Confirmatory Factor Analysis of the California Verbal Learning Test in Patients With Epilepsy: Relationship to Clinical and Neuropathological Markers of Temporal Lobe Epilepsy

Examining the factor structure of the Rey auditory verbal learning test in individuals across the life span

Objective: Previous studies analyzing the factor structure of the Rey Auditory Verbal Learning Test (RAVLT) have been limited in the number of scores included in the analysis. Often, they lacked inclusion of process scores that have been shown to add predictive value in identifying future cognitive decline. Therefore, the goal of the current study was to determine the factor structure of the RAVLT utilizing factor scores including serial position effects, repetitions, and intrusion errors, and to examine if the factor structure for older adults is similar to that found in the entire lifespan sample.Method: Exploratory factor analysis (EFA) was conducted on 718 participants (age 16-85 years) from the Nathan Kline Institute (NKI)-Rockland project. Confirmatory factor analyses (CFA) of a reduced model of the EFA was conducted on the entire sample and an older (ages 55-85 years; n = 265) and a younger (less than 55 years of age; n = 453) subsample.Results: EFA indicated three factors: Memory, Attention/Learning, and Inaccurate Memory (i.e., repetitions and intrusions). CFA of a reduced model indicated adequate fit in the entire sample and older subsample, and good fit in the younger subsample.Conclusion: The present study examined the factor structure of the RAVLT in a large lifespan sample utilizing a larger set of RAVLT scores than have been examined in prior studies, including total scores and process scores. The same factors were identified in the entire lifespan sample and the younger and older adult subsamples, although similar to previous studies, measures of model fit were less robust in the older adult subsample. These results provide additional support for the error scores (e.g., intrusions and repetitions) as separable from other aspects of learning and memory.

Spatial memory for asymmetrical dot locations predicts lateralization among patients with presurgical mesial temporal lobe epilepsy

This study examined the ability of an asymmetrical dot location memory test (Brown Location Test, BLT) and two verbal memory tests (Verbal Selective Reminding Test (VSRT) and California Verbal Learning Test, Second Edition (CVLT-II)) to correctly lateralize left (LTLE) or right (RTLE) mesial temporal lobe epilepsy that was confirmed with video-EEG. Subjects consisted of 16 patients with medically refractory RTLE and 13 patients with medically refractory LTLE who were left hemisphere language dominant. Positive predictive values for lateralizing TLE correctly were 87.5% for the BLT, 72.7% for the VSRT, and 80% for the CVLT-II. Binary logistic regression indicated that the BLT alone correctly classified 76.9% of patients with left temporal lobe epilepsy and 87.5% of patients with right temporal lobe epilepsy. Inclusion of the verbal memory tests improved this to 92.3% of patients with left temporal lobe epilepsy and 100% correct classification of patients with right temporal lobe epilepsy. Though of a limited sample size, this study suggests that the BLT alone provides strong laterality information which improves with the addition of verbal memory tests.

An Exploratory Study of Reading Comprehension in College Students After Acquired Brain Injury

PURPOSE

This exploratory study builds on the small body of existing research investigating reading comprehension deficits in college students with acquired brain injury (ABI).

METHOD

Twenty-four community college students with ABI completed a battery of questionnaires and standardized tests to characterize self-perceptions of academic reading ability, performance on a standardized reading comprehension measure, and a variety of cognitive functions of this population. Half of the participants in the sample reported traumatic brain injury (n = 12) and half reported nontraumatic ABI (n = 12).

RESULTS

College students with both traumatic and nontraumatic ABI cite problems with reading comprehension and academic performance postinjury. Mean performance on a standardized reading measure, the Nelson-Denny Reading Test (Brown, Fischo, & Hanna, 1993), was low to below average and was significantly correlated with performance on the Speed and Capacity of Language Processing Test (Baddeley, Emslie, & Nimmo-Smith, 1992). Injury status of traumatic versus nontraumatic ABI did not differentiate results. Regression analysis showed that measures of verbal attention and suppression obtained from the California Verbal Language Test-II (Delis, Kramer, Kaplan, & Ober, 2000) predicted total scores on the Nelson-Denny Reading Test.

