Stereo-electroencephalography identifies N2 sleep and spindles in human hippocampus.

OBJECTIVES: To describe the hippocampal stereo-electroencephalogram during sleep according to sleep stages (including N2 sleep) and cycles, together with the hippocampal spindles. METHODS: All patients with drug-resistant focal epilepsy undergoing intra-hippocampal implantation between August 2012 and June 2013 at Nancy University Hospital were screened. Six patients with explored hippocampus devoid of pathological features were analyzed. During one night, we identified continuous periods of successive N2, N3 and REM sleep for two full cycles. We performed a spectral analysis of the hippocampal signal for each labeled sleep period. RESULTS: N2, N3 and REM sleeps were individualized according to their spectral powers, for each frequency band and sleep cycle. Hippocampal spindles showed dynamic intrinsic properties, the 11.5-16Hz frequency band being mainly dominant, whereas the 9-11.5Hz frequency band heightening during the beginning and the end of the transient. For N3 and REM sleep stages, the power of the hippocampal signal was significantly decreased between the first and the second sleep cycle. CONCLUSION: Distinct N2 sleep, fast spindles and homeostatic profile are all common properties shared by hippocampus and cortex during sleep. SIGNIFICANCE: The close functional link between hippocampus and cortex may have various sleep-related substrates.

Manual Closed-Loop Insulin Delivery Using a Saddle Point Model Predictive Control Algorithm: Results of a Crossover Randomized Overnight Study.

BACKGROUND: The purpose was to assess the efficacy of a new closed-loop algorithm (Saddle Point Model Predictive Control, SP-MPC) in achieving nocturnal normoglycemia while reducing the risk of hypoglycemia in patients with type 1 diabetes. METHOD: In this randomized crossover study, 10 adult patients (mean hemoglobin A1c 7.35 ± 1.04%) were assigned to be treated overnight by open loop using sensor-augmented pump therapy (open-loop SAP) or manual closed-loop delivery. During closed loop, insulin doses were calculated using the SP-MPC algorithm and administered as manual boluses every 15 minutes from 9:00 pm to 8:00 am. Patients consumed a self-selected meal (65-125 g of carbohydrates) at 7:00 pm accompanied by their usual prandial bolus. Blood glucose was measured every 30 minutes. The primary endpoints were the time spent in target (70-145 mg/dl) and time spent below 70 mg/dl from 11:00 pm to 8:00 am. RESULTS: Time spent in target did not differ between closed-loop and open-loop SAP. The number of hypoglycemic events (<70 mg/dl) was reduced 2.8-fold in closed loop (n = 5, median = 0/patient/hour; interquartile range: 0-0.11) as compared to open-loop SAP (n = 14, median = 0.22/patient/hour, 0.02-0.22) ( P = .02). The area under the curve for sensor glucose values >145 mg/dl was significantly lower during closed-loop than during open-loop SAP ( P = .03) as well as HBGI ( P = .02). CONCLUSIONS: This pilot study suggests that the use of the SP-MPC algorithm may improve mean overnight glucose control and reduce the number of hypoglycemic events as compared to SAP therapy.

Thinker, Soldier, Scribe: cross-sectional study of researchers' roles and author order in the Annals of Internal Medicine.

OBJECTIVE: How researchers' contributions relate to author order on the byline remains unclear. We sought to identify researchers' contributions associated with author order, and to explore the existence of author profiles. DESIGN: Observational study. SETTING: Published record. PARTICIPANTS: 1139 authors of 119 research articles published in 2015 in the Annals of Internal Medicine. PRIMARY OUTCOMES: Presence or absence of 10 contributions, reported by each author, published in the journal. RESULTS: On average, first authors reported 7.1 contributions, second authors 5.2, middle authors 4.0, penultimate authors 4.5 and last authors 6.4 (p<0.001). The first author made the greatest contributions to drafting the article, designing the study, analysing and interpreting the data, and providing study materials or patients. The second author contributed to data analysis as well and to drafting the article. The last author was most involved in obtaining the funding, critically revising the article, designing the study and providing support. Factor analysis yielded three author profiles-Thinker (study design, revision of article, obtaining funding), Soldier (providing material or patients, providing administrative and logistical support, collecting data) and Scribe (analysis and interpretation of data, drafting the article, statistical expertise). These profiles do not strictly correspond to byline position. CONCLUSIONS: First, second and last authors of research articles made distinct contributions to published research. Three authorship profiles can be used to summarise author contributions. These findings shed light on the organisation of clinical research teams and may help researchers discuss, plan and report authorship in a more transparent way.

Kappa statistic to measure agreement beyond chance in free-response assessments.

BACKGROUND: The usual kappa statistic requires that all observations be enumerated. However, in free-response assessments, only positive (or abnormal) findings are notified, but negative (or normal) findings are not. This situation occurs frequently in imaging or other diagnostic studies. We propose here a kappa statistic that is suitable for free-response assessments. METHOD: We derived the equivalent of Cohen's kappa statistic for two raters under the assumption that the number of possible findings for any given patient is very large, as well as a formula for sampling variance that is applicable to independent observations (for clustered observations, a bootstrap procedure is proposed). The proposed statistic was applied to a real-life dataset, and compared with the common practice of collapsing observations within a finite number of regions of interest. RESULTS: The free-response kappa is computed from the total numbers of discordant (b and c) and concordant positive (d) observations made in all patients, as 2d/(b + c + 2d). In 84 full-body magnetic resonance imaging procedures in children that were evaluated by 2 independent raters, the free-response kappa statistic was 0.820. Aggregation of results within regions of interest resulted in overestimation of agreement beyond chance. CONCLUSIONS: The free-response kappa provides an estimate of agreement beyond chance in situations where only positive findings are reported by raters.

