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.

Morphofunctional evaluation of peripapillary retinoschisis associated with myopic posterior staphyloma and hyaloid traction: does it cause peripapillary vitreoretinal traction?

“…Clinical PR-VEP testing should be interpreted with consideration of the activity of the retinal visual field; thus, a check size of 1° elicits a mostly parafoveal response, whereas a check size of 15′ elicits a foveal response. In their work, Soares and coworkers reported that patients with mild vision loss may occasionally have normal PR-VEP findings, indicating integrity of the visual pathway (9) . Thus, in this case, the peripapillary findings observed on SS-OCT associated with functional tests led us to believe that PVT is present.…”

Evaluating the clinical applications of visual evoked potentials in patients presenting with visual dysfunctions - A retrospective study

“…[14] The tests are considered highly sensitive for the identification of malingering and factitious disorders. [15,16] Patients with clinical diagnosis of presumed ethambutol optic neuropathy were also investigated for VEP tests to detect ethambutol-induced toxic optic neuropathy. VEP records were characterized by varied abnormalities; bilateral P100 delay or reduced amplitudes, while in some, undetected waveforms and both P100 delays and amplitude reduction were noticed [ Table 2].…”