The feasibility of home polysomnographic recordings prescribed for sleep-related neurological disorders: a prospective observational study.

OBJECTIVE: Home polysomnography is being increasingly developed for sleep studies, with various grades of quality. This study aimed to determine the feasibility of affordable, high quality home polysomnographic recordings prescribed for suspected sleep-related neurological disorders. PATIENTS AND METHODS: We prospectively screened all patients referred to the specialist sleep disorders clinic in Nancy University Hospital between May 2011 and August 2011. Patients were eligible for inclusion if they required polysomnography for the diagnosis of a sleep-related neurological disorder. One-night, polysomnography was performed in each patient's home by a trained sleep technician. Financial cost was determined prior to inclusion. A recording was considered as satisfactory if all the following criteria were present: at least, one EEG channel with continuous signal allowing determination of sleep stages and wake during more than 66% of sleep time; at least, one usable respiratory channel (airflow or either band) during more than 66% of sleep time; and usable oximetry during more than 66% of sleep time. RESULTS: Forty-eight of the 139 screened patients were included. Among the 48 home polysomnography recordings, 35 (72.9%) were satisfactory. Thirteen (27.1%) tracings displayed an unsatisfactory loss of EEG data, including seven (14.6%) tracings with an unsatisfactory loss of respiratory data. CONCLUSION: Home polysomnography prescribed for suspected sleep-related neurological disorders is feasible, with affordable costs, whilst maintaining high quality recording. Further studies are needed to measure the real medico-economic impact of promoting outpatient domiciliary explorations for sleep-related neurological disorders.

Management of focal epilepsy in adults treated with polytherapy in France: the direct cost of drug resistance (ESPERA study).

PURPOSE: To estimate the direct costs associated with the current management of focal epilepsy in adults treated with a combination of antiepileptic drugs (AEDs) in France and the supplementary costs of drug resistant epilepsy as defined by the International League Against Epilepsy (ILAE) in 2009. METHODS: ESPERA was a multicentre, observational, cross-sectional study conducted in France in 2010. A random sample of neurologists, including specialists in epilepsy, prospectively enrolled adults with focal epilepsy treated with a combination of AEDs. Investigators classified their patients according to the 2009 ILAE criteria for drug resistance and this classification was then reviewed by two experts. All items of healthcare resource use associated with epilepsy over the previous year were documented retrospectively and valued from a societal perspective. RESULTS: Seventy-one neurologists enrolled 405 patients. After experts' review, 70.6% of patients were classified with drug-resistant epilepsy, 22.4% with drug-responsive epilepsy and 7% with undefined epilepsy. The mean annual epilepsy-related direct costs per patient were €4485±€4313 in patients with drug-resistant epilepsy compared to €1926±€1795 in patients with drug-responsive epilepsy. In these two groups, costs of AEDs were estimated at €2603 and €1544, respectively. Patients with drug-resistant epilepsy were more often hospitalised (mean annual cost: €1270 vs. €97) and underwent more additional tests (mean annual cost: €194 vs. €53). CONCLUSION: The direct cost of focal epilepsy in adults on AED combinations was estimated at €3850/patient/year. Drug resistance, as defined by the 2009 ILAE criteria, resulted in significant extra costs which varied with seizure frequency.

[Adult patients treated for focal epilepsy with antiepileptic drugs (AEDs) in combination in France: description according to the 2009 ILAE definition of AED resistance (ESPERA study)]. / Patients adultes traités par une association d'antiépileptiques pour une épilepsie focale en France: description et mode de prise en charge selon les nouveaux critères de définition de la pharmacorésistance (étude ESPERA).

