RESUMEN
Objective To study the analysis of auditory rehabilitation outcomes of patients with cochlear nerve canal stenosis after cochlear implantation(CI).Methods A cohort of 30 patients with bilateral profound senso-rineural hearing loss who were diagnosed with cochlear neural canal stenosis by high-resolution CT were tested with evoked compound action potential (ECAP)and evoked auditory brainstem response (EABR)during and 3 ,6 , 9 months after CI.Audiometry in sound field was also assessed before and 3 ,6 ,9 months after CI.Among the co-hort,1 7 patients over 3 years old underwent postoperative speech recognition rate test.All the auditory rehabilita-tion outcomes were analyzed.Results ① For all 30 patients,there were no obvious differences of ECAP and EABR waveforms tested in 3,6 and 9 months after CI.②The thresholds in sound field in 3,6,9 months after CI were 65 ±8 dB HL,62 ±4 dB HL and 61 ±7 dB HL,respectively.The thresholds in sound field were significantly im-proved after than before CI (100 ±5 dB HL).③ The single vowel recognition rates of 17 patients in 3 ,6 and 9 months after CI were 55%±7%,56%±8% and 80%±4%,respectively.The single vowel recognition rate was significantly improved in 9 months after than before CI(52%±8%).The single consonant recognition rates of 17 pa-tients in 3 ,6 and 9 months after CI were 9%±3%,8%±4% and 9%±2%,respectively.The single consonant recognition rates were not significantly improved after than before CI (8%±2%).Conclusion ① For patients with bi-lateral cochlear neural canal stenosis,neither ECAP nor EABR waves were produced during or after CI.The language com-munication of patients is limited as a result of their poor subjective thresholds in sound field and speech recognition rates.
RESUMEN
Objective To study the imaging manifestations and clinical significance of simple cochlear nerve canal(CNC)stenosis. Methods The HRCT findings of 14 patients(1 7 ears)with simple CNC stenosis diagnosed sensorineural hearing loss(SNHL)were retrospectively analyzed.The width of CNC and internal auditory canal was measured and compared with the normal ears,the data were statisti-cally analyzed by SPSS1 6.0.Thin-sliced MRI of internal auditory canal (axial and oblique sagittal position)was performed in 8 cases. Results HRCT displayed obvious CNC stenosis in all 14 patients(1 7 ears),2 ears with cochlear nerve canal atresia.Width of CNC and internal auditory canal was (0.5±0.3)mm and (4.6±1.0)mm,it was (2.1±0.2)mm and (5.1 ±1.3)mm in normal ears (1 1 ears),the width of CNC was of significant difference between normal ears and ears with SNHL,and there was no statistical sig-nificant difference in width of internal auditory canal.12 ears(from 1 7 ears with simple CNC stenosis)were lacking of fissure in the cribriform area,1 1 ears(normal ear)were existence of fissure in the cribriform area;cochlear nerves were not shown in 8 patients with MRI examination.Conclusion CNC stenosis can be isolated from internal auditory canal stenosis,MRI could display cochlear nerve dysplasia(CND).