轻度闭合性头颅外伤致听力损害的研究

目的探讨轻度闭合性头颅外伤造成听力损害的特点,为法医临床学鉴定提供理论依据。方法选取51例轻度闭合性头颅外伤后听力损害的患者,经详细询问病史、耳科及神经系统全面检查、颞骨或头颅CT扫描,对纯音测听（pure tone audiometry,PTA）、声导抗（acoustic immittance,AT）、听性脑干反应（auditory brainstem response,ABR）及40Hz听觉相关电位（40Hz auditory event related potential,40Hz AERP）检查进行分析研究。结果轻度闭合性头颅外伤后听力损害多为感音神经性耳聋,听力损失程度多≤60dB,少数患者听力损失较重或为混合性聋,部分患者可伴耳鸣、眩晕、恶心或短暂呕吐等症状;伤后不同就诊时间的各项听力检查与正常对照组比较均有明显差异（P〈0.05）,听力损失在高频区明显;ABR各波潜伏期、波间期与正常对照组比较,Ⅰ～Ⅲ波间期差异不显著（P〉0.05）,各波潜伏期、Ⅲ～Ⅴ波间期、Ⅰ～Ⅴ波间期均有显著差异（P〈0.05）。结论轻度闭合性头颅外伤可以造成一定程度的高频听力损害和脑干功能受损,部分患者伴有前庭功能障碍,结合临床表现及辅助检查,考虑迷路震荡在损伤机制中起着重要作用。

A clinical study on hearing impairment caused by mild closed head injury

Objective To explore features of hearing impairment caused by mild closed head injury,which would provide some theoretical basis for appraisal in clinical forensic medicine.Methods 51 patients with hearing impairment due to mild closed head injury were recruited.Detailed case histories were recorded.And a series of examinations were carried out,including head or temporal bone CT scanning,otological and neurological examinations.Data from audiologic testing including pure tone audiometry(PTA),acoustic immitance(AT),auditory brainstem response(ABR) and 40Hz auditory event related potential(40Hz AERP) were analyzed.Results Most of the patients after mild closed head injury had sensorineural hearing loss.The degree of hearing loss was mostly ≤ 60dB.While minority had serious hearing loss or mixed deafness.Some of the patients had such clinical manifestations as tinnitus,vertigo,nausea or vomiting etc.All the results abtained from auditory examination at different periods after injury were significantly different from those of control patients(P<0.05).Hearing loss was detected obviously in the high-frequency range.For ABR in injury group as compared with that in control patients,there were significant deviations(P<0.05) for latency period of wave and interpeak latency at Ⅲ～Ⅴ wave and Ⅰ～Ⅴwave except for interpeak latency of Ⅰ～Ⅲ wave(P>0.05).Conclusion Mild closed head injury may cause high-frequency hearing loss and functioning impairment of brain stem to some extent with vestibular dysfunction in some cases,suggesting that labyrinth concussion of the inner ear play an important role in combination with clinical symptom and auxiliary examinations.