Evaluation of Visual Acuity of Ametropia with Visual Event-Related Potential Nogo-P3 Component / 法医学杂志

OBJECTIVES@#To analyze the Nogo-P3 component of event-related potential (ERP) in the process of visual acuity processing, to provide electrophysiological evidence for objective evaluation of visual acuity.@*METHODS@#Twenty-six subjects with no other ocular diseases except for ametropia were recruited, and all subjects had uncorrected visual acuity both eyes 1/10 (evaluated using Monoyer chart). Block letter E with different visual angles and directions were used as graphic stimuli. The Go/Nogo paradigm was used for ERP studies. The visual angle of Go stimulation angle was 1°15', Nogo stimuli were 1°15', 55', 24' and 15'. The visual acuity test was performed on each of the two naked eyes separately in all subjects, and the characteristics of the Nogo-P3 component were analyzed.@*RESULTS@#The latency of Nogo-P3 showed no difference between the stimuli of 1°15' and 55', and between Nogo stimulation angle 24' and 15'. There was significant difference between Nogo stimulation angle 1°15' and 24', and between Nogo stimulation angle 1°15' and 15' (P<0.05). There was significant difference between Nogo stimulation angle 55' and 24', and between Nogo stimulation angle 55' and 15' (P<0.05). No significant differences were observed in the Nogo-P3 amplitude among Nogo stimulation.@*CONCLUSIONS@#In the Go/Nogo paradigm, Nogo-P3 can reflect the cognitive response of subjects to Nogo stimulation, which can be used for objective evaluation of visual acuity.

Comparison of ASSR, ABR and 40 Hz AERP Response Thresholds at Different Frequencies and Their Forensic Applications / 法医学杂志

OBJECTIVES@#To explore the relationship between the frequency characteristics and response threshold of auditory steady-state response (ASSR), auditory brainstem response (ABR) and 40 Hz auditory event related potential (40 Hz AERP), and their application values in forensic medicine.@*METHODS@#Thirty volunteers with normal hearing (60 ears) were selected to perform pure tone audiometry (PTA) threshold and ASSR, ABR and 40 Hz AERP response threshold tests in the standard sound insulation shielding room, and the results were statistically analyzed by SPSS 22.0 software.@*RESULTS@#At 0.5 kHz and 1.0 kHz frequencies, the correlation between 40 Hz AERP response threshold and PTA threshold was good, which was better than that of ASSR and ABR response threshold. At 2.0 kHz and 4.0 kHz frequencies, the correlation between ASSR and ABR response thresholds and PTA threshold was good, which was better than that of 40 Hz AERP response threshold.@*CONCLUSIONS@#To evaluate the hearing at 0.5 kHz and 1.0 kHz frequencies, it is recommended to use 40 Hz AERP and ASSR to comprehensively assess the PTA threshold of the subjects. To evaluate the hearing at 2.0 kHz and 4.0 kHz frequencies, ABR and ASSR are recommended to assess the PTA threshold of subjects comprehensively. The combination of ASSR, ABR and 40 Hz AERP can improve the accuracy of hearing function evaluation.

Frequency Characteristics of AEPs in Normal Young Adults and Comparison of Their Response Threshold and Pure Tone Audiometry Threshold / 法医学杂志

Objective The tests of three types of auditory evoked potentials （AEPs） were performed on normal young adults, to understand the frequency characteristics of different testing methods and the relationship between response threshold and pure tone audiometry threshold of different methods, and to discuss the forensic value of 3 types of AEPs to evaluate hearing function. Methods Twenty normal young adults were selected, their standard pure tone audiometry threshold, short-term pure tone audiometry threshold and the response threshold of 3 types of AEPs （tone burst-auditory brainstem response, 40 Hz auditory event-related potential and slow vertex response） at 0.5 kHz, 1.0 kHz, 2.0 kHz and 4.0 kHz were recorded. The relationship between the response threshold and standard pure tone audiometry threshold, short-term pure tone audiometry threshold of 3 types of AEPs at different frequencies as well as the differences between different types of AEPs were analyzed. Results The short-term pure tone audiometry threshold was higher than the standard pure tone audiometry threshold at each frequency. The response threshold and standard pure tone audiometry threshold of the 3 types of AEPs all had a certain correlation, and the response threshold of the 3 types of AEPs was higher than short-term pure tone audiometry threshold and standard pure tone audiometry threshold at each frequency. The differences in the differences between the response threshold and standard pure tone audiometry threshold of the 3 types of AEPs at different frequencies had statistical significance. Linear regression mathematical models were established to infer the standard pure tone audiometry threshold （hearing level） from response threshold （sound pressure level） of 3 types of AEPs of normal young adults. Conclusion When using response threshold of different types of AEPs to estimate pure tone audiometry threshold, conversion and correction are needed. Combined use of different types of AEPs could improve the accuracy of hearing function evaluation.

