Functional Status Of Auditory Cortex In Cleft Lip And/or Palate Patients

Objective: Patients with non-syndromic cleft lip and/or palate experienced facial anomalies and hearing loss in infancy and early childhood,some of them may also have speech dysfunction.This study used Pure Tone Audiometry(PTA),Auditory Brainstem Response(ABR),Acoustic Immittance Measurement(AIM)and Distortion Product Otoacoustic Emission(DPOAE)to determine the postoperative hearing in patients with cleft lip and/or palate(CL/P),and examined the auditory mismatch negativity(AMMN)to investigate the functional status of their auditory cortex(AC).After comparing the results with control group,the functional status of the AC in patients having surgical treatment was evaluated.This provided a theoretical basis for future discussion on the mechanism of speech dysfunction in CL/P patients and its relation with auditory center.Methods:(1)With a total of 131 patients having CL/P surgical treatment and volunteers(of which cleft lip and palate(CLP)were 44 cases,cleft lip only(CL)were 29 cases,cleft palate only(CP)were 19 cases and 39 volunteers were considered as control group),PTA and ABR were tested and subjects with normal hearing were screened out,AIM and DPOAE data were also analyzed to exclude the influence of hearing and middle ear abnormalities.(2)Among 131 cases,CL/P patients and control group with normal PTA and ABR thresholds received AMMN test,their latencies and amplitude data were recorded,the differences among CL/P patients and between CL/P patients and control group were compared.Results:(1)Only 5 cases in CLP,1 case in CL,2 cases in CP had abnormal PTA and ABR thresholds,of which 1 case in CP showed severe conductive hearing loss in the right ear and sensorineural hearing loss in the left ear,having ABR thresholds over 35 d B n HL in both ears;7 cases showed mild and moderate conductive hearing loss in the right ear with ABR thresholds over 35 d B n HL.Other subjects had normal PTA and ABR thresholds.(2)For each group with normal PTA and ABR thresholds,CP and CLP had lower normal rate than CL and control group in DPOAE and AIM tests,CL had relatively higher normal rate in AIM test and lower normal rate in DPOAE test than control group.However,there were no significant differences in statistics(P>0.05)among CP,CLP,CL and control group.(3)The AMMN latencies for each group with normal PTA and ABR thresholds were CLP patients 179.25±30.76 ms,CL patients 166.74±31.50 ms,CP patients 185.12±35.06 ms and control group 168.14±30.35 ms.Statistical analysis was carried out using analysis of variance,which showed CLP and CP groups had statistical significance(P<0.05),while CL and control groups had no obvious statistical significance(P>0.05).(4)The AMMN amplitude for each group with normal PTA and ABR thresholds were CLP patients 4.03±2.31μV,CL patients 3.85±2.43μV,CP patients 3.57±1.85μV,and control group 3.85±2.44μV.The analysis of variance showed CLP,CP,CL and control group had no statistical significance(P>0.05).Conclusion:(1)Patients with CL/P surgical treatment in individual cases may still have problems in middle ear functions and hearing.Therefore,patients having CL/P surgical treatment should be followed up to understand the recovery status of their middle ear functions and hearing.(2)A prolonged AMMN latency in CP and CLP patients after surgical treatment who had normal PTA and ABR thresholds denoted that the ability of their AC to process sound was getting worse.Considering their auditory cortical functions have abnormalities,and CL patients after surgical treatment behaved normal,since the plasticity is observed in AC,in future,the functional status of AC at early stage in CP and CLP patients shall be given more attention,so that to provide a reference and basis to the early rehabilitation of speech function.(3)There are many factors influencing the AMMN amplitude.The amplitude of AMMN in experimental groups with normal PTA and ABR thresholds had no significant difference in statistics,and the data of each group displayed large dispersion,which cannot show the problem of their auditory cortical functions.