IDEAL monitoring of musical skills during awake craniotomy: From step 1 to step 2.

The aim of awake brain surgery is to perform a maximum resection on the one hand, and to preserve cognitive functions, quality of life and personal autonomy on the other hand. Historically, language and sensorimotor functions were most frequently monitored. Over the years other cognitive functions, including music, have entered the operation theatre. Cases about monitoring musical abilities during awake brain surgery are emerging, and a systematic method how to monitor music would be the next step. According to the IDEAL framework for surgical innovations our study aims to present future recommendation based on a systematic literature search (PRISMA) in combination with lessons learned from three case reports from our own clinical practice with professional musicians (n = 3). We plead for structured procedures including individual tailored tasks. By embracing these recommendations, we can both improve clinical care and unravel music functions in the brain.

First-line surgery vs first-line ART to manage infertility in women with deep endometriosis without bowel involvement: A multi-centric propensity-score matching comparison.

OBJECTIVE: To compare first-line surgery with first-line assisted reproductive techniques (ART) in infertile women with deep infiltrating endometriosis (DIE) without colorectal involvement. STUDY DESIGN: A retrospective comparative cohort study with a propensity-score matching analysis, in four tertiary-care referral centers. The population was infertile women with DIE without colorectal involvement. The patients were managed either by first-line surgery followed by spontaneous conception attempts and/or ART, or by first-line ART. 284 patients were extracted from the databases. After matching, 92 patients were compared in each group. Clinical pregnancy rates (PR) and live-birth rates (LBR) were the primary outcomes, and cumulative pregnancy rate (CPR) and cumulative live birth rate (CLBR) were the secondary outcomes. RESULTS: The mean number of IVF-ICSI cycles per patient was 1.4, with a significant difference between the groups: 1.6 in the first-line ART group and 1.2 in the first-line surgery group (p = 0.006). The PR was significantly higher in the first-line surgery group (72 % vs 35 %; p < 0.001). In the first-line surgery group, non-ART pregnancies occurred in 18 % (17/92) while no non-ART pregnancies was noted in the first-line ART group. The LBR was significantly higher in the first-line surgery group (61 % vs 24 %; p < 0.001). After ART, the CPR were 72 % (47/67) in the first-line surgery group, and 35 % (32/92) in the first-line ART group (p < 0.001). CONCLUSION: After matching, our results support that first-line surgery offer higher pregnancy and live-birth rates than first-line ART in patients with DIE without colorectal involvement.

A short anogenital distance on MRI is a marker of endometriosis.