AIMS: To describe the adult population treated with antiepileptic drugs (AEDs) in combination for focal epilepsy according to the definition of AED resistance proposed by the International League Against Epilepsy (ILAE) in 2009 and to evaluate its implementation in current practice. METHODS: ESPERA was a multicenter, observational, cross-sectional study with a clinical data collection covering the past 12 months conducted by neurologists. Classifications according to AED responsiveness established by investigators for each enrolled patient were revised by two experts. RESULTS: Seventy-one neurologists enrolled 405 patients. Their mean age was 42.7 years (sex-ratioM/F 0.98). According to the investigators, 60% of epilepsies were drug-resistant, 37% drug-responsive and 3% had an undefined drug-responsiveness. After revision of experts, 71% of epilepsies were classified as drug resistant, 22% as responsive and 7% as undefined. Among the participating neurologists, 76% have made at least one error in classifying their patients according to the 2009 ILAE definition of AED resistance. Because of epilepsy, 24% of patients (age≤65) were inactive and 42% could not drive (respectively 29 and 49% of patients with AED resistant epilepsy). Half of patients had at least one other chronic condition. Number of prescribed drugs in combination and health care resource utilisation were significantly higher in patients with drug-resistant epilepsies than in patients with drug responsive epilepsies. CONCLUSION: ESPERA study shows that the use of new definition of drug-resistance in everyday practice seems difficult without any additional training and that the social and professional disability is frequent in adults with focal epilepsies treated with polytherapy.

Pitfalls in the diagnosis of new-onset frontal lobe seizures.

We reported the case of a young woman who received an antiepileptic drug after a first possible generalized tonic-clonic seizure with no clear inter-ictal epileptic paroxysms in the routine electroencephalogram. Her stereotypical movements decreased but did not disappear with treatment. Then a diagnosis of PNES was considered by neurologist after witnessing a stereotypical motor episode. While AED treatment was decreased and stopped, epileptic seizure frequency and severity increased with secondary generalized tonic-clonic seizures. Then she presented postictal psychotic features that combined with video-EEG findings led to the final diagnosis of new onset pre-frontal lobe epilepsy.

One-year outcome after a first clinically possible epileptic seizure: predictive value of clinical classification and early EEG.

OBJECTIVE: To assess the one-year outcome of patients referred to the emergency room for a first paroxysmal event of clinically certain or uncertain epileptic origin. METHODS: This prospective observational cohort study included 175 adult patients who were consecutively referred for a first paroxysmal event and excluding clinically certain syncope faints. Simple descriptive clinical criteria were used by emergency room physicians for epileptic assessment. Follow-up and final diagnosis were made by neurologists specialized in epilepsy. The risk of recurrence and epilepsy over time was described using Kaplan-Meier estimates. The effect of risk factors (including EEG results) was assessed using univariate log-rank tests and a Cox regression multivariate model. Negative and positive predictive values (NPV and PPV) at 1 year of significant factors were calculated. RESULTS: Clinical criteria were positive in 67 patients and negative in 108. At 1 year, the rate of recurrence was respectively 8% in the negative clinical criteria group (NCC) and 30% in the positive clinical criteria group (PCC) (RR=9.3; 95% CI=[1.22; 71.4]). The risk of subsequent epilepsy was respectively 16% in the NCC group and 57% in PCC group (RR=5.6; 95% CI=[2.0; 15.6]). Positive predictive value (PPV) of clinical criteria was 28.8% for recurrence and 57.6% for definite epilepsy. Negative predictive value (NPV) of clinical criteria was 93.2% for recurrence and 83.5% for definite epilepsy. The presence of significant abnormalities on early EEG (paroxysms or focal abnormalities) supported an epileptic origin in 17% of clinically uncertain seizures. It was associated with a higher risk of subsequent epilepsy (RR=2.50; 95% CI [1.37; 4.41]; P=0.007), but did not significantly improve the PPV of clinical criteria alone. CONCLUSION: These results may help provide a prognosis at 1 year after a first paroxysmal event of certain or uncertain epileptic origin. Future studies focusing on the outcome after a first epileptic seizure should take into consideration the degree of certainty of the clinical diagnosis and integrate the group of patients with uncertain epileptic seizure.

