突发性聋患者听觉中枢在功能性核磁的表现

Functional magnetic resonance imaging of auditory cortex in sudden sensorineural hearing loss

目的利用血氧水平依赖性的功能性磁共振成像(blood oxygen level dependent functional MRI,BOLD-fMRI)技术,观察突发性聋患者在接受纯音刺激时听觉中枢的变化。方法研究对象分为两组,突发性聋患者13例(均为左耳患病)为试验组,12例双耳听力正常的健康成年志愿者作为对照组。通过Cool Edit Pro2软件编辑1000Hz、127dB纯音,刺激模式采用ON/OFF组块设计,通过耳机分别给予右耳及双耳音频刺激,采用荷兰Philips Achieva 3.0T磁共振成像系统,采集脑部的BOLD-fMRI数据,最后通过SPM2软件对数据进行统计学分析(组分析),得到脑功能活动的图像。结果右耳接受纯音刺激时听力正常组主要中枢激活区在双侧颞上回、左枕叶、左额上回,此外还有左小脑、双侧海马及双侧旁中央小叶激活,听觉中枢表现为右侧优势偏向;突聋组见双侧颞上回,以及左侧海马、右枕叶和左侧距状裂区激活,听觉中枢表现为左侧优势偏向,突聋组听中枢激活容积小于正常组。双耳同时刺激时,听力正常组激活区主要在双侧颞中回,右侧扣带回和左胼胝体亦明显激活;突聋组双侧颞中回,以及右侧颞上回、右小脑、右侧额下回及右楔前叶激活,两组听觉中枢均表现为右侧优势偏向。听力正常组与突聋组比较,正常组左小脑、左胼胝体区明显激活,突聋组出现新的激活区右侧颞上回、右侧额下回及右小脑区;突聋组听中枢激活容积小于正常组。结论突聋患者在单耳刺激时听觉中枢出现优势偏向的改变,提示单侧耳聋的病人听觉皮质存在着结构重组;听觉中枢具有可塑性,突聋患者在双侧刺激时通过听觉重组使双耳对外界声音的感知尽量达到正常水平;突聋患者听觉中枢不仅本身存在重组现象,且同视觉皮质之间也发生了感觉交互作用。

Objective To characterize pure tone-induced activation in central auditory functional areas in patients with sudden sensorineural hearing loss （SSNHL） using blood oxygen level dependent functional MRI （BOLD-fMRI）. Methods A total of 13 subjects with SSNHL and 12 normal hearing volunteers were studied. A 1000 Hz pure tone at 127dB was presented to the right ear or binaurally. Cortical activation was recorded using functional imaging and analyzed using the SPM 2 software. Results 1. Monaural right side stimulation resulted in activation in bilateral superior temporal gyrus,.left occipital lobe, left superior frontal gyrus,.left cerebellum, bilateral hippoeampus and paracentral lobule in normal hearing subjects, and in bilateral superior temporal gyrus,.right occipital lobe, left hippocampus and left calaearine fissure in SSNHL patients. 2. Binaural acoustic stimulation induced activation in bilateral middle temporal gyrus, right cingulate gyms and left corpus callosum in normal subjects and in bilateral middle temporal gyrus,.right superior temporal gyms, right cerebellum, right inferior frontal gyms and right precuneus in SSNHL patients. Stronger activation was seen in the left cerebellum, and left corpus callosum in healthy subjects than in SSNHL subjects. Activation in right superior temporal gyms, right inferior frontal gyms and right cerebellum was seen only in SSNHL subjects, not in normal individuals. Conclusion There appears to be a directional preponderance change in activation by monaural sound stimulation in patients with SSNHL, indicating reorganization of the auditory cortex. Auditory cortical plasticity may help normalize auditory function in SSNHL patients. Activation of occipital lobes in SSNHL subjects may suggest cross-modal plasticity in these individuals.