In children aged 0 to 7 years, behavioral evaluation during cochlear implant programming is often difficult or unreliable. Objective, reproducible, and rapid markers are therefore essential. While objective measures such as ECAP (electrically evoked compound action potentials) help guide safe programming, they can show inter-electrode and inter-subject variability. Electrically evoked stapedius reflex threshold (eSRT) has emerged as a relevant objective marker to approximate the comfort level of stimulation. Pediatric studies indicate that eSRT can be measured in the majority of children, closely corresponds to the comfort level, and is associated with improved speech outcomes when programming is guided by eSRT. In our previous single-center study in children aged 8 to 17 years (N=30; 44 implanted ears), eSRT was obtained in 83.3% of patients, with strong correlation between C-subjective and C-eSRT thresholds (r\>0.94; p\<0.001) across all electrodes. Tonal performance remained stable, and speech intelligibility, particularly in noise (FraSiMat), significantly improved with an eSRT-based program after one month of habituation. Daily device use remained stable, reflecting good clinical acceptability. These results support the relevance of systematic integration of eSRT in routine programming. The aim of the eSRT2 study is to evaluate the feasibility and reliability of eSRT measurement in real-world clinical care for children aged 0 to 7 years, and to monitor its stability during post-operative follow-up. Improved auditory accessibility and better-controlled acoustic comfort through eSRT are expected to accelerate speech development in children by enabling earlier improvements in vocal performance and intelligibility.
Cochlear implant programming relies on determining the patient's auditory dynamic range. This corresponds to identifying, for each electrode, the threshold of first perception (T-level) and the most comfortable level of stimulation (C-level or MCL), which defines the functional stimulation range. Different implant manufacturers (Advanced Bionics, Cochlear, Med-El, Oticon Medical) provide specific recommendations for estimating these upper stimulation levels. Programming can be performed using behavioral measures or objective measures. Behavioral methods, based on patient responses, are widely used in adults. In children and in patients with associated pathologies, behavioral measures are often difficult due to limited auditory experience and potential confusion between loudness and pitch perception. Therefore, objective measures are recommended in pediatric populations to assist in programming. ECAP/EAP measures are commonly used but show variable performance depending on the measure and implant manufacturer Another objective measure, the electrically evoked stapedius reflex threshold (eSRT), shows a strong relationship with comfort levels (C-level/MCL) in both adults and children. eSRT appears to be a relevant tool for guiding programming, especially when subjective measures are limited. Recent studies have optimized the protocol (probe frequencies, reproducibility criteria) and confirmed its feasibility , including in pediatric populations using high-frequency probes (Palani et al., 2022) and normative data in children (Aini, 2022). Combined approaches using ECAP and eSRT to estimate C-levels/MCL are also emerging in pediatric programming . Functionally, better estimation of the comfort level improves auditory accessibility, which is associated with enhanced speech perception and vocal performance. Over the long term, this supports faster language development in children implanted early. Our previous eSRT study in children over 8 years old demonstrated a strong correlation between C-subjective and C-eSRT thresholds, and improved speech intelligibility (particularly in noise, FraSiMat) with eSRT-guided maps. These findings support the integration of eSRT into routine programming for pediatric populations.
Study Type
OBSERVATIONAL
Enrollment
48
During routine post-operative programming sessions (at 3, 6, and 12 months), each child will undergo eSRT measurement using a tympanometer placed in the ear canal
Hôpital Necker Enfants Malades - Service d'ORL et chirurgie cervico-faciale
Paris, Île-de-France Region, France
To study the stability of eSRT over time at 3, 6, and 12 months: quantifying intra-subject / intra-ear stability of eSRT thresholds throughout follow-up
Success (per session) is defined as obtaining at least 3 usable eSRT measurements distributed across apex, middle, and base (≥1 electrode per third of the array), with a normal tympanogram and meeting the reproducibility criterion (≤5 machine units \[MU\] variation between two attempts on the same electrode).
Time frame: 3, 6, and 12 months post-implantation
To study the stability of eSRT over time at 3, 6, and 12 months: quantifying intra-subject/intra-ear stability of eSRT thresholds throughout follow-up
The variability of eSRT values must be \< 5 machine units (MU) between each pair of visits (3↔6, 6↔12, and 3↔12 months).
Time frame: 3, 6, and 12 months post-implantation
To study the correlation between CeSRT and free-field tonal thresholds; association with speech performance (pediatric lists: Boorsmaa <4 years; Lafon ≥4 years - adjusted to the child's abilities; at the audiologist's discretion)
Correlation between CeSRT and free-field tonal thresholds will be evaluated. Associations with speech performance will be assessed using pediatric lists: Boorsmaa for children \<4 years and Lafon for children ≥4 years, adjusted to the child's abilities and at the audiologist's discretion.
Time frame: 3, 6, and 12 months post-implantation
To document the burden of integrating eSRT into routine clinical practice
eSRT measurement time will be recorded from probe placement to the last usable measurement. Success and failure rates per session will be documented, along with the types of failure causes (non-cooperative child, artifacts, middle ear pathology, equipment/logistics issues).
Time frame: 3, 6, and 12 months post-implantation
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