The effectiveness and unique contribution of neuropsychological tests and the δ latent phenotype in the differential diagnosis of dementia in the uniform data set

OBJECTIVE

Two main approaches to the interpretation of cognitive test performance have been utilized for the characterization of disease: evaluating shared variance across tests, as with measures of severity, and evaluating the unique variance across tests, as with pattern and error analysis. Both methods provide necessary information, but the unique contributions of each are rarely considered. This study compares the 2 approaches on their ability to differentially diagnose with accuracy, while controlling for the influence of other relevant demographic and risk variables.

METHOD

Archival data requested from the NACC provided clinical diagnostic groups that were paired to 1 another through a genetic matching procedure. For each diagnostic pairing, 2 separate logistic regression models predicting clinical diagnosis were performed and compared on their predictive ability. The shared variance approach was represented through the latent phenotype δ, which served as the lone predictor in 1 set of models. The unique variance approach was represented through raw score values for the 12 neuropsychological test variables comprising δ, which served as the set of predictors in the second group of models.

RESULTS

Examining the unique patterns of neuropsychological test performance across a battery of tests was the superior method of differentiating between competing diagnoses, and it accounted for 16-30% of the variance in diagnostic decision making.

CONCLUSION

Implications for clinical practice are discussed, including test selection and interpretation. (PsycINFO Database Record

RBANS factor structure in older adults with suspected cognitive impairment: Evidence for a 5-factor structure

Previous research has yielded minimal empirical support for the theoretically formulated five-factor structure of the RBANS, a brief, yet comprehensive standardized neuropsychological test battery used to assess cognitive impairment. The present study tested the theoretically formulated five-factor structure, as well as three alternative factor solutions, using a combination of exploratory and confirmatory factor analytic approaches. The present study utilized archival data from a clinical sample of 150 older adults who were evaluated at an outpatient neuropsychological service. A total of four RBANS models were specified using confirmatory factor analysis. Results of the five-factor model demonstrated good to excellent fit following modifications to the model. Results of chi-square difference tests demonstrated that the five-factor model was statistically superior to the two- and three-factor models (p < .001). In summary, results provide support for the theoretically derived five-factor structure of the RBANS in a clinical sample of older adults. Cautious interpretation of the RBANS index scores as five distinct cognitive domains may be warranted, particularly when there is minimal discrepancy across performance on the tests that comprise each index.

Practice Effects on Story Memory and List Learning Tests in the Neuropsychological Assessment of Older Adults

Two of the most commonly used methods to assess memory functioning in studies of cognitive aging and dementia are story memory and list learning tests. We hypothesized that the most commonly used story memory test, Wechsler's Logical Memory, would generate more pronounced practice effects than a well validated but less common list learning test, the Neuropsychological Assessment Battery (NAB) List Learning test. Two hundred eighty-seven older adults, ages 51 to 100 at baseline, completed both tests as part of a larger neuropsychological test battery on an annual basis. Up to five years of recall scores from participants who were diagnosed as cognitively normal (n = 96) or with mild cognitive impairment (MCI; n = 72) or Alzheimer's disease (AD; n = 121) at their most recent visit were analyzed with linear mixed effects regression to examine the interaction between the type of test and the number of times exposed to the test. Other variables, including age at baseline, sex, education, race, time (years) since baseline, and clinical diagnosis were also entered as fixed effects predictor variables. The results indicated that both tests produced significant practice effects in controls and MCI participants; in contrast, participants with AD declined or remained stable. However, for the delayed-but not the immediate-recall condition, Logical Memory generated more pronounced practice effects than NAB List Learning (b = 0.16, p < .01 for controls). These differential practice effects were moderated by clinical diagnosis, such that controls and MCI participants-but not participants with AD-improved more on Logical Memory delayed recall than on delayed NAB List Learning delayed recall over five annual assessments. Because the Logical Memory test is ubiquitous in cognitive aging and neurodegenerative disease research, its tendency to produce marked practice effects-especially on the delayed recall condition-suggests a threat to its validity as a measure of new learning, an essential construct for dementia diagnosis.

The Clinical Utility of the Conners' Continuous Performance Test-II in Traumatic Brain Injury

OBJECTIVE

The Conners' Continuous Performance Test Second Edition (CPT-II) is a measure commonly used in persons with suspected attentional deficits. Our study examined the utility of the CPT-II as a measure of attention in adults with traumatic brain injury (TBI) of varying severity.

METHOD

As part of a larger investigation, several measures of cognitive functioning, including the CPT-II, were administered to 30 healthy control participants (HCP), 30 mild TBI participants (M-TBI), and 30 moderate to severe TBI participants (MS-TBI). Multivariate and correlational analyses compared group performances and examined convergent and divergent relationships between the CPT-II and various measures, including other tests of attention and neuropsychological function.

RESULTS

Group differences were found for four of six CPT-II variables, with the MS-TBI group exhibiting greater impairment, relative to M-TBI and HCP. In addition, the CPT-II commission and detectability variables were found to correlate significantly with TBI severity. The CPT-II variables also demonstrated correlations of varying magnitude between commonly used neuropsychological measures.

CONCLUSIONS

These findings support the utility of the CPT-II for assessing attentional abilities in persons with TBI of varying severity, particularly those with moderate to severe status. Moreover, the current study also demonstrates relationships that are consistent with convergent validity but inconsistent findings with regard to divergent validity. As a result, the CPT-II measures components of attention that is unique to other commonly used neuropsychological measures of attentive functioning. Further research examining CPT-II performance in TBI populations is recommended.

Association of psychological, cognitive, and functional variables with self-reported executive functioning in a sample of nondemented community-dwelling older adults

Subjective executive functioning (EF) measures provide valuable information about real-world difficulties, although it is unclear what variables actually associate with subjective EF scores. We investigated subjective EF in 245 nondemented, community-dwelling older adults (aged 70 and above) from the Einstein Aging Study. Partial correlational analyses controlling for age were performed between the nine Behavior Rating Inventory of Executive Function-Adult version (BRIEF-A) clinical scales and objective EF tests, self-reported mood and personality, and informant-reported activities of daily living. The significance level was set at p < .006 for all analyses (two-tailed). Most notably, higher worry/oversensitivity, physiological anxiety, and fear of aging were significantly associated with increased EF difficulties on all nine BRIEF-A scales. Additionally, increased EF difficulties on five or more BRIEF-A scales were significantly associated with lower conscientiousness, higher neuroticism, and higher depressive symptom scores. The only objective neuropsychological test that significantly correlated with increased EF difficulties (on four BRIEF-A scales) was a measure of practical judgment. Overall, results indicate that interpretation of subjective EF scores must account for self-report of mood and personality. Moreover, the BRIEF-A only minimally taps objective EF as measured by performance-based measures. We discuss the theoretical and practical implications of these findings.