The neurobiology of human crying

Exploring Immune Cell Diversity in the Lacrimal Glands of Healthy Mice: A Single-Cell RNA-Sequencing Atlas

The lacrimal gland is responsible for maintaining the health of the ocular surface through the production of tears. However, our understanding of the immune system within the lacrimal gland is currently limited. Therefore, in this study, we utilized single-cell RNA sequencing and bioinformatic analysis to identify and analyze immune cells and molecules present in the lacrimal glands of normal mice. A total of 34,891 cells were obtained from the lacrimal glands of mice and classified into 18 distinct cell clusters using Seurat clustering. Within these cell populations, 26 different immune cell subpopulations were identified, including T cells, innate lymphocytes, macrophages, mast cells, dendritic cells, and B cells. Network analysis revealed complex cell-cell interactions between these immune cells, with particularly significant interactions observed among T cells, macrophages, plasma cells, and dendritic cells. Interestingly, T cells were found to be the main source of ligands for the Thy1 signaling pathway, while M2 macrophages were identified as the primary target of this pathway. Moreover, some of these immune cells were validated using immunohistological techniques. Collectively, these findings highlight the abundance and interactions of immune cells and provide valuable insights into the complexity of the lacrimal gland immune system and its relevance to associated diseases.

Multi-modal analysis of infant cry types characterization: Acoustics, body language and brain signals

BACKGROUND

Infant crying is the first attempt babies use to communicate during their initial months of life. A misunderstanding of the cry message can compromise infant care and future neurodevelopmental process.

METHODS

An exploratory study collecting multimodal data (i.e., crying, electroencephalography (EEG), near-infrared spectroscopy (NIRS), facial expressions, and body movements) from 38 healthy full-term newborns was conducted. Cry types were defined based on different conditions (i.e., hunger, sleepiness, fussiness, need to burp, and distress). Statistical analysis, Machine Learning (ML), and Deep Learning (DL) techniques were used to identify relevant features for cry type classification and to evaluate a robust DL algorithm named Acoustic MultiStage Interpreter (AMSI).

RESULTS

Significant differences were found across cry types based on acoustics, EEG, NIRS, facial expressions, and body movements. Acoustics and body language were identified as the most relevant ML features to support the cause of crying. The DL AMSI algorithm achieved an accuracy rate of 92%.

CONCLUSIONS

This study set a precedent for cry analysis research by highlighting the complexity of newborn cry expression and strengthening the potential use of infant cry analysis as an objective, reliable, accessible, and non-invasive tool for cry interpretation, improving the infant-parent relationship and ensuring family well-being.

Ictal crying in epileptic seizures and psychogenic nonepileptic seizures: What are the hints to differentiate them?

OBJECTIVES

Ictal crying (IC) is a quite rare semiological manifestation of epileptic seizures (ESs) and it has been mostly reported in psychogenic nonepileptic seizures (PNESs). However, labeling IC as a pathognomonic sign of PNES can be harmful. We first aimed to investigate IC frequency in ES and PNES and highlight the differences of IC between ES and PNES. Secondly, we aimed to analyze etiology, detailed semiology, treatment options, and outcome of patients with IC in ES in more detail.

METHODS

We retrospectively screened all video-EEG monitoring unit reports from Hacettepe University Hospitals' Epilepsy Center over a 20-year period (1996-2017) for the diagnosis of IC. We included the patients with IC who had at least one documented seizure. Patients who had IC with both facial expression and vocalization compatible with crying with or without weeping and subjective feeling of sadness, were included in the study. We classified patients with IC as ES and PNES. Demographic, historical, clinical, neuroimaging, electrophysiological parameters, video-EEG data, treatment options, and prognosis of all patients were recorded. Demographic, clinical, and video-EEG data were compared between ES and PNES.

