Interhemispheric functional connectivity: an fMRI study in callosotomized patients.

Introduction: Functional connectivity (FC) is defined in terms of temporal correlations between physiological signals, which mainly depend upon structural (axonal) connectivity; it is commonly studied using functional magnetic resonance imaging (fMRI). Interhemispheric FC appears mostly supported by the corpus callosum (CC), although several studies investigating this aspect have not provided conclusive evidence. In this context, patients in whom the CC was resected for therapeutic reasons (split-brain patients) provide a unique opportunity for research into this issue. The present study was aimed at investigating with resting-state fMRI the interhemispheric FC in six epileptic patients who have undergone surgical resection of the CC. Methods: The analysis was performed using fMRI of the Brain Software Library; the evaluation of interhemispheric FC and the recognition of the resting-state networks (RSNs) were performed using probabilistic independent component analysis. Results: Generally, bilateral brain activation was often observed in primary sensory RSNs, while in the associative areas, such as those composing the default mode and fronto-parietal networks, the activation was often unilateral. Discussion: These results suggest that even in the absence of the CC, some interhemispheric communication is still present. This residual FC might be supported through extra-callosal pathways that are likely subcortical, making it possible for some interhemispheric integration. Further studies are needed to confirm these conclusions.

Conversion to Brivaracetam Monotherapy in Clinical Practice: A Retrospective Study.

INTRODUCTION: The study aimed to evaluate the effectiveness and safety of brivaracetam (BRV) as conversion monotherapy in adults with focal epilepsy treated in the context of real-world clinical practice. METHODS: This was a retrospective, observational, non-interventional study in adults with focal epilepsy who converted to BRV monotherapy following the withdrawal of background antiseizure medications (ASMs). Primary effectiveness outcome was the retention rate of BRV as single ASM at 6 and 12 months. Secondary outcomes included the 6- and 12-month rates of seizure freedom. Safety and tolerability outcomes included the frequency and type of adverse events (AEs) and the occurrence of treatment discontinuation due to AEs. RESULTS: A total of 44 participants with a median age of 63.5 (interquartile range 44-73.5) years were included; 17 subjects were seizure free at baseline, and 9 of them switched from levetiracetam because of lack of tolerability. The retention rate of BRV monotherapy was 88.6% (39/44) at 6 months and 83.9% (26/31) at 12 months. The rates of seizure freedom were 72.7% (32/44) in subjects with 6-month follow-up and 58.1% (18/31) in subjects with 12-month follow-up. The median maintenance dosage of BRV monotherapy was 150 (100-200) mg/day at 6 months and 125 (100-200) mg/day in subjects with 12-month follow-up. Adverse events were recorded in 6/44 (13.6%) participants and led to BRV discontinuation in 2/44 (4.5%) cases. The reported AEs were somnolence (n = 3), fatigue (n = 2), and irritability (n = 1); no serious AEs were experienced. In 21/44 (47.7%) participants, BRV monotherapy resulted from the direct switch from levetiracetam. The rates of treatment retention and seizure freedom at 6 and 12 months were higher among people who switched from levetiracetam to BRV monotherapy. CONCLUSION: Brivaracetam may be a valuable treatment of focal seizures in people who converted to monotherapy in a real-life setting.

A real-world comparison among third-generation antiseizure medications: Results from the COMPARE study.