Characteristics of Pattern Visual Evoked Potential in Two Eyes with Varying Visual Acuity in One Eye and Forensic Application / 华中科技大学学报（医学）（英德文版）

In this study,we aimed to study the pattern visual evoked potentials (P-VEPs) in two eyes with varying visual acuity in one eye and to provide an objective estimation of visual acuity by comparing P-VEPs in one and two eyes.Thirty subjects were chosen,who had one eye with an acuity of 5.0,4.85,4.6,4.0,or scieropia and obstructed vision and the other eye with an acuity of 5.0,respectively.P-VEPs were detected under the large grating stimuli at 3×4 spatial frequency,moderate grating stimuli (12× 16 spatial frequency) and small grating stimuli (48×64 spatial frequency).Under large grating stimuli,there was no significant difference in P100 peak latency between the groups,nor was there a significant difference between the amplitude of two eyes and the amplitude of one normal-vision eye.Under moderate and small grating stimuli,there was a significant difference in P100 peak latency between the group with both eyes having an acuity of 5.0 and the group with visual acuity below 4.0 in one eye.There was a significant difference in P100 amplitude between the group with visual acuity of 5.0 in both eyes and the group with one normal-vision eye.There was no significant difference in the amplitude of two eyes and the amplitude of one normal-vision eye between any other two groups.In forensic identification,characteristics and variability of P-VEPs in one and two eyes can be used to identify malingering or decline in visual acuity.

Characteristics of Pattern Visual Evoked Potential in Two Eyes with Varying Visual Acuity in One Eye and Forensic Application / 华中科技大学学报（医学）（英德文版）

In this study,we aimed to study the pattern visual evoked potentials (P-VEPs) in two eyes with varying visual acuity in one eye and to provide an objective estimation of visual acuity by comparing P-VEPs in one and two eyes.Thirty subjects were chosen,who had one eye with an acuity of 5.0,4.85,4.6,4.0,or scieropia and obstructed vision and the other eye with an acuity of 5.0,respectively.P-VEPs were detected under the large grating stimuli at 3×4 spatial frequency,moderate grating stimuli (12× 16 spatial frequency) and small grating stimuli (48×64 spatial frequency).Under large grating stimuli,there was no significant difference in P100 peak latency between the groups,nor was there a significant difference between the amplitude of two eyes and the amplitude of one normal-vision eye.Under moderate and small grating stimuli,there was a significant difference in P100 peak latency between the group with both eyes having an acuity of 5.0 and the group with visual acuity below 4.0 in one eye.There was a significant difference in P100 amplitude between the group with visual acuity of 5.0 in both eyes and the group with one normal-vision eye.There was no significant difference in the amplitude of two eyes and the amplitude of one normal-vision eye between any other two groups.In forensic identification,characteristics and variability of P-VEPs in one and two eyes can be used to identify malingering or decline in visual acuity.

Advances in Event-related Potential and Its Forensic Application Value / 法医学杂志

The event-related potential (ERP) is considered as one of the most effective methods to study and analyze objectively human mental activity based on nerve electrophysiology. At present, ERP is not only used in the study of lie detection, but also in the clinical medicine for the cognitive assessment on patients with cerebrovascular disease, dementia or traumatic brain injury and auxiliary diagnosis of mental illness. With the further development of ERP detection technology, it would have a wider application prospect in the field of forensic medicine.

Analysis of forensic identification of traumatic macular hole in 16 cases / 法医学杂志

OBJECTIVE@#To analyze and summarize the characteristics of traumatic macular hole and to discuss the key points and matters need attention in forensic identification.@*METHODS@#Sixteen cases of traumatic macular hole were collected from Forensic Science Identification Center of China Medical University from 2004 to 2009 and analyzed.@*RESULTS@#All of the 16 cases resulted from closed ocular contusion. Traumatic macular hole was more common in young men and may occur immediately after injury or after a certain interval. Six months after injury, there was a spontaneous closure of macular hole in 2 cases and the vision of the injured in 12 cases improved to different degrees. According to the degree of vision dysfunction, 12 cases were identified as slight injury, 4 cases were identified as severe injury.@*CONCLUSION@#Traumatic macular hole has its characteristics. Its injury degree is all slight or severe injury. The time of identification should be within 3-6 months.