Focal electrical intracerebral stimulation of a face-sensitive area causes transient prosopagnosia.

Face perception is subtended by a large set of areas in the human ventral occipito-temporal cortex. However, the role of these areas and their importance for face recognition remain largely unclear. Here we report a case of transient selective impairment in face recognition (prosopagnosia) induced by focal electrical intracerebral stimulation of the right inferior occipital gyrus. This area presents with typical face-sensitivity as evidenced by functional neuroimaging right occipital face area (OFA). A face-sensitive intracerebral N170 was also recorded in this area, supporting its contribution as a source of the well-known N170 component typically recorded on the scalp. Altogether, these observations indicate that face recognition can be selectively impaired by local disruption of a single face-sensitive area of the network subtending this function, the right OFA.

Psychogenic nonepileptic seizures: characterization of two distinct patient profiles on the basis of trauma history.

This prospective study investigated and compared psychiatric features of 25 consecutive patients with psychogenic nonepileptic seizures (PNES) on the basis of presence of reported trauma. The "trauma" group comprised 19 patients (76%) and the "no-trauma" group comprised 6 patients (34%). We compared history of PNES, psychiatric comorbidity, alexithymia, and symptoms of dissociation. The study clearly characterized two distinct profiles of patients with PNES on the basis of trauma history. Patients with trauma had at least one psychiatric comorbidity or antecedent (vs 0% in the no-trauma group NT, P<0.001) and a higher median score of dissociation (P<0.001). Patients without trauma had more frequent "frustration situations" as a factor triggering PNES and subsequent sick leaves as perpetuating factors (P=0.001). Trauma antecedents correlated with a high rate of psychiatric comorbidity and a strong dissociative mechanism. Patients without trauma had no psychiatric comorbidity and a weaker dissociative mechanism.

Management of postural sensory conflict and dynamic balance control in late-stage Parkinson's disease.

Parkinson's disease (PD) is known to affect postural control, especially in situations needing a change in balance strategy or when a concurrent task is simultaneously performed. However, few studies assessing postural control in patients with PD included homogeneous population in late stage of the disease. Thus, this study aimed to analyse postural control and strategies in a homogeneous population of patients with idiopathic advanced (late-stage) PD, and to determine the contribution of peripheral inputs in simple and more complex postural tasks, such as sensory conflicting and dynamic tasks. Twenty-four subjects with advanced PD (duration: median (M)=11.0 years, interquartile range (IQR)=4.3 years; Unified Parkinson's Disease Rating Scale (UPDRS): M "on-dopa"=13.5, IQR=7.8; UPDRS: M "off-dopa"=48.5, IQR=16.8; Hoehn and Yahr stage IV in all patients) and 48 age-matched healthy controls underwent static (SPT) and dynamic posturographic (DPT) tests and a sensory organization test (SOT). In SPT, patients with PD showed reduced postural control precision with increased oscillations in both anterior-posterior and medial-lateral planes. In SOT, patients with PD displayed reduced postural performances especially in situations in which visual and vestibular cues became predominant to organize balance control, as was the ability to manage balance in situations for which visual or proprioceptive inputs are disrupted. In DPT, postural restabilization strategies were often inefficient to maintain equilibrium resulting in falls. Postural strategies were often precarious, postural regulation involving more hip joint than ankle joint in patients with advanced PD than in controls. Difficulties in managing complex postural situations, such as sensory conflicting and dynamic situations might reflect an inadequate sensory organization suggesting impairment in central information processing.

Drug-resistant temporal lobe epilepsy is associated with postural control abnormalities.

