P12-S Frontotemporal electrode set for ICU bedside cEEG monitoring for comatose patients after cardiac arrest

Background: Electroencephalogram (EEG) patterns within 24 h after cardiac arrest (CA) have shown to reliably predict neurological outcome. The recording set-up may be simplified by using a less extensive electrode set. We compared a 4-channel frontotemporal EEG headband (BrainStatus, Bittium, Oulu, Finland) to a 9-channel Ag-AgCl electrode set.Material and methods: Between July 2018 and January 2019, EEGs were recorded in 22 consecutive adult patients admitted after CA with both electrode sets simultaneously. EEG patterns were assessed visually, corresponding to the guidelines of the American Clinical Neurophysiology Society (ACNS). Five minute epochs at 24 h after CA were scored by three independent EEG readers blinded to clinical data. Final classification was determined by majority vote. To evaluate classification agreement between the electrode sets, confusion matrices and Cohen’s Kappa were used.Results: At 24 h after CA, the background patterns of 21 patients were available. With the 9 electrode set, nine patients had a continuous pattern, two patients had a discontinuous pattern, two patients showed burst-suppression without identical burst, one patient showed burst-suppression with identical bursts, and four patients had a suppressed background pattern. The background pattern of three patients was obscured by artefacts. The agreement for background pattern scoring of the 4 electrode set compared to this 9 electrode set was fair ( = 0.32).Conclusions: Visual classification of EEG patterns in patients with postanoxic coma with a 9-channel Ag-AgCl electrode set cannot be replaced with a 4-channel frontotemporal EEG headband

On Geometric Alignment in Low Doubling Dimension

In real-world, many problems can be formulated as the alignment between two geometric patterns. Previously, a great amount of research focus on the alignment of 2D or 3D patterns, especially in the field of computer vision. Recently, the alignment of geometric patterns in high dimension finds several novel applications, and has attracted more and more attentions. However, the research is still rather limited in terms of algorithms. To the best of our knowledge, most existing approaches for high dimensional alignment are just simple extensions of their counterparts for 2D and 3D cases, and often suffer from the issues such as high complexities. In this paper, we propose an effective framework to compress the high dimensional geometric patterns and approximately preserve the alignment quality. As a consequence, existing alignment approach can be applied to the compressed geometric patterns and thus the time complexity is significantly reduced. Our idea is inspired by the observation that high dimensional data often has a low intrinsic dimension. We adopt the widely used notion "doubling dimension" to measure the extents of our compression and the resulting approximation. Finally, we test our method on both random and real datasets, the experimental results reveal that running the alignment algorithm on compressed patterns can achieve similar qualities, comparing with the results on the original patterns, but the running times (including the times cost for compression) are substantially lower

Unraveling Island Economies through Organic Residue Analysis: The Case of Mocha Island (Southern Chile)

Biophysical conditions played a fundamental role in early human colonization of insular territories, particularly in food-producing societies dealing with limited resources and the challenges of maintaining a sustainable carrying capacity. Studies on past human colonization of small oceanic islands thus offer insights into economic plasticity, ecological impacts, and adaptation of early food-producing groups. On the coast of southern Chile, early evidence is dated to 950 cal BP of island colonization by coastal populations with mainland subsistence systems based on the exploitation of marine resources, along with gathering, managing, and cultivating plants and hunting terrestrial animals. Strikingly, the extent to which these mixed economies contributed to insular colonization efforts is largely unknown. Here we used organic residue analysis of ceramic artifacts to shed light on the subsistence of populations on Mocha Island in southern Chile. We extracted and analyzed lipids from 51 pottery sherds associated with the El Vergel cultural complex that flourished in southern Chile between 950 and 400 cal BP. Chemical and stable isotope analysis of the extracts identified a range of food products, including C3 and C4 plants and marine organisms. The results reveal the central role of mixed subsistence systems in fueling the colonization of Mocha Island

The role of salmon fishing in the adoption of pottery technology in subarctic Alaska

Ceramic technology makes an abrupt appearance in the New World Arctic at circa 2800 cal BP. While there is general consensus that the ultimate source of these Alaskan pottery traditions lay in continental NE Asia, the motivations for the adoption of pottery in Alaska have remained unclear. Through organic residue analysis we investigated the function of Norton pottery in Southwest Alaska, and the extent to which its function changed in later periods under the increasing northern influence of Thule culture in the region (from ca. 1000 cal BP). Our results show clear evidence of aquatic resource processing in all pottery vessels. Regional variability due to environmental and ecological differences are apparent in the pottery. The majority of Norton pottery was from inland riverine locations and the function of this early pottery was to process anadromous fish, with only limited evidence of other resources. After 1000 cal BP more sites appear on the coast, and while pottery technology changes dramatically at this time, this is not as clear in pottery function which remains aimed at local abundant aquatic resources. We hypothesize that pottery was adopted into Alaska as part of a riverine adaptation and suggest that targeted human exploitation of large riverine systems may have facilitated its expansion into Southwest Alaska. Furthermore, we suggest that this pattern might extend back into Siberia where Alaskan pottery originates

