Serial Recordings Research Articles

Ventricular and Supraventricular Ectopy in Subjects With Early Repolarization

Early repolarization (ER) is a common electrocardiographic (ECG) finding that is associated with an increased risk of idiopathic ventricular fibrillation and sudden cardiac death. This study investigated whether the presence of ER is a predictor of ventricular and supraventricular ectopy as a marker for electrical instability. Standard 12-lead electrocardiograms of the first follow-up in the population-based Study of Health in Pomerania (SHIP-1) (n= 3,300, age 20 to 79years) were analyzed to identify subjects with an ER pattern. Ventricular and supraventricular ectopy was assessed via portable tele-ECG cards recording 2 electrocardiograms daily over the course of 4weeks. Data of 1,630 subjects (n= 83,833 ECG card recordings, average 51.4 per subject) were analyzed for ventricular and supraventricular ectopy using a standardized automated algorithm. Associations of ER and several forms of arrhythmias were assessed using a 2-sided Fisher's exact test or t test, where appropriate. Overall, prevalence of ER in the SHIP-1 population was 4.8%. Presence of ER was not associated with the occurrence of ventricular and supraventricular arrhythmias (p ≥0.05 for all analyses). Furthermore, subgroup analyzes for ER localization (inferior) and ST-segment morphology (horizontal/descending) did not show any association with arrhythmic events. In conclusion, presence of the ER pattern is not associated with an increased occurrence of ventricular or supraventricular arrhythmias as assessed by serial ECG card recordings in this large population-based sample.

43. The quest for optimal electrodiagnosis of Guillain–Barre’ syndrome subtypes: criteria sets versus a linear discriminant analysis model

Up to 38% of Guillain-Barré syndrome (GBS) patients change electrophysiological classification after serial recordings. Aim of this study is to compare at the first electrodiagnostic test the predictivity of final diagnosis of three diagnostic criteria sets versus a regularized form of linear discriminant analysis (LDA) model. In 98 GBS patients with serial conduction studies in three motor and sensory nerves 24 electrophysiological variables were analyzed. Final diagnosis, established by serial studies and result of anti-ganglioside antibodies testing, revealed 54 demyelinating and 44 axonal GBS. We applied a sparse LDA method which is a technique for partitioning a vector of parameters (predictors) into one of the two classes (demyelinating or axonal) based on a linear projection learned from the 98 labeled patients. The evaluation of the discriminant power of sparse LDA is based on the leave one out cross validation procedure. We also employed the electrodiagnostic criteria sets developed by Hadden et al. (1998), by Rajabally et al. (2015) and by us. The overall misclassification error rate of sparse LDA at first test is 14% with a sensitivity for demyelinating GBS of 87% and a specificity of 84%. Distal motor latency, duration of distal motor potentials, proximal/distal motor amplitude ratio and sensory nerve action potential amplitude play a prominent role for the appropriate classification of patients. The overall misclassification error rates with the electrodiagnostic criteria are: 45% for Hadden’s, 43% for Rajabally’s and 26% for ours. Conclusions: (1) the model based on sparse LDA performs much better than the “a priori” established criteria sets; (2) the criteria set we developed, including the analysis of duration of distal motor potentials and of sensory nerve action potential amplitude, performs better than the other two; (3) only serial studies were able to demonstrate reversible conduction failure in motor and sensory fibers.

Analysis of macular sensitivity using multifocal electroretinogram and microperimetry in central serous chorioretinopathy patients after half‐dose photodynamic therapy