Epilepsy is responsible for falls that are not systematically associated with seizures and that therefore suggest postural impairment. There are very few studies of postural control in patients with epilepsy and none of them focus on temporal lobe epilepsy (TLE), although part of the vestibular cortex is located in the temporal cortex. The aim of this study was to evaluate the characteristics of postural control in a homogeneous population of patients with complex partial TLE. Twenty-six patients with epilepsy and 26 age-matched healthy controls underwent a sensory organization test combining six conditions, with and without sensory conflicting situations. Patients with epilepsy displayed poorer postural control, especially in situations where vestibular information is necessary to control balance. In addition to potential antiepileptic drug side effects, vestibular dysfunction could be related to the temporal pathology. Our study allows for a better understanding of the mechanism underlying falls in this population of patients.

EEG-MRI co-registration and sensor labeling using a 3D laser scanner.

This paper deals with the co-registration of an MRI scan with EEG sensors. We set out to evaluate the effectiveness of a 3D handheld laser scanner, a device that is not widely used for co-registration, applying a semi-automatic procedure that also labels EEG sensors. The scanner acquired the sensors' positions and the face shape, and the scalp mesh was obtained from the MRI scan. A pre-alignment step, using the position of three fiducial landmarks, provided an initial value for co-registration, and the sensors were automatically labeled. Co-registration was then performed using an iterative closest point algorithm applied to the face shape. The procedure was conducted on five subjects with two scans of EEG sensors and one MRI scan each. The mean time for the digitization of the 64 sensors and three landmarks was 53 s. The average scanning time for the face shape was 2 min 6 s for an average number of 5,263 points. The mean residual error of the sensors co-registration was 2.11 mm. These results suggest that the laser scanner associated with an efficient co-registration and sensor labeling algorithm is sufficiently accurate, fast and user-friendly for longitudinal and retrospective brain sources imaging studies.

Pre-existing arterial stiffness can predict hypotension during induction of anaesthesia in the elderly.

BACKGROUND: The aim of the present study was to establish whether elevated carotid-femoral pulse wave velocity (c-fPWV), an indicator of aortic stiffness, assessed before surgery, is correlated with variations in arterial pressure (AP) during induction of anaesthesia in elderly patients undergoing non-cardiovascular surgery. METHODS: c-fPWV was measured with the PulsePen(®) device during pre-surgical anaesthetic evaluation. Monitoring included electrocardiography, pulse oximetry, non-invasive AP, heart rate, bispectral index (BIS), and oxygen concentration during induction of anaesthesia with propofol and remifentanil. Anaesthesia was induced so as to maintain BIS values between 40 and 50. RESULTS: Forty-five patients, aged [mean (sd)] 71.1 (5.8) yr, were studied. The mean value of c-fPWV was 12.1 (3.9) m s⁻¹. There was no correlation between hypotension during anaesthesia induction and total dosage or rate of administration of propofol or remifentanil. In univariate analysis, only age and PWV significantly correlated with the decreases in AP, and the association between c-fPWV and a decrease in AP was also seen in multivariate analysis (r = 0.36, P< 0.05). Patients classified as having 'high stiffness' (c-fPWV ≥ 12.9 m s⁻¹) had 25% further decrease in systolic AP during anaesthesia induction than those with lower PWV [75.2 (5.7) vs 60.2 (4.2) mm Hg, P < 0.05]. CONCLUSIONS: Increased aortic stiffness, as assessed by PWV measured during preoperative anaesthetic evaluation, is associated with more pronounced hypotension during induction of anaesthesia. Measurement of aortic stiffness in the elderly may thus represent a valid indicator of the risk of hypotension during anaesthesia induction.

Seizure lateralization in scalp EEG using Hjorth parameters.