Chemical analysis of pottery reveals the transition from a maritime to a plant-based economy in pre-colonial coastal Brazil

Understanding long-term dynamics of past socio-ecological systems is essential for their future management. The southern Atlantic Forest coast of Brazil with its biodiverse littoral zone and artisanal fishing communities, is a priority for conservation. Traditional maritime knowledge is thought to have a deep-history and indeed, marine exploitation can be traced back to the middle Holocene. As part of one of South America’s largest diasporas, Guarani groups reached the southern Brazilian coast at around 1000 years ago. Their impact on the long-standing coastal economy is unknown, due to poor preservation of organic remains. Through the first organic residue study on Guarani pottery, we show that maize rather than aquatic foods was the most dominant product in pottery at this time. By developing a mixing model based on carbon isotope values of saturated and mono-unsaturated fatty acids we propose new criteria for the identification of maize, opening up avenues for future research. Our data confirms the importance of maize to the pre-colonial Guarani, even in a highly productive coastal environment. The Guarani occupation of this region marks a significant departure from previous socio-economic systems, potentially leading to loss of traditional knowledge and alleviating anthropogenic pressure, albeit temporarily, on the marine environment

The role of salmon fishing in the adoption of pottery technology in subarctic Alaska

Ceramic technology makes an abrupt appearance in the New World Arctic at circa 2800 cal BP. While there is general consensus that the ultimate source of these Alaskan pottery traditions lay in continental NE Asia, the motivations for the adoption of pottery in Alaska have remained unclear. Through organic residue analysis we investigated the function of Norton pottery in Southwest Alaska, and the extent to which its function changed in later periods under the increasing northern influence of Thule culture in the region (from ca. 1000 cal BP). Our results show clear evidence of aquatic resource processing in all pottery vessels. Regional variability due to environmental and ecological differences are apparent in the pottery. The majority of Norton pottery was from inland riverine locations and the function of this early pottery was to process anadromous fish, with only limited evidence of other resources. After 1000 cal BP more sites appear on the coast, and while pottery technology changes dramatically at this time, this is not as clear in pottery function which remains aimed at local abundant aquatic resources. We hypothesize that pottery was adopted into Alaska as part of a riverine adaptation and suggest that targeted human exploitation of large riverine systems may have facilitated its expansion into Southwest Alaska. Furthermore, we suggest that this pattern might extend back into Siberia where Alaskan pottery originates.</p

Tracking the Adoption of Early Pottery Traditions into Maritime Northeast Asia : Emerging Insights and New Questions

Understanding the emergence and development of coastal adaptations is a central theme in the archaeology of Maritime Northeast Asia. The capacity to harvest, store and share aquatic resources offered a novel economic strategy that could support greater sedentism and new forms of social life. In turn, growing reliance on the exploitation of rich coastal resources wouldhave generated powerful incentives to invent, adopt or refine food-processing technologies such as pottery. By the end of the Holocene, marine-adapted cultures were present along all habitable coastlines and most of them maintained some kind of pottery tradition, though the deeper origins of the apparent relationship remain obscure. To explore evolving associationsbetween early pottery dispersals and the emergence of coastal adaptations we undertake a broad-scale chrono-spatial analysis of the expansion of these two phenomena across Northeast Asia and into Alaska, and then use this framework to discuss regional trajectories in more detail. Our preliminary results suggest that pottery and coastal economies have complex, andlargely separate histories, and that closer associations only start to emerge in later times. While limitations in the quality and coverage of data make these insights tentative, this mapping exercise highlights important themes requiring further research. Improved chronological frameworks are needed in all areas to better correlate cultural developments with climatic and environmental changes. Many regions would also benefit from large-scale analysis of food residues preserved in pottery to clarify general patterns in vessel function. More contextual analysis is needed to clarify how pottery use relates to other food processing and storage technologies, and to explain why some only contemporary sites contain pottery while others do not. Finally, comparative insights from ethnography and oral history can shed light on laterdevelopments in food-processing technologies and will improve understanding of how ancestral cooking traditions continue to inform northern Indigenous food cultures

