'Interoceptive processing in Inflammatory Bowel Diseases' (AsPredicted #35477)
Author(s) This pre-registration is currently anonymous to enable blind peer-review. It has 3 authors.
Pre-registered on 02/12/2020 01:53 AM (PT)
1) Have any data been collected for this study already? No, no data have been collected for this study yet.
2) What's the main question being asked or hypothesis being tested in this study? Q1: Do IBD patients and HC differ in their interoceptive accuracy, interoceptive sensibility, and interoceptive awareness?
H1.1: Since cardiac and gastric perception have been shown to be positively correlated, we expect the IBD group to exhibit higher scores in the Heartbeat tracking Task, indicating higher interoceptive accuracy compared to the HC group. Moreover, IBD patients are expected to show greater interoceptive sensibility, and interoceptive awareness than HCs.
H1.2: We expect alterations in interoceptive accuracy and interoceptive sensibility to be modulated by severity and type of ACE.
Q2: Do IBD patients evaluate emotional stimuli differently from HC?
H2.1: IBD patients will report higher levels of arousal and higher valence intensity of emotional stimuli compared to HCs. These differences between both groups are expected to be more pronounced for negative affective stimuli.
H2.2: Alterations in emotional processing in IBD are expected to be modulated by ACE, with ACE being linked to evaluation of higher intensity of the valence of the emotion and higher arousal.
Q3: Can alterations in emotional processing be predicted by interoceptive processes?
H3.1: In both groups, the evaluation of emotional stimuli will be predicted by the interoceptive accuracy with higher interoceptive accuracy being associated with higher arousal and valence ratings of emotional stimuli.
H3.2: We expect the relationship between interoceptive accuracy and emotional processing to be modulated by ACE.
Q4: Are cardiac signals in IBD patients changed compared to HC?
H4: We expect decreased heartbeat variability (HRV) in the IBD group compared with HCs.
3) Describe the key dependent variable(s) specifying how they will be measured. Interoceptive accuracy: Interoceptive accuracy (IA) is assessed using a well validated objective task-Heartbeat Tracking Task (HBT) (Schandry, 1981). Participants have to silently count their heartbeats without relying on external cues during five randomly presented time intervals. While completing the task, an electrocardiogram is recorded. Accuracy corresponds to the size of the difference between heartbeats measured with the ECG and the number of reported heartbeats averaged across the five time intervals, with higher scores corresponding to higher IA. We assess IA before and after a standardized physical challenge (10 squats). To control for effects of individuals’ knowledge about their heart rate and time estimation abilities, a time estimation task is performed. This consists of 2 trials, each including 5 randomly presented time intervals presented before and after the physical challenge. Participants are asked to estimate how many seconds passed by during each of the intervals.
Interoceptive Sensibility: We assess interoceptive sensibility using a self-report questionnaire (Multidimensional Assessment of Interoceptive Awareness, MAIA). MAIA is a 32-item state/trait questionnaire to measure multiple dimensions of interoception: Noticing, Not-Distracting, Not-Worrying, Attention Regulation, Emotional Awareness, Self-Regulation, Body Listening, and Trust.
Visceral Sensitivity: General visceral sensitivity is captured by the Visceral Sensitivity Index (VSI). The 15-item scale assesses gastrointestinal symptom-specific anxiety, including five dimensions of gastrointestinal-related cognitions and behaviors, i.e. worry, Fear, Vigilance, Sensitivity, and Avoidance.
ACE: Adverse childhood experiences are assessed using the German version of the Childhood Trauma Questionnaire (CTQ; Klinitzke et al., 2012). This 28-item questionnaire consists of five subscales: emotional abuse physical abuse, sexual abuse, emotional neglect, and physical neglect. Addtionally, the German version of Childhood Experience of Care and Abuse Questionnaire (CECA; Kaess et al., 2011) is assessed.
Emotional processing: emotional processing is measured with an emotion intensity rating task during which positive (N=30), negative (N=30), and neutral (N=30) visual stimuli are presented in pseudorandom order. Participants are asked to rate in two separate blocks the level of subjectively experienced arousal and valence when presented with the stimuli. Sequence of blocks is counterbalanced across participants. DV are the intensity of valence and arousal rated on an 8-point scale.
Physiological measures: Cardiac activity will be measured during the Emotional processing and HBT tasks with electrocardiogram (ECG) recordings according to standard procedures.
4) How many and which conditions will participants be assigned to? Every group will undergo the same experimental procedure. For further details of the experimental conditions of the different tasks see dependent variables.
5) Specify exactly which analyses you will conduct to examine the main question/hypothesis. Q1: A) Interoceptive awareness is defined as the metacognitive awareness of interoceptive accuracy. Thus, the correlation between objective performance on the HBT, estimated as an interoceptive accuracy score, and subject’s overall score on MAIA will be computed across all subjects within the IBD and HC groups separately. This will result in a correlational coefficient for each group. To investigate differences in interocepive awareness between IBD patients and HCs, these coefficients will be compared. Differences in interoceptive accuracy and interoceptive sensibility between the IBD group and the HC group will be analysed with t-tests for independent samples.
B) To investigate if ACE influence interoceptive processes in IBD, linear regression analyses with interoceptive accuracy and sensibility as dependent variables and CTQ/CECA scores as independent variables will be computed.
Q2: A) Differences in emotional processing between IBD and HCs will be analysed with repeated measures analyses of variance. Arousal and valence ratings will constitute the dependent variables in two separate ANOVAs. 2x3 rm-ANOVAs with a between-subject factor group (IBD/HC) and stimulus valence (positive/neutral/negative) for arousal and valence ratings will be computed.
B) To investigate whether severity and type of childhood traumatization do influence emotional processing in IBD, regression analyses will be calculated to predict arousal and valence ratings based on individual’s scores on CTQ and CECA.
Q3: A) To investigate whether higher interoceptive accuracy is linked to higher levels of valence and arousal during emotional stimuli presentation, linear regression analyses will be computed. Valence and arousal ratings will constitute the dependent variables, whereas interoceptive accuracy scores will be used as independent variable in these analyses.
B) To test if ACE modulates the association between interoceptive processes and emotional processing in IBD, a moderation analysis with CTQ/CECA score as moderating variable will be computed.
Q4: To identify possible differences in the HRV between both groups, RR intervals will be calculated. Then, power spectral density for the different frequency bands will be computed. The resulting parameters will be compared between IBD and HC groups using a t-test for independent samples.
6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations. Participants exhibiting scores ±2.5 SD from the mean will be excluded from the analyses.
7) How many observations will be collected or what will determine sample size? No need to justify decision, but be precise about exactly how the number will be determined. We are aiming to collect data of 120 participants, including IBD patients (N=60) and healthy participants (N=60).
8) Anything else you would like to pre-register? (e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?) To test if the implemented physical challenge has influenced individuals’ interoceptive accuracy, a repeated measures 2x2 rm-ANOVA with a between-subject factor group (IBD/HC) and within-subject factor time (pre/post) will be computed.