PurposeTo evaluate macular functional changes using multifocal electroretinography and microperimetry after half‐dose photodynamic therapy with verteporfin (HD‐PDT) in acute and chronic central serous chorioretinopathy (CSC) patientsMethodsThe charts of 101 CSC patients submitted to half‐dose PDT were reviewed. A total of 117 eyes with acute or chronic CSC underwent half‐dose PDT using 3 mg/m2 verteporfin infused over 10 min. Serial recordings of BCVA using the ETDRS charts, macular thickness using OCT and retinal sensitivity using both microperimetry (MP) and mfERG were performed at baseline and at 3, 6, 12, 18, 24, 36, 48, 60 and 72 months after treatment. A longitudinal assessment for each of these parameters and a Spearmen's correlation analysis between them was performed.ResultsCompared to baseline, a significant increase in N1, P1 and N2 mean amplitudes was registered after HD‐PDT, as well as a significant decrease in N1, P1 and N2 mean implicit times, both for central and peripheral rings. A correlation analysis showed significant correlations between BCVA and the first‐order component of retinal response for the most central ring (<2°). Significant correlations were also found between P1 implicit time and mean central macular thickness both at 36 (p = 0.030) and 72 months (p = 0.037). Central 4 degrees retinal sensitivity significantly correlated with N1 amplitude ratio at 72 months (p < 0.01) and P1 implicit time differences at 6 (p = 0.013) and 12 months (p = 0.014).ConclusionsmfERG demonstrated an increased retinal sensitivity in PDT‐treated CSC patients. Changes in BCVA, central macular thickness and central retinal sensitivity significantly correlated with the mfERG responses. HD PDT treatment improved both structural and functional outcomes and mfERG is an important objective parameter to evaluate functional changes in follow‐up.

Syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL): A case report with serial electroencephalography (EEG) recordings.. Is there an association with human herpes virus type 7 (HHV-7) infection?

Introduction The syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL) is a diagnosis made by exclusion. In the literature, different etiological explanations are proposed for HaNDL, including an immune-mediated reaction after a viral infection. Case description We present a case of a 23-year-old woman with several episodes of transient headache, neurological deficits and cerebrospinal fluid lymphocytosis. All diagnostic criteria for the HaNDL syndrome were fulfilled; however, additional cerebrospinal fluid analysis showed a positive polymerase chain reaction (PCR) for human herpes virus type 7 (HHV-7). Discussion The possible role of a (prodromal) viral infection in the etiology of HaNDL is discussed. Also the role of electroencephalography (EEG) recordings is discussed. Serial EEG recordings showed generalized slowing, frontal intermittent rhythmic delta activity (FIRDA) and symmetric triphasic frontal waves with a dilation lag.

Normative Values for Intertrial Variability of Motor Responses to Nerve Root and Transcranial Stimulation: A Condition for Follow-Up Studies in Individual Subjects.

ObjectiveIntertrial variability (ITV) of motor responses to peripheral (CMAP) and transcranial (MEP) stimulation prevents their use in follow-up studies. Our purpose was to develop strategies to reduce and measure CMAP and MEP ITV to guide long-term monitoring of conduction slowing and conduction failure of peripheral and central motor pathway in the individual patient.MethodsMaximal compound muscle action potentials to High Voltage Electrical Stimulation (HVES) of lumbo-sacral nerve roots (r-CMAP) and activated, averaged motor evoked potentials (MEPs) to Transcranial Magnetic Stimulation (TMS) using double cone coil were recorded from 10 proximal and distal muscle districts of lower limbs. The procedure was repeated twice, 1–2 days apart, in 30 subjects, including healthy volunteers and clinically stable multiple sclerosis patients, using constant stimulating and recording sites and adopting a standardized procedure of voluntary activation. ITV for latency and area indexes and for the ratio between MEP and r-CMAP areas (a-Ratio) was expressed as Relative Intertrial Variation (RIV, 5th-95th percentile). As an inverse correlation between the size of area and ITV was found, raw ITV values were normalized as a function of area to make them comparable with one another.ResultsAll RIV values for latencies were significantly below the optimum threshold of ± 10%, with the exception of r-CMAP latencies recorded from Vastus Lateralis muscle. RIVs for a-Ratio, the most important index of central conduction failure, ranged from a maximum of -25.3% to +32.2% (Vastus Medialis) to a minimum of -15.0% to + 17.4% (Flexor Hallucis Brevis).ConclusionsThe described procedure represents an effort to lower as much as possible variability of motor responses in serial recording; the reported ITV normative values are the necessary premise to detect significant changes of motor conduction slowing and failure in the individual patient in follow-up studies.

Umbilical vein vasomotion detected in vivo by serial three-dimensional pixelwise spatially angle-corrected volume flow measurements.