Disruption of Brain-Heart Coupling in Sepsis

Purpose: To investigate heart rate and EEG variability and their coupling in patients with sepsis and determine their relationship to sepsis severity and severity of sepsis-Associated brain dysfunction. Methods: Fifty-Two patients with sepsis were prospectively identified, categorized as comatose (N = 30) and noncomatose (N = 22), and compared with 11 control subjects. In a 30-minute EEG and electrocardiogram recording, heart rate variability and EEG variability (measured by the variability of relative power in a modified alpha band = RAP) and their coupled oscillations were quantified using linear (least-square periodogram and magnitude square coherence) and nonlinear (Shannon entropy and mutual information) measures. These measures were compared between the three groups and correlated with outcome, adjusting for severity of sepsis. Results: Several measures of heart rate variability and EEG variability and of their coupled oscillations were significantly lower in patients with sepsis compared with controls and correlated with outcome. This correlation was not independent when adjusting for severity of sepsis. Conclusions: Sepsis is associated with lower variability of both heart rate and RAP on EEG and reduction of their coupled oscillations. This uncoupling is associated with the severity of encephalopathy. Combined EEG and electrocardiogram monitoring may be used to gain insight in underlying mechanisms of sepsis and quantify brainstem or thalamic dysfunction

SSEP amplitudes add information for prognostication in postanoxic coma

Objective: To investigate whether somatosensory evoked potential (SSEP) amplitude adds information for prediction of poor outcome in postanoxic coma. Methods: In this retrospective cohort study we included adult patients admitted after cardiac arrest between January 2010 and June 2018 who remained in coma and had SSEP recorded for prognostication. Outcome was dichotomized in poor (Cerebral Performance Category (CPC) 4–5) and good (CPC 1–3) at ICU discharge. Sensitivity of bilaterally absent N20 potential was calculated. In case the N20 potential was not bilaterally absent, the amplitude contralateral to stimulation side (baseline-N20, N20-P25, and maximum) was determined. At a specificity of 100%, SEPP amplitude sensitivities were determined for poor outcome. Results: SSEP recordings were performed in 197 patients of whom 57 had bilaterally absent N20 potentials. From 140 patients, 16 (11%) had a good outcome. The sensitivity for poor outcome of bilaterally absent N20 was 31%. At a specificity of 100%, contralateral amplitude thresholds were 0.34 μV (baseline-N20), 0.99 μV (N20-P25) and 1.0 μV (maximum), corresponding to a sensitivity for poor outcome of 38%, 44% and 40%. Combination of bilaterally absent N20 and a N20-P25 threshold below 0.99 μV yielded a sensitivity of 62%. Conclusions: Our results confirm that very low cortical SSEP amplitudes are highly predictive of poor outcome in patients with postanoxic coma. Adding ‘N20-P25 threshold amplitude’ to the ‘bilaterally absent N20′ criterion, increased sensitivity substantially

EEG in a four-electrode frontotemporal montage reliably predicts outcome after cardiac arrest

Aim: To increase efficiency of continuous EEG monitoring for prognostication of neurological outcome in patients after cardiac arrest, we investigated the reliability of EEG in a four-electrode frontotemporal (4-FT) montage, compared to our standard nine-electrode (9-EL) montage. Methods: EEG recorded with Ag/AgCl cup-electrodes at 12 and/or 24 h after cardiac arrest of 153 patients was available from a previous study. 220 EEG epochs of 5 minutes were reexamined in a 4-FT montage according to the ACNS criteria. Background classification was compared to the available 9-EL classification using Cohens kappa. Reliability for prognostication was assessed in 151 EEG epochs at 24 h after CA using sensitivity and specificity for prediction of poor (cerebral performance categories (CPC) 3–5) and good (CPC 1–2) neurological outcome. Results: Agreement for EEG background classification between the two montages was substantial with a kappa of 0.85 (95%-CI 0.81–0.90). Specificity for prediction of poor outcome was 100% (95%-CI 95–100) for both montages, sensitivity was 31% (95%-CI 21–43) for the 4-FT montage and 35% (95%-CI 24–47) for the 9-EL montage. Good outcome was predicted with 65% specificity (95%-CI 53–76) and 81% sensitivity (95%-CI 71–89) for the 4-FT montage, similar to the 9-EL montage. Conclusion: In this cohort, EEG background patterns determined in a four-electrode frontotemporal montage predict both poor and good outcome after CA with similar reliability. Our results may contribute to decreasing the workload of EEG monitoring in patients after CA without compromising reliability of outcome prediction. However, validation in a larger cohort is necessary, as is a multimodal approach