RESULTS

During the study period, 1983 patients were investigated. Six patients (all female) with ES and 37 patients (33 female) with PNES were identified. When we compared patients with PNES and ES with IC, the number of ASMs taken and duration of disease were significantly higher in patients with ES than PNES. Longer duration of seizure, longer duration of crying component, late onset of crying component in seizure, early responsiveness after seizure, not occurring during sleep, accompanied by eye closure and weeping, were found significantly higher in patients with PNES. Besides, if we analyze ES group in more detail, all had medical treatment refractory focal epilepsy and two of them whose IC was seen as an early semiological manifestation of their seizures had good outcome after nondominant anterior temporal lobectomy (ATL)+amygdalohippocampectomy (AH). However, three patients had various cortical lesions apart from temporal lobe on MRI and one patient had focal epilepsy with frontal lobe semiology with negative MRI.

CONCLUSION

Although the most common etiology for IC is PNES and it is rarely seen in ES, it can be harmful to label ictal crying as a pathognomonic sign for PNES. We proposed that there are some semiological differences in terms of IC between PNES and ES. These differences may help to distinguish IC in PNES and ES in daily practice. Moreover, it can be speculated that nondominant temporal lobe involvement may be associated with IC in ES.

How can cry acoustics associate newborns' distress levels with neurophysiological and behavioral signals?

Introduction

Even though infant crying is a common phenomenon in humans' early life, it is still a challenge for researchers to properly understand it as a reflection of complex neurophysiological functions. Our study aims to determine the association between neonatal cry acoustics with neurophysiological signals and behavioral features according to different cry distress levels of newborns.

Methods

Multimodal data from 25 healthy term newborns were collected simultaneously recording infant cry vocalizations, electroencephalography (EEG), near-infrared spectroscopy (NIRS) and videos of facial expressions and body movements. Statistical analysis was conducted on this dataset to identify correlations among variables during three different infant conditions (i.e., resting, cry, and distress). A Deep Learning (DL) algorithm was used to objectively and automatically evaluate the level of cry distress in infants.

Results

We found correlations between most of the features extracted from the signals depending on the infant's arousal state, among them: fundamental frequency (F0), brain activity (delta, theta, and alpha frequency bands), cerebral and body oxygenation, heart rate, facial tension, and body rigidity. Additionally, these associations reinforce that what is occurring at an acoustic level can be characterized by behavioral and neurophysiological patterns. Finally, the DL audio model developed was able to classify the different levels of distress achieving 93% accuracy.

Conclusion

Our findings strengthen the potential of crying as a biomarker evidencing the physical, emotional and health status of the infant becoming a crucial tool for caregivers and clinicians.

Mechanisms of Extraorbital Lacrimal Gland Aging in Mice: An Integrative Analysis of the Temporal Transcriptome

Purpose

This study used high-throughput RNA sequencing (RNA-Seq) and bioinformatics analysis to investigate the altered transcriptome profile of aging lacrimal glands in mice that occurs over the course of a 24-hour cycle.

Methods

Male C57BL/6J mice aged 12 weeks (young) and 20 months (aging) were housed in a pathogen-free setting with a 12-hour light/12-hour dark cycle. Throughout a 24-hour cycle, mouse extraorbital lacrimal glands (ELGs) were collected at eight time points at three-hour intervals. To prepare for the high-throughput RNA-Seq, whole mRNA was extracted. Differentially expressed genes (DEGs) in the young and aging groups were subjected to bioinformatic analysis based on diurnal patterns. Furthermore, the cell populations in which significant DEGs express and signaling pathways occur were validated at the single-cell RNA sequencing (scRNA-seq) level.

Results

The total transcriptome composition was significantly altered in aging ELGs compared with that in young mouse ELGs at eight time points during the 24-hour cycle, with 864 upregulated and 228 downregulated DEGs, which were primarily enriched in inflammatory pathways. Further comparative analysis of the point-to-point transcriptome revealed that aging ELGs underwent alterations in the temporal transcriptome profile in several pathways, including the inflammation-related, metabolism-related, mitochondrial bioenergetic function-associated, synaptome neural activity-associated, cell processes-associated, DNA processing-associated and fibrosis-associated pathways. Most of these pathways occurred separately in distinct cell populations.