OBJECTIVE: There are few comparative data on the third-generation antiseizure medications (ASMs). We aimed to assess and compare the effectiveness of brivaracetam (BRV), eslicarbazepine acetate (ESL), lacosamide (LCM), and perampanel (PER) in people with epilepsy (PWE). Efficacy and tolerability were compared as secondary objectives. METHODS: This multicenter, retrospective study collected data from 22 Italian neurology/epilepsy centers. All adult PWE who started add-on treatment with one of the studied ASMs between January 2018 and October 2021 were included. Retention rate was established as effectiveness measure and described using Kaplan-Meier curves and the best fitting survival model. The responder status and the occurrence of adverse events (AEs) were used to evaluate efficacy and safety, respectively. The odds of AEs and drug efficacy were estimated by two multilevel logistic models. RESULTS: A total of 960 patients (52.92% females, median age = 43 years) met the inclusion criteria. They mainly suffered from structural epilepsy (52.29%) with monthly (46.2%) focal seizures (69.58%). Compared with LCM, all the studied ASMs had a higher dropout risk, statistically significant in the BRV levetiracetam (LEV)-naïve (hazard ratio [HR] = 1.97, 95% confidence interval [CI] = 1.17-3.29) and PER groups (HR = 1.64, 95% CI = 1.06-2.55). Women were at higher risk of discontinuing ESL (HR = 5.33, 95% CI = 1.71-16.61), as well as PER-treated patients with unknown epilepsy etiology versus those with structural etiology (HR = 1.74, 95% CI = 1.05-2.88). BRV with prior LEV therapy showed lower odds of efficacy (odds ratio [OR] = .08, 95% CI = .01-.48) versus LCM, whereas a higher efficacy was observed in women treated with BRV and LEV-naïve (OR = 10.32, 95% CI = 1.55-68.78) versus men. PER (OR = 6.93, 95% CI = 3.32-14.44) and BRV in LEV-naïve patients (OR = 6.80, 95% CI = 2.64-17.52) had a higher chance of AEs than LCM. SIGNIFICANCE: Comparative evidence from real-world studies may help clinicians to tailor treatments according to patients' demographic and clinical characteristics.

Visual integration across fixation: automatic processes are split but conscious processes remain unified in the split-brain.

The classic view holds that when "split-brain" patients are presented with an object in the right visual field, they will correctly identify it verbally and with the right hand. However, when the object is presented in the left visual field, the patient verbally states that he saw nothing but nevertheless identifies it accurately with the left hand. This interaction suggests that perception, recognition and responding are separated in the two isolated hemispheres. However, there is now accumulating evidence that this interaction is not absolute; for instance, split-brain patients are able to detect and localise stimuli anywhere in the visual field verbally and with either hand. In this study we set out to explore this cross-hemifield interaction in more detail with the split-brain patient DDC and carried out two experiments. The aim of these experiments is to unveil the unity of deliberate and automatic processing in the context of visual integration across hemispheres. Experiment 1 suggests that automatic processing is split in this context. In contrast, when the patient is forced to adopt a conscious, deliberate, approach, processing seemed to be unified across visual fields (and thus across hemispheres). First, we looked at the confidence that DDC has in his responses. The experiment involved a simultaneous "same" versus "different" matching task with two shapes presented either within one hemifield or across fixation. The results showed that we replicated the observation that split brain patients cannot match across fixation, but more interesting, that DDC was very confident in the across-fixation condition while performing at chance-level. On the basis of this result, we hypothesised a two-route explanation. In healthy subjects, the visual information from the two hemifields is integrated in an automatic, unconscious fashion via the intact splenium, and this route has been severed in DDC. However, we know from previous experiments that some transfer of information remains possible. We proposed that this second route (perhaps less visual; more symbolic) may become apparent when he is forced to use a deliberate, consciously controlled approach. In an experiment where he is informed, by a second stimulus presented in one hemifield, what to do with the first stimulus that was presented in the same or the opposite hemifield, we showed that there was indeed interhemispheric transfer of information. We suggest that this two-route model may help in clarifying some of the controversial issues in split-brain research.

Individualized Prediction of Drug Resistance in People with Post-Stroke Epilepsy: A Retrospective Study.

BACKGROUND: The study aimed to develop a model and build a nomogram to predict the probability of drug resistance in people with post-stroke epilepsy (PSE). METHODS: Subjects with epilepsy secondary to ischemic stroke or spontaneous intracerebral hemorrhage were included. The study outcome was the occurrence of drug-resistant epilepsy defined according to International League Against Epilepsy criteria. RESULTS: One hundred and sixty-four subjects with PSE were included and 32 (19.5%) were found to be drug-resistant. Five variables were identified as independent predictors of drug resistance and were included in the nomogram: age at stroke onset (odds ratio (OR): 0.941, 95% confidence interval (CI) 0.907-0.977), intracerebral hemorrhage (OR: 6.292, 95% CI 1.957-20.233), severe stroke (OR: 4.727, 95% CI 1.573-14.203), latency of PSE (>12 months, reference; 7-12 months, OR: 4.509, 95% CI 1.335-15.228; 0-6 months, OR: 99.099, 95% CI 14.873-660.272), and status epilepticus at epilepsy onset (OR: 14.127, 95% CI 2.540-78.564). The area under the receiver operating characteristic curve of the nomogram was 0.893 (95% CI: 0.832-0.956). CONCLUSIONS: Great variability exists in the risk of drug resistance in people with PSE. A nomogram based on a set of readily available clinical variables may represent a practical tool for an individualized prediction of drug-resistant PSE.

