'Longitudinal trajectory of cardiac and respiratory interoception in infants' (AsPredicted #107154)
Author(s) This pre-registration is currently anonymous to enable blind peer-review. It has 3 authors.
Pre-registered on 2022/09/16 - 12:23 AM (PT)
1) Have any data been collected for this study already? It's complicated. We have already collected some data but explain in Question 8 why readers may consider this a valid pre-registration nevertheless.
2) What's the main question being asked or hypothesis being tested in this study? We want to investigate the longitudinal trajectory of cardiac and respiratory interoceptive sensitivity from the ages of 9 to 18 months. We expect that individual differences in interoceptive sensitivity stay stable from 9 to 18-months.
3) Describe the key dependent variable(s) specifying how they will be measured. To measure cardiac interoceptive sensitivity we used the iBEAT task in which infants are presented with stimuli that pulsate either synchronously or asynchronously with their own heartbeat.
To measure respiratory interoceptive sensitivity we used the iBREATH task in which infants are presented with stimuli that expand or decrease either synchronously or asynchronously with their respiration.
In both iBEAT and iBREATH we used an Eyelink 1000plus to record looking times at 500Hz. For each trial we will extract looking times falling into the range of the animated figures. Further, in both tasks a trial was terminated, and the next trial started, if after the initial 5s no looking times were recorded for 2s. A task was terminated if 80 trials were reached, or if the infant either became fuzzy/tired, or no looking times to e xtend the task beyond 5s were recorded in 5 successive trials.
Following the approach outlined in Maister et al. (2017) we will compute iBEAT and iBREATH scores as absolute proportion of sync and async trials.
4) How many and which conditions will participants be assigned to? In a within participants design infants did both tasks in randomized order.
5) Specify exactly which analyses you will conduct to examine the main question/hypothesis. We will implement a Bayesian paired t-test in R for each cardiac and respiratory interoceptive sensitivity comparing the change in interoceptive sensitivity scores between the age groups of 9- and 18-months.
6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations. For iBEAT and iBREATH we will include infants who completed at least four trials in the main analysis. We will exclude trials with looking times of 0. Further, for both iBEAT and iBREATH we will exclude trials with artifacts in the physiological signals. In the iBEAT we will exclude trials in which the ECG built-in function (AdInstruments, FastResponseOutput) recognized at least 85% of the R-Peaks in a trial. In the iBREATHs we will exclude trials which have extended periods of artifacts, so that no respiration like signal is observable.
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 have tested 90 infants at 9 months of age as part of a larger project. Further, we have tested 54 infants again at 18 months of age. A subsample of these infants has done the iBEAT and/or iBREATH.
8) Anything else you would like to pre-register? (e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?) We have already collected all data for this project. Further, we have analyzed and preprocessed the data of the 9-month-old infants. However, we have not preprocessed or analyzed the data of the 18-month-old infants. A preregistration for the 9-month-old infants can be found here https://aspredicted.org/QP9_6FP.
We will conduct additional exploratory analysis in which we will take the direction of infants' visual preference into account. That is, we will investigate whether infants' preference for synchronous or asynchronous trials changes between the age groups.