To explore changes in volume flow in the umbilical vein in healthy second-trimester fetuses. This was a prospective observational pilot study performed at Stavanger University Hospital, Norway, between May and October 2013. Serial three-dimensional ultrasound recordings from the umbilical vein were acquired every 30 s in a 5-min period in 43 fetuses at 17-20 weeks' gestation. The recordings were analyzed with pixelwise spatially angle-corrected volume flow measurements. We observed variation in the umbilical vein volume flow in all fetuses, ranging from a mean minimum of 1.01 mL/s to a mean maximum of 2.60 mL/s. The minimum of all measurements was 57% compared with the mean value and the maximum was 148% of the mean value. The individual flow volume measurements ranged between 0.11 and 4.14 mL/s (mean, 1.76 mL/s). Within this range, an undulating course of all perfusion parameters was observed, with a full period of 4-5 min duration. Healthy second-trimester fetuses show cyclical variation in blood flow in the umbilical vein. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Real-Time Evaluation of Anterior Choroidal Artery Patency During Aneurysm Clipping.

Inadvertent occlusion of the anterior choroidal artery during aneurysm clipping can cause a disabling stroke in minutes. We evaluate the clinical utility of direct cortical motor evoked potential (MEP) monitoring during aneurysm clipping, as a real-time assessment of arterial patency, prior to performing indocyanine green videoangiography. Direct cortical MEPs were recorded in seven patients undergoing surgery for aneurysms that involved or abutted the anterior choroidal artery. The aneurysms clipped in those seven patients included four anterior choroidal artery aneurysms and six posterior communicating artery aneurysms. Serial MEP recordings were performed during the intradural dissection, aneurysm exposure, and clip placement. A significant change in MEPs after clip placement would prompt immediate inspection and removal or repositioning of the clip. If the clip placement appeared satisfactory and MEP recordings were stable, then an intraoperative indocyanine green videoangiogram was performed to confirm obliteration of the aneurysm and patency of the arteries. Seven patients underwent successful clipping of anterior choroidal artery aneurysms and posterior communicating artery aneurysms using direct cortical MEP monitoring, with good clinical and radiographic outcomes. In six patients, no changes in MEP amplitudes were observed following permanent clip placement. In one patient, a profound decrease in MEP amplitude occurred 220 seconds after placement of a permanent clip on a large posterior communicating aneurysm. An inspection revealed that the anterior choroidal artery was kinked. The clip was immediately removed, and the MEP signals returned to baseline shortly thereafter. A clip was then optimally placed, and the patient awoke without neurologic deficit. Direct cortical MEPs are a useful adjunct to standard electrophysiologic monitoring in aneurysm surgery, particularly when the anterior choroidal artery or lenticulostriate arteries are at risk. When these arteries are occluded, infarction may occur before the occlusion is detected by indocyanine green videoangiography or intraoperative angiography. The use of MEPs allows real-time detection of ischemia to subcortical motor pathways.

Isoflurane versus sevoflurane with interscalene block for shoulder arthroscopic procedures: Value of process capability indices as an additional tool for data analysis.

Background and Aims:Hypotensive anaesthesia reduces intra-articular bleed and promotes visualisation during arthroscopy. The haemodynamic effects of inhalational agents isoflurane and sevoflurane were studied extensively, and both were found to reduce mean arterial pressures (MBP) to an equivalent magnitude. We investigated the relative ability of isoflurane vis-a-vis sevoflurane to maintain the target systolic blood pressure (SBP) in patients undergoing shoulder arthroscopic procedures.Methods:In a prospective randomised study, 59 patients in two groups of 30 and 29 patients each received concomitant general anaesthesia (1.2–1.5 MAC of isoflurane and sevoflurane) and interscalene brachial plexus block. Nitrous oxide was used in both groups. Intraoperatively, serial blood pressure recordings of SBP, diastolic blood pressure (DBP), MBP and heart rates were done at every 3rd min intervals. The manipulations needed to achieve target SBP (T = 90 mmHg) for optimal arthroscopic visualisation and treat unacceptable hypotensive episodes were noted. Conventional statistical tests and process capability index (PCI) evaluation were both deployed for data analysis.Results:Lower mean SBP and DBPs were recorded for isoflurane patients as compared to sevoflurane (P < 0.05, for mean, maximum and minimum recordings). Higher mean heart rates were recorded for isoflurane (P < 0.05). PCIs indicated that isoflurane was superior to sevoflurane in the ease of achieving target SBP of 90 mmHg as well as maintaining blood pressures in the range of 80–100 mmHg.Conclusion:Isoflurane provides better intraoperative haemodynamic status vis-a-vis sevoflurane in patients undergoing shoulder arthroscopic surgery with preliminary interscalene blockade. The PCI can be a useful additional medical data analysis tool.