A retrospective multicentric study on the effectiveness of intravenous brivaracetam in seizure clusters: Data from the Italian experience.

OBJECTIVE: Nearly half of people with epilepsy (PWE) are expected to develop seizure clusters (SC), with the subsequent risk of hospitalization. The aim of the present study was to evaluate the use, effectiveness and safety of intravenous (IV) brivaracetam (BRV) in the treatment of SC. METHODS: Retrospective multicentric study of patients with SC (≥ 2 seizures/24 h) who received IV BRV. Data collection occurred from January 2019 to April 2022 in 25 Italian neurology units. Primary efficacy outcome was seizure freedom up to 24 h from BRV administration. We also evaluated the risk of evolution into Status Epilepticus (SE) at 6, 12 and 24 h after treatment initiation. A Cox regression model was used to identify outcome predictors. RESULTS: 97 patients were included (mean age 62 years), 74 (76%) of whom had a history of epilepsy (with drug resistant seizures in 49% of cases). BRV was administered as first line treatment in 16% of the episodes, while it was used as first or second drug after benzodiazepines failure in 49% and 35% of episodes, respectively. On the one hand, 58% patients were seizure free at 24 h after BRV administration and no other rescue medications were used in 75 out of 97 cases (77%) On the other hand, SC evolved into SE in 17% of cases. A higher probability of seizure relapse and/or evolution into SE was observed in patients without a prior history of epilepsy (HR 2.0; 95% CI 1.03 - 4.1) and in case of BRV administration as second/third line drug (HR 3.2; 95% CI 1.1 - 9.7). No severe treatment emergent adverse events were observed. SIGNIFICANCE: In our cohort, IV BRV resulted to be well tolerated for the treatment of SC and it could be considered as a treatment option, particularly in case of in-hospital onset. However, the underlying etiology seems to be the main outcome predictor.

Long-term effectiveness of add-on perampanel in patients with Lennox-Gastaut syndrome: A multicenter retrospective study.

This retrospective study assessed long-term effectiveness of add-on perampanel (PER) in patients with Lennox-Gastaut syndrome (LGS). Outcomes included time to PER failure and time to seizure relapse in responders. PER failure was defined as either discontinuation of PER or initiation of another treatment. Seizure relapse in responders was defined as occurrence of a seizure in seizure-free patients and increase of at least 50% in average monthly seizure frequency for those who were responders. Eighty-seven patients were included. Treatment failure occurred in 52 (59.8%) subjects at a median time of 12 months. Treatment failure was due to lack of efficacy in 27 (52.0%) patients, lack of tolerability in 14 (27.0%), and both reasons in 11 (21.0%). A slower titration was associated with a lower risk of PER failure compared to faster titration schedules, and the occurrence of adverse events increased the risk of treatment failure. Thirty-six patients (41.4%) were responders during a median follow-up of 11 months. Seizure relapse occurred in 13 of 36 (36.1%) patients after a median time of 21 months. The overall rate of seizure responders was 23 of 87 (26.4%) at the end of follow-up. This study provides real-world evidence on the effectiveness of PER as adjunctive treatment in LGS patients.

Latency of poststroke epilepsy can predict drug resistance.

BACKGROUND AND PURPOSE: The progressive nature of epileptogenesis raises the question of whether the latent period may already carry information about the characteristics of the subsequent epilepsy. This study aimed to explore whether the time from stroke to epilepsy onset was related to the risk of drug resistance in patients with poststroke epilepsy (PSE). METHODS: Patients with epilepsy secondary to cerebral infarct or spontaneous intracerebral hemorrhage were included. Study outcome was the occurrence of drug resistance defined as failure of adequate trials of two tolerated and appropriately chosen and used antiseizure medication schedules to achieve sustained seizure freedom. RESULTS: One hundred fifty-nine patients with PSE and a median follow-up of 5 (interquartile range [IQR] = 3-9) years were included. In the study cohort, 29 (18.2%) participants were drug resistant. The median length of the time interval between stroke and PSE onset was 13 (IQR = 7-15) months in drug-resistant patients and 19 (IQR = 14-42) months (p < 0.001) in patients with seizure control. According to multivariable regression analysis, the time from stroke to PSE was an independent predictor of drug resistance (p < 0.001). The risk of drug resistance was highest when the onset of PSE occurred within the first months from stroke and decreased progressively with a steeper decline over the first 12 months. CONCLUSIONS: Substantial variability may exist in the pathways leading to PSE and distinguish patients with a variable risk of drug resistance.

