ABSTRACT
Objective To explore a method of detecting the horizontal localization ability in normal children aged 1~3 years old, and to obtain the minimum audible angle (MAA) at horizontal 0° degree in these children.Methods Using minimum audible angle measure procedure on the basis of conditioned play audiometry and behavioral audiometry methods, sound localization test at horizontal 0° degree was conducted in 37 children aged from 1 to 7 years old with stimulus of different frequencies.Results All 37 children completed the 1 000 Hz tests, 35 children completed the 500 Hz tests, and 30 children completed the 4 000 Hz test.An analysis of 30 children who completed all the tests was performed, 15 of them aged 1~3 years old and the rest aged 4~7 years old.The results for children aged 1~3 years old were as below: 1 000 Hz MAA(0°) =3.57°±1.35°,500 Hz MAA(0°) =5.03°±2.96°,and 4 000 Hz MAA(0°) =5.4°±2.86°, respectively.The results for children aged 4~7 years old were as below: 1 000 Hz MAA(0°) =3.56°±1.48°,500 Hz MAA(0°) =3.5°±2.17°,and 4 000 Hz MAA(0°) =6.13°±4.09°, respectively.There was no significant difference in MAA (0 °) at corresponding frequencies between the two groups.For the children aged 1~3 years old, there was no significant difference in MAA (0 °) among 500 Hz, 1 000 Hz and 4 000 Hz frequencies.For the children aged 4~7 years old, there was significant difference in MAA(0 °) between 500 Hz and 4 000 Hz as well as between 1 000 Hz and 4 000 Hz frequencies.However, there was no significant difference in MAA (0 °) between 500 Hz and 1 000 Hz frequencies.Conclusion MAA test procedure on the basis of conditioned behavioral audiometry and play audiometry could be used to evaluate the ability of sound localization in 1~3 years old children.The frequencies may have effects on children''s sound localization test results and there was no significant difference in MAA (0 °) between the 1~3 years old group and the 4~7 years age group.
ABSTRACT
Objective To investigate the effects of cochlear implantation on residual hearing and to evaluate the potential impact of long -term electrical stimulations on residual hearing .Methods 58 hearing impaired children with cochlear implants were included in this study .All subjects could cooperate with behavioral audiometry .Audio-metric evaluations were carried out pre -implantation and 3 ,12 ,24 months post -implantation respectively .Of 58 subjects ,43 were followed up more than 1 year and 17 were followed up more than 2 years .Results All 58 subjects showed significant differences (P0 .05) at 1 ,2 and 4 kHz .Of 17 subjects followed up more than 2 years ,there were significant differences (P<0 .05) between pre- and various return visits post-implantation .Post-implantation return visits ,there were significant differences between 3 months and 12 , 24 months at 0 .25 and 0 .5 kHz respectively ,not any significant differences on 1 ,2 and 4 kHz .There were no sig-nificant differences on each frequency between 12 months and 24 months post- implantation .Conclusion Residual hearing after cochlear implantation could decrease to some extent for various reasons .There were significant differ-ences between 3 and 12 months post-implantation at 0 .25 and 0 .5 kHz .Not any significant differences were ob-served between 12 months and 24 months post-implantation at each frequency .
ABSTRACT
Objective To investigate residual hearing of children with sensorineural hearing loss in whom wave V was not found in ABR testing and to emphasize the importance of behavioral audiometry in determining the residual hearing.Methods Residual hearing obtained by behavioral audiometry of 101 children with SNHL was studied in relation to the absence of wave V in both click-ABR and tone burst-ABR tests.Results All children have residual hearing of different degrees at different frequencies.There appeared to be a higher percentage of lowfrequency residual hearing than middle and high frequencies.Also,the residual hearing at low frequencies appeared to be better than those in the middle and high frequencies.Average residual hearing thresholds in the right ears from 500 to 4 000 Hz were 106.81±7.13,110.00±7.90,111.78±5.22,112.06±7.08 dB HL and those in the left ears were 98.01±3.98,111.30±7.18,112.06±7.08,108.33±7.23 dB HL.Conclusion The absence of wave V in ABR does not mean total deafness.For those children with no wave V in ABR,behavioral audiometry must be conducted to determine children's behavioral hearing thresholds in order to know their residual hearing.