described using linear models and that the contribution of each band is region specific. Specifically, it was found that sensory-motor cortices exhibit positive HRF shapes, whereas the lateral occipital cortex and areas in the parietal cortex, such as the inferior and superior parietal lobule exhibit negative HRF shapes. To validate the proposed method, we repeated the analysis using simultaneous EEG-fMRI measurements acquired during execution of a unimanual hand-grip task. Our results reveal significant associations between BOLD signal variations and electrophysiological power fluctuations in the ipsilateral primary motor cortex, particularly for the EEG beta band, in agreement with previous studies in the literature.

Topologic Reorganization of White Matter Connectivity Networks in Early-Blind Adolescents.

Blindness studies are important models for the comprehension of human brain development and reorganization, after visual deprivation early in life. To investigate the global and local topologic alterations and to identify specific reorganized neural patterns in early-blind adolescents (EBAs), we applied diffusion tensor tractography and graph theory to establish and analyze the white matter connectivity networks in 21 EBAs and 22 age- and sex-matched normal-sighted controls (NSCs). The network profiles were compared between the groups using a linear regression model, and the associations between clinical variables and network profiles were analyzed. Graph theory analysis revealed “small-world” attributes in the structural connection networks of both EBA and NSC cohorts. The EBA cohort exhibited significant lower network density and global and local efficiency, as well as significantly elevated shortest path length, compared to the NSC group. The network efficiencies were markedly reduced in the EBA cohort, with the largest alterations in the default-mode, visual, and limbic areas. Moreover, decreased regional efficiency and increased nodal path length in some visual and default-mode areas were strongly associated with the period of blindness in EBA cohort, suggesting that the function of these areas would gradually weaken in the early-blind brains. Additionally, the differences in hub distribution between the two groups were mainly within the occipital and frontal areas, suggesting that neural reorganization occurred in these brain regions after early visual deprivation during adolescence. This study revealed that the EBA brain structural network undergoes both convergent and divergent topologic reorganizations to circumvent early visual deprivation. Our research will add to the growing knowledge of underlying neural mechanisms that govern brain reorganization and development, under conditions of early visual deprivation.

Evaluation of Brain Functional Connectivity from Electroencephalographic Signals Under Different Emotional States.

The identification of the emotional states corresponding to the four quadrants of the valence/arousal space has been widely analyzed in the scientific literature by means of multiple techniques. Nevertheless, most of these methods were based on the assessment of each brain region separately, without considering the possible interactions among different areas. In order to study these interconnections, this study computes for the first time the functional connectivity metric called cross-sample entropy for the analysis of the brain synchronization in four groups of emotions from electroencephalographic signals. Outcomes reported a strong synchronization in the interconnections among central, parietal and occipital areas, while the interactions between left frontal and temporal structures with the rest of brain regions presented the lowest coordination. These differences were statistically significant for the four groups of emotions. All emotions were simultaneously classified with a 95.43% of accuracy, overcoming the results reported in previous studies. Moreover, the differences between high and low levels of valence and arousal, taking into account the state of the counterpart dimension, also provided notable findings about the degree of synchronization in the brain within different emotional conditions and the possible implications of these outcomes from a psychophysiological point of view.

Brain Metabolism Related to Mild Cognitive Impairment and Phenoconversion in Patients With Isolated REM Sleep Behavior Disorder.

Background and ObjectivesMild cognitive impairment (MCI) in isolated REM sleep behavior disorder (iRBD) is a risk factor for subsequent neurodegeneration. We aimed to identify brain metabolism and functional connectivity changes related to MCI in patients with iRBD and the neuroimaging markers' predictive value for phenoconversion.MethodsThis is a prospective cohort study of patients with iRBD with a mean follow-up of 4.2 ± 2.6 years. At baseline, patients with iRBD and age- and sex-matched healthy controls (HCs) underwent 18F-fluorodeoxyglucose (FDG)–PET and resting-state fMRI scans and a comprehensive neuropsychological test battery. Voxel-wise group comparisons for FDG-PET data were performed using a general linear model. Seed-based connectivity maps were computed using brain regions showing significant hypometabolism associated with MCI in patients with iRBD and compared between groups. A Cox regression analysis was applied to investigate the association between brain metabolism and risk of phenoconversion.ResultsForty patients with iRBD, including 21 with MCI (iRBD-MCI) and 19 with normal cognition (iRBD-NC), and 24 HCs were included in the study. The iRBD-MCI group revealed relative hypometabolism in the inferior parietal lobule, lateral and medial occipital, and middle and inferior temporal cortex bilaterally compared with HC and the iRBD-NC group. In seed-based connectivity analyses, the iRBD-MCI group exhibited decreased functional connectivity of the left angular gyrus with the occipital cortex. Of 40 patients with iRBD, 12 patients converted to Parkinson disease (PD) or dementia with Lewy bodies (DLB). Hypometabolism of the occipital pole (hazard ratio [95% CI] 6.652 [1.387–31.987]), medial occipital (4.450 [1.143–17.327]), and precuneus (3.635 [1.009–13.093]) was associated with higher phenoconversion rate to PD/DLB.DiscussionMCI in iRBD is related to functional and metabolic changes in broad brain areas, particularly the occipital and parietal areas. Moreover, hypometabolism in these brain regions was a predictor of phenoconversion to PD or DLB. Evaluation of cognitive function and neuroimaging characteristics could be useful for risk stratification in patients with iRBD.

