Depression and fatigue six months post-COVID-19 disease are associated with overlapping symptom constellations: A prospective, multi-center, population-based cohort study

BACKGROUND

Depression and fatigue are commonly observed sequelae following viral diseases such as COVID-19. Identifying symptom constellations that differentially classify post-COVID depression and fatigue may be helpful to individualize treatment strategies. Here, we investigated whether self-reported post-COVID depression and post-COVID fatigue are associated with the same or different symptom constellations.

METHODS

To address this question, we used data from COVIDOM, a population-based cohort study conducted as part of the NAPKON-POP platform. Data were collected in three different German regions (Kiel, Berlin, Würzburg). We analyzed data from >2000 individuals at least six months past a PCR-confirmed COVID-19 disease, using elastic net regression and cluster analysis. The regression model was developed in the Kiel data set, and externally validated using data sets from Berlin and Würzburg.

RESULTS

Our results revealed that post-COVID depression and fatigue are associated with overlapping symptom constellations consisting of difficulties with daily activities, perceived health-related quality of life, chronic exhaustion, unrestful sleep, and impaired concentration. Confirming the overlap in symptom constellations, a follow-up cluster analysis could categorize individuals as scoring high or low on depression and fatigue but could not differentiate between both dimensions.

LIMITATIONS

The data presented are cross-sectional, consisting primarily of self-reported questionnaire or medical records rather than biometric data.

CONCLUSIONS

In summary, our results suggest a strong link between post-COVID depression and fatigue, highlighting the need for integrative treatment approaches.

Eye did this! Sense of agency in eye movements

This study investigates the sense of agency (SoA) for saccades with implicit and explicit agency measures. In two eye tracking experiments, participants moved their eyes towards on-screen stimuli that subsequently changed color. Participants then either reproduced the temporal interval between saccade and color-change (Experiment 1) or reported the time points of these events with an auditory Libet clock (Experiment 2) to measure temporal binding effects as implicit indices of SoA. Participants were either made to believe to exert control over the color change or not (agency manipulation). Explicit ratings indicated that the manipulation of causal beliefs and hence agency was successful. However, temporal binding was only evident for caused effects, and only when a sufficiently sensitive procedure was used (auditory Libet clock). This suggests a feebler connection between temporal binding and SoA than previously proposed. The results also provide evidence for a relatively fast acquisition of sense of agency for previously never experienced types of action-effect associations. This indicates that the underlying processes of action control may be rooted in more intricate and adaptable cognitive models than previously thought. Oculomotor SoA as addressed in the present study presumably represents an important cognitive foundation of gaze-based social interaction (social sense of agency) or gaze-based human-machine interaction scenarios. PUBLIC SIGNIFICANCE STATEMENT: In this study, sense of agency for eye movements in the non-social domain is investigated in detail, using both explicit and implicit measures. Therefore, it offers novel and specific insights into comprehending sense of agency concerning effects induced by eye movements, as well as broader insights into agency pertaining to entirely newly acquired types of action-effect associations. Oculomotor sense of agency presumably represents an important cognitive foundation of gaze-based social interaction (social agency) or gaze-based human-machine interaction scenarios. Due to peculiarities of the oculomotor domain such as the varying degree of volitional control, eye movements could provide new information regarding more general theories of sense of agency in future research.

Preparing for simultaneous action and inaction: Temporal dynamics and target levels of inhibitory control

When a single action is required, along with the simultaneous inhibition of another action, this typically results in frequent false-positive executions of the latter (inhibition failures). The absence of inhibitory demands in dual-action trials can render performance less error-prone (and sometimes faster) than in single-action trials. In the present study, we investigated the temporal dynamics of inhibitory control difficulties by varying the preparation time (for simultaneous action execution and inhibition). In two experiments, participants responded to a single peripheral visual target either with an eye movement toward it (Single Saccade), with a spatially corresponding button press (Single Manual), or with both responses simultaneously (Dual Action) as indicated by a color cue. Preparation time was manipulated via the cue-stimulus interval within blocks (Experiment 1) and between blocks (Experiment 2). Overall, responses were faster with longer (vs. shorter) preparation time. Crucially, however, our results reveal the exact dynamics of how inhibition failures (and thus dual-action benefits) in both response modalities substantially decrease with longer preparation, even though the cue did not contain information regarding the fully specified response that needed to be inhibited (i.e., its direction). These results highlight the role of sufficient preparation time not only for efficient action execution but also for concurrent inhibitory performance. The study contradicts the idea that inhibition can only be exerted globally or on the level of a fully specified response. Instead, it may also be directed at effector system representations or all associated responses, suggesting a highly flexible targeting of inhibitory control in cognition. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Intentional binding: Merely a procedural confound?

Sense of agency (SoA) is the feeling of having control over one's actions and their outcomes. Previous research claimed that SoA is reflected in "intentional binding" effects, that is, the subjective compression of time between a voluntary action and an intended outcome. Conventional paradigms, however, typically lack an isolated manipulation of different degrees of agency (or intentionality), as the presence or absence of actions (along with subsequent perceptual changes) represents a potential confound variable. Using a newly developed paradigm, we were able to replicate typical "intentional binding" results in an initial experiment in which such a confound was deliberately included. We then eliminated this confound in a follow-up experiment by keeping the presence of actions and perceptual changes constant between conditions with and without agency while only manipulating subjective SoA. Here, explicit ratings showed that participants indeed felt responsible for effects in the Agency condition but not in the Baseline condition (demonstrating the successful manipulation of SoA), while we no longer found any differences in "intentional binding" effects between conditions. This indicates that previously reported relations between intentional binding and SoA could be merely based on procedural confounds. In particular, temporal compression effects usually interpreted in terms of "intentional binding" may rather result from more basic temporal grouping mechanisms for any (perceptual and/or motor) events that are perceived as meaningfully belonging together (e.g., as parts of a trial episode). (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Dual-action benefits: global (action-inherent) and local (transient) sources of action prepotency underlying inhibition failures in multiple action control

Previous research has shown that the simultaneous execution of two actions (instead of only one) is not necessarily more difficult but can actually be easier (less error-prone), in particular when executing one action requires the simultaneous inhibition of another action. Corresponding inhibitory demands are particularly challenging when the to-be-inhibited action is highly prepotent (i.e., characterized by a strong urge to be executed). Here, we study a range of important potential sources of such prepotency. Building on a previously established paradigm to elicit dual-action benefits, participants responded to stimuli with single actions (either manual button press or saccade) or dual actions (button press and saccade). Crucially, we compared blocks in which these response demands were randomly intermixed (mixed blocks) with pure blocks involving only one type of response demand. The results highlight the impact of global (action-inherent) sources of action prepotency, as reflected in more pronounced inhibitory failures in saccade vs. manual control, but also more local (transient) sources of influence, as reflected in a greater probability of inhibition failures following trials that required the to-be-inhibited type of action. In addition, sequential analyses revealed that inhibitory control (including its failure) is exerted at the level of response modality representations, not at the level of fully specified response representations. In sum, the study highlights important preconditions and mechanisms underlying the observation of dual-action benefits.