Serial Ramp Recordings for Rapid Testing of Generating Capacity of Isolated Hippocampal Neurons

Serial Ramp Recordings for Rapid Testing of Generating Capacity of Isolated Hippocampal Neurons

Age-dependent effects on sensory axonal excitability in normal mice

Serial recordings were performed to measure sensory excitability in peripheral nerves and elucidate age-dependent changes in neuronal ion currents in the peripheral sensory nervous system. The threshold tracking technique was used to measure multiple excitability indices in the tail sensory nerves of five normal male mice at four time points (6, 10, 14, and 19 weeks of age). A separate group of four mice was also measured at 43 weeks and at 60 weeks of age. Maturation was accompanied by an increase in early hyperpolarization and superexcitability at 10 weeks. At 60 weeks, the hyperpolarizing electrotonus shifted downward, while superexcitability became greater and subexcitability (double stimuli) decreased. Computer modeling showed that the most notable age-related interval changes in excitability parameters were Barrett–Barrett, H, and slow K+ conductances. Understanding age-related changes in the excitability of sensory axons may provide a platform for understanding age-dependent sensory symptoms and developing age-specific channel-targeting therapies.

Abstract 15367: Does the Intra-resuscitation Pupillary Light Reflex Predict Return of Spontaneous Circulation or Neurologic Outcome?

Objective: We previously demonstrated feasibility of prehospital pupillometry to quantify/qualify the pupillary light reflex (PLR) during resuscitation as a potential neurophysiological marker to guide efforts &amp; provide early neuroprognostication. We now report on the full cohort. Hypothesis: PLR during resuscitation is associated with ROSC &amp; neurologic outcome (following commands [FC]; mRS 0-3 &amp; CPC 1-2) at hospital discharge. Methods: Prospective, observational cohort in which we deployed hand-held pupillometers (NeurOptics, Inc) to EMS-treated OHCA subjects for serial recordings during pulse checks until ROSC, termination, or hospital arrival. We categorized PLR as normal/abnormal/absent with the Neurologic Pupillary Index (NPi), a continuous scale (0-5) combining facets of PLR (e.g. % change, velocity, latency). We abstracted patient data from prehospital &amp; hospital records, tabulated data, estimated test performance, and performed ROC analysis for best NPi &amp; outcomes. Results: From 2/14 - 4/15, 186 subjects were enrolled (61 ± 20 years, 58% male, 41% witnessed, 43% bystander CPR, 25% shockable rhythm). Most (92%) received epi (median 5mg), 12% atropine (median 1mg), 37% defibrillated (median 3.5 attempts). At submission, 173 (96%) had complete follow-up data (44% transported to hospital, 31% ROSC). Of 39 (22%) subjects admitted to hospital (76% hypothermia, 26% cardiac catheterization), 7 survived to discharge with 6 FC &amp; 5 mRS 0-3. Of 1,552 readings attempted (median 7/subject), 39% had usable data &amp; 74% subjects had ≥1 usable reading, Only 15% subjects had PLR during resuscitation. Best NPi &gt; 4.0 classified 92% of FC (LR+ 17; overall AUC 0.69), whereas best NPi &gt; 4.5 classified 98% favorable mRS &amp; CPC (LR+ 67; overall AUC 0.70). Conclusion: A minority of subjects had detectable PLR. Normal PLR was rare, but had high overall classification accuracy for FC, &amp; strong likelihood ratios for ROSC &amp; neurologic outcome. Best NPi had fair test performance by AUC.

