ABSTRACT
Objective T o explore the com position characteristic of event related potential (E R P ) in dif-ferent visual acuity levels, and to provide theoretical basis for the objective assessm ent of visual acuity. Methods M onocular stim ulus w as perform ed on 16 selected subjects. T he subjects w ere required to look straight at the screen ahead and count the am ount of stim uli from different directions. T he pictures of optotype stim ulus w hich corresponding to three different visual acuity levels w ere show ed in the center of the screen. The ERP results w ere recorded separately. Results (1) The P1 am plitudes of m atch stim uli recorded under the supra-threshold visual acuity level w ere higher than that of m atch stim uli recorded under the threshold and sub-threshold visual acuity levels. T here w as no significant difference betw een the P 1 am plitudes of m atch stim uli recorded under the threshold and sub-threshold visual acuity levels. T he tendency of conflict stim uli w as sim ilar to that of m atch stim uli under three visual acuity levels. (2) In the 340-500 m s post-stim ulus range, P 300 com ponent w as found under supra-threshold and threshold visual acuity levels; no P 300 com ponent w as found in corresponding tim e w indow under sub-threshold visual acuity. T he differences of P 300 am plitudes am ong three visual acuity levels w ere statistically significant. T he am plitudes from high to low w ere the supra-threshold, threshold and sub-threshold visual acuity levels. Conclusion E R P can be a potential new m ethod for the objective assessm ent of visual acuity in forensic m edicine.
ABSTRACT
Objective T o study the effect of different attentional conditions on the event-related potential (E R P ) com ponents generated by the visual inform ation stim uli related to visual acuity, and provide a theoretical reference for clinical forensic visual objective evaluation. Methods W ith visual acuity opto-types as norm al form of visual inform ation stim uli, 15 volunteers as study subjects w ere supposed to ac-count the visual acuity optotypes under the attentional condition of visual stim uli. Furtherm ore, the sub-jects w ere required to listen to the storytelling carefully under the non-attentional condition of visual stim uli, and after the exam ination, they needed to answ er the story-related questions. A ll the E E G re-sults of tw o different attentional conditions from the subjects w ere recorded by 32 channel E R P system . Results U nder tw o attentional conditions, P 1 and P 300 com ponents w ere evoked by the visual acuity opto-types on supra-threshold and threshold visual acuity levels, w hile only P 1 com ponent w ere evoked by the visual acuity optotypes on sub-threshold levels. In the E R P w aveform s evoked by the visual acuity optotypes on supra-threshold, P 1 and P 300 am plitudes under attentional condition w ere larger than that un-der non-attentional condition. Conclusion A ttentional conditions can influence the detection of visual acuity. P 300 com ponent can be used to distinguish the visual acuity levels w ith supra-threshold and sub-threshold under non-attentional condition.
ABSTRACT
Mild cognitive im pairm ent caused by craniocerebral traum a is the key points and difficulties in judicial authentication. This article has com parative analysis of eachmode of event-related potential (classical O ddball, E riksen flanker task and so on), which can provide a more objective m ethod for such craniocerebral traum a cases in clinical forensic judicial authentication.