Hypothesis: Undesirable behaviors in young children with cochlear implants suggest device soft failure.
Background: Cochlear implant soft failure refers to nonoptimal performance not detectable with routine hardware checks. Pediatric failures may delay language development, but failure detection is difficult. A 2005 soft failure consensus statement recommended a checklist for suspected device malfunctions. That checklist included the appearance of "bad" behaviors and aggression (externalizing behaviors) or self-injury and inattentiveness (internalizing behaviors) as indicators of soft failure. Accordingly, these behaviors should predict slowed language growth, and the analyses reported here sought evidence of that predictive power.
Methods: Data from a longitudinal study of 80 children with cochlear implants collected at 6 times between 18 and 48 months were reexamined. Language measures included auditory comprehension, expressive vocabulary, and unstructured language. A parent questionnaire, the Child Behavior Checklist, examined externalizing and internalizing behaviors. Behavior measures were correlated with language measures in a series of analyses.
Results: Externalizing and internalizing behaviors did not consistently correlate with language at the ages tested. Additionally, early behaviors did not predict later language abilities. Individual language measures correlated best with overall language development 12 months later.
Conclusion: This study fails to support the hypothesis that externalizing and internalizing behaviors in pediatric cochlear implant users correlate with slowed language advance. These behaviors should not be seen as evidence of declining language performance as may be seen with device soft failure. Instead clinical assessments of language abilities are necessary.