Abstract 18786: Real Time Gene Knock Out in Human Induced Pluripotent Stem Cell Derived Cardiomyocytes Allows Rapid Evaluation of Gene Function in Cellular Electrophysiology

Background and objective: Modeling of human physiologic traits using pluripotent stem cell derived cardiomyocytes has been hampered in part by variability between cardiomyocytes derived from different stem cell lines. While the advent of genome editing affords unprecedented opportunities to evaluate gene function, the variation between cell lines creates challenges in distinguishing signal from noise. We recently developed a genetically encoded voltage sensing fluorescent protein, Arclight, that enables serial recording of cellular electrical activity. Using an inducible CRISPR-CAS9 nuclease we have developed a method to knockout genes of interest in differentiated cardiomyocytes. The use of the Arclight voltage reporter allows monitoring of the loss of gene function over time. This real-time knockout method is demonstrated for the KCNH2 gene and compared to shRNA mediated knockdown. Methods and Results: Human iPSCs that were genetically engineered to contain a doxycycline (DOX) inducible Cas9 allele were differentiated into cardiomyocytes and transduced with lentiviral vector carrying the genetically encoded fluorescent voltage indicator, A242-Arclight. These human Cas9 iPSC-CMs expressing Arclight were further transduced with lentiviral vector containing a guide RNA (gRNA) targeting KCNH2 to achieve knockout upon DOX treatment. Arclight fluorescence was repeatedly recorded in these cardiomyocytes at day 0, 3, 5, 7, and 9 after DOX treatment. APDs at 90% repolarization (APD90) were analyzed and compared to APD90 from CMs without DOX treatment. APD90 in DOX treated iPSC-CMs gradually prolonged from day 3 to day 5 and remained relatively stable between days 5 and 9. At day 7, APD90 was significantly prolonged in DOX treated iPSC-CMS (321 ± 21 ms) compared to untreated cardiomyocytes (231 ±15 ms). RNAi-mediated knockdown of KCNH2 using short hairpin RNA (shRNA) on the iPSC-CMs expressing Arclight did not significantly alter APD90 throughout the study time course. Conclusion: In this in vitro human cell model, Crispr/Cas9 knockout of KCNH2 results in APD prolongation in iPSC-CMs in a real-time manner, which provides a powerful cellular platform to evaluate gene function in cellular electrophysiology.

WHY DO PEOPLE RECORD THEIR CRIMINAL ACTIVITY?

ObjectiveTo raise awareness of a new trend: serial recording of own criminal activity.MethodExamples recruited: newspapers and my own Medico-legal practice.ResultsIncreasing number of crimes are self-recorded over weeks or months including...

The role of neurovascular ultrasound in intensive care units

The neurovascular ultrasound methods are cheap and noninvasive methods that are performed at the bedside of critically ill patients. Transcranial Doppler sonography (TCD), transcranial color Doppler sonography (TCCD) and ultrasound examination of the neck vessels can provide valuable information for timely treatment decisions. In patients with acute stroke, TCD can detect intracranial arterial steno-occlusive disease and presence of collateral flow. The recanalization rate after reperfusion treatment can be monitored with serial TCD recordings in acute ischemic stroke. TCD bubble test can detect the presence of heart right to left shunt, and with detection of microembolic signals the risk of cerebral embolization can be assessed. With TCD, it is possible to determine the cerebral blood flow and intracranial pressure in patients with severe stroke, closed head trauma or encephalopathy of various etiologies. TCCD may be useful in assessing the movement of mediosagital brain structures. Serial TCD is routinely used for monitoring vasospasm in subarachnoid hemorrhage. Inevitably, TCD has its role in confirming brain death and its findings are not affected by sedation, hypothermia or metabolic disorders. Besides assessing changes in vessel wall or lumen, extracranial ultrasound is, also, a valuable method in guiding the placement of central venous catheters.

USING THE SERIAL RAMP RECORDINGS FOR RAPID TESTING OF THE GENERATING ABILITY OF IMPULSE ACTIVITY OF ISOLATED HIPPOCAMPAL NEURONS

In this study we investigated changes of impulse activity of hippocampal neurons of the hippocampus by using ramp recordings. We have described the usage of serial ramp recordings of neuronal electrical activity for rapid testing of the generating ability of isolated hippocampal neurons. An analysis of the data has shown that the proposed protocol of serial ramp recordings allows to define additional characteristics of the neuronal impulse activity: (i) the thresholds for initiation of generation and suppression of the generation, (ii) the shape and amplitude of relationship between the interpulse intervals and neuronal depolarizations. The suggested stimulation protocols and related analysis are tools that can be effectively used to justify influence of chemicals or other experimental factors on the impulse activity of neurons.