OBJECTIVE: This paper describes and assesses a new semi-automatic method for temporal lobe seizures lateralization using raw scalp EEG signals. METHODS: We used the first two Hjorth parameters to estimate quadratic mean and dominant frequency of signals. Their mean values were computed on each side of the brain and segmented taking into account the seizure onset time identified by the electroencephalographist, to keep only the initial part of the seizure, before a possible spreading to the contralateral side. The means of segmented variables were used to characterize the seizure by a point in a (frequency, amplitude) plane. Six criteria were proposed for the partitioning of this plane for lateralization. RESULTS: The procedure was applied to 45 patients (85 seizures). The two best criteria yielded, for the first one, a correct lateralization for 96% of seizures and, for the other, a lateralization rate of 87% without incorrect lateralization. CONCLUSIONS: The method produced satisfactory results, easy to interpret. The setting of procedure parameters was simple and the approach was robust to artifacts. It could constitute a help for neurophysiologists during visual inspection. SIGNIFICANCE: The difference of quadratic mean and dominant frequency on each side of the brain allows lateralizing the seizure onset.

[Risk of epilepsy after a first epileptic seizure in adults: Can we predict the future?]. / Prise en charge d'une première crise épileptique de l'adulte : peut-on prévoir l'avenir ?

The new definition of epilepsy recently proposed by an international panel of experts relies on the association of a first clinically certain seizure and of an enduring predisposition of the brain increasing the likelihood of future seizures. In the first part of this review, we will expose and organize into a hierarchical order the risk factors of subsequent recurrence. The major factors are: seizure(s) prior to presentation, paroxysmal abnormalities on early EEG, a remote symptomatic etiology. In the second part of this review, we will address the issue of clinical uncertainty when assessing the epileptic origin of a first clinical paroxysmal event, the reasons of uncertainty and the means to minimize it. We will analyze successively: the accuracy of eyewitness observations of transient loss of consciousness, the reliability and predictive validity of clinical criteria used for seizure assessment, the issue of overlapping clinical features between seizure and other non epileptic paroxysmal events (such as psychogenic non epileptic seizures), and finally the reliability and diagnostic value of early EEG for seizure assessment. To conclude, seizure assessment and diagnosis of epilepsy cannot be dissociated from syndrome and etiology diagnosis, which should be periodically reassessed towards a greater accuracy during the course of the disease.

Combined SEEG and source localisation study of temporal lobe schizencephaly and polymicrogyria.

OBJECTIVES: Type 1 schizencephaly (SZ) is a cerebral malformation characterised by a cleft lined and surrounded by a polymicrogyric cortex, extending from the pial region to the peri-ventricular heterotopia. Our purpose was to combine and compare dipole source imaging technique and Stereo-EEG (SEEG) technique in determining the irritative and epileptogenic zones in a case of type 1 schizencephaly. METHODS: High-resolution (64-channel) video-EEG with electrical source imaging and SEEG recordings were performed during a pre-surgical evaluation for medically intractable epilepsy. RESULTS: Anatomo-electro-clinical correlations based on SEEG and source localisation identified two irritative and epileptogenic zones partially overlapping the polymicrogyric cortex surrounding the SZ: an anterior medio-lateral network primarily involving dysplasic limbic structures and a lateral network involving the anterior and middle part of the cleft and polymicrogyric cortex. The most posterior part (at the temporo-parieto-occipital junction) displayed a normal background activity. CONCLUSIONS: Both epileptogenic and electrophysiologically normal cortices coexisted within the same widespread malformation: only the anterior part belonged to the anterior medio-lateral epileptogenic network defined by the SEEG. SIGNIFICANCE: In cases of widespread cortical malformation such as SZ, source localization techniques can help to define the irritative zone and relevant targets for SEEG.

Wernicke encephalopathy and Creutzfeldt-Jakob disease.

We assessed the prevalence of Wernicke encephalopathy (WE) in all 657 cases suspected of Creutzfeldt-Jakob (CJD) referred from 2001 to 2006 to the French Neuropathology Network of CJD. Clinical, biological and imaging data were reviewed when the diagnosis of WE was made at autopsy. No CJD was found in five cases suspected of sporadic CJD. In these five cases, myoclonus had been observed in four, CSF 14-3-3 protein in two. In 14 other cases, WE was combined with CJD, 13 of which were sporadic. These belonged mainly to the molecular variants of sporadic CJD associated with a long duration of disease. This stresses the necessity of remaining alert to the diagnosis of WE when CJD is suspected.

