Irena Holeckova

The impact of general versus local anesthesia on early subclinical cognitive function following carotid endarterectomy evaluated using P3 event-related potentials

BackgroundPostoperative cognitive dysfunction (POCD) is detected in 25% of patients undergoing carotid endarterectomy (CEA). The mechanism of POCD is poorly understood, but it is believed that general anesthesia (GA) itself may contribute significantly to POCD. The aim of our prospective study was to compare, with the aid of event-related potentials, the impact of general anesthesia (GA) and local anesthesia (LA) on POCD in patients undergoing CEA.MethodsSixty patients were included in this study and were divided into two groups: CEA was performed in 30 patients placed under GA (total intravenous anesthesia), herein the GA group, while 30 patients underwent CEA under LA (cervical plexus block), herein LA group. Cognitive outcome was assessed with the use of auditory event-related potentials (ERPs), P3 response. The measurements were taken before surgery (pre-op) and on the first (1.post-op) and the sixth postoperative days (6.post-op).ResultsPreoperative cognitive functions did not differ significantly between the two groups. A significant decrease in P3 amplitude was found on the first postoperative day (1.post-op) in the GA group (p = 0.0005), but normalization of P3 amplitude was detected at the second postoperative measurement (6.post-op). The patients operated on under local anesthesia (LA group) showed stable P3 amplitudes in all three measurements. No significant changes in P3 latencies were observed in either group. There were no significant differences between the two groups regarding demographic characteristics, preoperative and postoperative clinical condition, percentage significance of carotid artery stenosis, duration of carotid cross-clamping or in the frequency of shunt use (zero frequency for both groups).ConclusionsOur study showed that general anesthesia, used for patients undergoing CEA, negatively influenced cognitive function during the immediate period after surgery (the first postoperative day). However, by the sixth postoperative day, this cognitive impairment was no longer being detected. POCD occurring shortly after carotid endarterectomy is the result of general anesthesia, which is probably an independent evoking factor in itself. The cognitive deficit recorded only during the immediate postoperative period, is not a negative effect of GA but merely a side-effect and thus GA should not be considered inferior to LA for use during CEA.

Auditory ERPs in Children with Developmental Coordination Disorder

The present study aims to investigate and compare the auditory attention performance of children with developmental coordination disorder (DCD) and normally developing children (NDC) using cognitive evoked potentials (ERPs) in passive conditions. ERPs data showed that children with DCD have less ability to detect small physical differences between acoustic stimuli (no MMN response in DCD children) and have a reduced attentional engagement and stimulus evaluation of salient stimuli (a reduction of P3 amplitude in DCD children). The results of our study suggest that children with DCD do not only suffer from a visuospatial attention deficit as previous studies reported but also have auditory attention deficit.

Urgent Extracranial-Intracranial Bypass in the Treatment of Acute Hemodynamic Ischemic Stroke: Case Report

Extracranial-intracranial (EC-IC) bypass surgery is performed to allow flow augmentation in selected cases of occlusive cerebrovascular disease. The majority of EC-IC bypasses are described as an elective procedure in the prevention of hemodynamic ischemic stroke. There is only limited and controversial experience of superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis performed under urgent circumstances as a treatment of acute cerebral ischemia. We describe a unique case of a 75-year-old patient presenting with acute progressive hemodynamic ischemia after carotid endarterectomy (CEA), which developed contralaterally to the performed CEA in the region of chronic internal carotid artery (ICA) occlusion. Urgent performance of a standard STA-MCA bypass rapidly improved the cerebral hemodynamic and had an excellent therapeutic effect. The patient had recovered completely within 4 weeks of surgery. The role of urgent EC-IC bypass for stroke treatment is discussed.

