The Study On Applying Event-related Potentials With Judge Figures Difference In Detecting Feigned Cognitive Impairment After Traumatic Brain Injury

【Background】Deception or exaggeration the degree of intellectual disability is quitecommon in the cases of identificating cognitive impairment after traumatic brain injury,because expert conclusions were identified economic or other benefit. Therefore, to proveidentified patient’s subjective experience whether authentic or whether there is deception,and in order to make an objective appraisal conclusion, the application of camouflagerecognition technology is essential.Event-related potentials (event-related potentials, ERP) reflect the electrical activity ofthe sensory and cognitive processes in real time, and cognitive event lock (time-lock), thetime and high precision, and less susceptible to be influenced by subjective wishes, it has aunique advantage in the polygraph field of application. Studies have shown that theendogenous component of the ERP within the P300is a better indication in the detection ofdeception, the use of the P300parameters such as amplitude and latency to exploratedisguised cognitive processes of the brain and nerve electrophysiological mechanism isfeasible. Explore simple, standardized ERP for the detection of camouflage cognitiveimpairment, would be helpful for providing an objective electrophysiological reference forthe forensic identification.【Objectives】Develop graphical similarities and differences stimulate sequence which isinaccordance with the ERP technical requirements, basing on the identification of thosecamouflage cognitive impairment psychology characteristics and according to the principleof Binomial Forced Choice Digit Memory Test (BFDMT), comparing ERP compositionalcharacteristics elicited by the graphical similarities and differences stimulate sequencebetween normal control group, traumatic brain injury cooperation group and traumaticbrain injury camouflage group in order to evaluating the value in forensic.【Methods】According to the result of BEDMT,select10cases patients with traumatic brain injury (7males and3females, aged39.77years±7.34years) under camouflage andcooperation both condition, presenting the graphical similarities and differences stimulussequence by the Neuroscan ERP instrument, select10cases of normal volunteers (5males,5females, age) as a control, get BFDMT score of easy points and difficult points, partialquotient and ERP components such as amplitude and latency observed. Compare ERPcharacteristics of the various groups of subjects composition and differences.【Results】The total of the normal control group, difficult project (24,12), cooperative group,followed by (22.9,11.2), trauma uncooperative group (15.2,5.2), Analog the camouflageGroup (8.93,3.6) Minimum of four groupsBFDMT results between the two groups havesignificant difference (P <0.01), multiple comparisons showed that the difficult project ofthe uncooperative trauma group (5.2) to simulate the camouflage group (3.6) points arelower than the normal control group (12) and co-operation group (11.2)(P <0.01), analogcamouflage group lower than the uncooperative trauma group, but no statisticalsignificance; uncooperative trauma group (21.8), analog camouflage group (19.18) of thequotient are biased due to higher than normal control group (0) and trauma co-operationgroup (0) to simulate camouflage group was lower than that of the uncooperative traumagroup (P <0.01);normal group leads to the N1and P2, N2, P3, and the N3waveform is more obvious, scalpdistribution of Cz in the midline, FCz, the various components of waveform CPz point themost significant and well differentiated; traumaN2, P3, latency to group the same graphicsleads extend higher than the normal group (P <0.05, P <0.01), leads to independent graphicsP3amplitude than the normal group decreased (P <0.05), independent graphics stimulationcompared with the same graphics leads P3,N3latency (P <0.05), the N3amplitudeincreased (P <0.05); compared with the same independent graphics graphics leads P2, P3latency was prolonged, the N3amplitude increased (P <0.05).Trauma camouflage group P3latency prolonged, compared with the normal group and thetrauma co-operation group were statistically significant (P <0.01); the N3incubation periodthan the normal group extension, there are statistically significant (P <0.05); the N3amplitude than the normal group and trauma lower group, a statistically significant (P <0.01,P <0.05), trauma camouflage group P2incubation period than the normal group increased (P <0.05), and trauma cooperation group, no significant difference; N2latency in thenormal group and the trauma cooperation was longer (P <0.01, P <0.05), P3, the incubationperiod compared to extend the normal group and the trauma co-operation group (P <0.01);the N3incubation period than extend the normal group (P <0.05).Simulated camouflage same set of graphics to stimulate P3latency compared with thetrauma co-operation group, the uncooperative trauma group shortened (P <0.01); P3, theamplitude compared with normal control group, trauma co-operation group, uncooperativetrauma were decreased (P <0.01); N3latency in normalcontrol group, trauma co-operationgroup, uncooperative trauma shortening (P <0.01); N3amplitude than the normal controlgroup, the trauma co-operation group, uncooperative trauma group increased (P <0.01);independent graphics P3latency than the trauma group,uncooperative trauma groupshortened compared with control group (P <0.01); P3, volatility, trauma cooperation group,uncooperative trauma group (P <0.01) lower; the N3incubation period compared withcontrol group, trauma co-operation group, trauma reduce the non-cooperative group (P<0.01); the N3amplitude than the normal control group, trauma co-operation group,uncooperative trauma group increased (P <0.01).Brain mapping feature, the normal group before the activation of frontal and parietal lobesmainly trauma in cooperation with the part of the occipital region activated traumacamouflage group occipital lobe activation than the more obvious trauma CooperationGroup; independent graphics compared to the same graphical brain activation higherintensity broader; between the two groups found that brain activation intensity and scope ofthe normal group, the trauma co-operation group, followed by, trauma camouflage groupminimum.【Conclusion】Graphical similarities and differences stimulate sequence in this study caninduce a relatively stable ERP components, in turn leads to the picture stimulus fiveingredients wave, N1(negative), P2(positive), N2(negative), P3(positive), N3(negative),latency and amplitude of the N3have statistical significance between groups, could be anobjective electrophysiological parameters in disguise judgment.