| Background:The sound is collected, conducted, sensed, through the auditorypathway to the auditory cortex, thus we can hear. If organic or functional lesionsoccur in this process, it can lead to hearing dysfunction, resulting in different degreesof hearing loss, which we call deafness [1]. Deafness is a common disease worldwide.In China, hearing disability rank only second to physical disabilities, seriously affectthe quality of life. In2006the second national sample survey of persons withdisabilities assert that the disabled in China accounted for6.34%of the country’spopulation, of which20.04million hearing disability, accounting for24.16%[2]. Thedeafness is divided into conductive hearing loss, sensorineural hearing loss(SNHL)and mixed hearing loss. The majority of conductive deafness due to otitis media,nevertheless the etiology of sensorineural deafness is complex [3]. The use of hearingaids is common in patients with sensorineural hearing loss. But for patients withprofound sensorineural hearing loss, cochlear implantation is a more effective way.Most of the patients can get better hearing abilities after surgery, but a few patientsstill can’t get a better hearing,even ruling out the the failure of cochlear equipment,some even have no significant improvement compared with the preoperative. Thecurrent preoperative tests such as cranial MRI can evaluate the anatomy of auditorycortex, butuntil now there was no possible ways to assess the changes of auditorypathway in patients with sensorineural hearing loss.Introduction and purpose: We try to detect if there is any change of auditorypathway in patient with Sensorineural Hearing Loss compared with normal volunteer; whether there are differences of auditory pathways between different degrees ofsensorineural deafness, comparing different degree of sensorineural deafness patientsand normal volunteer and to find out whether there are differences in auditorypathways.Materials and method:22patients of SNHL and12healthy volunteers underwentDTI on GE Signa HDxt3T, and3D-FIESTA to exclude inner ear malformation. Ashearing loss was unilateral in4patients, so we have21ears with profound SNHL,19ears with non-profound SNHL and28normal ears in all. Profound SNHL wasdefined as a hearing threshold greater than90dB. Non-profound SNHL was definedas a hearing threshold greater than25dB and less than90dB. Two regions of interest(ROIs) were drawn at the lateral lemniscus(LL) and the inferior colliculus (IC). Wemeasured axial diffusivity(λ‖), radial diffusivity(λ⊥), fractional anisotropy (FA) ofboth ROIs in all subjects.Result: The DTI measures of controls in LL and IC are as follows: FA:0.74±0.04,0.25±0.04;λ⊥:（0.34±0.05）×10-3mm2/sec,（0.81±0.14）×10-3mm2/sec;λ‖（:1.37±0.25）×10-3mm2/sec、（1.09±0.18）×10-3mm2/sec。The DTI measuresof non-profound SNHL in LL and IC are as follows: FA:0.73±0.06,0.27±0.07;λ⊥:（0.36±0.09）×10-3mm2/sec,（0.85±0.17）×10-3mm2/sec;λ‖:（1.43±0.16）×10-3mm2/sec,（1.14±0.23）×10-3mm2/sec; The DTI measures of profoundSNHL in LL and IC are as follows: FA:0.66±0.04,0.20±0.05;λ⊥:（0.42±0.06）×10-3mm2/sec（,0.89±0.13）×10-3mm2/sec;λ‖（:1.40±0.08）×10-3mm2/sec（,1.17±0.21）×10-3mm2/sec. The FA value was reduced and theλ⊥was increased both atthe LL and the IC of patients with profound SNHL compared with controls. Nochanges were observed between non-profound SNHL and the controls. The FA valuewas reduced and the λ⊥was increased at the LL of patients with non-profoundSNHL compared with profound SNHL.Conclusion: The FA value was reduced and theλ⊥was increased both at the ROIsof patients with profound SNHL compared with controls. FA values of the LL and ICare negatively correlated with auditory threshold. |
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