Use of 90° Hopkin's Telescopic Examination as an OPD Tool to Clinically Evaluate and Record Oral Cavity Lesions: Our Experience in Early Detection, Especially in Patients with Limited Mouth Opening.

Restricted mouth opening due to premalignant lesions like oral sub-mucous fibrosis, malignancies of oral cavity and postoperative status is very common in Indian patients. It is very difficult to evaluate, document and biopsy the lesions due to inability to access, vast area and diversity of premalignant lesions and subject variations. 90° Hopkin's slender out-patient examination telescope was found useful tool in this. The aim of the study was to evaluate the use of magnified view and reach of a slender telescope to document and examine the oral cavity for any premalignant and malignant lesions, especially for patients with restricted mouth opening and to study its impact on management. A 90(0) Hopkin's telescope was used to evaluate and document oral cavity examination in the Out Patients Department (OPD). The data of first 2000 patients was analysed. Difficult to reach areas, where mouth opening was severely restricted was the significant subset. A total of 1394 patients approached OPD for primary diagnosis at our tertiary cancer care centre. Six hundred and six patients were the ones in follow up after treatment in form of Surgery, Chemotherapy or Radiotherapy, or combination. Five twenty three patients (of 1394) with mouth opening ≤ 20mm formed the study group. Telescope guided biopsies were also taken in 50 patients from 56 sites. Serial recordings were compared objectively in premalignant, treatment evaluation and close watch groups. An increase of 5.6% in rate of diagnosis of malignancy was made possible with the help of telescopic examination in patients with mouth opening ≤ 20mm. A 90(0) Hopkin's telescopic examination is a useful tool to evaluate and record oral cavity lesions, especially in patients with restricted mouth openings. It is a useful tool for screening high risk group, giving definite advantage of objective evaluation and recording of the lesion. It can also be used to objectively evaluate response of neo-adjuvant chemotherapy and as a teaching tool for the fellows.

Perkütan Mitral Balon Valvuloplastinin Etkinliğini Değerlendirmede Empedans Kardiyografinin Kullanımı

Objective: Impedance Cardiography (ICG) method, facilitates measuring hemodynamic parameters indirectly by recording thoracic impedance variations induced by cyclic changes in blood flow. The aim of this study is to evaluate alterations in hemodynamic parameters obtained by impedance cardiography (ICG) in addition to conventional echocardiographic and catheterization data after percutaneous mitral balloon valvuloplasty (PMBV). Material and Methods: 18 patients with severe rheumatic mitral stenosis to whom PMBV had been performed were included in this study. Impedance cardiographic measurements were performed in addition to routine echocardiographic examination and invasive left atrial and pulmonary arterial pressure recordings before and after the procedure. Cardiac output was calculated with direct Fick method before PMBV. Average values of several measurements were used to obtain the most accurate results for atrial fibrillation patients in the study group. Results: Following successful PMBV, in impedance cardiographic evaluation an increase in cardiac output (4.69±1.46 and 5.68±1.3 l/min, before and after PMBV, respectively, p<0.001) and cardiac index (2.72±0.81 and 3.29±0.73 l/min/m2, before and after PMBV, respectively, p<0.001) an evident prolongation in ejection period (246.8±40.3 and 275.2±32.1 msec, before and after PMBV, respectively, p<0.001); and a statistically significant reduction in pre-ejection period (103.7±41.8 and 82.7±16.8 msec, before and after PMBV, respectively, p=0.033), and thoracic fluid content (34.3±11.2 and 27.7±5.31/kΩ, before and after PMBV, respectively, p=0.037) was observed. There was a strong correlation between preprocedural cardiac output calculations of ICG and direct Fick method (r:0.89, p<0.001). Conclusion: In addition to the conventional methods, serial recordings of impedance cardiographic outputs may yield beneficial information for the assessment of PMBV efficacy. As a non-invasive and easily applicable method, it might be utilized during in-hospital follow-up.

Serial aEEG recordings in a cohort of extremely preterm infants: feasibility and safety.

