Identification of an early-stage Parkinson's disease neuromarker using event-related potentials, brain network analytics and machine-learning.

OBJECTIVE: The purpose of this study is to explore the possibility of developing a biomarker that can discriminate early-stage Parkinson's disease from healthy brain function using electroencephalography (EEG) event-related potentials (ERPs) in combination with Brain Network Analytics (BNA) technology and machine learning (ML) algorithms. BACKGROUND: Currently, diagnosis of PD depends mainly on motor signs and symptoms. However, there is need for biomarkers that detect PD at an earlier stage to allow intervention and monitoring of potential disease-modifying therapies. Cognitive impairment may appear before motor symptoms, and it tends to worsen with disease progression. While ERPs obtained during cognitive tasks performance represent processing stages of cognitive brain functions, they have not yet been established as sensitive or specific markers for early-stage PD. METHODS: Nineteen PD patients (disease duration of ≤2 years) and 30 healthy controls (HC) underwent EEG recording while performing visual Go/No-Go and auditory Oddball cognitive tasks. ERPs were analyzed by the BNA technology, and a ML algorithm identified a combination of features that distinguish early PD from HC. We used a logistic regression classifier with a 10-fold cross-validation. RESULTS: The ML algorithm identified a neuromarker comprising 15 BNA features that discriminated early PD patients from HC. The area-under-the-curve of the receiver-operating characteristic curve was 0.79. Sensitivity and specificity were 0.74 and 0.73, respectively. The five most important features could be classified into three cognitive functions: early sensory processing (P50 amplitude, N100 latency), filtering of information (P200 amplitude and topographic similarity), and response-locked activity (P-200 topographic similarity preceding the motor response in the visual Go/No-Go task). CONCLUSIONS: This pilot study found that BNA can identify patients with early PD using an advanced analysis of ERPs. These results need to be validated in a larger PD patient sample and assessed for people with premotor phase of PD.

Deep Brain Stimulation Can Differentiate Subregions of the Human Subthalamic Nucleus Area by EEG Biomarkers.

Introduction: Precise lead localization is crucial for an optimal clinical outcome of subthalamic nucleus (STN) deep brain stimulation (DBS) treatment in patients with Parkinson's disease (PD). Currently, anatomical measures, as well as invasive intraoperative electrophysiological recordings, are used to locate DBS electrodes. The objective of this study was to find an alternative electrophysiology tool for STN DBS lead localization. Methods: Sixty-one postoperative electrophysiology recording sessions were obtained from 17 DBS-treated patients with PD. An intraoperative physiological method automatically detected STN borders and subregions. Postoperative EEG cortical activity was measured, while STN low frequency stimulation (LFS) was applied to different areas inside and outside the STN. Machine learning models were used to differentiate stimulation locations, based on EEG analysis of engineered features. Results: A machine learning algorithm identified the top 25 evoked response potentials (ERPs), engineered features that can differentiate inside and outside STN stimulation locations as well as within STN stimulation locations. Evoked responses in the medial and ipsilateral fronto-central areas were found to be most significant for predicting the location of STN stimulation. Two-class linear support vector machine (SVM) predicted the inside (dorso-lateral region, DLR, and ventro-medial region, VMR) vs. outside [zona incerta, ZI, STN stimulation classification with an accuracy of 0.98 and 0.82 for ZI vs. VMR and ZI vs. DLR, respectively, and an accuracy of 0.77 for the within STN (DLR vs. VMR)]. Multiclass linear SVM predicted all areas with an accuracy of 0.82 for the outside and within STN stimulation locations (ZI vs. DLR vs. VMR). Conclusions: Electroencephalogram biomarkers can use low-frequency STN stimulation to localize STN DBS electrodes to ZI, DLR, and VMR STN subregions. These models can be used for both intraoperative electrode localization and postoperative stimulation programming sessions, and have a potential to improve STN DBS clinical outcomes.

Machine learning-based personalized subthalamic biomarkers predict ON-OFF levodopa states in Parkinson patients.