Executive functioning moderates neural mechanisms of irritability during reward processing in youth

Pediatric irritability is the most robust indicator of transdiagnostic psychopathology risk. It is associated with altered neural reward processing, including neural networks related to cognitive control, and better cognitive control has been hypothesized to mitigate irritability. We evaluated the relationship of executive functioning (EF) with irritability-related neural correlates of reward processing in youths with varying levels of irritability. Participants (N = 51, mean age=13.80 years, SD=1.94) completed a monetary incentive delay task during multiband fMRI acquisition. Irritability and EF were measured via the Affective Reactivity Index and the NIH Toolbox cognition battery, respectively. Whole-brain analyses, controlling for age, examined the moderating role of EF on irritability-related brain activation and connectivity (seeds: striatum, amygdala) during reward anticipation and performance feedback. Irritability-related neural patterns during reward processing depended on EF, in occipital areas during reward anticipation and limbic, frontal, and temporal networks during performance feedback. Higher irritability combined with higher EF was associated with neural patterns opposite to those observed for higher irritability with lower co-occurring EF. Although preliminary, findings suggest that EF may buffer irritability-related reward processing deficits. Additionally, individual differences in EF and their relation to irritability may be related to varied etiologic mechanisms of irritability with important implications for personalized prevention and intervention.

Morphometric similarity deviations in stimulant use disorder point towards abnormal brain ageing

Chronic drug use negatively impacts ageing, resulting in diminished health and quality of life. However, little is known about biomarkers of abnormal ageing in stimulant drug users. Using morphometric similarity network mapping, a novel approach to structural connectomics, we first mapped cross-sectional morphometric similarity trajectories of ageing in the publicly available Rockland Sample (20–80 years of age, n = 665). We then compared morphometric similarity and neuropsychological function between non-treatment-seeking, actively using patients with stimulant use disorder (n = 183, mean age: 35.6 years) and healthy control participants (n = 148, mean age: 36.0 years). The significantly altered mean regional morphometric similarity was found in 43 cortical regions including the inferior and orbital frontal gyri, pre/postcentral gyri and anterior temporal, superior parietal and occipital areas. Deviations from normative morphometric similarity trajectories in patients with stimulant use disorder suggested abnormal brain ageing. Furthermore, deficits in paired associates learning were consistent with neuropathology associated with both ageing and stimulant use disorder. Morphometric similarity mapping provides a promising biomarker for ageing in health and disease and may complement existing neuropsychological markers of age-related cognitive decline. Neuropathological ageing mechanisms in stimulant use disorder warrant further investigation to develop more age-appropriate treatments for older people addicted to stimulant drugs.

Enhanced Resting-State Functional Connectivity of the Nucleus Accumbens in First-Episode, Medication-Naïve Patients With Early Onset Schizophrenia.

There is abundant evidence that early onset schizophrenia (EOS) is associated with abnormalities in widespread regions, including the cortical, striatal, and limbic areas. As a main component of the ventral striatum, the nucleus accumbens (NAc) is implicated in the pathology of schizophrenia. However, functional connection patterns of NAc in patients with schizophrenia, especially EOS, are seldom explored. A total of 78 first-episode, medication-naïve patients with EOS and 90 healthy controls were recruited in the present study, and resting-state, seed-based functional connectivity (FC) analyses were performed to investigate temporal correlations between NAc and the rest of the brain in the two groups. Additionally, correlation analyses were done between regions showing group differences in NAc functional integration and clinical features of EOS. Group comparison found enhanced FC of the NAc in the EOS group relative to the HCs with increased FC in the right superior temporal gyrus and left superior parietal gyrus with the left NAc region of interest (ROI) and elevated FC in left middle occipital gyrus with the right NAc ROI. No significant associations were found between FC strength and symptom severity as well as the age of the patients. Our findings reveal abnormally enhanced FC of the NAc with regions located in the temporal, parietal, and occipital areas, which were implicated in auditory/visual processing, sensorimotor integration, and cognitive functions. The results suggest disturbed relationships between regions subserving reward, salience processing, and regions subserving sensory processing as well as cognitive functions, which may deepen our understanding of the role of NAc in the pathology of EOS.