Conclusions

Transcriptome profiles of aging lacrimal glands undergo considerable diurnal time-dependent changes; this finding offers a comprehensive source of information to better understand the pathophysiology of lacrimal gland aging and its underlying mechanisms.

Non-targeted Metabolomics Analysis Reveals Distinct Metabolic Profiles Between Positive and Negative Emotional Tears of Humans: A Preliminary Study

Background Basal, reflex, and emotional tears differ in chemical components. It is not yet known whether chemical differences exist in tears of different emotions. We investigated the biochemical basis of emotional tears by performing non-targeted metabolomics analyses of positive and negative emotional tears of humans. Methods Samples of reflex, negative, and positive emotional tears were obtained from 12 healthy college participants (11 females and one male). Untargeted metabolomics was performed to identify metabolites in different types of tears. The differentially altered metabolites were screened and assessed using univariate and multivariate analyses. Results The orthogonal partial least squares discriminant analysis model showed that reflex, negative, and positive emotional tears were clearly separated. A total of 133 significantly differentially expressed metabolites of electrospray ionization source (ESI-) mode were identified between negative and positive emotional tears. The top 50 differentially expressed metabolites between negative and positive emotional tears were highly correlated. Pathway analysis revealed that secretion of negative emotional tears was associated with some synapses in the brain, regulation of a series of endocrine hormones, including the estrogen signaling pathway, and inflammation activities, while secretion of positive emotional tears was correlated with biotin and caffeine metabolism. Conclusions It is indicated that metabolic profiles of reflex, positive, and negative emotional tears of humans are distinct, and secretion of the tears involves distinct biological activities. Therefore, we present a chemical method for detecting human emotions, which may become a powerful tool for the diagnosis of mental diseases and the identification of fake tears.

Decoding brain basis of laughter and crying in natural scenes

Laughter and crying are universal signals of prosociality and distress, respectively. Here we investigated the functional brain basis of perceiving laughter and crying using naturalistic functional magnetic resonance imaging (fMRI) approach. We measured haemodynamic brain activity evoked by laughter and crying in three experiments with 100 subjects in each. The subjects i) viewed a 20-minute medley of short video clips, and ii) 30 minutes of a full-length feature film, and iii) listened to 15 minutes of a radio play that all contained bursts of laughter and crying. Intensity of laughing and crying in the videos and radio play was annotated by independent observes, and the resulting time series were used to predict hemodynamic activity to laughter and crying episodes. Multivariate pattern analysis (MVPA) was used to test for regional selectivity in laughter and crying evoked activations. Laughter induced widespread activity in ventral visual cortex and superior and middle temporal and motor cortices. Crying activated thalamus, cingulate cortex along the anterior-posterior axis, insula and orbitofrontal cortex. Both laughter and crying could be decoded accurately (66-77% depending on the experiment) from the BOLD signal, and the voxels contributing most significantly to classification were in superior temporal cortex. These results suggest that perceiving laughter and crying engage distinct neural networks, whose activity suppresses each other to manage appropriate behavioral responses to others' bonding and distress signals.

Eyes don't lie: Eye movements differ during covert and overt autobiographical recall

In everyday life, autobiographical memories are revisited silently (i.e., covert recall) or shared with others (i.e., overt recall), yet most research regarding eye movements and autobiographical recall has focused on overt recall. With that in mind, the aim of the current study was to evaluate eye movements during the retrieval of autobiographical memories (with a focus on emotion), recollected during covert and overt recall. Forty-three participants recalled personal memories out loud and silently, while wearing eye-tracking glasses, and rated these memories in terms of mental imagery and emotional intensity. Analyses showed fewer and longer fixations, fewer and shorter saccades, and fewer blinks during covert recall compared with overt recall. Participants perceived more mental images and had a more intense emotional experience during covert recall. These results are discussed considering cognitive load theories and the various functions of autobiographical recall. We theorize that fewer and longer fixations during covert recall may be due to more intense mental imagery. This study enriches the field of research on eye movements and autobiographical memory by addressing how we retrieve memories silently, a common activity of everyday life. More broadly, our results contribute to building objective tools to measure autobiographical memory, alongside already existing subjective scales.