CONCLUSIONS

College students with ABI are vulnerable to reading comprehension problems. Results align with other research suggesting that verbal attention and suppression problems may be contributing factors.

The relationship between hippocampal volumes and nonverbal memory in patients with medial temporal lobe epilepsy

OBJECTIVE

To explore the involvement of medial temporal lobe structures such as the hippocampus, amygdala, and entorhinal cortex (EC) in memory consolidation by volumetric magnetic resonance imaging (MRI).

METHODS

Sixty-two consecutive patients with medial temporal lobe epilepsy (MMTLE) were assessed using the Clinical Memory Scale (CMS) and MRI to measure the volumes of the hippocampus, amygdala, and EC. Participants were grouped according to MRI findings into 3 groups: left MRI-positive (abnormal hippocampal formation on the left side; n=17), right MRI-positive (abnormal hippocampal formation on the left side; n=9), and MRI-negative (normal hippocampal formation; n=36). One-way analysis of variance (ANOVA) was used to assess group differences for all volumetric data (Z scores or asymmetry indexes (AI)), memory scale scores, and clinical parameters. Post hoc analyses were done with Fisher's least significant difference (LSD) tests. AI=100×(L-R)/(L+R). "L" and "R" refer to the left and right volumes of each structure, respectively.

RESULTS

The nonsense graphical recognition tests and the facial memory tests were significantly different between the three groups. Post hoc analyses showed that the right MRI-positive group performed significantly worse than the MRI-negative group on nonsense graphical recognition tests (P=0.008) and the left MRI-positive group had significantly lower scores than the MRI-negative group on facial memory tests (P=0.023).

CONCLUSIONS

Nonverbal memory was correlated with the status of the right hippocampus.

Neuronal correlates of brain-derived neurotrophic factor Val66Met polymorphism and morphometric abnormalities in bipolar disorder

The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has been proposed as a possible candidate for involvement in the pathophysiology of bipolar disorder (BD). To determine whether an association exists between the BDNF Val66Met genotype and morphometric abnormalities of the brain regions involved in memory and learning in BD and healthy subjects. Forty-two BD patients and 42 healthy subjects were studied. Interactions between BDNF Val66Met genotype and diagnosis in gray (GM) volumes were analyzed using an optimized voxel-based morphometry technique. Declarative memory function was assessed with the California Verbal Learning Test II. Left and right anterior cingulate GM volumes showed a significant interaction between genotype and diagnosis such that anterior cingulate GM volumes were significantly smaller in the Val/Met BD patients compared with the Val/Val BD patients (left P=0.01, right P=0.01). Within-group comparisons revealed that the Val/Met carriers showed smaller GM volumes of the dorsolateral prefrontal cortex compared with the Val/Val subjects within the BD patient (P=0.01) and healthy groups (left P=0.03, right P=0.03). The Val/Met healthy subjects had smaller GM volumes of the left hippocampus compared with the Val/Val healthy subjects (P<0.01). There was a significant main effect of diagnosis on memory function (P=0.04), but no interaction between diagnosis and genotype was found (P=0.48). The findings support an association between the BDNF Val66Met genotype and differential gray matter content in brain structures, and suggest that the variation in this gene may play a more prominent role in brain structure differences in subjects affected with BD.

The Factor Structure of the CVLT-C in Pediatric Epilepsy

The current study used archival data to evaluate the fit of six latent variable models, originally generated by Donders (1999), for the California Verbal Learning Test-Children's Version (CVLT-C; Delis, Kramer, Kaplan, & Ober, 1994) in a large (N = 289) sample of pediatric epilepsy cases presenting at three tertiary treatment centers. Using confirmatory factor analysis, we found that a model including factors of Attention Span, Learning Efficiency, Free Delayed Recall, Cued Delayed Recall, and Inaccurate Recall demonstrated the best relative fit for our data. These findings are consistent with those reported by Donders (1999) in his reanalysis of the CVLT-C standardization sample data, supporting the validity of this factorial model in pediatric epilepsy populations.