Pattern-reversal visual evoked potentials as a diagnostic tool for ocular malingering

ABSTRACT Purpose: To investigate the contributions of transient pattern-reversal visual evoked potentials in the diagnosis of ocular malingering at a Brazilian university hospital. Methods: Adult patients with suspected malingering in one or both eyes were referred for visual evoked potential testing. Data from patients' medical records were reviewed and analyzed retrospectively. Data analysis included the distance optotype visual acuity based on a ETDRS retro-illuminated chart and the transient pattern-reversal visual evoked potential parameters of latency (milliseconds) and amplitude (microvolts) for the P100 component, using checkerboards with visual subtenses of 15' and 60'. Motivations for malingering were noted. Results: The 20 subjects included 11 (55%) women. Patient ages ranged from 21 to 61 years (mean= 45.05 ± 11.76 years; median= 49 years). In 8 patients (6 women), both eyes exhibited reduced visual acuity with normal pattern-reversal visually evoked potential parameters (pure malingerers). The remaining 12 patients (7 men) exhibited reduced vision in only 1 eye, with simulated reduced vision in the contralateral eye (exaggerators). Financial motivation was noted in 18 patients (9 men). Conclusion: Normal pattern-reversal visually evoked potential parameters with suspected ocular malingering were observed in a 20 patient cohort. This electrophysiological technique appeared to be useful as a measure of visual pathway integrity in this specific population.

摘要
研究目的：探讨巴西某大学附属医院中，瞬态图形翻转视觉诱发电位（transient pattern-reversal visual evoked potentials）在眼部伪装视力障碍诊断中的应用价值。
研究方法：纳入因单眼或双眼疑似伪装视力障碍而转诊行视觉诱发电位检测的成年患者，对其病历资料进行回顾性审查与分析。本次数据分析涵盖基于ETDRS背光视力表（ETDRS retro-illuminated chart）测得的远距离字母视力，以及视角为15′和60′的棋盘格刺激下，P100成分的潜伏期（毫秒）与振幅（微伏）等瞬态图形翻转视觉诱发电位参数，并记录患者伪装视力障碍的动机。
研究结果：本队列共纳入20名受试者，其中11名（55%）为女性；患者年龄范围为21至61岁，平均年龄45.05±11.76岁，中位年龄49岁。8例患者（6名女性）自述双眼视力下降，但图形翻转视觉诱发电位参数正常，归为单纯伪装视力障碍者；剩余12例患者（7名男性）仅单眼存在真性视力下降，对侧眼为模拟性视力下降，归为夸大伪装者。18例患者（9名男性）存在经济类伪装动机。
研究结论：在20例疑似眼部伪装视力障碍的患者队列中，观察到部分个体的图形翻转视觉诱发电位参数正常。该电生理技术可作为此类特定人群视觉通路完整性的评估手段，具备一定临床应用价值。