Digital biomarkers in depression: A systematic review and call for standardization and harmonization of feature engineering.

BACKGROUND: General physicians misclassify depression in more than half of the cases. Researchers have explored the feasibility of leveraging passively collected data points, also called digital biomarkers, to provide more granular understanding of depression phenotypes as well as a more objective assessment of disease. METHOD: This paper provides a systematic review following the PRISMA guidelines (Page et al., 2021) to understand which digital biomarkers might be relevant for passive screening of depression. Pubmed and PsycInfo were systematically searched for studies published from 2019 to early 2024, resulting in 161 records assessed for eligibility. Excluded were intervention studies, studies focusing on a different disease or those with a lack of passive data collection. 74 studies remained for a quality assessment, after which 27 studies were included. RESULTS: The review shows that depressed participants' real-life behavior such as reduced communication with others can be tracked by passive data. Machine learning models for the classification of depression have shown accuracies up to 0.98, surpassing the quality of many standardized assessment methods. LIMITATIONS: Inconsistency of outcome reporting of current studies does not allow for drawing statistical conclusions regarding effectiveness of individual included features. The Covid-19 pandemic might have impacted the ongoing studies between 2020 and 2022. CONCLUSION: While digital biomarkers allow real-life tracking of participant's behavior and symptoms, further work is required to align the feature engineering of digital biomarkers. With shown high accuracies of assessments, connecting digital biomarkers with clinical practice can be a promising method of detecting symptoms of depression automatically.

A retrospective study on the prevalence of primary cataracts in two pedigrees from the German population of English Cocker Spaniels.

OBJECTIVE: Two pedigrees from the German English Cocker Spaniel population are presented to illustrate the familial occurrence of primary cataract (CAT) in single- and multicolored English Cocker Spaniels. The aim was to characterize similarities and differences in the prevalence and formation of CAT in these separately bred color variants of English Cocker Spaniels. MATERIALS: The study was based on the veterinary records for presumed inherited eye diseases of 1232 English Cocker Spaniels which were provided by the German panel of the European Eye Scheme for diagnosis of inherited eye diseases in animals (DOK, ). Data included information on 615 single-colored and 617 multicolored English Cocker Spaniels. RESULTS: CAT was diagnosed in 92 (14.96%) of the single-colored and 34 (5.51%) of the multicolored English Cocker Spaniels. The pedigree of the single-colored English Cocker Spaniels included 40 ophthalmologically examined dogs with 18 unaffected and 22 affected dogs. The pedigree of the multicolored English Cocker Spaniels contained 16 ophthalmologically examined dogs with 11 unaffected and five affected dogs. CONCLUSIONS: In both color variants of the English Cocker Spaniels different forms of primary CAT with respect to location within the lens occurred among close relatives. Appearance of CAT was very heterogeneous without obvious sex differences. The sample pedigrees do not support the assumption of familial segregation of specific forms of primary CAT in English Cocker Spaniels.

Analysis of systematic and genetic effects on the prevalence of primary cataract, persistent pupillary membrane and distichiasis in the two color variants of English Cocker Spaniels in Germany.

Genetic parameters were estimated for prevalences of primary cataract (CAT), persistent pupillary membrane (PPM) and distichiasis (DIST) in 615 single-colored and 617 multi-colored English Cocker Spaniels (ECS) bred in the German kennel club for Spaniels (Jagdspaniel-Klub e.V.). CAT or CAT diagnosed in dogs up to three and a half years of age (early-onset cataract, CAT-early) and CAT diagnosed in dogs over three and a half years of age (late-onset cataract, CAT-late), PPM and DIST were included as binary traits in multivariate genetic analyses. Heritabilities on the underlying liability scale were 0.15 for CAT, 0.34 for CAT-early, 0.13 for CAT-late, 0.46 for PPM, and 0.62 for DIST in single-colored ECS and 0.06 for CAT, 0.13 for CAT-early, 0.14 for CAT-late, 0.10 for PPM, and 0.61 for DIST in multi-colored ECS. There were indications for a different genetic basis of CAT-early and CAT-late in single-colored ECS as genetic correlations were close to zero. In multi-colored ECS, a similar tendency for CAT-early and CAT-late could be observed.