Objective.Adaptive deep brain stimulation (aDBS) based on subthalamic nucleus (STN) electrophysiology has recently been proposed to improve clinical outcomes of DBS for Parkinson's disease (PD) patients. Many current models for aDBS are based on one or two electrophysiological features of STN activity, such as beta or gamma activity. Although these models have shown interesting results, we hypothesized that an aDBS model that includes many STN activity parameters will yield better clinical results. The objective of this study was to investigate the most appropriate STN neurophysiological biomarkers, detectable over long periods of time, that can predict OFF and ON levodopa states in PD patients.Approach.Long-term local field potentials (LFPs) were recorded from eight STNs (four PD patients) during 92 recording sessions (44 OFF and 48 ON levodopa states), over a period of 3-12 months. Electrophysiological analysis included the power of frequency bands, band power ratio and burst features. A total of 140 engineered features was extracted for 20 040 epochs (each epoch lasting 5 s). Based on these engineered features, machine learning (ML) models classified LFPs as OFF vs ON levodopa states.Main results.Beta and gamma band activity alone poorly predicts OFF vs ON levodopa states, with an accuracy of 0.66 and 0.64, respectively. Group ML analysis slightly improved prediction rates, but personalized ML analysis, based on individualized engineered electrophysiological features, were markedly better, predicting OFF vs ON levodopa states with an accuracy of 0.8 for support vector machine learning models.Significance.We showed that individual patients have unique sets of STN neurophysiological biomarkers that can be detected over long periods of time. ML models revealed that personally classified engineered features most accurately predict OFF vs ON levodopa states. Future development of aDBS for PD patients might include personalized ML algorithms.

Dicer Sequencing, Whole Genome Methylation Profiling, mRNA and smallRNA Sequencing Analysis in Basal Cell Carcinoma.

BACKGROUND/AIMS: Perturbations in the expression of microRNAs (miRNAs) and their maturing machinery components such as Dicer have been previously described for basal cell carcinoma (BCC). However, the mutational status of Dicer in BCC is unclear. Further, the sclerodermiform subtype of BCC (sBCC) has not been previously investigated regarding its methylation profile or its smallRNA expression profile via RNA sequencing. We conducted this study to investigate the mutational status of Dicer in BCC. METHODS: Dicer sequencing was performed on the Illumina MiSeq System in a total of 16 BCC samples (8 nodular BCCs, 8 sBCCs) and mapped against the human reference genome (i.e., hg19). Dicer sequencing was performed in all 16 BCC samples. We performed whole genome methylation profiling with Infinium MethylationEPIC BeadChips as well as mRNA and smallRNA sequencing in 5 sBCCs with the Illumina NextSeq500 next-generation sequencing system. RESULTS: Compared to the wildtype Dicer sequence, we found 5 to 7 variants per sBCC sample including insertion, deletion, and multiple nucleotide variants. Global methylation profiles were highly similar between groups. mRNA sequencing revealed S100A9, KRT14, KRT10, S100A8, S100A7, COX1, KRT1, COX3, and smallRNA sequencing analysis miR-21, miR-99a, miR26-a-2, let-7f, let-7g, let-7i, miR-100, and miR-205 were the most strongly expressed in sBCCs. CONCLUSION: We identified a variety of Dicer mutations that could play a role in aberrant miRNA expression in BCC. The noted RNA sequences should be further evaluated in functional studies to explore their potential pathogenetic role in sBCC.

Talbot-Lau x-ray phase-contrast setup for fast scanning of large samples.

Compared to conventional attenuation x-ray radiographic imaging, the x-ray Talbot-Lau technique provides further information about the scattering and the refractive properties of the object in the beam path. Hence, this additional information should improve the diagnostic process concerning medical applications and non-destructive testing. Nevertheless, until now, due to grating fabrication process, Talbot-Lau imaging suffers from small grating sizes (70 mm diameter). This leads to long acquisition times for imaging large objects. Stitching the gratings is one solution. Another one consists of scanning Talbot-Lau setups. In this publication, we present a compact and very fast scanning setup which enables imaging of large samples. With this setup a maximal scanning velocity of 71.7 mm/s is possible. A resolution of 4.1 lines/mm can be achieved. No complex alignment procedures are necessary while the field of view comprises 17.5 × 150 cm2. An improved reconstruction algorithm concerning the scanning approach, which increases robustness with respect to mechanical instabilities, has been developed and is presented. The resolution of the setup in dependence of the scanning velocity is evaluated. The setup imaging qualities are demonstrated using a human knee ex-vivo as an example for a high absorbing human sample.

Circular RNA expression in cutaneous squamous cell carcinoma.