Automated cortical projection of EEG sensors: anatomical correlation via the international 10-10 system.

Several studies have described cranio-cerebral correlations in accordance with the 10-20 electrode placement system. These studies have made a significant contribution to human brain imaging techniques, such as near-infrared spectroscopy and trans-magnetic stimulation. With the recent development of high resolution EEG, an extension of the 10-20 system has been proposed. This new configuration, namely the 10-10 system, allows the placement of a high number (64-256) of EEG electrodes. Here, we describe the cranio-cerebral correlations with the 10-10 system. Thanks to the development of a new EEG-MRI sensor and an automated algorithm which enables the projection of electrode positions onto the cortical surface, we studied the cortical projections in 16 healthy subjects using the Talairach stereotactic system and estimated the variability of cortical projections in a statistical way. We found that the cortical projections of the 10-10 system could be estimated with a grand standard deviation of 4.6 mm in x, 7.1 mm in y and 7.8 mm in z. We demonstrated that the variability of projections is greatest in the central region and parietal lobe and least in the frontal and temporal lobes. Knowledge of cranio-cerebral correlations with the 10-10 system should enable to increase the precision of surface brain imaging and should help electrophysiological analyses, such as localization of superficial focal cortical generators.

[Specificity of epileptic seizures in the elderly: A proposed electro-clinical scale]. / Spécificités des crises d'épilepsie chez le sujet âgé : proposition d'un score électro-radioclinique d'orientation.

Diagnosis of epileptic seizure may be difficult in older patients because seizure manifestations are often unusual: confusion, paresis... and because there are multiple differential diagnoses (syncope, transient ischemic attack, transient global amnesia...). To promote and facilitate the diagnosis of seizures in the elderly, neurologists and gerontologists must work together and focus their strategy on two points: firstly, the knowledge of the specific presentation of seizures in elderly patients, and secondly, the adoption of a reasoning based on seizures and not epileptic syndromes. A multidisciplinary group worked on epilepsy of the elderly to elaborate an electro-clinical score which aims to help establish the diagnosis of epilepsy in elderly patients in different clinical settings. This electro-clinical score is based on a systematic review of scientific literature and the recommendations are explicitly linked to supporting evidence. Further, clinical validation of the electro-clinical score is required.

Automatic localization and labeling of EEG sensors (ALLES) in MRI volume.

Spatial localization of scalp EEG electrodes is a major step for dipole source localization and must be accurate, reproducible and practical. Several methods have been proposed in the last 15 years. The most widely used method is currently electromagnetic digitization. Nevertheless, this method is difficult to use in a clinical environment and has not been validated with a high number of electrodes. In this paper, we introduce a new automatic method for localizing and labeling EEG sensors using MRI. First, we design a new scalp EEG sensor. Secondly, we validate this new technique on a head phantom and then in a clinical environment with volunteers and patients. For this, we compare the reproducibility, accuracy and performance of our method with electromagnetic digitization. We demonstrate that our method provides better reproducibility with a significant difference (p<0.01). Concerning precision, both methods are equally accurate with no statistical differences. To conclude, our method offers the possibility of using MRI volume for both source localization and spatial localization of EEG sensors. Automation makes this method very reproducible and easy to handle in a routine clinical environment.

Cerebral venous thrombosis caused by spontaneous intracranial hypotension: two cases.

The association of spontaneous intracranial hypotension (SIH) with cerebral venous thrombosis (CVT) is rare. We are reporting two new cases. In one case, CVT is extensive concerning three sinuses and bilateral parietal cortical veins and, in the other case, only a cortical vein is involved. Both the patients presented had no thrombosis risk factors. There is certainly a link between these two pathologies. SIH should be considered as a risk factor of CVT. Modification of symptoms of SIH leading to CVT must be known to start early treatment.