STUDY QUESTION: Could the anogenital distance (AGD) as assessed by MRI (MRI-AGD) be a diagnostic tool for endometriosis? SUMMARY ANSWER: A short MRI-AGD is a strong diagnostic marker of endometriosis. WHAT IS KNOWN ALREADY: A short clinically assessed AGD (C-AGD) is associated with the presence of endometriosis. STUDY DESIGN SIZE DURATION: This study is a re-analysis of previously published data from a case-control study. PARTICIPANTS/MATERIALS SETTING METHODS: Women undergoing pelvic surgery from January 2018 to June 2019 and who had a preoperative pelvic MRI were included. C-AGD was measured at the beginning of the surgery by a different operator who was unaware of the endometriosis status. MRI-AGD was measured retrospectively by a senior radiologist who was blinded to the final diagnosis. Two measurements were made: from the posterior wall of the clitoris to the anterior edge of the anal canal (MRI-AGD-AC), and from the posterior wall of the vagina to the anterior edge of the anal canal (MRI-AGD-AF). MAIN RESULTS AND THE ROLE OF CHANCE: The study compared MRI-AGD of 67 women with endometriosis to 31 without endometriosis (controls). Average MRI-AGD-AF measurements were 13.3 mm (±3.9) and 21.2 mm (±5.4) in the endometriosis and non-endometriosis groups, respectively (P < 10-5). Average MRI-AGD-AC measurements were 40.4 mm (±7.3) and 51.1 mm (±8.6) for the endometriosis and non-endometriosis groups, respectively (P < 10-5). There was no difference of MRI-AGD in women with and without endometrioma (P = 0.21), or digestive involvement (P = 0.26). Moreover, MRI-AGD values were independent of the revised score of the American Society of Reproductive Medicine and the Enzian score. The diagnosis of endometriosis was negatively associated with both the MRI-AGD-AF (ß = -7.79, 95% CI (-9.88; -5.71), P < 0.001) and MRI-AGD-AC (ß = -9.51 mm, 95% CI (-12.7; 6.24), P < 0.001) in multivariable analysis. Age (ß = +0.31 mm, 95% CI (0.09; 0.53), P = 0.006) and BMI (ß = +0.44 mm, 95% CI (0.17; 0.72), P = 0.001) were positively associated with the MRI-AGD-AC measurements in multivariable analysis. MRI-AGD-AF had an AUC of 0.869 (95% CI (0.79; 0.95)) and outperformed C-AGD. Using an optimal cut-off of 20 mm for MRI-AGD-AF, a sensitivity of 97.01% and a specificity of 70.97% were noted. LIMITATIONS REASONS FOR CAUTION: This was a retrospective analysis and no adolescents had been included. WIDER IMPLICATIONS OF THE FINDINGS: This study is consistent with previous works associating a short C-AGD with endometriosis and the absence of correlation with the disease phenotype. MRI-AGD is more accurate than C-AGD in this setting and could be evaluated in the MRI examination of patients with suspected endometriosis. STUDY FUNDING/COMPETING INTERESTS: N/A. TRIAL REGISTRATION NUMBER: The protocol was approved by the 'Groupe Nantais d'Ethique dans le Domaine de la Santé' and registered under reference 02651077.

Anogenital distance in adult women is a strong marker of endometriosis: results of a prospective study with laparoscopic and histological findings.

STUDY QUESTION: Could anogenital distance (AGD) be a non-invasive marker of endometriosis and correlated to the American Society for Reproductive Medicine revised score (r-ASRM) and ENZIAN classifications? SUMMARY ANSWER: Surgically and histologically proven endometriosis is associated with a short AGD in women of reproductive age but not correlated either to the severity or to the location of the disease. WHAT IS KNOWN ALREADY: AGD is a marker of intrauterine androgen exposure and exposure to oestrogen-like chemicals such as phthalates. Moreover, exposure to endocrine disruptors, such as organochlorine chemicals, is associated with endometriosis. It has been suggested that a short AGD in women is associated with an increased risk of endometriosis based on clinical and ultrasound exams. STUDY DESIGN SIZE DURATION: A prospective cohort study was conducted from January 2018 to June 2019 in a tertiary-care centre including 168 adult women undergoing pelvic surgery. PARTICIPANTS/MATERIALS SETTING METHODS: Of the 168 women included, 98 patients had endometriosis (endometriosis group) and 70 did not (non-endometriosis group). An operator (not the surgeon) measured the distance from the clitoral surface to the anus (AGD-AC) and from the posterior fourchette to the anus (AGD-AF) before surgery using a millimetre accuracy ruler. Endometriosis was diagnosed on exploration of the abdominopelvic cavity, and the r-ASRM and ENZIAN scores were calculated. All removed tissues underwent pathological examination. MAIN RESULTS AND THE ROLE OF CHANCE: Mean (±SD) AGD-AF measurements were 21.5 mm (±6.4) and 32.3 mm (±8.1), and average AGD-AC measurements were 100.9 mm (±20.6) and 83.8 mm (±12.9) in the endometriosis and non-endometriosis groups (P < 0.001), respectively. Mean AGD-AF and AGD-AC measurements were not related to r-ASRM stage (P = 0.73 and 0.80, respectively) or ENZIAN score (P = 0.62 and 0.21, respectively). AGD-AF had a better predictive value than AGD-AC for discriminating the presence of endometriosis (AUC = 0.840 (95% CI 0.782-0.898) and 0.756 (95% CI 0.684-0.828)), respectively. For AGD-AF, an optimal cut-off of 20 mm had a specificity of 0.986 (95% CI 0.923-0.999), sensitivity of 0.306 (95% CI 26.1-31.6) and positive predictive value of 0.969 (95% CI 0.826-0.998). In multivariable analysis, the diagnosis of endometriosis was the only variable independently associated with the AGD-AF (ß = -9.66 mm 95% CI -12.20--7.12), P < 0.001). LIMITATIONS REASONS FOR CAUTION: The sample size was relatively small with a high proportion of patients with colorectal endometriosis reflecting the activity of an expert centre. Furthermore, we did not include adolescents and the AGD-AF measurement could be particularly relevant in this population. WIDER IMPLICATIONS OF THE FINDINGS: The measurement of AGD could be a useful non-invasive tool to predict endometriosis. This could be especially relevant for adolescents and virgin women to avoid diagnostic laparoscopy and empiric treatment. STUDY FUNDING/COMPETING INTERESTS: None.

