Effectiveness of the Comalli Stroop Test as a measure of negative response bias.

Practice guidelines recommend the use of multiple performance validity tests (PVTs) to detect noncredible performance during neuropsychological evaluations, and PVTs embedded in standard cognitive tests achieve this goal most efficiently. The present study examined the utility of the Comalli version of the Stroop Test as a measure of response bias in a large sample of "real world" noncredible patients (n = 129) as compared with credible neuropsychology clinic patients (n=233). The credible group performed significantly better than the noncredible group on all trials, but particularly on word-reading (Stroop A) and color-naming (Stroop B); cut-scores for Stroop A and Stroop B trials were associated with moderate sensitivity (49-53%) as compared to the low sensitivity found for the color interference trial (29%). Some types of diagnoses (including learning disability, severe traumatic brain injury, psychosis, and depression), very advanced age (⩾80), and lowered IQ were associated with increased rates of false positive identifications, suggesting the need for some adjustments to cut-offs in these subgroups. Despite some previous reports of an inverted Stroop effect (i.e., color-naming worse than color interference) in noncredible subjects, individual Stroop word reading and color naming trials were much more effective in identifying response bias.

Cross validation of the Lu and colleagues (2003) Rey-Osterrieth Complex Figure Test effort equation in a large known-group sample.

A Rey-Osterrieth Complex Figure Test (ROCFT) equation incorporating copy and recognition was found to be useful in detecting negative response bias in neuropsychological assessments (ROCFT Effort Equation; Lu, P. H., Boone, K. B., Cozolino, L., & Mitchell, C. (2003). Effectiveness of the Rey-Osterrieth Complex Figure Test and the Meyers and Meyers recognition trial in the detection of suspect effort. Clinical Neuropsychologist, 17, 426-440). In the current cross validation of this validity, the credible patient group (n = 146; 124 with equation data) outperformed the noncredible group (n = 157; 115 with equation data) on copy, 3-min recall, total recognition correct and the Effort Equation, but the latter was most effective in classifying subjects. A cut-off of ≤50 maintained specificity of 90% and achieved sensitivity of 80%. Results of the current cross validation provide corroboration that the ROCFT Effort Equation is an effective measure of neurocognitive response bias.

Antiretroviral adherence and the nature of HIV-associated verbal memory impairment.

The authors investigated the relationship between antiretroviral adherence and HIV-associated verbal memory impairment. HIV-positive participants demonstrated poorer verbal memory than HIV-negative participants. Both good (≥90%) and poor (<90%) adherers displayed encoding deficits as compared with controls, but only poor adherers exhibited retrieval deficits. Encoding deficits primarily accounted for reduced delayed recall in good adherers, but both encoding and retrieval deficits accounted for reduced delayed recall in poor adherers. The retrieval difference between the adherence groups might be explained by a neuroprotective effect of good antiretroviral adherence or preexisting HIV-related retrieval deficits that result in poorer adherence.

Non-credible language deficits following mild traumatic brain injury.

Identification of non-credible memory and other cognitive symptoms has received widespread attention within the past two decades. However, minimal information is available regarding patterns of non-credible language symptoms. We present the case of a 36-year-old female civil litigant who displayed delayed onset, severe, relatively focal speech and language symptoms, including difficulties with articulation, dysfluent speech, expressive language impairments with minor receptive difficulties, and lack of prosody, subsequent to a minor head trauma. On neuropsychological evaluation 3 years post injury, the patient presented with the same speech/language characteristics, but additionally exhibited a vague "foreign accent." Cognitive scores generally were normal with the exception of poor performance on many language tasks and processing/motor speed. The patient showed passing performance on most measures of response bias, but she failed effort indicators requiring rapid letter discrimination (b Test), rapid verbal repetition (timed forward digit span), and sensory function (finger agnosia errors) while passing effort indicators falling within the domains of memory, math/number skills, visuo-constructional ability, and attention. Thus, the type of failed effort indicators predicted the categories of standard cognitive tests on which she underperformed. Personality testing revealed patterns generally consistent with hysterical personality orientation. Given her long-standing history of multiple unexplained medical symptoms, the patient was diagnosed with a somatization disorder, as well as a current conversion disorder involving language symptoms. However, given her compensation-seeking status, the possibility of additional conscious feigning of symptoms could not be ruled out. The need for validation of additional measures to detect feigned language impairment is recommended.