Adjunctive Perampanel in Older Patients With Epilepsy: A Multicenter Study of Clinical Practice.

BACKGROUND: Clinical data regarding use of newer antiseizure medications (ASMs) in an older population are limited. In randomized-controlled, placebo-controlled trials, older patients are under-represented, and protocols deviate markedly from routine clinical practice, limiting the external validity of results. Studies performed in a naturalistic setting are a useful complement to characterize the drug profile. Perampanel is a third-generation ASM and the first and only non-competitive alfa-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor antagonist. OBJECTIVE: The aim of this study was to assess the effectiveness and tolerability of adjunctive perampanel over a 1-year period in a population of older patients with epilepsy treated in a real-world setting. METHODS: Older (≥ 65 years of age) patients prescribed add-on perampanel at 12 Italian epilepsy centers were retrospectively identified. Seizure occurrence, adverse events (AEs), and drug withdrawal were analyzed. Effectiveness outcomes included the rates of seizure response (≥ 50% reduction in baseline monthly seizure frequency), seizure freedom, and treatment discontinuation. Safety and tolerability outcomes were the rate of treatment discontinuation due to AEs and the incidence of AEs. RESULTS: A total of 92 patients with a median age of 69 (range 65-88) years were included. The median daily dose of perampanel at 12 months was 6 mg (interquartile range 4-6 mg). At 12 months, 53 (57.6%) patients were seizure responders, and 22 (23.9%) patients were seizure free. Twenty (21.7%) patients discontinued perampanel; the reasons for treatment withdrawal were insufficient efficacy (n = 6/20; 30.0%), AEs (n = 12/20; 60.0%), and a combination of both (n = 2/20; 10%). The most common AEs included irritability (8.7%), somnolence (4.3%), and dizziness/vertigo (4.3%). The rate of behavioral and psychiatric AEs was higher in patients with history of psychiatric comorbidities (p = 0.044). There were no differences in the occurrence of behavioral and psychiatric AEs according to the concomitant use of levetiracetam (p = 0.776) and history of cognitive decline (p = 0.332). CONCLUSIONS: Adjunctive perampanel was associated with improvement in seizure control and good tolerability in a real-life setting and can represent a viable therapeutic option in older patients with epilepsy.

Perampanel effectiveness and tolerability in patients with epilepsy at long-term follow-up.

INTRODUCTION: The main of the present study was to assess the effectiveness and tolerability of perampanel (PER) in association with 1 or 2 concomitant antiseizure medications (ASMs) in patients with epilepsy throughout a follow-up period of 24 months or longer in a real-world setting. METHODS: This retrospective, observational, multi-center study collected data from both underage (<18 years old) and adult patients who had started PER in association with 1 or 2 ASMs. Only patients who had started PER and were followed up for at least 24 months were included. Response to treatment was analyzed at the 24-, 36-, and 48-month visits by considering the last visit undergone by patients. Subgroup analyses were performed according to age, gender, and epilepsy type and patients were categorized following PER treatment in concomitance with 1 or 2 ASMs to evaluate the factors affecting the achievement of seizure freedom (SF) at the 24-month FU. RESULTS: Ninety-four patients were included (mean age 36.89 years; 51.1% female). At the 24-month follow-up visit, 90 (95.74%) patients were still receiving PER concomitantly with 1 or 2 ASMs. The mean PER dose was 6.02 mg/day and SF was achieved by 33 (35.1%) patients. A significantly higher SF rate was found in patients who had started PER with only 1 ASM when compared to those who had started PER with 2 concomitant ASMs. Effectiveness was maintained also in the subgroups of patients with a 36- or 48-month follow-up visit. Adult patients had a higher final daily dosage of PER than underage patients. Logistic regression found that the lowest number of previously failed ASMs was associated with a higher SF rate (p = 0.036). CONCLUSION: Perampanel demonstrated a good effectiveness in association with 1 or 2 ASMs in both pediatric and adult patients, without having to use a high dose of the drug. The possibility to present SF was higher when PER was added early. Finally, the maintenance of effectiveness was observed also in the subgroups of patients with a follow-up of 36 and 48 months.