A Near-Global Slowing of Background Activity and Epileptic Discharges in Children With Mild to Moderately Symptomatic COVID-19 Infection: An Electro-Neurophysiological Study.

Background. To assess the functional involvement of the central nervous system (CNS) via quantitative electroencephalography (EEG) analysis in children with mild to moderate COVID-19 infection who were otherwise previously healthy children. Methods. This prospective, case-control study was conducted between June and September 2020. Sleep EEG records of at least 40 min were planned for children who tested positive for COVID-19 using real-time PCR analysis and within 4–6 months post-recovery. All of the EEG analyses in this study were performed on an Ubuntu 20.04.2 LTS Operating System with the developed software using Python 3.7.6. The quantitative analysis of the epileptic discharges within the EEG records was performed using random forest after elimination of the artifacts with a model training accuracy of 98% for each sample data point. The frequency analysis was performed using the Welch method. Results. Among the age and sex-matched groups, the global mean frequency was significantly lower among the COVID-19 patients, with a P-value of 0.004. The spike slow-wave and sharp slow-wave indices were significantly higher in the patients when compared to the controls. The mean frequency values were significantly lower in almost all of the electrodes recording the frontal, central, and occipital areas. For the temporal and parietal areas, those significantly low mean frequencies were limited to the right hemisphere. Conclusion. A near-global involvement of background activity with decreased frequency, in addition to epileptic discharges, was recorded in mild to moderately COVID-19 infected children post-infection.

Automatized FACEmemory\xae scoring is related to Alzheimer\u2019s disease phenotype and biomarkers in early-onset mild cognitive impairment: the BIOFACE cohort

BackgroundFACEmemory® is the first computerized, self-administered verbal episodic memory test with voice recognition. It can be conducted under minimal supervision and contains an automatic scoring system to avoid administrator errors. Moreover, it is suitable for discriminating between cognitively healthy and amnestic mild cognitive impairment (MCI) individuals, and it is associated with Alzheimer’s disease (AD) cerebrospinal fluid (CSF) biomarkers. This study aimed to determine whether FACEmemory scoring is related to performance on classical memory tests and to AD biomarkers of brain magnetic resonance imaging (MRI) and CSF in patients with early-onset MCI (EOMCI).MethodsNinety-four patients with EOMCI from the BIOFACE study completed FACEmemory, classical memory tests (the Spanish version of the Word Free and Cued Selective Reminding Test -FCSRT-, the Word List from the Wechsler Memory Scale, third edition, and the Spanish version of the Rey–Osterrieth Complex Figure Test), and a brain MRI. Eighty-two individuals also underwent a lumbar puncture.ResultsFACEmemory scoring was moderately correlated with FCSRT scoring. With regard to neuroimaging MRI results, worse execution on FACEmemory was associated with lower cortical volume in the right prefrontal and inferior parietal areas, along with the left temporal and associative occipital areas. Moreover, the total FACEmemory score correlated with CSF AD biomarkers (Aβ1-42/Aβ1-40 ratio, p181-tau, and Aβ1-42/p181-tau ratio). When performance on FACEmemory was compared among the ATN classification groups, significant differences between the AD group and normal and SNAP groups were found.ConclusionsFACEmemory is a promising tool for detecting memory deficits sensitive to early-onset AD, but it also allows the detection of memory-impaired cases due to other etiologies. Our findings suggest that FACEmemory scoring can detect the AD endophenotype and that it is also associated with AD-related changes in MRI and CSF in patients with EOMCI. The computerized FACEmemory tool might be an opportunity to facilitate early detection of MCI in younger people than 65, who have a growing interest in new technologies.