Fertility outcomes in women experiencing severe complications after surgery for colorectal endometriosis.

STUDY QUESTION: What are the fertility outcomes in women wishing to conceive after experiencing a severe complication from surgical removal of colorectal endometriosis? SUMMARY ANSWER: The pregnancy rate (PR) among women who wished to conceive after a severe complication of surgery for colorectal endometriosis was 41.2% (spontaneously for 80%, after ART procedure for 20%). WHAT IS KNOWN ALREADY: While the long-term benefit of surgery on pain and quality of life is well documented for women with colorectal endometriosis, it exposes women to the risk of severe complications. However, little is known about fertility outcomes in women experiencing such severe postoperative complications. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study included women who experienced a severe complication after surgery for colorectal endometriosis between January 2004 and June 2014, and who wished to conceive. A total of 53 patients met the inclusion criteria. The fertility outcome was available for 48 women, who were therefore included in the analysis. The median follow-up was 5 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: All the women underwent complete removal of colorectal endometriosis. Postoperative severe complications were defined as grades III-IV of the Clavien-Dindo classification. Fertility outcomes, PR and cumulative pregnancy rate (CPR), were estimated. MAIN RESULTS AND THE ROLE OF CHANCE: Most women experienced a grade IIIb complication (83.3%). Of 48 women, 20 became pregnant (overall PR: 41.2%); spontaneously for 16 (80%) and after ART procedure for 4 (20%). The median interval between surgery and first pregnancy was 3 years. The live birth rate was 14/48 (29.2%). The 5-year CPR was 46%. A lower CPR was found for women who experienced anastomotic leakage (with or without rectovaginal fistula) (P = 0.02) or deep pelvic abscess (with or without anastomotic leakage) (P = 0.04). LIMITATIONS REASONS FOR CAUTION: Due to a lack of information, no sub-analysis was done to investigate other parameters potentially impacting fertility outcomes. WIDER IMPLICATIONS OF THE FINDINGS: The PR for our population was slightly lower to that observed in the literature for women who experience such surgery without consideration for the occurrence of complications. However, 'severe complications' covers a range of conditions which are likely to have a very different impacts on fertility. Even if the PR and CPR appear satisfactory, septic complications can negatively impact fertility outcomes. Rapid ART may be a good option for these patients. STUDY FUNDING/COMPETING INTEREST(S): No funding was required for the current study. Pr H. Roman reported personal fees from Plasma Surgical Inc. (Roswell, GA, USA) for participating in a symposium and a masterclass, in which he presented his experience in the use of PlasmaJet®. None of the other authors declared any conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

[Ultrasound screening for birth defects: A medico-economic review]. / Aspects médico-économiques du dépistage échographique des malformations fœtales : revue de la littérature.