Analysis of 158 forensic identification cases involved with peripheral nerve injury / 法医学杂志

OBJECTIVE@#To study the characteristics of forensic identification cases involved with peripheral nerve injury, and to discuss how to apply the clinical information, forensic examination and neurophysiological testing.@*METHODS@#One hundred and fifty-eight cases which were diagnosed peripheral nerve injury in clinic, were collected. Then the individual characteristics, injuries, identification results, exaggeration or camouflage were analysed.@*RESULTS@#The male, the unemployed, and the young and middle-aged were common in our cases. The main reasons of "peripheral nerve injury" were traffic accidents and sharp injuries. Most wounded parts were in limbs. Also the exaggeration and camouflage accounted for a considerable proportion in our cases.@*CONCLUSION@#The forensic identification of "peripheral nerve injury" cases should be evaluated with clinical information, forensic examination and electrophysiological testing comprehensively.

Application of spiral CT reconstruction in the forensic identification of atlantoaxial injuries / 法医学杂志

OBJECTIVE@#To evaluate diagnostic value of spiral CT reconstruction in atlantoaxial injuries.@*METHODS@#The images of 25 cases of spiral CT reconstruction were analyzed and compared with images of CT scan and X-ray.@*RESULTS@#In 7 cases of odontoid process fracture, X-ray demonstrated 4 cases and CT demonstrated 5 cases, whereas the spiral CT reconstruction diagnosed 7 cases, which could display the displacement of fracture clearly. The X-ray and CT showed asymmetric space between left and right gaps of atlantoaxial joint in 6 cases, while spiral CT reconstruction showed normal and excluded the possibility of atlantoaxial dislocation. There was one case of lateral atlantoaxial joint dislocation, which was demonstrated by the spiral CT reconstruction clearly but not by the X-ray and CT scan. There were 3 cases of atlantoaxial congenital deformity (1 case of absence of both posterior arch of atlas and odontoid process and 2 cases of maldevelopment of the odontoid process), which were displayed clearly by spiral CT reconstruction, but misdiagnosed as odontoid process fracture and atlantoaxial subluxation by X-ray and CT scan.@*CONCLUSION@#Spiral CT reconstruction can provide the most accurate and integrity imaging information and is very useful in the diagnosis of atlantoaxial injuries and deformity.

Auditory P300 in the patients with traumatic brain injury / 法医学杂志

OBJECTIVE@#To assess the cognitive dysfunction in patients with the traumatic brain injury (TBI) by auditory P300.@*METHODS@#Auditory P300 was recorded in the normal subjects and patients with TBI at the active (foot pedal) and passive task.@*RESULTS@#In healthy persons, N2 and P3 in active task state showed higher amplitude than that in passive task state, and no significant prolongation of the latency. The amplitude of N1 and P2 at Cz was higher than that at Pz. In passive task state, N2 and P3 showed higher amplitude and longer latency in the patients than that in the healthy persons. N2 and P3 of the patients in the active task showed higher amplitude and longer latency than that in the passive task. Obvious change of P3 latency was observed in the patients with attention disorder.@*CONCLUSION@#The type of task mainly affect the amplitude of N2 and P3. The latency of N2 and P3 in passive task can be used as an indication for evaluating cognitive function in patients with diffuse brain injury.

The PRVEPs evoked by different fields stimulation / 法医学杂志

OBJECTIVE@#To study the character of the PRVEPs evoked by different stimulation fields in normal-vision subjects and its value in forensic medicine.@*METHODS@#The PRVEPs were evoked by full-field, central-field and peripheral-field respectively in 30 subjects (60 eyes) and the latency and amplitude of N1 and P1 were analyzed.@*RESULTS@#There was no statistically significant difference in the latency and amplitude of PRVEPs between right and left eyes. The appearance probability of all the waves was 100% at the different stimulations but that of N1 was 36.77% at the central-field. There was statistically significant difference in the latency of N1 at the full field and peripheral field stimulations and there was no statistically significant difference in the amplitude. There was statistically significant difference in the latency and amplitude of P1 at the full field, central field and peripheral field stimulation.@*CONCLUSION@#The PRVEPs evoked by different field stimulations can be used to evaluate the functions of the different area retina and can be used to identify the exaggerated or pretended visual dysfunction.

