Longitudinal Evaluation of Auditory and Speech Performance in Pediatric Cochlear Implant Recipients Using IT-MAIS, MESP, CAP, and SIR Scales

Summary

Here, we present a longitudinal protocol for evaluating auditory and speech development in pediatric cochlear implant recipients using IT-MAIS, CAP, MESP, and SIR scales, providing a standardized framework for monitoring rehabilitation outcomes and guiding individualized auditory-verbal therapy.

Abstract

Considerable variability in auditory and speech outcomes among pediatric cochlear implant (CI) recipients has raised ongoing debate regarding whether early auditory perception directly determines later speech intelligibility, particularly in tonal language environments where pitch cues are critical for communication. This longitudinal study evaluated 64 prelingually deaf children aged 1–5 years over 12 months following unilateral implantation, integrating four standardized behavioral scales—the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS), Categories of Auditory Performance (CAP), Monosyllabic-Trochee-Polysyllabic Word Test (MESP), and Speech Intelligibility Rating (SIR)—together with cortical auditory evoked potentials (CAEP). All measures demonstrated significant time-dependent improvement (p < 0.001): IT-MAIS and CAP increased rapidly within 3 months post-activation, followed by progressive gains in MESP and SIR reflecting enhanced speech perception and intelligibility. Multiple regression analysis showed that CAP at 3 months was significantly associated with SIR outcomes at 12 months (β = 0.201, p = 0.010), explaining 26.6% of the variance, supporting a hierarchical relationship between early auditory comprehension and later expressive language development. Furthermore, P1 latency shortening on CAEP correlated with higher SIR scores (r = 0.275, p = 0.028), supporting cortical plasticity as a neural mechanism underlying behavioral recovery. No significant between-group differences were observed for most auditory and speech perception measures. However, SIR scores at 12 months were modestly higher in children with normal cochlear anatomy. Overall developmental trajectories remained comparable between groups, suggesting that functional auditory experience plays a major role in rehabilitation outcomes. These findings provide longitudinal behavioral and electrophysiological evidence suggesting that early auditory integration is associated with later speech production outcomes. The proposed multimodal framework offers a reproducible, evidence-based approach for monitoring auditory–speech trajectories and guiding individualized rehabilitation in pediatric CI users.

Introduction

Cochlear implantation (CI) has emerged as the most effective intervention for children with severe to profound sensorineural hearing loss, restoring access to sound and providing a foundation for speech and language development¹. Early auditory stimulation through CI promotes not only the perception of environmental sounds but also the formation of neural connections essential for speech comprehension, cognitive growth, and social communication². The rapid expansion of pediatric implantation programs worldwide has enabled many deaf children to achieve near-normal auditory and linguistic milestones³

Protocol

Ethics statement
All procedures involving human participants were conducted in compliance with institutional and national research guidelines and in accordance with the Declaration of Helsinki. This study was approved by the Institutional Review Board of Hunan Provincial Children's Hospital under approval number KYSQ2023-312 and conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants' parents or legal guardians prior to enrollment. All methods were performed in compliance with institutional guidelines for human research ethics, and all data were anonymized before analysis.

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Results

Participant characteristics
A total of 64 prelingually deaf children completed the 12-month follow-up after cochlear implantation, including 32 with inner-ear malformations and 32 with normal cochlear anatomy. Sex (male/female) and implant side (left/right) were evenly distributed between groups (χ² = 0.00, p = 1.00 for both). The mean age at activation was comparable between the malformation and normal groups (3.27 ±± 0.94 vs. 3.32 ±± 0.92 years; t = -0.269, p = 0.789). Detailed baseline .......

