Objective measurement of auditory perception in pediatric cochlear cases by near-infrared spectroscopy (NIRS)

As the objective measure for auditory perception in small children is limited, usefulness of NIRS was evaluated in pediatric cochlear implant (CI) cases when their devices were switched on. Of nine children who participated in the study, two wore Nucleus 24 and seven Clarion-S. Gneders were five boys and four girls. The mean age was 5.0 y.o. (ranged from 3.3 to 8.3 y.o) The NIRS system of Shimazu Co. Ltd. (OMM-2001, Kyoto/Japan) was used. It consists of three light emitting and three light receiving probes, which were attached on the temporal region on the opposite side of CI. Changes of oxidized (oxy-Hb), deoxidized (deoxy-Hb) and total hemoglobin (total-Hb) were recorded at seven locations when auditory stimulations through CI were presented. Significant changes of oxy-HB, deoxy-Hb and total-Hb were observed in eight subjects during the auditory stimulation. The increases of oxy-Hb and total-Hb were observed in seven and five patients, respectively, indicating the increase of the regional cerebral blood flow. It is thought that these changes occur by the activation of the auditory cortices of CI children. The auditory cortical responses to tonal stimuli were objectively measured by the NIRS system.