BACKGROUND: CircularRNAs (circRNAs) are a reinvented class of abundant, stable, and evolutionary conserved non-coding RNAs with pivotal impacts on the cellular regulatory network and epigenetics by sequestering microRNAs (miRNAs) like a sponge. OBJECTIVE: Purpose of the present study was to investigate circRNA expression in cutaneous squamous cell carcinoma (cSCC). METHODS: A total of six cSCC and six non-lesional skin (control) biopsies were harvested. Microarray based circRNA expression was determined in the cSCC (n=3) and compared with the non-lesional skin (n=3) from a group of 13,617 distinct human circRNAs found in the Arraystar circRNA Array V2.0 (Arraystar, Rockville, USA). Microarray data were validated by quantitative real-time reverse transcription polymerase chain reaction in a separate group (cSCC, n=3 and non-lesional skin, n=3). miRNA binding to miRNA response elements (MREs) sequence data were acquired bioinformatically. Further data mining was performed to identify circRNAs containing MRE sequences that interacted with previously described miRNAs playing a role in cSCC formation. RESULTS: A total of 322 circRNAs (143 up- and 179 down-regulated; fold change ≥2 and p<0.05) were identified as differentially expressed in cSCC. Furthermore, we identified a total of 1603 MREs that were part of the differentially expressed circRNAs. Among those circRNAs, a complementary MRE sequence was identified in 23 miRNAs previously known to be cSCC relevant. CONCLUSION: This study showed that circRNAs are differentially expressed in cSCC and play an important role in tumor formation by interfering with cSCC relevant miRNAs through miRNA sequence complementary MREs participating in epigenetic control.

Expression profiles of long noncoding RNAs in cutaneous squamous cell carcinoma.

BACKGROUND: Despite there being over 35,000 different long noncoding RNA (lncRNA) sequences described little is known regarding their molecular-pathological role in cutaneous squamous cell carcinoma (cSCC). MATERIALS & METHODS: In this pilot study, lncRNA and mRNA expression profiles were determined in cSCC and control (n = 6) by an Arraystar human lncRNA Microarray. Kyoto Encyclopedia of Genes and Genomes pathway enrichment and gene ontology analysis of mRNAs was performed. RESULTS: Analysis of differential expression revealed 1516 upregulated lncRNAs and 2586 downregulated lncRNAs in cSCC compared with controls. Data analysis identified known oncogenic lncRNAs, such as the HOX transcript antisense RNA HOTAIR, among the differentially expressed lncRNA sequences. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that focal adhesion, extracellular matrix and the oncogenic phosphatidylinositol 3'-kinase-Akt signaling pathway had the highest enrichment scores. CONCLUSION: This study provides the first evidence for differential expression of lncRNA in cSCC and serves as a template for further, larger functional in-depth analyses regarding cSCC molecular lncRNAs.

Circular RNA expression in basal cell carcinoma.

AIM: Circular RNAs (circRNAs), are nonprotein coding RNAs consisting of a circular loop with multiple miRNA, binding sites called miRNA response elements (MREs), functioning as miRNA sponges. This study was performed to identify differentially expressed circRNAs and their MREs in basal cell carcinoma (BCC). MATERIALS & METHODS: Microarray circRNA expression profiles were acquired from BCC and control followed by qRT-PCR validation. Bioinformatical target prediction revealed multiple MREs. Sequence analysis was performed concerning MRE interaction potential with the BCC miRNome. RESULTS: We identified 23 upregulated and 48 downregulated circRNAs with 354 miRNA response elements capable of sequestering miRNA target sequences of the BCC miRNome. CONCLUSION: The present study describes a variety of circRNAs that are potentially involved in the molecular pathogenesis of BCC.

Long-noncoding RNAs in basal cell carcinoma.

