A child's proficiency in oral language is largely dependent on the child's experience and exposure to language during their first few years of life [
1]. Pre-lingual sensorineural hearing loss (SNHL) limits this exposure resulting in a significant lag in the mastery of language in its spoken form compared to normal hearing peers [
2]. Cochlear implantation (CI) enables a deaf child access to sound and audition [
3], and over half of children identified with early SNHL currently receive a CI [
4].
Traditionally clinicians have assessed outcomes after CI by measuring speech perception, discrimination [
5], and communicative capacity, utilizing speech and language metrics such as the Early Speech Perception Test [
6] and the Reynell Developmental Language Scales [
7]. However, such measures may incompletely capture a child's communicative abilities in a normal listening environment, where background noise and non-ideal listening conditions predominate [
8]. The World Health Organization's International Classification of Functioning (ICF) distinguishes between communicative
capacity, an individual's ability to communicate in a standardized environment (e.g. clinic setting), and communicative
performance, an individual's ability to communicate in real-world environments [
9]. Measuring communicative performance after cochlear implantation is complicated further by the young age of CI recipients with many undergoing implantation before one year of age. This has created a demand for a validated assessment tool which fully captures speech development in these pre-verbal children [
10].
A number of novel measures have been developed to better capture speech perception and language skills in this pediatric population. These measures rely on either direct measurement of the child's performance (visual-habitual procedures in the presence of speech competitors [
1]), or more commonly by proxy assessment. Two of the most frequently used parent-proxy instruments include the Infant-Toddler Meaningful Auditory Integration Scale (ITMAIS) and the Little Ears Auditory Questionnaire. The IT-MAIS consists of 10 items probing a child's response to sounds in the everyday environment, and parents respond on a five level scale [
11]. The well-validated Little Ears Auditory Questionnaire also surveys the auditory behaviors of children up to 24 months with 35 binary items that are based on parental report [
10]. In contrast to these instruments focused on the early auditory behaviors of infants and toddlers <24 months, the Functioning after Pediatric Cochlear Implantation instrument (FAPCI) assesses the communicative abilities of children > 24 months and was designed to supplement these other instruments [
12].
The FAPCI instrument is a psychometrically-validated scale that was designed from the ground up to assess the communicative performance of 2-5 year-old CI children based on the conceptual framework of the World Health Organization's International Classification of Functioning [
9]. The instrument consists of 23 items () with each item having a five-level response scale (range of possible total scores: 23 to 115). The measure queries a young child's everyday expressive and receptive communicative behaviors as reported by the parent or primary caregiver. The FAPCI instrument was developed through a rigorous three phase process [
12]. Phase I consisted of qualitative instrument development consisting of domain/item identification and instrument pretesting. This was achieved through discussion and interviewing experts working with CI children, parents of CI recipients, and a review of the current literature. Phase II and III consisted of quantitative instrument validation and refinement using psychometric analysis where excellent reliability was demonstrated (Cronbach's α≥0.86) [
12]. The FAPCI instrument has been translated into German [
13] and Korean [
14] and is currently being used in ongoing NIH and industry-sponsored studies of CI outcomes in young pediatric populations.
In the current study we developed a framework for the interpretation of FAPCI scores by developing preliminary growth curves of FAPCI scores in normal hearing (NH) children. We then compared trajectories of FAPCI scores among a cohort of CI children to these normal hearing growth curves.