IntroductionAmplitude-integrated EEG (aEEG) monitoring is increasing in the neonatal population, but the safety and feasibility of performing aEEG in extremely preterm infants have not been systematically evaluated.MethodsInborn infants 230/7 – 286/7 weeks gestation or birth weight 401–1000 grams were eligible. Serial, six-hour aEEG recordings were obtained from first week of life until 36 weeks postmenstrual age. Adverse events were documented, and surveys evaluated the impact of the aEEGs on routine care. Success of performing aEEGs according to protocol and aEEG quality were assessed.Results102 infants were enrolled, with 755 recordings performed. 83% of recordings were performed according to schedule, and 96% were without adverse event. Bedside nurses reported no interference with routine care for 89% of recordings. 92% of recordings had acceptable signal quality.ConclusionsSerial aEEG monitoring is safe in preterm infants, with few adverse events and general acceptance by nursing staff.

Abstract 231: Preliminary Experience with Prehospital Pupillometry: A Prospective, Observational Study in Out-of-Hospital Cardiac Arrest

Objective: Physiologic monitoring &amp; neuroprognostication during resuscitation are relatively crude. Real time assessment of neurophysiology could be useful to guide resuscitative efforts. Objective assessment of the pupillary light reflex [PLR] is feasible during IHCA with a portable pupillometer, &amp; PLR is associated with survival &amp; neurologic outcome. We are conducting a prospective, observational study to assess the translational potential of pupillometry in the prehospital setting for OHCA. Hypotheses: Prehospital pupillometry is feasible &amp; qualitative assessment of PLR is associated with patient outcomes. Methods: Portable pupillometers (NeurOptics, Inc) were deployed for subjects with EMS treated OHCA. Serial recordings were obtained during routine pulse checks until ROSC, termination, or hospital arrival. We qualified PLR as normal/abnormal/absent with Neurologic Pupillary Index (NPiTM), a continuous scale that combines facets of PLR (e.g. % change, velocity, latency). We reviewed prehospital &amp; hospital records to identify patient characteristics &amp; outcomes, tabulated data as means/medians/proportions, &amp; estimated test performance characteristics. Results: From 2/14 - 6/14, a pupillometer was deployed to 38/58 (66%) patients with EMS treated OHCA (63 ± 16 years, 66% male, 33% witnessed, 54% bystander CPR, 11% shockable rhythm). Of 38 subjects, 21 (56%) were transported (19 ROSC &amp; 2 CPR). At the time of submission, follow-up data were available on 27 (71%) patients (6 survived to admission, 4 had therapeutic hypothermia, 3 had cardiac catheterization, 1 survived to discharge with excellent neurologic recovery). In total, 385 readings were attempted (median 8.5 attempts/patient; IQR 6-12). Median 47% (IQR 25%, 67%) readings had usable data. Most (92%) patients had ≥1 usable reading and 9/38 (24%) had any PLR during resuscitation. Conclusion: Prehospital pupillometry is feasible &amp; may yield prognostic information during resuscitation.

Early-onset cortico-cortical synchronization in the hemiparkinsonian rat model.

Changes in synchronized neuronal oscillatory activity are reported in both cortex and basal ganglia of Parkinson's disease patients. The origin of these changes, in particular their relationship with the progressive nigrostriatal dopaminergic denervation, is unknown. Therefore, in the present study we studied interregional neuronal synchronization in motor cortex and basal ganglia during the development of dopaminergic degeneration induced by a unilateral infusion of 6-hydroxydopamine (6-OHDA) into the rat medial forebrain bundle. We performed serial local field potential recordings bilaterally in the motor cortex and the subthalamic nucleus of the lesioned hemisphere prior to, during, and after development of the nigrostriatal dopaminergic cell loss. We obtained signal from freely moving rats in both resting and walking conditions, and we computed local spectral power, interregional synchronization (using phase lag index), and directionality (using Granger causality). After neurotoxin injection the first change in phase lag index was an increment in cortico-cortical synchronization. We observed increased bidirectional Granger causality in the beta frequency band between cortex and subthalamic nucleus within the lesioned hemisphere. In the walking condition, the 6-OHDA lesion-induced changes in synchronization resembled that of the resting state, whereas the changes in Granger causality were less pronounced after the lesion. Considering the relatively preserved connectivity pattern of the cortex contralateral to the lesioned side and the early emergence of increased cortico-cortical synchronization during development of the 6-OHDA lesion, we suggest a putative compensatory role of cortico-cortical coupling.