Long noncoding RNAs (lncRNAs) are fundamental regulators of pre- and post-transcriptional gene regulation. Over 35,000 different lncRNAs have been described with some of them being involved in cancer formation. The present study was initiated to describe differentially expressed lncRNAs in basal cell carcinoma (BCC). Patients with BCC (n = 6) were included in this study. Punch biopsies were harvested from the tumor center and nonlesional epidermal skin (NLES, control, n = 6). Microarray-based lncRNA and mRNA expression profiles were identified through screening for 30,586 lncRNAs and 26,109 protein-coding transcripts (mRNAs). The microarray data were validated by RT-PCR in a second set of BCC versus control samples. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of mRNAs were performed to assess biologically relevant pathways. A total of 1851 lncRNAs were identified as being significantly up-regulated, whereas 2165 lncRNAs were identified as being significantly down-regulated compared to nonlesional skin (p < 0.05). Oncogenic and/or epidermis-specific lncRNAs, such as CASC15 or ANRIL, were among the differentially expressed sequences. GO analysis showed that the highest enriched GO targeted by up-regulated transcripts was "extracellular matrix." KEGG pathway analysis showed the highest enrichment scores in "Focal adhesion." BCC showed a significantly altered lncRNA and mRNA expression profile. Dysregulation of previously described lncRNAs may play a role in the molecular pathogenesis of BCC and should be subject of further analysis.

Mutation Scanning of D1705 and D1709 in the RNAse IIIb Domain of MicroRNA Processing Enzyme Dicer in Cutaneous Melanoma.

Since the discovery of microRNAs (miRNAs) there have been performed several studies showing perturbations in the expression of miRNAs and the miRNA expression machinery in cutaneous melanoma. Dicer, a pivotal cytosolic enzyme of miRNA maturation has shown to be affected by both somatic and germline mutations in a variety of cancers. Recent studies have shown that recurrent somatic mutations of Dicer frequently affect the metal-ion-binding sites D1709 and D1705 of its RNase IIIb domain, therefore called hot spot mutations. The present study investigates metal-ion-binding sites D1709 and D1705 of the Dicer RNase IIIb domain in cutaneous melanomas and melanoma metastasis by Sanger sequencing. All investigated samples showed wildtype sequence and no single mutation was detected. The miRNA processing enzyme Dicer of melanoma and melanoma metastasis does not appear to be affected by mutation in the metal-ion-binding sites D1709 and D1705 of its RNase IIIb domain.

A pilot study of quality of life in German prehospital emergency care physicians.

BACKGROUND: Quality of life in patients represents an important area of assessment. However, attention to health professionals should be equally important. The literature on the quality of life (QOL) of emergency physicians is scarce. This pilot study investigated QOL in emergency physicians in Germany. MATERIALS AND METHODS: We conducted a cross-sectional study from January to June in 2015. We approached the German Association of Emergency Medicine Physicians and two of the largest recruitment agencies for emergency physicians in Germany and invited their members to participate. We used the WHO Q-BREF to obtain QOL scores in four domains that included physical, mental, social, and environmental health. RESULTS: The 478 German emergency physicians included in the study held board certifications in general medicine (n = 40; 8.4%), anesthesiology (n = 243; 50.8%), surgery (n = 63; 13.2%), internal medicine (n = 81; 17.0%), or others (n = 51; 10.7%). The women surveyed tended to report a better QOL but worse general health than the men. Regarding specific domains, women scored worse in physical health, particularly energy during everyday work (relative risk ratio [RRR]: 1.98 [1.21-3.24]). Both men and women scored worse in psychological health than general health, particularly young women. Women were also more likely to view their safety (RRR: 1.87 [1.07-3.28]) and living place (RRR: 2.51 [1.10-5.73]) as being poor than their male counterparts. CONCLUSION: QOL in German prehospital emergency care physicians is satisfactory for the included participants; however, there were some negative effects in the psychological health domain. This is particularly obvious in young female emergency physicians.

Microbial keratitis in los angeles: the doheny eye institute and the los angeles county hospital experience.

OBJECTIVE: To evaluate the spectrum and antibiotic susceptibility panel of infectious keratitis at a major tertiary care referral eye center and a major county hospital in Southern California. DESIGN: Retrospective case series. PARTICIPANTS: All cultured infectious keratitis cases from July 1, 2008, through December 31, 2012, from the Doheny Eye Institute (DEI) and the Los Angeles County + University of Southern California Medical Center (LAC+USC) were evaluated. METHODS: Microbiology records were reviewed retrospectively. MAIN OUTCOME MEASURES: Microbial isolates as well as antibiotic susceptibility patterns were analyzed. RESULTS: One hundred eighty-four (63%) of 290 cases showed positive culture results at DEI and 152 (82%) of 186 cases showed positive culture results at LAC+USC. Gram-positive pathogens were found to be the most common at both DEI (70%) and LAC+USC (68%), with coagulase-negative Staphylococcus being the most common gram-positive organism (58% at DEI and 44% at LAC+USC). Pseudomonas aeruginosa was the most common gram-negative organism (57% at DEI and 43% at LAC+USC). Ciprofloxacin and levofloxacin susceptibility for all tested pathogens was 73% at DEI and 81% at LAC+USC (P = 0.16). Oxacillin-resistant Staphylococcus aureus (ORSA) was found in 42% of cases at DEI and in 45% of cases at LAC+USC (P = 1.00). CONCLUSIONS: There is no significant difference in the spectrum of pathogens or antibiotic susceptibility of pathogens at DEI versus LAC+USC, and ORSA was found in approximately half of all S. aureus samples.

