The Research Of Etiology,Audiological Characteristics And Cortical Plasticity In Congenital Microtia

First part The Research of Etiology in Congenital MicrotiaObjectives:To investigate the environmental risk factors associated with congenital microtia,and provide basis for preventing the onset of microtia.Methods:A hospital-based case-control study was performed.Cases were patients with severe microtia(Marx III-IV)who presented to our hospital between January 2014 and October 2017.A total of 322 patients with severe microtia were enrolled and 322 normal controls matched 1:1 with the patients by sex and age were enrolled.The designed questionnaires were completed and data were gathered.The content of the questionnaire included:the basic information of the patients and their parents,pregnant age of father and mother,history of mother's pregnancy,birth and abortion,mother's threatened abortion and spuc history in the first trimester,mother's acute or chronic illness and medical history in the first trimester,history of toxic exposures,bad lifestyle habit such as drinking and smoking and family history.Odds ratios were estimated with chi-square test and logistic regression models along with 95%confidence intervals in severe microtia.Results:Univariate analysis showed that threatened abortion,NSAIDs,virus infection,anemia,miscarriages,maternal age,paternal age and chemical exposure were associated with microtia.Multivariate logistic regression analysis showed that threatened abortion(OR 4.066,95%CI=2.360-7.007),NSAIDs(OR 2.576,95%CI=1.079-6.148),virus infection(OR 1.933,95%CI=1.148-3.256),anemia(OR 1.902,95%CI=1.026-3.526),miscarriages(OR 1.804,95%CI=1.425-2.285),maternal age(OR 1.079,95%CI=1.015-1.148)and paternal age(OR 1.061,95%CI=1.003-1.122)were associated with a higher risk of severe microtia.Conclusion:These results support that some maternal risk factors could be associated with microtia.Second part The Research of Audiological characteristics and Cortical Plasticity in Congenital MicrotiaObjective:To evaluate audiological characteristics and brain function in patients with congenital microtia by utilizing speech test,auditory scale and resting-state functional magnetic resonance imaging(rs-fMRI),thereby provide basis for clinical therapeutic intervention in unilateral microtia.Methods:A total of 40 unilareal congenital microtia patients and 40 sex-and age-matched healthy controls were recruited from our hospital.All participants performed speech discrimination test in quiet and noisy environment and SSQ(Speech,Spatial and Qualities)questionaire.16 right-sided microtia patients in adulthood were selected to complete the rs-fMRI and high-resolution 3D-T1WI whole-brain imaging scan.All the subjects were right handed.The data of rs-fMRI were preprocessed by using DPABI.The fractional amplitude of low frequency amplitude(fALFF)and regional homogeneity(ReHo)were analyzed and compared between microtia group and control group.The left and right primary auditory cortex and posterior cingulate cortex were selected as seed regions to investigate the intrinsic functional connectivity(FC)within the whole brain.And the FC were also analyzed and compared between microtia group and control group.In addition,to evaluate the cognitive abilities,all participants have completed the Mini-Mental State Examination(MMSE),Montreal cognitive assessment(MoCA),Auditory verbal learning test(AVLT),Trail making test-A(TMT-A),Trail making test-B(TMT-B),Digit span test(DST),verbal fluency test(VFT),Stroop color-word test and Clock drawing test(CDT).Results:Compared to normal controls,the patients with unilateral microtia perform worse in speech discrimination test both in quiet and noisy environment.There is significant difference in the scores of SSQ questionaire.The fALFF results revealed that patients with unilateral congenital microtia have increased fALFF in the right inferior temporal gyrus,fusiform gyrus,caudate nucleus,the left angular gyrus,supramarginal gyrus,supplementary motor area,decreased fALFF in the left Heschl's gyrus,superior temporal gyrus,insula and cingulate gyrus.The ReHo results revealed that patients with unilateral congenital microtia have increased ReHo in the right parahippocampal gyrus,fusiform gyrus,left caudate nucleus and bilateral supplementary motor area,decreased ReHo in the left superior temporal gyrus and cingulate gyrus.Furthermore,when selecting the left primary auditory cortex as seed,we found increased FC in the right inferior temporal gyrus,parahippocampal gyrus,posterial cingulate gyrus,bilateral middle temporal gyrus and middle frontal gyrus,decreased FC in the cerebellum,left superior frontal gyrus and cuneus;when selecting the right primary auditory cortex as seed,we found increased FC in the cerebellum,thalamus,anterior cingulate gyrus,decreased FC in the left parahippocampal gyrus,right inferior frontal gyrus,right superior temporal gyrus,cunes and precunes.when selecting posterial cingulate gyrus as seed,we found increased FC in the left superior temporal gyrus,cerebellum,bilateral caudate nucleus,decreased FC in the right superior temporal gyrus,superior frontal gyrus,cuneus,left superior temporal gyrus and right precuneus.Furthermoe,we found no significant difference in cognitive tests.Conclusion:The patients with unilateral microtia have poor ability in speech discrimination and sound localization.These rs-fMRI results suggest that congenital unilateral hearing loss not only alters the organization of the sensorial brain but also affects the function of the cognitive brain;early hearing intervention in patients with unilateral microtia may be beneficial.