Predictors of Pharmaco-Resistance in Patients with Post-Stroke Epilepsy.

OBJECTIVES: The study aimed to explore the clinical predictors of pharmaco-resistance in patients with post-stroke epilepsy (PSE). METHODS: Patients with epilepsy secondary to cerebral infarct or spontaneous intracerebral hemorrhage were included. The study outcome was the occurrence of pharmaco-resistance defined as the failure of adequate trials of two tolerated and appropriately chosen and used antiseizure medication schedules, whether as monotherapies or in combination, to achieve sustained seizure freedom. RESULTS: One-hundred and fifty-nine patients with PSE and a median follow-up of 5 (3-9) years were included. The mean age of the patients at stroke onset was 56.7 (14.9) years, and 104 (65.4%) were males. In the study cohort, 29 participants were pharmaco-resistant. Age at stroke onset [odds ratio (OR) 0.97, 95% confidence interval (CI) 0.93-0.99; p = 0.044], history of intracerebral hemorrhage (OR 2.95, 95% CI 1.06-8.24; p = 0.039), severe stroke (OR 5.43, 95% CI 1.82-16.16; p = 0.002), status epilepticus as initial presentation of PSE (OR 7.90, 1.66-37.55; p = 0.009), and focal to bilateral tonic-clonic seizures (OR 3.19, 95% CI 1.16-8.79; p = 0.025) were independent predictors of treatment refractoriness. CONCLUSIONS: Pharmaco-resistance developed in approximately 20% of patients with PSE and was associated with younger age at stroke onset, stroke type and severity, status epilepticus occurrence, and seizure types.

Singularity and consciousness: A neuropsychological contribution.

In common sense experience based on introspection, consciousness is singular. There is only one 'me' and that is the one that is conscious. This means that 'singularity' is a defining aspect of 'consciousness'. However, the three main theories of consciousness, Integrated Information, Global Workspace and Recurrent Processing theory, are generally not very clear on this issue. These theories have traditionally relied heavily on neuropsychological observations and have interpreted various disorders, such as anosognosia, neglect and split-brain as impairments in conscious awareness without any reference to 'the singularity'. In this review, we will re-examine the theoretical implications of these impairments in conscious awareness and propose a new way how to conceptualize consciousness of singularity. We will argue that the subjective feeling of singularity can coexist with several disunified conscious experiences. Singularity awareness may only come into existence due to environmental response constraints. That is, perceptual, language, memory, attentional and motor processes may largely proceed unintegrated in parallel, whereas a sense of unity only arises when organisms need to respond coherently constrained by the affordances of the environment. Next, we examine from this perspective psychiatric disorders and psycho-active drugs. Finally, we present a first attempt to test this hypothesis with a resting state imaging experiment in a split-brain patient. The results suggest that there is substantial coherence of activation across the two hemispheres. These data show that a complete lesioning of the corpus callosum does not, in general, alter the resting state networks of the brain. Thus, we propose that we have separate systems in the brain that generate distributed conscious. The sense of singularity, the experience of a 'Me-ness', emerges in the interaction between the world and response-planning systems, and this leads to coherent activation in the different functional networks across the cortex.

Is the Imitative Competence an Asymmetrically Distributed Function?

This study reconsiders behavioral and functional data from studies investigating the anatomical imitation (AI) and the related mental rotation (MR) competence, carried out by our group in healthy subjects, with intact interhemispheric connections, and in split-brain patients, completely or partially lacking callosal connections. The results strongly point to the conclusion that AI and MR competence requires interhemispheric communication, mainly occurring through the corpus callosum, which is the largest white matter structure in the human brain. The results are discussed in light of previous studies and of future implications.

Voice gender categorization in the connected and disconnected hemispheres.