Cognitive impairment measured by event-related potentials during early and late postoperative period following intravenous or inhalation anaesthesia

OBJECTIVE This study investigated modification in cognitive function following inhalation (IA) and total intravenous (TIVA) anaesthesia measured using auditory ERPs (Event Related Potentials). METHODS Auditory ERPs examination with N1, P3a and P3b component registration was carried out one day before surgery (D-1) and on the first (D+1), sixth (D+6) and 42nd (D+42) days after surgery. Results were compared between two anaesthetic groups. RESULTS On D+1, N1 latency was increased in the IA group. A significant reduction was observed in amplitude of the P3a component on D+6, which persisted up to D+42 for both IA and TIVA groups. A reduction in the amplitude of P3b on D+1 with normalization by D+6 was found in both groups as well. CONCLUSIONS Intravenous and inhalation anaesthesia lead to similar changes in cognitive function as determined by ERPs, both during the early and late postoperative periods. It cannot be clearly confirmed whether the observed effects are due to anaesthesia or other unmonitored perioperative factors. SIGNIFICANCE Post anaesthetic changes represent a subclinical impairment; nevertheless, they represent a potential risk for subsequent development of cognitive difficulties.

T113. The changes in motor cortex localisation and organisation in motor eloquent tumorous brain lesions detected by navigated transcranial magnetic stimulation

Introduction Navigated transcranial magnetic stimulation (nTMS) is non invasive method to map the motor cortex including primary motor cortex (PrG - precentral gyrus) and premotor areas (PMa). This study aimed to investigate whether tumorous brain lesion induce a change in motor cortex localization or organisation investigated by nTMS. Methods We enrolled 10 patients with intraaxial motor tumor (gliomas). All patients underwent preoperative navigational MRI folowed by nTMS. Both lesional and non lesional hemispheres were stimulated. MEPs were recorded by EMG. The measured muscle was APB. MEPs latency for each positive stimulation point was measured. The surface of positive stimulation areas on the cortex were calculated for both hemispheres and results were compared. Results The positive MEPs responses were registered from PrG as well as from PMa with different latencies. There were mosaic distribution of short and long latencies of MEPs responses without dependence on the location in the PrG or PMa in both hemispheres. The positive motor area distributions were significantly larger from lesional than for non lesional hemisphere for both PrG and PMa areas (PrG lesional vs. non lesional surface = 947 mm2 vs. 393 mm2, PMa lesional vs. non lesional surface = 620 mm2 vs. 545 mm2). Conclusion The intraaxial motor eloquent tumors induce changes in motor cortex. The motor areas spread widely in the anterior-posterior direction in lesional hemisphere. The localisation short latencies found in PMa suggesting for detection of primary motor areas outside the PrG. This study was supported by the Charles University Research Fund Progress Q 39.

Developmental coordination disorder in children – experimental work and data annotation

Abstract Background Developmental coordination disorder (DCD) is described as a motor skill disorder characterized by a marked impairment in the development of motor coordination abilities that significantly interferes with performance of daily activities and/or academic achievement. Since some electrophysiological studies suggest differences between children with/without motor development problems, we prepared an experimental protocol and performed electrophysiological experiments with the aim of making a step toward a possible diagnosis of this disorder using the event-related potentials (ERP) technique. The second aim is to properly annotate the obtained raw data with relevant metadata and promote their long-term sustainability. Results The data from 32 school children (16 with possible DCD and 16 in the control group) were collected. Each dataset contains raw electroencephalography (EEG) data in the BrainVision format and provides sufficient metadata (such as age, gender, results of the motor test, and hearing thresholds) to allow other researchers to perform analysis. For each experiment, the percentage of ERP trials damaged by blinking artifacts was estimated. Furthermore, ERP trials were averaged across different participants and conditions, and the resulting plots are included in the manuscript. This should help researchers to estimate the usability of individual datasets for analysis. Conclusions The aim of the whole project is to find out if it is possible to make any conclusions about DCD from EEG data obtained. For the purpose of further analysis, the data were collected and annotated respecting the current outcomes of the International Neuroinformatics Coordinating Facility Program on Standards for Data Sharing, the Task Force on Electrophysiology, and the group developing the Ontology for Experimental Neurophysiology. The data with metadata are stored in the EEG/ERP Portal.