Discussion

This longitudinal study characterized auditory and speech development in pediatric cochlear implant recipients using four complementary behavioral scales: IT-MAIS, CAP, MESP, and SIR. The results demonstrate a non-linear recovery trajectory, with rapid early improvements after activation followed by gradual stabilization. Improvements across behavioral domains occurred in a sequential pattern, in which early auditory awareness (IT-MAIS) preceded environmental sound comprehension (CAP), followed by phonological discrimina.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Absorbable suture (Vicryl 4-0)	Ethicon (Johnson & Johnson)	VICRYL-4-0-V392H	Layered soft-tissue closure; absorbable braided polyglactin 910.
Adobe Illustrator	Adobe Inc. (USA)	2023 (v27.5.1)	Final figure assembly and labeling per journal requirements.
Alcohol swabs (70% IPA)	BD (Becton, Dickinson and Company)	ALC-70%-SWAB	Skin cleaning before electrode placement and after removal.
Calibrated sound level meter (Type 2250)	Brüel & Kjær (Denmark)	2250-SLM	Field calibration of sound-field output for behavioral testing.
CAP (Categories of Auditory Performance)	Cochlear Ltd. / Nottingham group	Publication year: 2001; Revised: 2004	Hierarchical auditory performance scale; clinician-rated; used at 1, 3, 6, 12 months.
Chlorhexidine gluconate 0.5% (skin prep)	Shanghai Likang (China)	CHG-0.5%-SKINPREP	Preoperative skin antisepsis of operative site; applied per institutional protocol.
Clinical audiometer (AC40)	Interacoustics (Denmark)	AC40	Pure-tone audiometry and warble tones in sound field; ANSI S3.6 compliant.
Cochlear implant internal device (HiRes Ultra 3D)	Advanced Bionics (USA)	HiRes-Ultra-3D	Internal CI receiver–stimulator and electrode array implanted in all participants.
Conductive electrode gel/paste	Parker Laboratories (USA)	Tensive 15-25	Reduces electrode–skin impedance during electrophysiology recording.
CT scanner (Somatom Definition AS)	Siemens Healthineers (Germany)	Somatom-Def-AS	Temporal bone/inner-ear CT when clinically indicated for electrode visualization.
Disposable EEG electrodes (Ag/AgCl)	Ambu (Denmark)	BlueSensor N	Surface electrodes for CAEP/eABR acquisition; pediatric size; skin-prepped with CHG.
eABR/CAEP recording system (SmartEP)	Intelligent Hearing Systems, IHS (USA)	SmartEP v3.90	Electrophysiology platform for eABR and CAEP acquisition; pediatric settings.
Electrode cap (pediatric size)	EASYCAP (Germany)	E-32-PED	Optional cap for standardized scalp placements in CAEP acquisition.
Ethics approval ID	West China Hospital Ethics Committee	KYSQ2023-312	Approved human-subject protocol; informed consent obtained from legal guardians.
External speech processor (Naída CI Q90)	Advanced Bionics (USA)	Naida-CI-Q90	External processor paired with implanted device; programming per clinical map.
Free-field speaker system (FF-70)	Interacoustics (Denmark)	FF-70	Sound-field presentation of calibrated stimuli during CAP/MESP testing.
GraphPad Prism	GraphPad Software (USA)	Version 10.0	Scientific graphing; mean±SD error bars; export to PDF/TIFF for publication.
High-speed otologic drill system	Stryker (USA)	CORE-Drill-5400	Cortical mastoidectomy and posterior tympanotomy; compatible otology burs.
Impedance/tympanometry system (Titan)	Interacoustics (Denmark)	Titan	Middle-ear status evaluation (tympanometry/ART) pre- and post-implant.
Insert earphones (ER-3A)	Etymotic Research (USA)	ER-3A	Air-conduction stimuli delivery for electrophysiology and behavioral testing; calibrated.
IT-MAIS (Infant–Toddler Meaningful Auditory Integration Scale)	University of Nottingham (UK)	Publication year: 1998; Mandarin adaptation: 2008	Parent-reported auditory behavior; used at 1, 3, 6, 12 months; trained audiologists administered.
Lidocaine 1% (local anesthetic)	Sichuan Kelun Pharmaceutical (China)	LIDO-1%-10ML	Local infiltration at incision line before incision/closure; dose per pediatric anesthesia.
MATLAB	MathWorks (USA)	R2023a	Signal processing for CAEP waveform extraction and latency estimation.
Medical tape (hypoallergenic)	3M (USA)	Micropore 1530-1	Secures electrodes and cables during recording; pediatric skin-friendly.
MESP (Mandarin Early Speech Perception Test)	CAS Institute of Psychology (China)	Release year: 2008	Speech perception (closed-set) for pediatric CI users; tested at 3, 6, 12 months.
Micro-instruments set (otology)	Aesculap / B. Braun	OT-MICROSET	Standard middle ear/CI micro-instrument set (elevators, suction, picks).
MRI scanner (3.0 T, MAGNETOM Skyra)	Siemens Healthineers (Germany)	Skyra-3T	Preoperative inner-ear anatomy and postoperative surveillance; DTI when indicated.
Operating microscope (OPMI PENTERO)	ZEISS (Germany)	OPMI-PENTERO	Microsurgical visualization during mastoidectomy and facial recess approach.
Povidone–iodine 10% (skin prep)	Betadine / Mundipharma (Singapore)	PVP-I-10%-SKIN	Alternative/adjunct surgical antiseptic for skin and drapes; avoid middle ear contamination.
Python (matplotlib/numpy/scipy)	Python Software Foundation	Python 3.10; matplotlib 3.8; scipy 1.11	Custom plotting and statistics; reproducible figure generation (Figures 2–5).
R (tidyverse)	R Core Team	R 4.3.1; tidyverse 2.0	Sensitivity analyses and plotting; correlation heatmaps; reproducible scripts.
SIR (Speech Intelligibility Rating)	University College London (UK)	Publication year: 1997	Five-level global speech intelligibility scale; clinician-rated at 6 and 12 months.
Skin prep abrasive gel	Nuprep (Weaver and Company, USA)	10-30 g tubes	Preps skin to achieve <5 kΩ impedance for scalp recordings.
SPSS Statistics	IBM (USA)	Version 27.0	Primary statistical analysis (RM-ANOVA, t-tests, χ², regression); Windows 10 environment.
Sterile saline solution (0.9%, 500 mL)	Baxter Healthcare (USA)	SAL-0.9%-500ML	Irrigation of surgical field and electrode array; used during implantation and wound care.
Sterile surgical drapes & gowns	3M / Cardinal Health	STERI-DRAPE-PED	Maintains sterile field during CI surgery; pediatric size drapes and gowns.