The role of the left and right hemispheres in processing the gender of voices is controversial, some evidence suggesting a bilateral involvement, some others suggesting a right-hemispheric superiority. We investigated this issue in a gender categorization task involving healthy participants and a male split-brain patient: female or male natural voices were presented in one ear during the simultaneous presentation of white noise in the other ear (dichotic listening paradigm). Results revealed faster responses by the healthy participants for stimuli presented in the left than in the right ear, although no asymmetries emerged between the two ears in the accuracy of both the patient and the control group. Healthy participants were also more accurate at categorizing female than male voices, and an opposite-gender bias emerged - at least in females - showing faster responses in categorizing voices of the opposite gender. The results support a bilateral hemispheric involvement in voice gender categorization, without asymmetries in the patient, but with a faster categorization when voices are directly presented to the right hemisphere in the healthy sample. Moreover, when the two hemispheres directly interact with one another, a faster categorization of voices of the opposite gender emerges, and it can be an evolutionary grounded bias.

Unified tactile detection and localisation in split-brain patients.

In 'split-brain' patients, the corpus callosum has been surgically severed to alleviate medically intractable, severe epilepsy. The classic claim is that after removal of the corpus callosum an object presented in the right visual field will be identified correctly verbally and with the right hand but not with the left hand. When the object is presented in the left visual field the patient verbally states that he saw nothing but nevertheless identifies it accurately with the left hand. This interaction suggests that perception, recognition and responding are separated in the two isolated hemispheres. However, there is now accumulating evidence that this interaction is not absolute. Recently, we (Pinto et al., 2017) showed that accurate detection and location of stimuli anywhere in the visual field could be performed with both hands. In this study, we explored detection and localisation of tactile stimulation on the body. In line with our previous results, we observed that split-brain patients can signal detection and localisation with either hand anywhere on the body (be it the arm or the leg) but they remain unable to match positions touched on both arms or legs simultaneously. These results add to the evidence suggesting that the effects of removal of the corpus callosum may be less severe than sometimes claimed.

Geometry, landmarks and the cerebral hemispheres: 2D spatial reorientation in split-brain patients.

A right-hemispheric superiority in spatial encoding based on geometric cues has been largely documented in a variety of species, together with a left-hemispheric specialization for encoding based on landmarks. In humans, hemispheric asymmetries for spatial encoding have been little explored. In this study, we compared a patient with a complete callosal resection (D.D.C.) and a patient with a wide callosal resection saving the splenium (A.P.), with healthy participants. In two 2D versions of the 'reorientation task', participants were asked to find the target corner of a rectangle-shaped environment, by exploiting either geometric information alone or the combination of geometric and landmark information. In Experiment 1, the landmark consisted of a coloured side of the rectangle; in Experiment 2, this cue was replaced by a coloured disc located inside the rectangle. In both experiments, the rectangular shape ensured the geometric cue. D.D.C. was always unable to recall the target, whereas A.P. correctly solved the task when only the geometric information was available, without difference with respect to the controls. Importantly, the performance of A.P. did not differ from controls' when the right hemisphere was tested with the landmark cues (the task being carried out using the left hand), whereas when the left hemisphere was tested (right-hand session) his performance was worse than controls' with the coloured side of the space, but it was better than controls' with the coloured disc. The results are discussed comparing them with data collected on other species, and with theories of spatial processing.

Lacosamide during pregnancy and breastfeeding.

BACKGROUND: The epilepsy treatment during pregnancy represents a balance between teratogenic hazard and seizure control. The aim of the study was to evaluate the safety and efficacy of lacosamide (LCS) during pregnancy and breastfeeding. METHODS: Patients referred to our Epilepsy Center for pregnancy planning who became pregnant while taking LCS were prospectively followed-up. Data on seizure frequency, side effects, pregnancy course, delivery and breastfeeding, birth outcome, congenital malformation and development of newborns were collected. RESULTS: Three cases of maternal exposure to LCS were reported. Treatment with LCS was continued throughout pregnancy and breastfeeding at a median daily dose of 400mg. Lacosamide was used as monotherapy in two patients and as add-on treatment in one woman. Seizure frequency did not change throughout pregnancy and two subjects remained seizure free. The median gestational age at delivery was 39 weeks. The median Apgar scores at 1 and 5min were 9 and 10, respectively; no major or minor congenital malformations were observed in the offspring. Normal developmental milestone were reached by all new-borns. CONCLUSIONS: Worldwide pregnancy registries have provided consistent and increasing information about the efficacy and safety of the older antiepileptic drugs during gestation, while data are lacking for many of the newer generations. These cases could suggest a good level of efficacy and safety for LCS throughout pregnancy and breastfeeding and argue against teratogenic or toxic potentialities.