Comparative microarray analysis of microRNA expression profiles in primary cutaneous malignant melanoma, cutaneous malignant melanoma metastases, and benign melanocytic nevi.

Perturbations in microRNA (miRNA) expression profiles have been reported for cutaneous malignant melanoma (CMM) predominantly when examined in cell lines. Despite the rapidly growing number of newly discovered human miRNA sequences, the availability of up-to-date miRNA expression profiles for clinical samples of primary cutaneous malignant melanoma (PCMM), cutaneous malignant melanoma metastases (CMMM), and benign melanocytic nevi (BMN) is limited. Specimens excised from the center of tumors (lesional) from patients with PCMM (n=9), CMMM (n=4), or BMN (n=8) were obtained during surgery. An exploratory microarray analysis was performed by miRNA expression profiling based on Agilent platform screening for 1205 human miRNAs. The results from the microarray analysis were validated by TaqMan quantitative real-time polymerase chain reaction. In addition to several miRNAs previously known to be associated with CMM, 19 unidentified miRNA candidates were found to be dysregulated in CMM patient samples. Among the 19 novel miRNA candidates, the genes hsa-miR-22, hsa-miR-130b, hsa-miR-146b-5p, hsa-miR-223, hsa-miR-301a, hsa-miR-484, hsa-miR-663, hsa-miR-720, hsa-miR-1260, hsa-miR-1274a, hsa-miR-1274b, hsa-miR-3663-3p, hsa-miR-4281, and hsa-miR-4286 were upregulated, and the genes hsa-miR-24-1*, hsa-miR-26a, hsa-miR-4291, hsa-miR-4317, and hsa-miR-4324 were downregulated. The results of this study partially confirm previous CMM miRNA profiling studies identifying miRNAs that are dysregulated in CMM. However, we report several novel miRNA candidates in CMM tumors; these miRNA sequences require further validation and functional analysis to evaluate whether they play a role in the pathogenesis of CMM.

Haloperidol-induced changes in neuronal activity in the striatum of the freely moving rat.

The striatum is the main input structure of the basal ganglia, integrating input from the cerebral cortex and the thalamus, which is modulated by midbrain dopaminergic input. Dopamine modulators, including agonists and antagonists, are widely used to relieve motor and psychiatric symptoms in a variety of pathological conditions. Haloperidol, a dopamine D2 antagonist, is commonly used in multiple psychiatric conditions and motor abnormalities. This article reports the effects of haloperidol on the activity of three major striatal subpopulations: medium spiny neurons (MSNs), fast spiking interneurons (FSIs), and tonically active neurons (TANs). We implanted multi-wire electrode arrays in the rat dorsal striatum and recorded the activity of multiple single units in freely moving animals before and after systemic haloperidol injection. Haloperidol decreased the firing rate of FSIs and MSNs while increasing their tendency to fire in an oscillatory manner in the high voltage spindle (HVS) frequency range of 7-9 Hz. Haloperidol led to an increased firing rate of TANs but did not affect their non-oscillatory firing pattern and their typical correlated firing activity. Our results suggest that dopamine plays a key role in tuning both single unit activity and the interactions within and between different subpopulations in the striatum in a differential manner. These findings highlight the heterogeneous striatal effects of tonic dopamine regulation via D2 receptors which potentially enable the treatment of diverse pathological states associated with basal ganglia dysfunction.

MicroRNA in non-melanoma skin cancer.

MicroRNAs (miRNAs) are a fairly novel class of 17- to 23-nucleotide (nt), short, non-coding RNA molecules that have revolutionized our understanding of gene regulation and opened new possibilities in the future of gene therapy. Here, we review the potential role of miRNAs in non-melanoma skin cancer (NMSC) and summarize the current studies available in this new aspect of NMSC research.