Electrophysiological examination of peripheral nerve injury and its significance in forensic medicine / 法医学杂志

Assessment of peripheral nerve injury is a common task in forensic practice. As an objective assistance of inspection, electrophysiological examination is significant in the evaluation of peripheral nerve function after injury. There are currently several methods of electrophysiological examination, including I-T curve, EMG, NCV and SEP. Because electrophysiological examination can assess the injury and regeneration of peripheral nerve injury at different times, it is valuable to estimate prognosis of peripheral nerve injury in forensic medicine. Besides the electrophysiological examination, evaluation of the peripheral nerve injury needs to combine other clinical manifestations to provide an accurate appraisal.

Advancement in the study on electrophysiology of color vision and its applicability in forensic medicine / 法医学杂志

Color vision is a major component of vision function. Examination of color vision mostly relies on subjectivity at present. It is important to establish an objective method of color vision examination that would have particular clinical significance and forensic medicine value. With the development of new technology, the examination of visual electrophysiology has become a basic method of clinical diagnosis and investigation. Electroretinogram (ERG) could discriminate different cone cells and color abnormality. Visual evoked potential (VEP) generated characteristic negative wave after stimulation with different colors. Different visual electrophysiology detection methods were reviewed and in particular important new advancement of color vision research of ERG, F-VEP and P-VEP were introduced. The application prospect of color vision research in the clinical forensic medicine was also discussed. It is likely that color vision research study and visual electrophysiology will provide objective evaluation of retina and brain function.

The retrospective analysis of 23 cases of post-traumatic abortion / 法医学杂志

OBJECTIVE@#To analyze the clinical characteristics of post-traumatic abortion and the relationship between trauma and abortion.@*METHODS@#We collected and analyzed 23 cases of post-traumatic abortion encountered in the department of clinical forensic medicine, faculty of forensic medicine, China Medical University in recent years.@*RESULTS@#All 23 post-traumatic abort inns were early abortions. Their traumata were mild and external only. Vagina bleeding and abortion occurred shortly after trauma. Most patients were older, from countryside, or unemployed.@*CONCLUSION@#The causes of abortion are complex. Post-traumatic abortion can only be diagnosed after excluding non-traumatic factors. For those cases abortion occur shortly after injuries and non-traumatic factors can not be excluded, trauma should be assessed for its role in abortions as primary, secondary or induction factors correlated with clinical symptoms and pre-

Abortion etiologies and their forensic identification / 法医学杂志

The causes of abortion are complicated and variable. Genetic abnormalities, immune disorders, endocrine disorders, and sperm abnormalities are the most common etiologies. Other risk factors include infections, genital malformation and diseases, systemic diseases, environmental factors, psychiatric problems, fections, genital malformation and diseases, systemic diseases, environmental factors, psychiatric problems, surgery, and maternal trauma. In forensic assessment of abortion and its etiology, trauma-induced abortion can only be determined after exclusion of all other non-traumatic causes.

The application of the same frequency tone masking test in forensic identification / 法医学杂志

OBJECTIVE@#To investigate the relationship between minimum contralateral masking level (MCML) and pure tone threshold of the masking ears by the same frequency tone masking test.@*METHODS@#The pure tone thresholds of 30 subjects (60 ears) were measured by pure tone audiometry and MCML was obtained by means of the same frequency tone masking test.@*RESULTS@#When the stimulus was at the threshold of masked ears, the differences between MCML and pure tone threshold of masking ears were among 0-30 dBHL. 82.4 percent of results showed the differences not higher than 10 dBHL, 97.1 percent of results showed the differences not higher than 15 dBHL. When the stimulus was at 10 dBHL above the threshold of masked ears, the differences between MCML and pure tone threshold of masking ears were among 0-35 dBHL. 90.5 percent of results showed the differences not higher than 25 dBHL, 98.1 percent of results showed the differences not higher than 30 dBHL.@*CONCLUSION@#The real thresholds can be deduced correctly by the same frequency tone masking test.