Split brain: divided perception but undivided consciousness.

In extensive studies with two split-brain patients we replicate the standard finding that stimuli cannot be compared across visual half-fields, indicating that each hemisphere processes information independently of the other. Yet, crucially, we show that the canonical textbook findings that a split-brain patient can only respond to stimuli in the left visual half-field with the left hand, and to stimuli in the right visual half-field with the right hand and verbally, are not universally true. Across a wide variety of tasks, split-brain patients with a complete and radiologically confirmed transection of the corpus callosum showed full awareness of presence, and well above chance-level recognition of location, orientation and identity of stimuli throughout the entire visual field, irrespective of response type (left hand, right hand, or verbally). Crucially, we used confidence ratings to assess conscious awareness. This revealed that also on high confidence trials, indicative of conscious perception, response type did not affect performance. These findings suggest that severing the cortical connections between hemispheres splits visual perception, but does not create two independent conscious perceivers within one brain.

Face gender categorization and hemispheric asymmetries: Contrasting evidence from connected and disconnected brains.

We investigated hemispheric asymmetries in categorization of face gender by means of a divided visual field paradigm, in which female and male faces were presented unilaterally for 150ms each. A group of 60 healthy participants (30 males) and a male split-brain patient (D.D.C.) were asked to categorize the gender of the stimuli. Healthy participants categorized male faces presented in the right visual field (RVF) better and faster than when presented in the left visual field (LVF), and female faces presented in the LVF than in the RVF, independently of the participants' sex. Surprisingly, the recognition rates of D.D.C. were at chance levels - and significantly lower than those of the healthy participants - for both female and male faces presented in the RVF, as well as for female faces presented in the LVF. His performance was higher than expected by chance - and did not differ from controls - only for male faces presented in the LVF. The residual right-hemispheric ability of the split-brain patient in categorizing male faces reveals an own-gender bias lateralized in the right hemisphere, in line with the rightward own-identity and own-age bias previously shown in split-brain patients. The gender-contingent hemispheric dominance found in healthy participants confirms the previously shown right-hemispheric superiority in recognizing female faces, and also reveals a left-hemispheric superiority in recognizing male faces, adding an important evidence of hemispheric imbalance in the field of face and gender perception.

Brivaracetam add-on for refractory focal epilepsy: A systematic review and meta-analysis.

OBJECTIVE: To evaluate the efficacy and safety of the new antiepileptic drug brivaracetam (BRV) as add-on treatment for drug-resistant partial epilepsy using meta-analytical techniques. METHODS: Randomized, placebo-controlled, single- or double-blind, add-on trials of BRV in adult patients with drug-resistant partial epilepsy were identified through a systematic literature search. The following outcomes were assessed: 50% or greater reduction in seizure frequency, seizure freedom, incidence of treatment-emergent adverse events (TEAEs), and treatment withdrawal. Risk ratio (RR) with 95% confidence interval was estimated for each outcome. RESULTS: Six trials were included involving 2,399 participants according to the intent-to-treat, 1,715 for BRV, and 684 for placebo groups, respectively. The pooled RRs for the 50% responders and seizure freedom were 1.79 (1.51-2.12) and 4.74 (2.00-11.25), respectively. The subanalysis by levetiracetam (LEV) status did not show a statistically significant difference in the 50% responder rate when comparing BRV with placebo in patients with concomitant assumption of LEV. The TEAEs significantly associated with BRV were irritability (2.99 [1.28-6.97]), fatigue (2.19 [1.44-3.33]), somnolence (1.97 [1.45-2.68]), and dizziness (1.66 [1.19-2.31]). The overall RRs for treatment withdrawal due to TEAEs or any reason were 1.58 (1.04-2.40) and 1.27 (0.93-1.73), respectively. CONCLUSIONS: In adults with drug-refractory focal epilepsy, add-on BRV was effective to reduce seizure frequency and fairly well-tolerated. Further studies are needed to draw definitive conclusions about its efficacy in non-LEV-naive participants and evaluate its long-term safety profile.