PROTOPHONE CLASSIFICATION

Protophone Classification in Greek CI Toddlers

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Summary

The purpose of this study was to examine changes in prelinguistic vocal production during the first 20 months of life. Vocalizations were classified into 23 mutually exclusive and exhaustive types, and grouped into five ascending levels using the Stark Assessment of Early Vocal Development-Revised (SAEVD-R). Data from 30 typically developing infants, aged 0-20 months, show that older toddlers attained higher developmental levels on the SAEVD-R than younger toddlers. Toddlers 0-2, 3-5, and 6-8 months of age primarily produced vocalizations from Levels 1 (Reflexive), 2 (Control of Phonation), and 3 (Expansion). Toddlers 9-20 months of age also produced vocalizations from Level 4 (Basic Canonical Syllables). Only toddlers from 16-20 months of age produced Level 5 (Advanced Forms) vocalizations in significant quantities. The outcomes indicate that the SAEVD-R is a valuable instrument for evaluating prelinguistic vocal development. The protocol of data acquisition, procedures, investigated parameters, methods of measurements, and apparatus were described in sufficient detail to allow other scientists to reproduce the results. Names and references to established methods were given. References and a brief description was provided for methods that had been published but were not well known, whereas new or substantially modified methods were described in full. The reasons for using particular methods were provided along with an evaluation of their limitations. Drugs and other chemicals were precisely identified, including generic name, dose, and route of administration.

Key Words: Protophone, Toddlers, Classification, Cochlear, Implants

Protophone Classification in Greek CI Toddlers

Background

The substantial benefit derived from cochlear implants by adults led to the application of these devices in toddlers. Unlike adults, however, most pediatric candidates acquire their deafness before speech and language are learned (prelingually deafened). Thus, toddlers must depend on an auditory prosthesis to learn the auditory code underlying spoken language—a formidable task, given the exquisite temporal and frequency-resolving powers of the normal ear. On the other hand, young toddlers may be the most successful users of implantable auditory prostheses because of the plasticity of the central nervous system (Robbins & Osberger, 2000).

The challenges faced in determining candidacy in toddlers require balancing the risks of surgery versus the potential benefits of early implantation for the acquisition of spoken language. Initially, the use of cochlear implants in toddlers was highly controversial. Thus, candidacy requirements were stringent, and the first toddlers to receive cochlear implants were older (schoolage or adolescents) and demonstrated no benefit from conventional hearing aids—not even sound awareness—even after many years of use and rehabilitation. These toddlers were considered “ideal” cochlear implant candidates because their hearing could be reliably evaluated and it was obvious that no improvement in their auditory skills would occur with conventional hearing aids (Waltzman, 2000).

Material and Methods

The first devices used with toddlers were singlechannel implants (see Cochlear Implants). Even though performance was limited, the toddlers who received these devices derived more benefit from their implants than from ...