Brain dynamics in alpha and beta frequencies underlies response activation during readiness of goal-directed hand movement

How the brain generates response readiness and preparation for hand movements is not yet understood. We hypothesised that coupled interactions in alpha and beta frequencies become modulated in central-motor brain areas during response readiness. Phase synchronization in alpha (~9–11 Hz) and beta (~18–22 Hz) frequencies was analysed prior to a finger response in people with normal lateralised readiness potentials (LRP). Specifically, Phase Locking Values (PLV) and source topographies were assessed in EEG data with Go-NoGo tasks in 18 healthy participants. Analyses involving alpha and beta phase-coupled activity in electrodes overlying central-motor brain regions and from adjacent frontal sites were compared to address the hypothesised specificity of motor area modulations as underlying response readiness. Control analyses using alpha-beta phase-coupling with the alpha at electrodes overlying occipital areas were included. Results revealed smaller PLVs in the alpha-beta phase interactions using alpha from C3, Cz, C4 electrodes compared with alpha from F3, Fz, F4, thereby isolating motor regions specifically. Analyses of the source topography of synchronous beta signals (coupled with central-motor alpha) revealed parietal, occipital and right frontal areas, possibly implicating a role of motor and visual attention, movement intention in the time window of the LRP. In sum, we isolated central-motor interactions involving centrally located alpha, coupled with parietal, occipital, and frontal beta activity in association with processes of movement readiness.

Intravenous Transplantation of Human Hair Follicle-Derived Mesenchymal Stem Cells Ameliorates Trabecular Bone Loss in Osteoporotic Mice.

Background: Hair follicles harbor a rich autologous stem cell pool and human hair follicle-derived mesenchymal stem cells (hHF-MSCs) have multi-lineage differentiation potential. Many sources of MSCs include hHF-MSCs have been attractive candidates for cell therapy, regenerative medicine and tissue engineering. The present study is to explore the effect of intravenous transplantation of hHF-MSCs on bone mass in osteoporotic mice and its mechanism, and provides prospects for clinical applications for the treatment of osteoporosis with hHF-MSCs. Methods: Physically pull out about 20 hairs with intact hair follicles from the occipital area of the scalp of healthy volunteers, and extract hair follicle-derived fibroblast-like cells. These cells were cultured and characterized in vitro. Intravenous injection of hHF-MSCs was performed on ovariectomy-induced and age-related osteoporotic SCID mice for osteoporosis treatment. The mice were sacrificed 7 weeks after the second injection and samples were collected. The long bones and L1 vertebrae were collected for micro-CT scan, histomorphometry and immunohistochemical analysis. Peripheral serum were collected for ELISA analysis and antibody array. Results: Hair follicle-derived fibroblast-like cells were defined as hHF-MSCs. Intravenous transplantation of hHF-MSCs can better restores trabecular bone mass in osteoporotic mice. The double calcein labeling assay, trap staining of bones and ELISA analysis in peripheral serum showed enhanced bone formation and weakened bone resorption after transplantation. Antibody array and immunohistochemical analysis showed that several cytokines including OPG, Wnt2b, Noggin, VCAM-1 and RANKL might be involved in this process. Conclusion: Human HF-MSCs transplantation can combat trabecular bone loss induced by menopause and aging in mice. And the above mechanism that hHF-MSCs transplantation inhibits bone resorption and promote bone formation is related to OPG, Wnt2b, VCAM-1, Noggin and RANKL.

Generalized EEG Slowing Across Phasic REM Sleep, Not Subjective RBD Severity, Predicts Neurodegeneration in Idiopathic RBD.

PurposeIdiopathic rapid eye movement sleep behavior disorder (iRBD) is the prodromal marker of α-synuclein degeneration with markedly high predictive value. We aim to evaluate the value of electroencephalography (EEG) data during rapid eye movement (REM) sleep and subjective RBD severity in predicting the conversion to neurodegenerative diseases in iRBD patients.MethodsAt the baseline, iRBD patients underwent clinical assessment and video-polysomnography (PSG). Relative spectral power for nine frequency bands during phasic and tonic REM sleep in three regions of interest, slow-to-fast ratios, clinical and PSG variables were estimated and compared between iRBD patients who converted to neurodegenerative diseases (iRBD-C) and iRBD patients who remained disease-free (iRBD-NC). Receiver operating characteristic (ROC) curves evaluated the predictive performance of slow-to-fast ratios, and subjective RBD severity as assessed with RBD Questionnaire-Hong Kong.ResultsTwenty-two (33.8%) patients eventually developed neurodegenerative diseases. The iRBD-C group showed shorter total sleep time (p < 0.001), lower stage 2 sleep percentage (p = 0.044), more periodic leg-movement-related arousal index (p = 0.004), increased tonic chin electromyelographic activity (p = 0.040) and higher REM density in the third REM episode (p = 0.034) than the iRBD-NC group. EEG spectral power analyses revealed that iRBD phenoconverters showed significantly higher delta and lower alpha power, especially in central and occipital regions during the phasic REM state compared to the iRBD-NC group. Significantly higher slow-to-fast ratios were observed in a more generalized way during the phasic state in the iRBD-C group compared to the iRBD-NC group. ROC analyses of the slowing ratio in occipital areas during phasic REM sleep yielded an area under the curve of 0.749 (p = 0.001), while no significant predictive value of subjective RBD severity was observed.ConclusionOur study shows that EEG slowing, especially in a more generalized manner during the phasic period, may be a promising marker in predicting phenoconversion in iRBD, rather than subjective RBD severity.

