Referral criteria for preschool hearing screening in resource-constrained settings : a comparison of protocols

Abstract

PURPOSE : This study aimed to describe and compare the performance of two screening protocols used for preschool hearing screening in resource-constrained settings. METHOD : Secondary data analysis was done to determine the performance of two protocols implemented during a preschool hearing screening program using mobile health technology in South Africa. Pure-tone audiometry screening at 25 dB HL for 1000, 2000, and 4000 Hz in each ear was used by both protocols. The fail criterion for the first protocol (2,147 children screened) constituted a no-response on one or more frequencies in either ear. The second protocol required two or more no-responses (5,782 children). Multivariate logistic regression models were used to investigate associations between outcomes and protocol, age, gender, and duration. RESULTS : Fail rates for the one-frequency fail protocol was 8.7% (n = 186) and 4.3% (n = 250) for the two-frequency fail protocol. Children screened with the two-frequency fail protocol were 52.9% less likely to fail (p < .001; OR = 0.471; 95% confidence interval [0.385, 0.575]). Gender (p = .251) and age (p = .570) had no significant effect on screening outcome. A percentage of cases screened (44.7%) exceeded permissible noise levels in at least one ear at 1000 Hz across both protocols. True- and false-positive cases did not differ significantly between protocols. Protocol type (p = .204), gender (p = .314), and age (p = .982) did not affect the odds of being a true-positive result. Average screening time was 72.8 s (78.66 SD) and 64.9 s (55.78 SD) for the onefrequency and two-frequency fail protocols, respectively. CONCLUSIONS : A two-frequency fail criterion and immediate rescreen of failed frequencies significantly reduced referral rate for follow-up services that are often overburdened in resourced-constrained settings. Future protocol adaptations can also consider increasing the screening levels at 1000 Hz to minimize the influence of environmental noise.