Excessive Crying, Behavior Problems, and Amygdala Volume: A Study From Infancy to Adolescence

OBJECTIVE

Excessive crying in infancy has been associated with increased risk of later behavioral problems. To identify individuals at risk for behavioral problems and to understand the mechanisms underlying excessive crying and irritability in infancy, research into the neurobiology of excessive crying is needed. We examined whether excessive crying and irritability in infancy are associated with behavioral problems and amygdala volume among children and adolescents.

METHOD

This study included 4,751 singleton children from the prospective population-based Generation R Study cohort, born in the Netherlands in 2002 to 2006. Excessive crying (>3 hours on at least 1 day/wk) and irritability (Mother and Baby Scales questionnaire) were parent-rated at 3 months. Amygdala volume was measured at 10 years using magnetic resonance imaging, and internalizing and externalizing were parent-rated at 1.5, 3, 6, 10, and 14 years and self-rated at 14 years. Covariates included child age, sex, national origin, gestational age, and maternal age, psychopathology score, parity, education, relationship status, and family income.

RESULTS

Children who cried excessively in infancy had higher parent-rated internalizing (effect estimate = 0.20 SD-units, 95% CI = 0.14, 0.27) and externalizing (0.17 SD-units, 95% CI = 0.10, 0.24) throughout childhood (linear mixed models), and smaller amygdala volume at 10 years (-0.19 SD-units, 95% CI = -0.32, -0.06) (linear regression model). The pattern of associations for both behavioral problems and amygdala volume was similar for irritability.

CONCLUSION

Excessive crying and irritability in infancy may reflect an early vulnerability to behavioral problems and may be linked with neurobiological differences in the development of the amygdala.

Neurostimulation for dry eye disease

PURPOSE OF REVIEW

To review the neuroanatomy and physiology of the basal and reflex tearing and present the available and developing therapies using the concept of neurostimulation in dry eye disease (DED).

RECENT FINDINGS

The most prevalent current DED treatments seek to supplement low tear volume and tear components or reduce inflammation. Neurostimulation is a unique approach gaining momentum in recent years, geared toward increasing the production of all basal tear components by stimulating the nerves responsible for producing the various tear components. The neuroanatomy of the lacrimal unit provides several possible access points to stimulate tear production through two arms of the sensory trigeminal nerves. Modes of stimulation include chemical or energy in electrical or magnetic form. Research thus far has shown that neurostimulation can achieve lacrimal, goblet cell, and meibomian gland stimulation. Subjectively it improves symptoms of DED. Clinically, neurostimulation has improved the signs and symptoms of DED by increasing basal tear production and tear volume.

SUMMARY

Neurostimulation using electrical, mechanical, or chemical means is a novel concept to increase tear production and was demonstrated to be an effective, safe, and well-tolerated method for managing DED.

Reading Your Emotions in My Physiology? Reliable Emotion Interpretations in Absence of a Robust Physiological Resonance

