Accuracy of Artificial Intelligence-Based Technologies for the Diagnosis of Atrial Fibrillation: A Systematic Review and Meta-Analysis.

Atrial fibrillation (AF) is the most common arrhythmia with a high burden of morbidity including impaired quality of life and increased risk of thromboembolism. Early detection and management of AF could prevent thromboembolic events. Artificial intelligence (AI)--based methods in healthcare are developing quickly and can be proved as valuable for the detection of atrial fibrillation. In this metanalysis, we aim to review the diagnostic accuracy of AI-based methods for the diagnosis of atrial fibrillation. A predetermined search strategy was applied on four databases, the PubMed on 31 August 2022, the Google Scholar and Cochrane Library on 3 September 2022, and the Embase on 15 October 2022. The identified studies were screened by two independent investigators. Studies assessing the diagnostic accuracy of AI-based devices for the detection of AF in adults against a gold standard were selected. Qualitative and quantitative synthesis to calculate the pooled sensitivity and specificity was performed, and the QUADAS-2 tool was used for the risk of bias and applicability assessment. We screened 14,770 studies, from which 31 were eligible and included. All were diagnostic accuracy studies with case-control or cohort design. The main technologies used were: (a) photoplethysmography (PPG) with pooled sensitivity 95.1% and specificity 96.2%, and (b) single-lead ECG with pooled sensitivity 92.3% and specificity 96.2%. In the PPG group, 0% to 43.2% of the tracings could not be classified using the AI algorithm as AF or not, and in the single-lead ECG group, this figure fluctuated between 0% and 38%. Our analysis showed that AI-based methods for the diagnosis of atrial fibrillation have high sensitivity and specificity for the detection of AF. Further studies should examine whether utilization of these methods could improve clinical outcomes.

Does refining the phenotype improve replication rates? A review and replication of candidate gene studies on Major Depressive Disorder and Chronic Major Depressive Disorder.

Replication has been poor for previously reported candidate genes involved in Major Depressive Disorder (MDD). One possible reason is phenotypic and genetic heterogeneity. The present study replicated genetic associations with MDD as defined in DSM-IV and with a more narrowly defined MDD subtype with a chronic and severe course. We first conducted a systematic review of genetic association studies on MDD published between September 2007 and June 2012 to identify all reported candidate genes. Genetic associations were then tested for all identified single nucleotide polymorphisms (SNPs) and the entire genes using data from the GAIN genome-wide association study (MDD: n = 1,352; chronic MDD subsample: n = 225; controls: n = 1,649). The 1,000 Genomes database was used as reference for imputation. From 157 studies identified inthe literature, 81 studies reported significant associations with MDD, involving 245 polymorphisms in 97 candidate genes, from which we were able to investigate 185 SNPs in 89 genes. We replicated nine candidate SNPs in eight genes for MDD and six in five genes for chronic MDD. However, these were not more than expected by chance. At gene level, we replicated 18 genes for MDD and 17 genes for chronic MDD, both significantly more than expected by chance. We showed that replication rates were improved for MDD compared to a previous, highly similar, replication study based on studies published before 2007. Effect sizes of the SNPs and replication rates of the candidate genes were improved in the chronic subsample compared to the full sample. Nonetheless, replication rates were still poor.

Temporal dynamics of physical activity and affect in depressed and nondepressed individuals.

OBJECTIVE: The association between physical activity and affect found in longitudinal observational studies is generally small to moderate. It is unknown how this association generalizes to individuals. The aim of the present study was to investigate interindividual differences in the bidirectional dynamic relationship between physical activity and affect, in depressed and nondepressed individuals, using time-series analysis. METHOD: A pair-matched sample of 10 depressed and 10 nondepressed participants (mean age = 36.6, SD = 8.9, 30% males) wore accelerometers and completed electronic questionnaires 3 times a day for 30 days. Physical activity was operationalized as the total energy expenditure (EE) per day segment (i.e., 6 hr). The multivariate time series (T = 90) of every individual were analyzed using vector autoregressive modeling (VAR), with the aim to assess direct as well as lagged (i.e., over 1 day) effects of EE on positive and negative affect, and vice versa. RESULTS: Large interindividual differences in the strength, direction and temporal aspects of the relationship between physical activity and positive and negative affect were observed. An exception was the direct (but not the lagged) effect of physical activity on positive affect, which was positive in nearly all individuals. CONCLUSION: This study showed that the association between physical activity and affect varied considerably across individuals. Thus, while at the group level the effect of physical activity on affect may be small, in some individuals the effect may be clinically relevant.