Microarray analysis of microRNA expression in cutaneous squamous cell carcinoma.

BACKGROUND: MicroRNAs (miRNAs) are a novel class of short RNAs that are capable epigenetically regulating gene expression in eukaryotes. MicroRNAs have been shown to be dysregulated in a variety of cancers. The data on miRNA expression in cutaneous squamous cell carcinoma (cSCC) are very limited, and microarray-based miRNA expression profiles of cSCC have not yet been determined. OBJECTIVE: To describe differentially expressed miRNAs in cSCC. METHODS: Seven patients with cSCC were enrolled in the present study. Tumor biopsies (n=7) were taken from the center of each tumor. Adjacent healthy skin (n=7) was biopsied as a control (intraindividual control). miRNA expression profiles of all specimens were detected by microarray miRNA expression profiling based on miRBAse 16 scanning for 1205 potential human miRNA target sequences. The microarray results were confirmed by TaqMan quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: Non-stringent filtering with a non-adjusted p ≤ 0.05 revealed thirteen up-regulated and eighteen down-regulated miRNAs. Non-stringent filtering with a non-adjusted p ≤ 0.01 revealed three up-regulated (hsa-miR-135b, hsa-miR-424 and hsa-miR-766) and six down-regulated (hsa-miR-30a*, hsa-miR-378, hsa-miR-145, hsa-miR-140-3p, hsa-miR-30a and hsa-miR-26a) miRNAs in cSCC. CONCLUSION: This study reveals differentially expressed miRNAs that may play a role in the molecular pathogenesis of cSCC and that are excellent candidates for further validation and functional analysis.

The miRNA machinery in primary cutaneous malignant melanoma, cutaneous malignant melanoma metastases and benign melanocytic nevi.

Although several studies have shown a dysregulation of microRNA (miRNA) expression profiles in cutaneous melanoma, there has been little research on the miRNA machinery itself. In this study, we investigated the mRNA expression profiles of different miRNA machinery components in primary cutaneous malignant melanoma (PCMM), cutaneous malignant melanoma metastases (CMMM) and benign melanocytic nevi (BMN). Patients with PCMM (n = 7), CMMM (n = 6) and BMN (n = 7) were included in the study. Punch biopsies were harvested from the centers of tumors (lesional) and from BMN (control). In contrast to previous reports exploring specific clusters of miRNAs in PCMM, the present study investigates mRNA expression levels of Dicer, Drosha, Exp5, DGCR8 and the RISC components PACT, argonaute-1, argonaute-2, TARBP1, TARBP2, MTDH and SND1, which were detected by TaqMan real-time reverse transcription polymerase chain reaction (RT-PCR). Argonaute-1, TARBP2 and SND1 expression levels were significantly higher in BMN compared to PCMM (p < 0.05). TARBP2 expression levels were significantly higher in CMMM compared to PCMM (p < 0.05). SND1 expression levels were significantly higher in CMMM compared to PCMM and BMN (p < 0.05). Dicer, Drosha, DGCR8, Exp5, argonaute-2, PACT, TARBP1 and MTDH expression levels showed no significant differences within groups (p > 0.05). The results of this study show that the miRNA machinery components argonaute-1, TARBP2 and SND1 are dysregulated in PCMM and CMMM compared to BMN and may play a role in the process of malignant transformation.

Medical emergencies on board commercial airlines: is documentation as expected?

INTRODUCTION: The purpose of this study was to perform a descriptive, content-based analysis on the different forms of documentation for in-flight medical emergencies that are currently provided in the emergency medical kits on board commercial airlines. METHODS: Passenger airlines in the World Airline Directory were contacted between March and May 2011. For each participating airline, sample in-flight medical emergency documentation forms were obtained. All items in the sample documentation forms were subjected to a descriptive analysis and compared to a sample "medical incident report" form published by the International Air Transport Association (IATA). RESULTS: A total of 1,318 airlines were contacted. Ten airlines agreed to participate in the study and provided a copy of their documentation forms. A descriptive analysis revealed a total of 199 different items, which were summarized into five sub-categories: non-medical data (63), signs and symptoms (68), diagnosis (26), treatment (22) and outcome (20). CONCLUSIONS: The data in this study illustrate a large variation in the documentation of in-flight medical emergencies by different airlines. A higher degree of standardization is preferable to increase the data quality in epidemiologic aeromedical research in the future.