OBJECTIVES: The systematic use of ultrasound during pregnancy aims at birth defect detection. Our objective was to assess the economic efficiency of prenatal ultrasound screening for fetal malformations. METHODS: We carried out a literature review on Medline via PubMed between 1985 and 2015, from the economic perspective of the prenatal ultrasound screening for fetal malformations. RESULTS: The literature on this subject was sparse and we selected only twelve articles presenting relevant economic data, of which only eight were proper medico-economic studies. We found arguments for the economic effectiveness of ultrasound screening for fetal malformation detection, which is largely linked to the terminations of pregnancies and to the cost of the handicaps "avoided". However, none of the reviewed articles could reach medico-economic conclusions. Additionally, we highlighted various elements making economic analyses more complex in this field: the choice of the method, the uncertainty around two essential parameters (the efficiency of ultrasound and the costs of procedures) and the difficulties to compare or to generalize results. We also noticed important methodological heterogeneity among the studies and the absence of French study. CONCLUSIONS: Previously published data are insufficient to assess the economic efficiency of prenatal ultrasound screening for fetal malformations.

Evoked versus spontaneous high frequency oscillations in the chronic electrocorticogram in focal epilepsy.

OBJECTIVE: Spontaneous high frequency oscillations (HFOs; ripples 80-250Hz, fast ripples (FRs) 250-500Hz) are biomarkers for epileptogenic tissue in focal epilepsy. Single pulse electrical stimulation (SPES) can evoke HFOs. We hypothesized that stimulation distinguishes pathological from physiological ripples and compared the occurrence of evoked and spontaneous HFOs within the seizure onset zone (SOZ) and eloquent functional areas. METHODS: Ten patients underwent SPES during 2048Hz electrocorticography (ECoG). Evoked HFOs in time-frequency plots and spontaneous HFOs were visually analyzed. We compared electrodes with evoked and spontaneous HFOs for: percentages in the SOZ, sensitivity and specificity for the SOZ, percentages in functional areas outside the SOZ. RESULTS: Two patients without spontaneous FRs showed evoked FRs in the SOZ. Percentages of evoked and spontaneous HFOs in the SOZ were similar (ripples 32:33%, p=0.77; FRs 43:48%, p=0.63), but evoked HFOs had generally a lower specificity (ripples 45:69%, p=0.02; FRs 83:92%, p=0.04) and higher sensitivity (ripples 85:70%, p=0.27; FRs 52:37%, p=0.05). More electrodes with evoked than spontaneous ripples were found in functional (54:30%, p=0.03) and 'silent' areas (57:27%, p=0.01) outside the SOZ. CONCLUSIONS: SPES can elicit SOZ-specific FRs in patients without spontaneous FRs, but activates ripples in all areas. SIGNIFICANCE: SPES is an alternative for waiting for spontaneous HFOs, but does not warrant exclusively pathological ripples.

Why many polymers are so fragile: A new perspective.

Many polymers exhibit much steeper temperature dependence of their structural relaxation time (higher fragility) than liquids of small molecules, and the mechanism of this unusually high fragility in polymers remains a puzzle. To reveal additional hints for understanding the underlying mechanism, we analyzed correlation of many properties of polymers to their fragility on example of model polymer polystyrene with various molecular weights (MWs). We demonstrate that these correlations work for short chains (oligomers), but fail progressively with increase in MW. Our surprising discovery is that the steepness of the temperature dependence (fragility) of the viscosity that is determined by chain relaxation follows the correlations at all molecular weights. These results suggest that the molecular level relaxation still follows the behavior usual for small molecules even in polymers, and its fragility (chain fragility) falls in the range usual for molecular liquids. It is the segmental relaxation that has this unusually high fragility. We speculate that many polymers cannot reach an ergodic state on the time scale of segmental dynamics due to chain connectivity and rigidity. This leads to sharper decrease in accessible configurational entropy upon cooling and results in steeper temperature dependence of segmental relaxation. The proposed scenario provides a new important insight into the specifics of polymer dynamics: the role of ergodicity time and length scale. At the end, we suggest that a similar scenario can be applicable also to other molecular systems with slow intra-molecular degrees of freedom and to chemically complex systems where the time scale of chemical fluctuations can be longer than the time scale of structural relaxation.

