They are not destined to fail: a systematic examination of scores on embedded performance validity indicators in patients with intellectual disability

ABSTRACT

This study was designed to determine the clinical utility of embedded performance validity indicators (EVIs) in adults with intellectual disability (ID) during neuropsychological assessment. Based on previous research, unacceptably high (>16%) base rates of failure (BR_Fail) were predicted on EVIs using on the method of threshold, but not on EVIs based on alternative detection methods. A comprehensive battery of neuropsychological tests was administered to 23 adults with ID (M_Age = 37.7 years, M_FSIQ = 64.9). BR_Fail were computed at two levels of cut-offs for 32 EVIs. Patients produced very high BR_Fail on 22 EVIs (18.2%-100%), indicating unacceptable levels of false positive errors. However, on the remaining ten EVIs BR_Fail was <16%. Moreover, six of the EVIs had a zero BR_Fail, indicating perfect specificity. Consistent with previous research, individuals with ID failed the majority of EVIs at high BR_Fail. However, they produced BR_Fail similar to cognitively higher functioning patients on select EVIs based on recognition memory and unusual patterns of performance, suggesting that the high BR_Fail reported in the literature may reflect instrumentation artefacts. The implications of these findings for clinical and forensic assessment are discussed.

KEYWORDS:

• Intellectual disability
• performance validity
• embedded validity indicators
• false positive rate
• forensic assessment

Acknowledgments

Relevant ethical guidelines were followed throughout the project. All data collection, storage and processing was done with the approval of relevant institutional authorities regulating research involving human participants, in compliance with the 1964 Helsinki Declaration and its subsequent amendments or comparable ethical standards.

Disclosure statement

No potential conflict of interest was reported by the author(s).