A Research Of Pathophysiological Mechanisms And Hearing Dysfunctional Degree In ANSD Patients

Objective: To explore the application of ECoch G in the diagnosis of lesion in ANSD patients.Methods: ECoch G were recorded in 25 ANSD patients in department of ENT of Tongji Hospital affiliated to Tongji Medical College, Huazhong university of science and technology between January 2009 and February 2016 and 21 normal hearing adults(control group). According to the differences of-SP, AP latency and amplitude between the ANSD patients and normal hearing group, we divided the ANSD patients into presynaptic type and non-presynaptic type. We analyzed the ECoch G characteristics in the two groups of patients.Results: The-SP amplitude and AP amplitude in Pre-ANSD group were 0.32±0.24?V and 0.56±0.31?V respectively, they were significantly lower than normal group(P<0.01); while the-SP latency was 0.61±0.36 ms and the AP latency was 1.21±0.10 ms, which had no different to the normal hearing group(P>0.05). The AP amplitude in Non Pre-ANSD group was 0.96±0.51?V which was significantly smaller than normal group(P<0.01) and the latency was 1.24±0.50 ms which was significantly longer than normal group(P<0.01); while the-SP latency was 0.66±0.14 ms and-SP amplitude was 0.65±0.22?V, which had no different to the normal hearing group(P>0.05).Conclusions: ECoch G can be used to diagnose the lesion in ANSD patients. The ANSD patients can be divided into presynaptic type and non-presynaptic type by the-SP amplitude was abnormal or normal.Objective: To evaluate the dimensions of cochlear nerve(CN) in adult auditory neuropathy spectrum disorder(ANSD) patients on 3.0-Tesla magnetic resonance imaging(MRI) and confirm the hypothesis that CN deficiency is one of the lesions for ANSD patients.Methods: Medical records and MRI of 24 adult ANSD patients in department of ENT of Tongji Hospital affiliated to Tongji Medical College, Huazhong university of science and technology from January 2009 to February 2016 reviewed retrospectively and 20 Non-ANSD SNHL and 24 volunteers with normal hearing were recruited as control groups. The long diameter(LD), short diameter(SD) and cross-sectional area(CSA) of CN and facial nerve(FN) were measured and compared between the three groups. The ANSD patients can be divided into presynaptic type and non-presynaptic type by the-SP amplitude was abnormal or normal. The LD, SD and CSA of CN and FN between the two groups were compared.Results: Among the 24 ANSD patients, we were able to reconstruct and measure the CN of 91.7%(22/24, total 43 ears) patients and FN of 83.3%(20/24, total 38 ears) patients. The mean values and standard deviations of LD, SD and CSA of CN in ANSD patients were 0.65 ± 0.20 mm, 0.44 ± 0.15 mm and 0.30 ± 0.19 mm2, respectively. They were significantly smaller in ANSD patients than in control groups(P<0.001). The LD, SD and CSA of CN and FN between the two types of ANSD groups had no significant difference, while which were all significantly smaller than the normal hearing group.Conclusions: The size of CN is atrophic in adult ANSD patients. Presynaptic ANSD patients exist cochlear nerve dysplasia.Objective: To analyze of the ability of speech information processing in ANSD patients.Methods: 13 patients diagnosed with ANSD in department of ENT of Tongji Hospital affiliated to Tongji Medical College, Huazhong university of science and technology from February 2014 to February 2016 reviewed retrospectively; 13 Non-ANSD SNHL and 32 volunteers with normal hearing were recruited as control groups. Sentence Discrimination Test, Gap Detection Test(1KHz Tone-1KHz Tone, White noise-White noise), Noise Threshold Test and Tone Recognition Test were done. Differences between the three groups were compared.Results: Sentence Discrimination Test in ANSD group was 83.38±22.39 % and the tone recognition rate in ANSD group was 63.87±15.66%, which were significantly lower than that in normal hearing group and non-ANSD SNHL group; the GDT threshold in ANSD patients between 1KHz Tone-1KHz Tone was 6.91±4.82 ms while it between White noise-White noisewas10.29±7.23 ms and the noise threshold in ANSD patients was 5.58±10.78 d B, which were all significantly higher than that in control groups(all P<0.001).Conclusions: The speech recognition rate and the tone recognition rate were significantly lower in ANSD patients while the GDT threshold and the noise threshold were significantly higher in ANSD patients.