Effects of Repeated Administration and Comparability of Alternate Forms for the Global Neuropsychological Assessment (GNA).

The Global Neuropsychological Assessment (GNA) is an extremely brief battery of cognitive tasks assessing episodic memory, processing speed, working memory, verbal fluency, executive function, and mood. It can be given in under 15 minutes, has five alternate forms, and does not require an examinee to be literate. The purpose of this study was to quantify practice effects over repeated administrations and assess comparability of the GNA's five alternate forms, preparing the battery for repeated administration in research and clinical settings. Forty participants each completed all five GNA forms at weekly intervals following a Latin square design (i.e., each form was administered at every position in the sequence an equal number of times). In a cognitively intact population, practice effects of 0.56 to 1.06 SD were observed across GNA measures when comparing the first and fifth administration. Most GNA tests showed nonsignificant interform differences with cross-form means differing by 0.35 SD or less, with the exception of modest but statistically significant interform differences for the GNA Story Memory subtest across all five forms. However, post hoc analysis identified clusters of two and three Story Memory alternate forms that were equivalent.

Brief Report: Using the Internet to Identify Persons with Cognitive Impairment for Participation in Clinical Trials.

Identifying, recruiting, and enrolling persons in clinical trials of dementia treatments is extremely difficult. One approach to first-wave screening of potential participants is the use of online assessment tools. Initial studies using the Dementia Risk Assessment (DRA)-which includes a previously validated recognition memory test-support the use of this self-administered assessment to identify individuals with "suspected MCI" or "suspected dementia." In this study, we identified between 71 and 622 persons with suspected dementia and between 128 and 1653 persons with suspected mild cognitive impairment (depending on specific criteria) over the course of 22 months. Assessment tools that can inexpensively and easily identify individuals with higher than average risk for cognitive impairment can facilitate recruitment for large-scale clinical trials for dementia treatments.

Severity of hypertension predicts the generalized neurocognitive deficit in schizophrenia.

Individuals with schizophrenia have been found to display neurocognitive deficits on the order of 1 standard deviation below the mean of healthy controls on a range of cognitive domains, with no clear pattern of deficits that characterizes the majority of individuals with schizophrenia. Such findings have led some to suggest that schizophrenia is characterized by a "generalized" neurocognitive deficit, implying that a common underlying etiology impacts all cognitive domains. Central nervous system accounts of the generalized deficit have been proposed (e.g., NMDA and GABA interneuron receptor dysfunction); however, there may also be more diffuse "general systems" abnormalities that affect brain function. The current study evaluated the role of one type of general systems abnormality, metabolic dysfunction, on global cognitive functioning in a sample of outpatients with schizophrenia (n=27) and demographically matched healthy controls (n=33). Participants completed a battery of neuropsychological tests, as well as metabolic measurements to assess blood glucose, blood pressure, and abdominal obesity. Results indicated that higher pulse pressure predicted the generalized neurocognitive deficit in schizophrenia, but not healthy controls; however, blood glucose and abdominal obesity did not predict cognitive performance in either group. These findings provide support for the role of metabolic abnormalities in the generalized neurocognitive deficit in schizophrenia, and suggest that treatment of hypertension may be a novel adjunctive treatment target for remediating cognitive deficits in schizophrenia.

Avolition in schizophrenia is associated with reduced willingness to expend effort for reward on a Progressive Ratio task.

The current study examined whether effort-cost computation was associated with negative symptoms of schizophrenia (SZ). Participants included outpatients diagnosed with SZ (n=27) and demographically matched healthy controls (n=32) who completed a Progressive Ratio task that required incrementally greater amounts of physical effort to obtain monetary reward. Breakpoint, the point at which participants was no longer willing to exert effort for a certain reward value, was examined as an index of effort-cost computation. There were no group differences in breakpoint for low, medium, or high value rewards on the Progressive Ratio task. However, lower breakpoint scores were associated with greater severity of avolition and anhedonia symptoms in SZ patients. Findings provide further evidence that impaired effort-cost computation is linked to motivational abnormalities in SZ.

Predictors of neuropsychological effort test performance in schizophrenia.

There is some evidence that insufficient effort may be common in schizophrenia, posing significant threats to the validity of neuropsychological test results. Low effort may account for a significant proportion of variance in neuropsychological test scores and the generalized cognitive deficit that characterizes the disorder. The current study evaluated clinical predictors of insufficient effort in schizophrenia using an embedded effort measure, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Effort Index (EI). Participants were 330 patients meeting DSM-IV-TR criteria for schizophrenia, schizoaffective disorder, or another psychotic disorder who received a battery of neuropsychological tests, including: Wechsler Test of Adult Reading (WTAR), Wechsler Abbreviated Scale of Intelligence (WASI), and RBANS. Clinical assessments designed to measure functional outcome and symptoms were also obtained. Results indicated that 9.4% of patients failed the EI. Patients who failed had lower full-scale, verbal, and performance IQ, as well as poorer performance on RBANS domains not included in the EI (immediate memory, language, and visuospatial/construction). Patients who failed the EI also displayed poorer community-based vocational outcome, greater likelihood of having "deficit schizophrenia" (i.e., primary and enduring negative symptoms), and increased severity of positive symptoms. Regression analyses revealed that insufficient effort was most significantly predicted by a combination of low IQ, negative symptoms, and positive symptoms. Findings suggest that although insufficient effort may be relatively uncommon in schizophrenia, it is associated with important clinical outcomes. The RBANS EI may be a useful tool in evaluating insufficient effort in schizophrenia.

The role of low cognitive effort and negative symptoms in neuropsychological impairment in schizophrenia.

OBJECTIVE: Two experiments were conducted to examine whether insufficient effort, negative symptoms (e.g., avolition, anhedonia), and psychological variables (e.g., anhedonia and perception of low cognitive resources) predict generalized neurocognitive impairment in individuals with schizophrenia (SZ). METHOD: In Experiment 1, participants included 97 individuals with SZ and 63 healthy controls (CN) who completed the Victoria Symptom Validity Test (VSVT), the MATRICS Consensus Cognitive Battery (MCCB), and self-report anhedonia questionnaires. In Experiment 2, participants included 46 individuals with SZ and 33 CN who completed Green's Word Memory Test (WMT), the MCCB, and self-reports of anhedonia, defeatist performance beliefs, and negative expectancy appraisals. RESULTS: RESULTS indicated that a low proportion of individuals with SZ failed effort testing (1.0% Experiment 1; 15.2% Experiment 2); however, global neurocognitive impairment was significantly predicted by low effort and negative symptoms. CONCLUSIONS: Findings indicate that low effort does not threaten the validity of neuropsychological test results in the majority of individuals with schizophrenia; however, effort testing may be useful in SZ patients with severe negative symptoms who may be more likely to put forth insufficient effort due to motivational problems. Although the base rate of failure is relatively low, it may be beneficial to screen for insufficient effort in SZ and exclude individuals who fail effort testing from pharmacological or cognitive remediation trials.