Single Pulse Electrical Stimulation to identify epileptogenic cortex: Clinical information obtained from early evoked responses.

OBJECTIVE: Single Pulse Electrical Stimulation (SPES) probes epileptogenic cortex during electrocorticography. Two SPES responses are described: pathological delayed responses (DR, >100 ms) associated with the seizure onset zone (SOZ) and physiological early responses (ER, <100 ms) that map cortical connectivity. We analyzed properties of ERs, including frequencies >80 Hz, in the SOZ and seizure propagation areas. METHODS: We used data from 12 refractory epilepsy patients. SPES consisted of 10 pulses of 1 ms, 4-8 mA and 5s interval on adjacent electrodes pairs. Data were available at 2048 samples/s for six and 512 samples/s (22 bits) for eight patients and analyzed in the time-frequency (TF) and time-domain (TD). RESULTS: Electrodes with ERs were stronger associated with SOZ than non-SOZ electrodes. ERs with frequency content >80 Hz exist and are specific for SOZ channels. ERs evoked by stimulation of seizure onset electrodes were associated with electrodes involved in seizure propagation. CONCLUSION: Analysis of ERs can reveal aspects of pathology, manifested by association with seizure propagation and areas with high ER numbers that coincide with the SOZ. SIGNIFICANCE: Not only DRs, but also ERs could have clinical value for mapping epileptogenic cortex and help to unravel aspects of the epileptic network.

Expression of neurodegenerative disease-related proteins and caspase-3 in glioneuronal tumours.

AIMS: Recent evidence supports the activation of mechanisms underlying cellular ageing and neurodegeneration in developmental lesions associated with epilepsy. The present study examined the ongoing cell injury and vulnerability to neuronal degeneration in glioneuronal tumours (GNT). METHODS: We evaluated a series of GNT (n = 31 gangliogliomas, GG and n = 30 dysembryoplastic neuroepithelial tumours, DNT). Sections were processed for immunohistochemistry using markers for the evaluation of caspase-3 and neurodegeneration-related proteins/pathways and their expression was correlated with the tumour features and the clinical history of epilepsy. RESULTS: Both GG and DNT specimens contained caspase-3-positive cells. In GG, expression of activated caspase-3 was negatively correlated the with the BRAF V600E mutation status. We also observed an abnormal expression of death receptor-6 and ß-amyloid precursor protein (APP). Moreover, dysplastic neurones expressed p62, phosphorylated (p)TDP43 and pTau. Double labelling experiments showed colocalization of phosphorylated S6 (marker of mammalian target of rapamycin, mTOR, pathway activation) with pTau and p62. In GG, neuronal p62 expression was positively correlated with pS6. The immunoreactivity score (IRS) of caspase-3, APP, DR6, p62 and pTDP43 were found to be significantly higher in GG than in DNT. Expression of APP, DR6, pTau (in GG and DNT) and caspase-3 (in GG) positively correlated with duration of epilepsy. In GG, the expression of neuronal caspase-3, DR6 and glial p62 was associated with a worse postoperative seizure outcome. CONCLUSIONS: Our observations in GNT provide evidence of premature activation of mechanisms of neurodegeneration which are associated with the clinical course of epilepsy in patient with GG.

High frequency oscillations in intra-operative electrocorticography before and after epilepsy surgery.

