[Comparison and analysis of ASSR test in sensorineural hearing loss children with cochlear lesion and retrocochlear lesion].

OBJECTIVE

To compare the auditory steady-state response (ASSR) test data of severe sensorineural hearing loss children with cochlear lesion and those with retrocochlear lesion and find some specific phenomena of retrocochlear lesion in ASSR, then to improve diagnostic accuracy in clinical practice.

METHOD: Between 2008 to 2012. 96 children (179 ears) were diagnosed with "retrocochlear auditory nerve lesion" and recieved ASSR test (" retrocochlear lesion" group). Eighty-one (143 ears) the same age children (143 ears) were diagnosed as "cochlear auditory nerve lesion" and selected them as the "cochlear lesion" group. Twenty-six (50 ears) normal hearing children at the same age who had ASSR test records selected from the pediatric hearing center database of our hospital were selected as "normal control" group. Compare the difference of ASSR threshold, ASSR elicit rate and ASSR audiogram among the three groups.

RESULT: (1) ASSR threshold: Compared each frequency threshold in ASSR test with cochlear.lesion group, the retrocochlear lesion group with wave V and wave I had no significant difference in 500 Hz and 1000 Hz but had significant difference in 2000 Hz and 4000 Hz. As for the retrocochlear lesion group without wave V and wave I, there was a decline in 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz compared with cochlear lesion group. (1) ASSR elicit rate: When compared to retrocochlear lesion group, the cochlear lesion group had a significance lower elicit rate in the four frequency. (3) Number of elicit reactions in ASSR test . In the retrocochlear lesion group, the elicit reactions in all the four frequency in ASSR test was significantly higher than ochlear lesion group. (4) ASSR audiogram type. The proportion of rising curve audiogram in retrocochlear lesion group was 26.83% (with wave I and wave V), 40% (with wave I and without wave V ) and 33.80% (without wave I and wave V).

CONCLUTION: (1) Children with a severe hearing loss in ABR test and a rise type audiogram in ASSR test should be most possibly considered as retrocochlear lesion. (2) ASSR threshold cannot be used in determinate the severity of hearing loss in children with retrocochlear lesion.