Abstract for presentation at 6th World Congress on Brain Injury

The Delis-Kaplan Executive Function System (D-KEFS) is a comprehensive test battery of the cognitive abilities associated with the frontal and sub-cortical systems. The D-KEFS standardization sample is contiguous across the 9 sub-tests including improved versions of the trail making, verbal fluency, and tower test. Executive functioning is integral to adaptive functioning and is consequently a domain of assessment critical to the evaluation of impairment and competence in medico-legal and forensic settings. The D-KEFS therefore represents a desirable alternative to its predecessors and may be the assessment tool of choice for examining executive function in medico-legal and forensic settings. Medico-legal and forensic assessments are contexts in which people are highly motivated to intentionally feign cognitive impairment. The current study reports on how the utility of the D-KEFS in these settings might be enhanced by employing a new standardized procedure for detecting malingering. The symptom validity tests developed include an assessment of an Improbable Battery Profile based on the extremity of score, process error frequency and relative performance on tests varying in difficulty. A new D-KEFS stimulus anchored Improbable Symptom Interview © (ISI©) was developed and tested. The usefulness of these two devices will be demonstrated through the comparison of vignettes of two cases who presented for personal injury compensation assessments. The first case was of a young male who was a confirmed malingerer; as identified by his pattern of responding on two symptom validity tests, and inbuilt validity tests in standardized scales. The second case was a middle aged male who presented for assessment of incapacity due to a frontal lobe injury who showed a genuine pattern of responding and impairment. The general approach for developing the new D-KEFS indicies of malingering and possible cut-off scores and profiles for their use in forensic settings will be discussed.