OBJECTIVE: Removal of brain tissue showing high frequency oscillations (HFOs; ripples: 80-250Hz and fast ripples: 250-500Hz) in preresection electrocorticography (preECoG) in epilepsy patients seems a predictor of good surgical outcome. We analyzed occurrence and localization of HFOs in intra-operative preECoG and postresection electrocorticography (postECoG). METHODS: HFOs were automatically detected in one-minute epochs of intra-operative ECoG sampled at 2048Hz of fourteen patients. Ripple, fast ripple, spike, ripples on a spike (RoS) and not on a spike (RnoS) rates were analyzed in pre- and postECoG for resected and nonresected electrodes. RESULTS: Ripple, spike and fast ripple rates decreased after resection. RnoS decreased less than RoS (74% vs. 83%; p=0.01). Most fast ripples in preECoG were located in resected tissue. PostECoG fast ripples occurred in one patient with poor outcome. Patients with good outcome had relatively high postECoG RnoS rates, specifically in the sensorimotor cortex. CONCLUSIONS: Our observations show that fast ripples in intra-operative ECoG, compared to ripples, may be a better biomarker for epileptogenicity. Further studies have to determine the relation between resection of epileptogenic tissue and physiological ripples generated by the sensorimotor cortex. SIGNIFICANCE: Fast ripples in intra-operative ECoG can help identify the epileptogenic zone, while ripples might also be physiological.

Frequency specific spatial interactions in human electrocorticography: V1 alpha oscillations reflect surround suppression.

Electrical brain signals are often decomposed into frequency ranges that are implicated in different functions. Using subdural electrocorticography (ECoG, intracranial EEG) and functional magnetic resonance imaging (fMRI), we measured frequency spectra and BOLD responses in primary visual cortex (V1) and intraparietal sulcus (IPS). In V1 and IPS, 30-120 Hz (gamma, broadband) oscillations allowed population receptive field (pRF) reconstruction comparable to fMRI estimates. Lower frequencies, however, responded very differently in V1 and IPS. In V1, broadband activity extends down to 3 Hz. In the 4-7 Hz (theta) and 18-30 Hz (beta) ranges broadband activity increases power during stimulation within the pRF. However, V1 9-12 Hz (alpha) frequency oscillations showed a different time course. The broadband power here is exceeded by a frequency-specific power increase during stimulation of the area outside the pRF. As such, V1 alpha oscillations reflected surround suppression of the pRF, much like negative fMRI responses. They were consequently highly localized, depending on stimulus and pRF position, and independent between nearby electrodes. In IPS, all 3-25 Hz oscillations were strongest during baseline recording and correlated between nearby electrodes, consistent with large-scale disengagement. These findings demonstrate V1 alpha oscillations result from locally active functional processes and relate these alpha oscillations to negative fMRI signals. They highlight that similar oscillations in different areas reflect processes with different functional roles. However, both of these roles of alpha seem to reflect suppression of spiking activity.

Near-infrared spectroscopy can predict the onset of cerebral hyperperfusion syndrome after carotid endarterectomy.

