Classification accuracy of the word memory test genuine memory impairment index

Area of Science:

• Neuropsychology
• Cognitive Assessment
• Traumatic Brain Injury (TBI) Research

Background:

• The Word Memory Test (WMT) is used to detect non-credible performance in neuropsychological evaluations.
• The Genuine Memory Impairment Profile (GMIP) was developed to reduce false positives in patients with severe cognitive dysfunction.
• The accuracy of GMIP in clinical settings remains uncertain due to limited research.

Purpose of the Study:

• To evaluate the classification accuracy of the GMIP in a simulated mild traumatic brain injury (TBI) context.
• To assess how different levels of coaching influence the detection of simulated memory impairment using the WMT and GMIP.

Main Methods:

• A simulation experiment involving 80 healthy individuals randomly assigned to four groups: naïve simulators, sophisticated simulators, test-coached simulators, and an honest responding control group.
• Participants completed the Word Memory Test (WMT) and the California Verbal Learning Test-2 (CVLT-2).
• Performance validity was assessed using WMT indices and the GMIP.

Main Results:

• High classification accuracy for WMT indices in detecting simulated memory impairment across simulator groups (90-100%).
• Simulators performed worse than controls on the CVLT-2.
• The GMIP incorrectly identified genuine memory impairment in 60% of naïve simulators, 27% of sophisticated simulators, and 6% of test-coached simulators.

Conclusions:

• The GMIP may misclassify individuals with genuine memory impairment, especially when simulation efforts are unsophisticated.
• Individuals employing less sophisticated methods to feign cognitive impairment are more likely to be misclassified by the GMIP.
• The GMIP should be used with caution when differentiating genuine memory impairment from non-credible performance, particularly in mild TBI evaluations.