Verbal fluency deficits co-occur with memory deficits in geriatric patients at risk for dementia: Implications for the concept of mild cognitive impairment.

We tested the notion that patients at high risk for progression to Alzheimer's disease (AD) display relatively isolated memory deficits by assessing the relationship between memory and fluency performances in a sample of 92 geriatric subjects with cognitive complaints and normal to mild clinical presentations. Patient groups were formed on the basis of memory test scores. Patients with normal memory scores also performed normally on fluency tests, and their fluency scores were significantly higher than those of patients with low memory performances. Patients falling between these two groups in memory abilities also displayed intermediate level fluency performances. Whereas the normal memory group performed at equivalent levels on semantic and phonemic fluency tasks, both the impaired memory group and the intermediate group displayed relatively greater weaknesses in semantic fluency. This pattern is similar to that seen in AD. Since the impaired memory patients meet criteria for Amnestic Mild Cognitive Impairment, these findings suggest that memory deficits in "pre-clinical" AD are likely to be accompanied by fluency weaknesses, with semantic fluency weaknesses predominating.

The Warrington Recognition Memory Test for words as a measure of response bias: total score and response time cutoffs developed on "real world" credible and noncredible subjects.

Several studies have examined the usefulness of the Warrington Recognition Memory Test-Words as a measure to detect suspect effort, although samples have generally been small and/or comprised of simulators rather than "real world" credible and noncredible patients. The current study examined the Warrington Recognition Memory Test-Words total score and response time of "real world" noncredible patients (as determined by motive to feign, failure on > or =2 independent measures of response bias, low cognitive scores inconsistent with normal ADLs; n = 190) versus credible patients (as determined by no motive to feign, failure of < or =1 measure of response bias; n = 124) derived from an archival database of individuals from the Harbor-UCLA Medical Center, Department of Psychiatry, Outpatient Neuropsychology Service, and the private practice of the second author. Noncredible patients obtained significantly lower total scores and longer times to complete the task. A total correct cutoff of < or =42 was found to have excellent specificity (91.9%) and sensitivity (88.9%), whereas a time cutoff of > or =207'' was associated with 65.5% sensitivity at 90.7% specificity, and when the time cut-score was used in combination with the total score cutoff, an additional 5% of the noncredible participants were captured, raising overall sensitivity to 93.7% (at 87.1% specificity). Thus, the Warrington Recognition Memory Test-Words, although not originally created for the purposes of measuring suspect effort, appears to be an excellent measure for detecting response bias on neuropsychological testing.

Examination of various WMS-III logical memory scores in the assessment of response bias.

The assessment of response validity during neuropsychological evaluation is an integral part of the testing process. Research has increasingly focused on the use of "embedded" effort measures (derived from standard neuropsychological tasks) because they do not require additional administration time and are less likely to be identified as effort indicators by test takers because of their primary focus as measures of cognitive function. The current study examined the clinical utility of various WMS-III Logical Memory scores in detecting response bias, as well as the Rarely Missed Index, an embedded effort indicator derived from the WMS-III Logical Memory Delayed Recognition subtest. The Rarely Missed Index cut-off only identified 24.1% of 63 non-credible participants (at >/=90% specificity in 125 credible patients), and cut-offs for other Logical Memory variables were in fact found to be more sensitive to non-credible performance. A new indicator, consisting of the weighted combination of the two most sensitive Logical Memory subtest scores (Logical Memory II raw score and Logical Memory Delayed Recognition raw score), was associated with 53% to 60% sensitivity, and thus may be an effective adjunct when utilized in conjunction with other validated effort indicators and collateral information in identifying non-credible performance.