BACKGROUND: Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy (CEA) is a potential life-threatening complication. Therefore, early identification and treatment of patients at risk is essential. CHS can be predicted by a doubling of postoperative transcranial Doppler (TCD)-derived mean middle cerebral artery blood velocity (V(mean)) compared to preoperative values. However, in approximately 15% of CEA patients, an adequate TCD signal cannot be obtained due to an insufficient temporal bone window. Moreover, the use of TCD requires specifically skilled personnel. An alternative and promising technique of noninvasive cerebral monitoring is relative frontal lobe oxygenation (rSO(2)) measured by near-infrared spectroscopy (NIRS), which offers on-line information about cerebral oxygenation without the need for specialized personnel. In this study, we assess whether NIRS and perioperative TCD are related to the onset CHS following CEA. METHODS: Patients who underwent CEA under general anesthesia and had a sufficient TCD window were prospectively included. The V(mean) and rSO(2) measured before induction of anesthesia were compared to measurements performed in the first postoperative hour (ΔV(mean), ΔrSO(2), respectively). Logistic regression analysis was performed to determine the relationship between ΔV and ΔrSO(2) and the occurrence of CHS. Subsequently, receiver operating characteristic (ROC) curve analysis was used to determine the optimal cutoff values. Diagnostic values were shown as positive and negative predictive values (PPV and NPV). RESULTS: In total, 151 patients were included, of which 7 patients developed CHS. The ΔV(mean) and ΔrSO(2) differed between CHS and non-CHS patients (median, interquartile range), i.e. 74% (67-103) versus 16% (-2 to 41), p = 0.001, and 7% (4-15) versus 1% (-6 to 7), p = 0.009, respectively. The mean arterial blood pressure did not change. Postoperative ΔV(mean) and ΔrSO(2) were significantly related to the occurrence of CHS [odds ratio (OR) 1.40 (95% CI 1.02-1.93) per 30% increase in V(mean) and OR 1.82 (95% CI 1.11-2.99) per 5% increase in rSO(2)]. ROC curve analysis showed an area under the curve of 0.88 (p = 0.001) for ΔV(mean) and an optimal cutoff value of 67% increase (PPV 38% and NPV 99%), and an area under the curve of 0.79 (p = 0.009) for ΔrSO(2) and an optimal cutoff value of 3% rSO(2) increase (PPV 11% and NPV 100%). The combination of both monitoring techniques provided a PPV of 58% and an NPV of 99%. CONCLUSIONS: Both TCD and NIRS measurements can be used to safely identify patients not at risk of developing CHS. It appears that NIRS is a good alternative when a TCD signal cannot be obtained.

The effects of blood vessels on electrocorticography.

Electrocorticography, primarily used in a clinical context, is becoming increasingly important for fundamental neuroscientific research, as well as for brain-computer interfaces. Recordings from these implanted electrodes have a number of advantages over non-invasive recordings in terms of band width, spatial resolution, smaller vulnerability to artifacts and overall signal quality. However, an unresolved issue is that signals vary greatly across electrodes. Here, we examine the effect of blood vessels lying between an electrode and the cortex on signals recorded from subdural grid electrodes. Blood vessels of different sizes cover extensive parts of the cortex causing variations in the electrode-cortex connection across grids. The power spectral density of electrodes located on the cortex and electrodes located on blood vessels obtained from eight epilepsy patients is compared. We find that blood vessels affect the power spectral density of the recorded signal in a frequency-band-specific way, in that frequencies between 30 and 70 Hz are attenuated the most. Here, the signal is attenuated on average by 30-40% compared to electrodes directly on the cortex. For lower frequencies this attenuation effect is less pronounced. We conclude that blood vessels influence the signal properties in a non-uniform manner.

Prefrontal cortex lesions and MAO-A modulate aggression in penetrating traumatic brain injury.

OBJECTIVE: This study investigates the interaction between brain lesion location and monoamine oxidase A (MAO-A) in the genesis of aggression in patients with penetrating traumatic brain injury (PTBI). METHODS: We enrolled 155 patients with PTBI and 42 controls drawn from the Vietnam Head Injury Study registry. Patients with PTBI were divided according to lesion localization (prefrontal cortex [PFC] vs non-PFC) and were genotyped for the MAO-A polymorphism linked to low and high transcriptional activity. Aggression was assessed with the aggression/agitation subscale of the Neuropsychiatric Inventory (NPI-a). RESULTS: Patients with the highest levels of aggression preferentially presented lesions in PFC territories. A significant interaction between MAO-A transcriptional activity and lesion localization on aggression was revealed. In the control group, carriers of the low-activity allele demonstrated higher aggression than high-activity allele carriers. In the PFC lesion group, no significant differences in aggression were observed between carriers of the 2 MAO-A alleles, whereas in the non-PFC lesion group higher aggression was observed in the high-activity allele than in the low-activity allele carriers. Higher NPI-a scores were linked to more severe childhood psychological traumatic experiences and posttraumatic stress disorder symptomatology in the control and non-PFC lesion groups but not in the PFC lesion group. CONCLUSIONS: Lesion location and MAO-A genotype interact in mediating aggression in PTBI. Importantly, PFC integrity is necessary for modulation of aggressive behaviors by genetic susceptibilities and traumatic experiences. Potentially, lesion localization and MAO-A genotype data could be combined to develop risk-stratification algorithms and individualized treatments for aggression in PTBI.