32. Perioperative monitoring of cognitive functions by event-related potentials and psychometric tests

Introduction Postoperative cognitive dysfunction (POCD) is well recognized, but poorly understood syndrome. The role of used anaesthetics remains unclear. Neurophysiologic method – auditory event-related potentials (ERPs) are widely used for assessment of cognitive brain functions. Objectives To test the difference in occurrence of POCD between patients undergoing sevoflurane and propofol anaesthesia using standard psychometric tests and ERPs. Methods We present results of scheduled interim analysis of the prospective randomized trial after inclusion of 30 patients undergoing lumbar discectomy. Patients were randomized to receive either sevoflurane (group S; n =18) or propofol anaesthesia (group P; n =12). Anaesthesia depth was controlled by BIS monitoring. POCD was assessed using modified standard psychometric test battery and ERPs (wave N100 and P3) in defined time-points (preoperatively and postoperatively on day 1, 7 and 40). POCD was defined as a decline of more than one standard deviation in three or more tests. Results ERPs analysis of the S group showed increase in the latency (84.9±1.4 vs. 81.4±1, p =0.03) and decrease of the amplitude (6.3±0.6 vs. 8.0±0.8, p p =0.01) lasting till day 40 (6.3±0.9; p =0.004). POCD using standard tests was diagnosed in 6 patients (33 %) of S group versus 2 (17 %) in P, p =0.41. Temporary occurrence of new POCD development did not differ between groups (4, 5 and 4 pts. vs. 1, 1 and 0 pts.; on day 1, 7 and 40 in groups S and P respectively; p =0.31). In the S arm a significant decrease in Categorical Verbal Fluency score (CVF) was observed on day 1 (13.7±0.8; p p =0.01) compared to baseline value (22.2±1.5) with normalization on day 40. No differences in other tests were observed. Conclusions ERPs analysis showed early auditory sensory impairment and late cognitive decline after sevoflurane use, however these changes were subclinical. POCD occurrence was non-significantly more frequent among patients after sevoflurane anaesthesia, possibly associated with short-term semantic memory impairment assessed by CVF decline. The study is supported by Charles University grant PRVOUK P36 and grant GACR P407/12/1525.

P821: Recognition of vocal emotional cues in children measured by ERPs

bers is strongly recommended to gain better knowledge and understanding of autistic children’s hearing and behavior patterns References: [1] Ceponiene R, Cheour M, Naeaetaenen R. Interstimulus interval and auditory event-related potentials in children: evidence for multiple generators. Electroenceph. Clin Neuroph. 1998; 108: 345-354 [2] Sininger YS, Abdala C. Physiologic assessment of hearing. In: Lalwani A, Grundfast KM, editors. Pediatric Otology and Neur. Phi. (PA): LippincottRaven Publ.; 1998. p. 127-154.

P9.10 Auditory event related potentials in children with developmental coordination disorder

Introduction and Objectives: Recent studies have combined Transcranial Magnetic Stimulation (TMS) and high density Electroencephalography (hdEEG) to evaluate how cortico-cortical information transmission changes upon falling asleep (Massimini et al., 2007, Massimini et al., 2005). These experiments show that during slow wave sleep (SWS) TMS-evoked responses are larger, more stereotypical and more local than during wakefulness. This suggests that a break-down of effective connectivity may underlie the loss of consciousness that occurs in SWS. However, the interpretation of TMS/hd-EEG recordings is limited by a coarse spatial grain. In the present study we employ intracerebral stimulations and recordings in humans to validate and generalize TMS/hd-EEG results on a finer spatial scale (mm). Methods: Five patients with drug resistant epilepsy had been implanted with multi-channels depth electrodes for clinical evaluation (Nobili et al., 2006). During wakefulness and SWS, stimulation trains (30 shocks, 1 Hz, 5 mA) were delivered through one single channel, while recordings of local field potentials were obtained from all other channels. Results: Morphology of intracerebral evoked potentials (iEP) changed markedly upon falling asleep. The number of oscillations and the complexity of the signal decreased during SWS. In addition, while during wakefulness the stimulation of one channel resulted in a widespread response which involved distant cortical areas, during SWS the iEPs remained rather localized around the stimulation site. Conclusion: Intracerebral stimulations and recordings show that the brain’s response to direct cortical perturbation becomes more stereotypical and local upon falling asleep. These results are consistent with previous TMS/hd-EEG recordings. Thus, these invasive experiments support the idea that changes in effective connectivity may underlie the loss of consciousness during SWS and be reliably studied using noninvasive techniques such as TMS/hd-EEG.