Affective states are expressed in an individual’s physical appearance, ranging from facial expressions and body postures, to indicators of physiological arousal (e.g., a blush). Confirming the claimed communicative function of these markers, humans are capable of distinguishing between a variety of discrete emotion displays. In an attempt to explain the underlying mechanism, characteristic bodily changes within the observer, including physiological arousal and mimicry, have been suggested to facilitate the interpretation of an expression. The current study aims to create a holistic picture of emotion perception by (1) using three different sources of emotional information (prototypical facial expressions, bodily expressions, and subtle facial cues) and (2) measuring changes in multiple physiological signals (facial electromyography, skin conductance level, skin temperature, and pupil size). While participants clearly discriminated between perceived emotional expressions, there was no overall 1–1 correspondence with their physiological responses. Some specific but robust effects were observed. Angry facial expressions were consistently responded to with a peak in skin conductance level. Furthermore, sad body expressions were associated with a drop in skin temperature. In addition to being the best recognized expression, viewing happy faces elicited congruent facial muscle responses, which supports the potential role of embodied simulation in emotion recognition. Lastly, tears were not only rated as highly emotional intense but also evoked a peak in skin conductance level in the observer. The absence of distinct physiological responses to other expressions could be explained by the lacking functionality of affect sharing in a non-interactive experimental context. Consequentially, emotional alignment in body and mind might especially take place in real social situations, which should be considered in future research.

Emotional authenticity modulates affective and social trait inferences from voices

The human voice is a primary tool for verbal and nonverbal communication. Studies on laughter emphasize a distinction between spontaneous laughter, which reflects a genuinely felt emotion, and volitional laughter, associated with more intentional communicative acts. Listeners can reliably differentiate the two. It remains unclear, however, if they can detect authenticity in other vocalizations, and whether authenticity determines the affective and social impressions that we form about others. Here, 137 participants listened to laughs and cries that could be spontaneous or volitional and rated them on authenticity, valence, arousal, trustworthiness and dominance. Bayesian mixed models indicated that listeners detect authenticity similarly well in laughter and crying. Speakers were also perceived to be more trustworthy, and in a higher arousal state, when their laughs and cries were spontaneous. Moreover, spontaneous laughs were evaluated as more positive than volitional ones, and we found that the same acoustic features predicted perceived authenticity and trustworthiness in laughter: high pitch, spectral variability and less voicing. For crying, associations between acoustic features and ratings were less reliable. These findings indicate that emotional authenticity shapes affective and social trait inferences from voices, and that the ability to detect authenticity in vocalizations is not limited to laughter. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part I)'.

Pathological laughter and crying: insights from lesion network-symptom-mapping

The study of pathological laughter and crying (PLC) allows insights into the neural basis of laughter and crying, two hallmarks of human nature. PLC is defined by brief, intense and frequent episodes of uncontrollable laughter or crying provoked by trivial stimuli. It occurs secondary to CNS disorders such as stroke, tumours or neurodegenerative diseases. Based on case studies reporting various lesions locations, PLC has been conceptualized as dysfunction in a cortico-limbic-subcortico-thalamo-ponto-cerebellar network. To test whether the heterogeneous lesion locations are indeed linked in a common network, we applied 'lesion network-symptom-mapping' (LNSM) to 70 focal lesions identified in a systematic literature search for case reports of PLC. In LNSM normative connectome data (resting state functional MRI, n = 100) is used to identify the brain regions which are likely affected by diaschisis based on the lesion locations. With LNSM we were able to identify a common network specific for PLC when compared with a control cohort (n = 270). This bilateral network is characterized by positive connectivity to the cingulate and temporomesial cortices, striatum, hypothalamus, mesencephalon and pons and negative connectivity to the primary motor and sensory cortices. In the most influential pathophysiological model of PLC, a center for the control and coordination of facial expressions, respiration and vocalization in the periaqueductal grey is assumed which is controlled via two pathways: an emotional system that exerts excitatory control of the periaqueductal grey descending from the temporal and frontal lobes, basal ganglia and hypothalamus and a volitional system descending from the lateral premotor cortices which can suppress laughter or crying. To test whether the positive and negative PLC subnetworks identified in our analyses can indeed be related to an emotional system and a volitional system, we identified lesions causing emotional (n = 15) or volitional facial paresis (n = 46) in a second literature search. Patients with emotional facial paresis show preserved volitional movements but cannot trigger emotional movements in the affected hemiface, while the reverse is true for volitional facial paresis. Importantly, these lesions map differentially onto the PLC subnetworks: the 'positive PLC subnetwork' is part of the emotional system and the 'negative PLC subnetwork' overlaps with the volitional system for the control of facial movements. Based on this network analysis we propose a two-hit model of PLC: a combination of direct lesion and indirect diaschisis effects cause PLC through the loss of inhibitory cortical control of a dysfunctional emotional system.