Consequence of excess configurational entropy on fragility: the case of a polymer-oligomer blend.

By taking advantage of the molecular weight dependence of the glass transition of polymers and their ability to form perfectly miscible blends, we propose a way to modify the fragility of a system, from fragile to strong, keeping the same glass properties, i.e., vibrational density of states, mean-square displacement, and local structure. Both slow and fast dynamics are investigated by calorimetry and neutron scattering in an athermal polystyrene-oligomer blend, and compared to those of a pure 17-mer polystyrene considered to be a reference, of the same Tg. Whereas the blend and the pure 17-mer have the same heat capacity in the glass and in the liquid, their fragilities differ strongly. Thus, the difference in fragility is related to an extra configurational entropy created by the mixing process and acting at a scale much larger than the interchain distance, without affecting the fast dynamics and the structure of the glass.

Interictal magnetoencephalography and the irritative zone in the electrocorticogram.

Magnetoencephalography (MEG) is considered a useful tool for planning electrode placement for chronic intracranial subdural electrocorticography (ECoG) in candidates for epilepsy surgery or even as a substitute for ECoG. MEG recordings are usually interictal and therefore, at best, reflect the interictal ECoG. To estimate the clinical value of MEG, it is important to know how well interictal MEG reflects interictal activity in the ECoG. From 1998 to 2008, 38 candidates for ECoG underwent a 151-channel MEG recording and 3D magnetic resonance imaging as a part of their presurgical evaluation. Interictal MEG spikes were identified, clustered, averaged and modelled using the multiple signal classification algorithm and co-registered to magnetic resonance imaging. ECoG was continuously recorded with electrode grids and strips for approximately 1 week. In a representative sample of awake interictal ECoG, interictal spikes were identified and averaged. The different spikes were characterized and quantified using a combined amplitude and synchronous surface-area measure. The ECoG spikes were ranked according to this measure and plotted on the magnetic resonance imaging surface rendering. Interictal spikes in MEG and ECoG were allocated to a predefined anatomical brain region and an association analysis was performed. All interictal MEG spikes were associated with an interictal ECoG spike. Overall, 56% of all interictal ECoG spikes had an interictal MEG counterpart. The association between the two was >or=90% in the interhemispheric and frontal orbital region, approximately 75% in the superior frontal, central and lateral temporal regions, but only approximately 25% in the mesial temporal region. MEG is a reliable indicator of the presence of interictal ECoG spikes and can be used to plan intracranial electrode placements. However, a substantial number of interictal ECoG spikes are not detected by MEG, and therefore MEG cannot be considered a substitute for ECoG.

Illusory shadow person causing paradoxical gaze deviations during temporal lobe seizures.

Generally, activation of the frontal eye field during seizures can cause versive (forced) gaze deviation, while non-versive head deviation is hypothesised to result from ictal neglect after inactivation of the ipsilateral temporo-parietal area. Almost all non-versive head deviations occurring during temporal lobe seizures are directed to the side of seizure onset, so in derogatory cases it is worth while explaining the paradoxical event. We present a patient with a paradoxical direction of gaze deviation during temporal lobe seizures with an unexpected explanation. Electrocortical stimulation of the temporo-parieto-occipital junction elicited an irrepressible urge to look towards an illusory shadow person besides the patient. Paradoxical non-versive gaze deviations in temporal lobe seizures may be due to illusory experiences masked by postictal amnesia.