Altered spontaneous cortical activity predicts pain perception in individuals with cerebral palsy.

Cerebral palsy is the most common paediatric neurological disorder and results in extensive impairment to the sensorimotor system. However, these individuals also experience increased pain perception, resulting in decreased quality of life. In the present study, we utilized magnetoencephalographic brain imaging to examine whether alterations in spontaneous neural activity predict the level of pain experienced in a cohort of 38 individuals with spastic diplegic cerebral palsy and 67 neurotypical controls. Participants completed 5 min of an eyes closed resting-state paradigm while undergoing a magnetoencephalography recording. The magnetoencephalographic data were then source imaged, and the power within the delta (2–4 Hz), theta (5–7 Hz), alpha (8–12 Hz), beta (15–29 Hz), low gamma (30–59 Hz) and high gamma (60–90 Hz) frequency bands were computed. The resulting power spectral density maps were analysed vertex-wise to identify differences in spontaneous activity between groups. Our findings indicated that spontaneous cortical activity was altered in the participants with cerebral palsy in the delta, alpha, beta, low gamma and high gamma bands across the occipital, frontal and secondary somatosensory cortical areas (all pFWE < 0.05). Furthermore, we also found that the altered beta band spontaneous activity in the secondary somatosensory cortices predicted heightened pain perception in the individuals with cerebral palsy (P = 0.039). Overall, these results demonstrate that spontaneous cortical activity within individuals with cerebral palsy is altered in comparison to their neurotypical peers and may predict increased pain perception in this patient population. Potentially, changes in spontaneous resting-state activity may be utilized to measure the effectiveness of current treatment approaches that are directed at reducing the pain experienced by individuals with cerebral palsy.

190 Brain Structural MRI Predicts Outcome of Radiosurgical Treatment in Trigeminal Neuralgia

INTRODUCTION: Growing evidence supports the role of the central nervous system (CNS) in the modulation of pain in trigeminal neuralgia (TN) patients. METHODS: Thirty patients with idiopathic or classic TN, who underwent GKSRS and were followed for at least 24 months, were retrospectively included. Pre-treatment structural MRI and pre- and serial, post-operative clinical features were investigated. Fifteen age- and sex-matched healthy controls were also enrolled. Cortical thickness and gray matter (GM) volumes were assessed in TN patients relative to controls, as well as between patient subgroups according to treatment outcomes (initial responders/non-responders, patients with pain recurrence/long-lasting pain relief at the last follow-up). Clinical and MRI predictors of treatment outcomes were explored. RESULTS: Cortical thinning of temporal, prefrontal, cingulate, somatosensory and occipital areas bilaterally was found in TN patients relative to controls. No cortical thickness and GM volume differences were observed when TN initial responders and non-responders were compared. Patients who experienced TN recurrence after initial pain relief were characterized by thicker parahippocampal and temporal cortices bilaterally and greater volume of right amygdala and hippocampus compared to patients with long-lasting pain relief. In TN patients, disease duration and baseline cortical thinning of right parahippocampal, left fusiform and middle temporal cortices were associated with poor outcome after GKSRS at the last follow-up (R2 = 0.57, p &lt; 0.001). CONCLUSION: The study provides novel insights into structural brain alterations of TN patients, which might contribute to disease development and pain maintenance.

Multiscale Weighted Permutation Entropy Analysis of Schizophrenia Magnetoencephalograms.

Schizophrenia is a neuropsychiatric disease that affects the nonlinear dynamics of brain activity. The primary objective of this study was to explore the complexity of magnetoencephalograms (MEG) in patients with schizophrenia. We combined a multiscale method and weighted permutation entropy to characterize MEG signals from 19 schizophrenia patients and 16 healthy controls. When the scale was larger than 42, the MEG signals of schizophrenia patients were significantly more complex than those of healthy controls (). The difference in complexity between patients with schizophrenia and the controls was strongest in the frontal and occipital areas (), and there was almost no difference in the central area. In addition, the results showed that the dynamic range of MEG complexity is wider in healthy individuals than in people with schizophrenia. Overall, the multiscale weighted permutation entropy method reliably quantified the complexity of MEG from schizophrenia patients, contributing to the development of potential magnetoencephalographic biomarkers for schizophrenia.