Emotion context insensitivity in depression: Toward an integrated and contextualized approach

Major depressive disorder (MDD) is characterized by pervasive mood disturbance as well as deficits in emotional processing, reactivity, and regulation. There is accumulating evidence that MDD is characterized by emotional patterns consistent with environmental disengagement, as reflected in attenuated positive and negative emotional reactivity, consistent with Emotion Context Insensitivity (ECI) theory. However, MDD individuals vary considerably in the extent to which they exhibit specific alterations in patterns of emotional responding. Emotions are complex, multicomponent processes that invoke responses across multiple functional domains and levels of analysis, including subjective experience, behavior, autonomic regulation, cognition, and neural processing. In this article, I review the current state of the literature on emotional responding and MDD from the lens of ECI. I focus on the importance of assessing emotional indices from multiple levels of analysis across development and contexts. I also discuss methodological and measurement issues that may contribute to inconsistent findings. In particular, I emphasize how psychophysiological measures can help elucidate emotional processes that underlie the pathophysiology of MDD as part of an integrated and contextualized approach.

Crying with depressed affect induced by electrical stimulation of the anterior insula: A stereo EEG case study

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Anterior insular stimulation produces reproducible episodes of emotional crying.

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This is due to activation of complex neural network with its connectivity to the anterior cingulate cortex.

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This study increases our understanding of the complex functionality of the insula.

Stereo-EEG (sEEG) is an invasive recording technique used to localize the seizure-onset zone for epilepsy surgery in people with drug-resistant focal seizures. Pathological crying reflects disordered emotional expression and the anterior insula is known to play a role in empathy and socio-emotional processing. We describe a patient where electrical stimulation mapping (ESM) of the anterior insula during sEEG generated pathological crying and profound sadness that was time-locked to the electrical stimulus.

We evaluated a 35-year-old left-handed female for repeat epilepsy surgery. The patient had drug resistant focal impaired awareness seizures despite a previous left temporal neocortical resection informed by an invasive study using subdural grid and strip electrodes seven years earlier. She was studied invasively with 10 sEEG electrodes sampling temporal, occipital, and insular targets. In the process of functional mapping, stimulation of the anterior insular cortex provoked tearful crying with sad affect, reproducible upon repeat stimulation.

Our case is unique in demonstrating transitory pathological crying with profound sadness provoked by ESM of the left anterior insula. Furthermore we demonstrate repeated time-synched crying from electrical stimulation, which supports the hypothesis that the anterior insula in the brain plays an important role in the biology of emotion, as implicated by previous studies.

Being emotionally moved is associated with phasic physiological calming during tonic physiological arousal from pleasant tears

The experience of being emotionally "moved" is considered a valuable emotional experience. Although pleasant chills (goosebumps and shivers) and tears (weeping and a lump in the throat) are commonly associated with the experience of being emotionally moved, no previous studies have examined which of these psychophysiological responses is the most intrinsic to the phenomenon of being moved. We conducted two music listening experiments to examine this question. Both experiments revealed that, when chills and tears were reliably separated, chills evoked phasic increases in electrodermal activity, whereas tears induced phasic decreases in heart and respiration rate during tonic physiological arousal. Importantly, whereas tears predicted the experience of being moved, experiencing chills did not. Furthermore, psychoacoustic features of music did not explain the physiological response of chills and tears. The results demonstrated that the experience of being moved involved a sense of pleasure coupled with psychophysiological relief from tension. Based on extended attachment theory, the sequential process of physiological arousal to physiological calming, which is derived from abstract life-guiding ideas via the combination of sound and lyrics, may be important for evoking the experience of being emotionally moved. These psychophysiological characteristics could explain why people seek to be moved.