Whole-body MRI in children: Would a 3D STIR sequence alone be sufficient for investigating common paediatric conditions? A comparative study.

OBJECTIVES: To test the performance of a single 3D IR T2-Weighted sequence compared to a Whole-body MRI protocol including DWI, T1-Weighted and STIR 3D IR (3S) in a pediatric population. METHODS: Two radiologists (15 and 30 years of experience),reviewed WBMRIs: first the STIR alone and 2 weeks later the 3S protocol. The indications were variable. Only positive findings were explicitly reported. A third reader compared the results to gold standard (GS) exams specific for the pathology. Agreement between the two readers, sensitivity and positive predictive value of STIR were calculated. RESULTS: fifty-four WBMRIs were included (16 suspected child abuse, 8 chronic recurrent multifocal osteomyelitis (CRMO), 11 lymphomas, 4 osteosarcomas, 9 neuroblastomas, 6 histiocytosis). The mean age was 6 years 10 months, range: 1 month to 15 years. Agreement between readers was of 0.87 [0.82-0.91] for 3D STIR, and 0.89 [0.83-0.93] for the 3S protocol. For reader 1 sensitivity of 3D STIR was 81.6% and of 3S 81.0%. For reader 2 it was 74.1% for 3D STIR and 74.7% for 3S. For both readers and for both protocols, the positive predictive value (PPV) depended on the type of disease (for example 100% histocytosis and osteosarcomas, >90% for child abuse, >85% CRMO but <70% for lymphoma and neuroblastoma). CONCLUSIONS: Sensitivities were not different between the 2 protocols, for each reader and were different between the 2 readers for each protocol.

Quality of diabetes care and health insurance coverage: a retrospective study in an outpatient academic public hospital in Switzerland.

BACKGROUND: Socioeconomic disadvantage is associated with an increased risk of adverse diabetes outcomes. In Switzerland, a country with theoretical universal healthcare coverage, people without health insurance face barriers in accessing to and in receiving standard quality care. The Geneva University Hospitals (HUG) have implemented policies aiming at reducing these gaps. We compared quality of diabetes care and ambulatory healthcare services utilization among insured and uninsured diabetic patients. METHODS: This retrospective study linked health and administrative data of type 2 diabetic outpatients with at least one HbA1c test performed in 2012-2013 at HUG. Quality of care evaluation relied on processes (annual serum HbA1c, cholesterol and microalbuminuria tesing) and outcomes (HbA1c) assessment. Healthcare utilization was assessed by the number of ambulatory clinical and laboratory visits. Results were stratified by disease course (newly diagnosed versus prevalent diabetes). RESULTS: Of the 198 patients included, 80 (40.4 %) were uninsured. Both groups underwent annual testing of HbA1c, cholesterol, kidney function and microalbuminuria at comparably high rates and numbers of ambulatory visits did not significantly differ. After adjustments for age and sex, there were no significant differences in serum HbA1c between groups both in those with prevalent or with newly diagnosed diabetes. Initial medical intervention entailed comparable glycaemic improvement after 6 months in incident diabetes among insured and uninsured patients. CONCLUSIONS: This study did not find any difference in quality of diabetes care between insured and uninsured patients in a public hospital enforcing health-equity policies for access to and for delivery of standard diabetes care. It highlights the frontline role of public hospitals in contributing to care delivery equity even in countries with theoretical universal healthcare coverage.

Incidence of venous thromboembolism in psychiatric units.

INTRODUCTION: Incidence and risk factors of venous thromboembolism (VTE) are well established in surgical and medical settings, but data in psychiatric units are lacking. The aim of this study was to estimate the incidence of VTE in hospitalized psychiatric patients, and to assess the risk factors for VTE in this specific population. MATERIALS AND METHODS: All consecutive adult patients, admitted for a psychiatric disorder for at least seven days in psychiatric units were considered for inclusion. Patients were evaluated for signs and symptoms of VTE during hospitalization. At Day 10, all participants were interviewed and a systematic compression ultrasonography of the lower limbs was performed. Patients were followed-up until Day 90. RESULTS: Among the 471 included patients, 449 were evaluable at Day 10, and 458 were followed-up until Day 90. Ten deep vein thromboses (DVT) were diagnosed by Day 10 leading to an incidence of VTE of 2.2% (95% CI, 1.1%-4.1%). Six additional symptomatic VTE occurred between Day 10 and Day 90, leading to a 3.5% incidence at Day 90 (95% CI, 2.0%-5.6%). The main factors associated with VTE were age, bed rest, and diagnosis of dementia. The incidence of VTE in patients aged 75 or over with a diagnosis of dementia reached 8.2% at Day 10 and 12.5% at Day 90. CONCLUSIONS: The incidence of VTE in psychiatric units appeared low. However, in older patients, especially those with dementia, the incidence of VTE increased considerably. Further studies are needed to confirm these results.