Attrition Rate in Infant fNIRS Research: A Meta-Analysis

Abstract

Understanding the trends and predictors of attrition rate, or the proportion of collected data that is excluded from the final analyses, is important for accurate research planning, assessing data integrity, and ensuring generalizability. In this pre-registered meta-analysis, we reviewed 182 publications in infant (0-24 months) functional near-infrared spectroscopy (fNIRS) research published from 1998 to April 9, 2020 and investigated the trends and predictors of attrition. The average attrition rate was 34.23% among 272 experiments across all 182 publications. Among a subset of 136 experiments which reported the specific reasons of subject exclusion, 21.50% of the attrition were infant-driven while 14.21% were signal-driven. Subject characteristics (e.g., age) and study design (e.g., fNIRS cap configuration, block/trial design, and stimulus type) predicted the total and subject-driven attrition rates, suggesting that modifying the recruitment pool or the study design can meaningfully reduce the attrition rate in infant fNIRS research. Based on the findings, we established guidelines on reporting the attrition rate for scientific transparency and made recommendations to minimize the attrition rates. We also launched an attrition rate calculator (LINK) to aid with research planning. This research can facilitate developmental cognitive neuroscientists in their quest toward increasingly rigorous and representative research.

Longitudinal assessments of functional near-infrared spectroscopy background functional connectivity in low- and middle-income infants during a social cognition task.

“…Of those infants, 64 infants at 6 months and 57 infants at 24 months were excluded as a result of not completing the NIRS experiment (n6 = 4, n24 = 2), not attending to the screen for at least 50% of the task (n6 = 31, n24 = 12), poor cap placement (n6 =, 9, n24 = 3), less than 2/3 valid channels (n6 = 5, n24 = 3), less than 3 trials (n6 = 5, n24 = 2), less than 90 s of data (n6 = 4, n24 = 2), or not having any behavioural coding (n6 = 6, n24 = 33). The attrition rates for both ages is consistent with the average attrition rate reported in infant fNIRS research (34%; see metaanalysis by Baek et al, 2021).…”

Predictive brain signals mediate association between shared reading and expressive vocabulary in infants

“…In the current study, the attrition rate is 43.9% (18 out of 41 infants’ collected data was excluded due to excessive movement or failure to watch a sufficient number of trials). Although this rate compares well with the average attrition rate of 34.2% reported in a recent meta-analysis with 272 experiments across 182 publications in infants aged under 24 months [ 54 ], future studies should attempt to modify the study design to reduce the attrition rate and increase generalizability. We would also note that the final sample consisted of relatively high SES families which may limit the generalizability of the current findings.…”

“…Firstly, given the demands of all neuroimaging methods (EEG, fNIRS, fMRI), subject attrition is typically as high as 50%. Although fNIRS is non-invasive and increases infants’ task compliance compared to other neuroimaging techniques that also measures cortical hemodynamic responses such as fMRI [ 52 , 53 ], a substantial proportion of collected data were excluded from final analyses due to a range of reasons such as infants’ shorter attention span [ 54 ]. In the current study, the attrition rate is 43.9% (18 out of 41 infants’ collected data was excluded due to excessive movement or failure to watch a sufficient number of trials).…”

Frontal asymmetry assessed in infancy using functional near‐infrared spectroscopy is associated with emotional and behavioral problems in early childhood

“…Seventy-three additional children participated in both the infant and 5-year testing sessions but were excluded from the present analyses because (a) they refused to wear the fNIRS cap (n = 18), (b) their cap deviated beyond 1.5 cm from the correct placement (n = 16), (c) equipment failed (n = 6), (d) they failed to reach our pre-determined looking criterion (n = 11), or (e) channels in areas of interest did not pass quality thresholds applied during pre-processing (n = 22). This rejection criterion and attrition rate are similar to those in other infant fNIRS studies (Baek et al, 2021;Bayet et al, 2021;Farris et al, 2022;Filippetti et al, 2014;Kelsey et al, 2019Kelsey et al, , 2021Lloyd-Fox et al, 2015). As displayed in Table 1, the final analytic sample was predominately Non-Hispanic White, and parents were highly educated.…”