AimTo examine the relationship between electrographic seizures and long‐term outcome in neonates with hypoxic–ischemic encephalopathy (HIE).MethodFull‐term neonates with HIE born in Cork University Maternity Hospital from 2003 to 2006 (pre‐hypothermia era) and 2009 to 2012 (hypothermia era) were included in this observational study. All had early continuous electroencephalography monitoring. All electrographic seizures were annotated. The total seizure burden and hourly seizure burden were calculated. Outcome (normal/abnormal) was assessed at 24 to 48 months in surviving neonates using either the Bayley Scales of Infant and Toddler Development, Third Edition or the Griffiths Mental Development Scales; a diagnosis of cerebral palsy or epilepsy was also considered an abnormal outcome.ResultsContinuous electroencephalography was recorded for a median of 57.1 hours (interquartile range 33.5–80.5h) in 47 neonates (31 males, 16 females); 29 out of 47 (62%) had electrographic seizures and 25 out of 47 (53%) had an abnormal outcome. The presence of seizures per se was not associated with abnormal outcome (p=0.126); however, the odds of an abnormal outcome increased over ninefold (odds ratio [OR] 9.56; 95% confidence interval [95% CI] 2.43–37.67) if a neonate had a total seizure burden of more than 40 minutes (p=0.001), and eightfold (OR: 8.00; 95% CI: 2.06–31.07) if a neonate had a maximum hourly seizure burden of more than 13 minutes per hour (p=0.003). Controlling for electrographic HIE grade or treatment with hypothermia did not change the direction of the relationship between seizure burden and outcome.InterpretationIn HIE, a high electrographic seizure burden is significantly associated with abnormal outcome, independent of HIE severity or treatment with hypothermia.

A decreased seizure burden was seen in neonates with moderate HIE who received cooling. This finding may explain some of the therapeutic benefits of cooling seen in term neonates with moderate HIE.

Neonatal seizures are a common emergency in the neonatal intensive care unit (NICU). There are many questions yet to be answered regarding the temporal/spatial characteristics of seizures from different pathologies, response to medication, effects on neurodevelopment and optimal detection. The dataset presented in this descriptor contains EEG recordings from human neonates, the visual interpretation of the EEG by the human experts, supporting clinical data and codes to assist access. Multi-channel EEG was recorded from 79 term neonates admitted to the NICU at the Helsinki University Hospital. The median recording duration was 74 min (IQR: 64 to 96 min). The presence of seizures in the EEGs was annotated independently by three experts. An average of 460 seizures were annotated per expert in the dataset; 39 neonates had seizures and 22 were seizure free, by consensus. The dataset can be used as a reference set of neonatal seizures, in studies of inter-observer agreement and for the development of automated methods of seizure detection and other EEG analyses.

SUMMARYPurpose: Hypoxic ischemic encephalopathy (HIE) accounts for 60% of all neonatal seizures. There is emerging evidence that seizures cause additional injury to the developing brain that has sustained hypoxic ischemic injury. Temporal evolution of clinical seizure burden in HIE has been characterized, with maximum clinical seizure burden (the period of maximum seizure activity) being observed between 12 and 24 h of age. The purpose of our study was to investigate the distribution of electrographic seizure burden (the accumulated duration of seizures over a defined time period), following the initial hypoxic ischemic insult. Methods: Fifteen full-term newborns with HIE and seizures, and a minimum of 48 h of continuous videoelectroencephalography (EEG), were included in this retrospective study. Medical records of the infants were reviewed and details of clinical seizures and antiepileptic drugs were recorded. The time of maximum seizure burden was defined as the midpoint of an hour-long window, shifted in time by 1 s across the full EEG recording, which contained the maximum duration of seizures. The degree of temporal evolution of seizure burden within this period was tested. Temporal evolution was further analyzed by segmenting the time series into two periods; the time between the first recorded seizure and the maximum seizure burden (T 1 ), and the time between the maximum seizure burden and the last recorded seizure (T 2 ). Seizure burden, duration, and number of seizures per hour were analyzed within each time period. Key Findings: EEG was commenced at a median of 14 h of age. Maximum electrographic seizure burden was reached at a median age of 22.7 h. Time from first recorded seizure to maximum seizure burden (T 1 ) was significantly shorter than time from maximum seizure burden to last recorded seizure (T 2 ) (p-value = 0.01). Median seizure burden during T 1 was significantly higher than during T 2 (p-value = 0.007). There is temporal evolution of electrographic seizure burden in full-term newborns with HIE. There is a short period of high seizure burden (T 1 ) followed by a longer period of lower seizure burden (T 2 ). Significance: Understanding the temporal evolution of seizure burden in HIE contributes further to our understanding of neonatal seizures, helps identify an optimal therapeutic window for seizure treatment, and provides a benchmark against which to measure the efficacy of new and innovative forms of neuroprotection and antiepileptic medication.

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Abstract-The detection of seizure in the newborn is a critical aspect of neurological research. Current automatic detection techniques are difficult to assess due to the problems associated with acquiring and labelling newborn electroencephalogram (EEG) data. A realistic model for newborn EEG would allow confident development, assessment and comparison of these detection techniques. This paper presents a model for newborn EEG that accounts for its self-similar and nonstationary nature. The model consists of background and seizure submodels. The newborn EEG background model is based on the short-time power spectrum with a time-varying power law. The relationship between the fractal dimension and the power law of a power spectrum is utilized for accurate estimation of the short-time power law exponent. The newborn EEG seizure model is based on a well-known time-frequency signal model. This model addresses all significant time-frequency characteristics of newborn EEG seizure which include; multiple components or harmonics, piecewise linear instantaneous frequency laws and harmonic amplitude modulation. Estimates of the parameters of both models are shown to be random and are modelled using the data from a total of 500 background epochs and 204 seizure epochs. The newborn EEG background and seizure models are validated against real newborn EEG data using the correlation coefficient. The results show that the output of the proposed models have a higher correlation with real newborn EEG than currently accepted models (a 10% and 38% improvement for background and seizure models, respectively).

This study aimed to provide a description of the continuous recording of the true load regime experienced during daily living by the abutment of a trans-femoral amputee fitted with an osseointegrated fixation. The specific objectives: (i) To present an apparatus and a procedure allowing recording of the load regime, and (ii) an example of the raw data and six performance indicators of the usage of the prosthesis obtained with this method. A subject was monitored for a period of 5 hours as he went about his daily activities. The load regime was directly measured and recorded using a commercial transducer and data logger. The overall load profile presented alternative periods of variable length of inactivity (64%) and activity (36%), respectively. The maximum load applied on the mediolateral, anteroposterior and the long axes represented 21%, 21% and 120% of the body weight, respectively. The anteroposterior, mediolateral and long components of the impulse were 395 kN.s, 359 kN.s and 2,323 kN.s, respectively. The amputee generated a total of 2312 gait cycles of the prosthetic leg, giving an approximate overall cadence of 8 stride/min. Preliminary outcomes indicated that the proposed method was an improvement on the current techniques as it provided the true loading and actual usage of the prosthesis during daily living. This study is a stepping stone in the development of future affordable, on-board and user-friendly load recording systems that can be used in evidence-based practice.

This method enables the visualisation of sleep state in preterm infants which can assist clinical management in the neonatal intensive care unit.