Crying Therapy Intervention for Breast Cancer Survivors: Development and Effects

BACKGROUND

crying therapy is currently being applied in some countries to treat cancer patients, manage pain, and promote mental health. However, little nursing and medical research on the effects of crying therapy has been conducted in other parts of the world. This study aimed to develop a crying therapy program for breast cancer survivors and assess its effects. Interventions/method: data from 27 breast cancer survivors in South Korea were analyzed. The intervention, employing a single group, pre-post-test quasi-experimental design, was divided into three phases, and effects were verified for emotional (distress, fatigue, and mood conditions) and physiological (cortisol, immunoglobulin G, and blood pressure) variables.

RESULTS

there were significant changes in distress, mood changes, and immunoglobulin G and smaller changes in blood pressure postintervention. Fatigue and cortisol showed no significant changes.

CONCLUSIONS

this study demonstrated the effectiveness of a short-term crying therapy program that can induce positive emotional changes and physiological effects in breast cancer survivors. This intervention can improve quality of life, indicating its value as a self-care program for cancer survivors.

Tear Metabolomics in Dry Eye Disease: A Review

Dry eye disease (DED) is a multifactorial syndrome that can be caused by alteration in the quality or quantity of the precorneal tear film. It is considered one of the most common ocular conditions leading patients to seek eye care. The current method for diagnostic evaluations and follow-up examinations of DED is a combination of clinical signs and symptoms determined by clinical tests and questionnaires, respectively. The application of powerful omics technologies has opened new avenues toward analysis of subjects in health and disease. Metabolomics is a new emerging and complementary research discipline to all modern omics in the comprehensive analysis of biological systems. The identification of distinct metabolites and integrated metabolic profiles in patients can potentially inform clinicians at an early stage or during monitoring of disease progression, enhancing diagnosis, prognosis, and the choice of therapy. In ophthalmology, metabolomics has gained considerable attention over the past decade but very limited such studies have been reported on DED. This paper aims to review the application of tear metabolomics in DED.

Can Gender and Age Impact on Response Pattern of Depressive Symptoms Among College Students? A Differential Item Functioning Analysis

Background: Self-reported depressive complaints among college students might indicate different degrees of severity of depressive states. Through the framework of item response theory, we aim to describe the pattern of responses to items of the Beck Depression Inventory-II (BDI-II), in terms of endorsement probability and discrimination along the continuum of depression. Potential differential item functioning of the scale items of the BDI-II is investigated, by gender and age, to compare across sub-groups of students. Methods: The 21-item BDI-II was cross-sectionally administered to a representative sample of 12,677 Brazilian college students. Reliability was evaluated based on Cronbach's alpha coefficient. Severity (b _i ) and discrimination (a) parameters of each BDI-II items were calculated through the graded response model. The influence of gender and age were tested for differential item functioning (DIF) within the item response theory-based approach. Results: The BDI-II presented good reliability (α = 0.91). Women and younger students significantly presented a higher likelihood of depression (cut-off > 13) than men and older counterparts. In general, participants endorsed more easily cognitive-somatic items than affective items of the scale. "Guilty feelings," "suicidal thoughts," and "loss of interest in sex" were the items that most likely indicated depression severity (b ≥ 3.60). However, all BDI-II items showed moderate-to-high discrimination (a ≥ 1.32) for depressive state. While two items were flagged for DIF, "crying" and "loss of interest in sex," respectively for gender and age, the global weight of these items on the total score was negligible. Conclusions: Although respondents' gender and age might present influence on response pattern of depressive symptoms, the measures of self-reported symptoms have not inflated severity scores. These findings provide further support to the validity of using BDI-II for assessing depression in academic contexts and highlight the value of considering gender- and age-related common symptoms of depression.