Relative Age Effects in Dutch Adolescents: Concurrent and Prospective Analyses.

The literature on relative age position effects is rather inconsistent. In this study we examined intra-classroom age position (or relative age) effects on Dutch adolescents' school progress and performance (as rated by teachers), physical development, temperamental development (fear and frustration), and depressive symptoms, all adjusted for age at the time of measurement. Data were derived from three waves of Tracking Adolescents' Individuals Lives Survey (TRAILS) of 2230 Dutch adolescents (baseline mean age 11.1, SD = 0.6, 51% girls). Albeit relative age predicted school progress (grade retention ORs = 0.83 for each month, skipped grade OR = 1.47, both p<.001), our key observation is the absence of substantial developmental differences as a result of relative age position in Dutch adolescents with a normative school trajectory, in contrast to most literature. For adolescents who had repeated a grade inverse relative age effects were observed, in terms of physical development and school performance, as well as on depressive symptoms, favoring the relatively young. Cross-cultural differences in relative age effect may be partly explained by the decision threshold for grade retention.

Bidirectional prospective associations between physical activity and depressive symptoms. The TRAILS Study.

PURPOSE: Low levels of physical activity (PA) have been shown to be associated with depression in adults. The few studies that focused on adolescents yielded mixed and inconsistent results. Efforts to examine the direction of this relationship have been inconclusive up to now. The aims of this study were therefore to investigate (1) the direction of the inverse association between PA and depressive symptoms over time, and (2) whether these associations are specific to particular clusters of depressive symptoms in adolescents. METHODS: Depressive symptoms and PA were assessed in a population sample of adolescents (N = 2,230) who were measured at three waves between age 10 and age 17. Depressive symptoms were measured by the Affective Problems scale of the Youth Self-Report and Child Behavior Checklist, whereas PA was operationalized as the amount of time spent on physical exercise. Structural equation modeling was used to examine bidirectional effects of PA and depressive symptoms over time. RESULTS: We found significant cross-lagged paths from prior PA to later depression as well as from prior depression to later PA (beta values = -.039 to -.047). After subdividing depression into affective and somatic symptoms, the affective symptoms were reciprocally related to PA, whereas the paths between somatic symptoms and PA did not reach statistical significance. CONCLUSIONS: An inverse bidirectional association between PA and general depressive symptoms was observed. This association was restricted to affective symptoms.

Human 5-HT transporter availability predicts amygdala reactivity in vivo.

The amygdala plays a central role in fear conditioning, emotional processing, and memory modulation. A postulated key component of the neurochemical regulation of amygdala function is the neurotransmitter 5-hydroxytryptamine (5-HT), and synaptic levels of 5-HT in the amygdala and elsewhere are critically regulated by the 5-HT transporter (5-HTT). The aim of this study was to directly examine the relationship between 5-HTT availability and amygdala activity using multimodal [positron emission tomography (PET) and functional magnetic resonance imaging (fMRI)] imaging measures in the same individuals. Healthy male volunteers who had previously undergone an [11C]-3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile ([11C]-DASB) PET scan to determine 5-HTT availability completed an fMRI emotion recognition task. [11C]-DASB binding potential values were calculated for the amygdala using arterial input function and linear graphical (Logan) analysis. fMRI was performed on a 3T Philips Intera scanner, and data were analyzed using SPM2 (Wellcome Department Imaging Neuroscience, University College London). Percentage signal change during the task was extracted from the amygdala using MarsBaR (Brett et al., 2002). fMRI analysis revealed significant amygdala activation during the emotion recognition task. Region of interest analyses demonstrated a significant negative correlation between fMRI signal change in the left amygdala and 5-HTT availability in the left amygdala, with 5-HTT availability accounting for approximately 42% of the variability in left amygdala activity. Our novel in vivo data highlight the central importance of the serotonergic system in the responsiveness of the human amygdala during emotional processing.