Detecting feigned cognitive impairment using pupillometry on the Warrington Recognition Memory Test for Words

Area of Science:

• Neuroscience
• Psychology
• Biometrics

Background:

• Pupillometry measures physiological and psychological states, including cognitive load, familiarity, and deception.
• These pupillary responses are involuntary and offer insights into an individual's cognitive processes.
• Performance validity testing (PVT) is crucial in neuropsychological evaluations, especially for traumatic brain injury (TBI).

Purpose of the Study:

• To investigate pupillary dilation patterns during a PVT in adults with genuine TBI and those feigning impairment.
• To determine if pupillometry can differentiate between true TBI and simulated cognitive deficits.

Main Methods:

• 214 adults participated: 51 with TBI, 72 healthy controls (HC), and 91 simulating TBI (SIM).
• Pupillary dilation indices (PD-Baseline, PD-Range) and a pupillary-behavioral index (Dilation-Response Inconsistency - DRI) were evaluated during a PVT.
• The Recognition Memory Test (RMT) was administered as part of a neuropsychological battery.

Main Results:

• All three pupillary indices significantly differed among groups (TBI, HC, SIM) with medium-to-large effect sizes.
• PD-Baseline was lower in the TBI group, indicating oculomotor dysfunction.
• PD-Range showed SIM > TBI > HC, suggesting differential dynamic engagement.
• DRI was significantly higher in simulators (SIM) compared to other groups, particularly distinguishing simulators with invalid RMT scores from TBI patients with invalid scores.

Conclusions:

• Pupillometry shows promise as a biometric tool for performance validity assessment in TBI evaluations.
• The findings support further research into using pupillary indices in multimethod assessments of performance validity.
• Pupillary measures, especially DRI, can aid in identifying feigned cognitive impairment.