Retrospective Analysis of 24 Cases of Forensic Medical Identification on Traumatic Tympanic Membrane Perforations / 法医学杂志

OBJECTIVES@#To study the case characteristics of forensic medical identification of traumatic tympanic membrane perforations, and to discuss the key points of forensic medical identification and evaluations methods for tympanic membrane perforations.@*METHODS@#Twenty-four cases of traumatic tympanic membrane perforations accepted by the Academy of Forensic Science during 2017 were retrospectively analysed. The data of perforation size, form, predilection site, healing time and healing mode were evaluated.@*RESULTS@#For the traumatic tympanic membrane perforations, the study showed that the small size of perforation （<1/2 quadrant） with irregular shape was common. The location of perforations was almost on the anterior and inferior quadrant, and centripetal migration healing was common. The healing rate within 6 weeks was up to 90%.@*CONCLUSIONS@#In the identification cases of traumatic tympanic membrane perforations, the key is to determine whether it is traumatic and whether it will heal spontaneously within 6 weeks. It is suggested to check the tympanic membrane weekly by an otic endoscope combined with acoustic impedance measurement at the sixth week, which can improve the accuracy, objectivity and scientificity of the identification.

Forensic medical identification of 355 cases with hearing impairment / 法医学杂志

OBJECTIVE@#To analyze the difference of subjective hearing threshold and objective hearing threshold, and to discuss the importance of standard for hearing evaluation in forensic medicine.@*METHODS@#Three hundred and fifty-five cases (387 ears) of forensic medical identification with hearing impairment were retrospectively analyzed including the items entrusted and hearing test results. All cases were collected from 2004 to 2012 in the forensic science center.@*RESULTS@#In the 387 ears, 218 ears (56.3%) were evaluated the degree of disability and 106 ears (27.4%) were identified the degree of damage. In the disability degree evaluation, the subjective hearing threshold and the objective hearing threshold were significant different in 120 ears (55.0%), while in damage degree evaluation, the subjective hearing threshold and the objective hearing threshold were significant different in 69 ears (65.1%).@*CONCLUSION@#Because of camouflaging or exaggerating the hearing impairment by the wounded, the subjective hearing threshold can't accurately assess the existence and the degree of hearing impairment. In the forensic identification, auditory brainstem response, 40 Hz auditory event related potential and auditory steady-state response should be combined in the application to evaluate the hearing impairment for the wounded in order to ensure the reliability of the evaluation of hearing impairment.

Comparisons among three frequency-specific auditory evoked potentials in normal hearing adults / 法医学杂志

OBJECTIVE@#To provide supports for the application of auditory evoked potential (AEP) in the evaluation of behavioral threshold, by studying the difference and relevance between the pure tone audiometry (PTA) and three frequency-specific auditory evoked potentials, including 40 Hz auditory event related potentials (40 Hz AERP), tone burst auditory brainstem response (Tb-ABR) and auditory steady-state response (ASSR).@*METHODS@#Three frequency-specific AEP and PTA thresholds were recorded at speech frequency (0.5, 1, 2, 4 kHz) from thirty-four adults with normal hearing (68 ears). Then, the relationship between the AEP thresholds and PTA thresholds were analyzed respectively.@*RESULTS@#There were good correlations between three frequency-specific AEP thresholds and PTA thresholds at speech frequency. However, the difference of thresholds between each frequency-specific AEP and PTA was not same. The difference of thresholds were the smallest and the relevance were the best between 40 Hz AERP and PTA at 0.5 kHz, and between ASSR and PTA at 2, 4 kHz. At 1 kHz, there were not statistical difference between ASSR, 40 Hz AERP and PTA, while the relevance of 40 Hz AERP was better than ASSR.@*CONCLUSION@#Different methods should be chosen to assess the objective behavioral thresholds at different frequency.

The progress in the study on slow vertex response / 法医学杂志

Slow vertex response (SVR) is one of long latency auditory evoked potentials. It is a biological and electric response originating from brain cortical neuron evoked by sound stimulus with the latency from 50 to 500 milliseconds. Of all the neuroelectric physiological audiometries, it is the earliest method applied in assessing the function of the auditory neural conduction pathway. The concept, neural generators of SVR have been introduced in this article. Influencing factors on SVR were discussed such as stimulus parameters, consciousness state, age, maturation of the subject. Applications of SVR in clinical and forensic medicine identification were also discussed.

Image analysis of avulsion fracture, permanent osteoepiphyte, sesamoid and accessory bones / 法医学杂志

OBJECTIVE@#To investigate a method to distinguish avulsion fracture from sesamoid, accessory bone, and permanent osteoepiphyte.@*METHODS@#Fourteen cases of suspicious avulsion fractures of articular portion of tubular bones were reviewed. Direct/indirect signs and the injury mechanism of avulsion fractures were analyzed and compared with permanent osteoepiphyte, sesamoid and accessory bones for their morphological characteristics.@*RESULTS@#There are two cases of permanent osteoepiphytes, three cases of sesamoids, and three cases of accessory bones. These cases were characterized by smooth edges, contiguous bony cortex, without swelling of the surrounding soft tissue or obvious image changes after consecutive radiography.@*CONCLUSION@#It is fundamental in image analysis to distinguish avulsion fracture from physiological small osteoepiphyte, sesamoid bone, and aberrant accessory bone.

Identification opportunity for several types of eye injuries / 法医学杂志

OBJECTIVE@#To study the stability duration of visual acuity after eye injuries in several types, in order to define the earliest and best opportunity for identification.@*METHODS@#160 cases were divided into five groups, in which their stable visual acuity after injuries were divided into several ranges. Then the relationship between stability duration of visual acuity and their visual acuity level, as well as eye injury types were analyzed.@*RESULTS@#Significant correlation existed between eye injury types, stable visual acuity level and stability duration of visual acuity after injuries.@*CONCLUSION@#The earliest and best opportunity for identification after eyes injuries related to injury types and visual acuity level.