Marc A. Norman

Demographically corrected norms for the California Verbal Learning Test

The California Verbal Learning Test (CVLT) is designed to quantify components of verbal learning, retention and retrieval. The present study used multiple regression analyses to correct for demographic characteristics on CVLT performance measures. There were 906 subjects, of whom 549 were Caucasians (61%) and 357 were African Americans (39%). Age, education, ethnicity, and gender were found to be significant predictors of performance on several CVLT indices, including Total Words Recalled, Trial 1, Trial 5, List B, Short Delay Free Recall (SDFR), and Long Delay Free Recall (LDFR). Demographically corrected T-scores were calculated for a base sample of 672 subjects and cross-validated on 234 separate subjects. Tables and regression equations are offered to convert raw scores into T-scores corrected for age, gender, education, and ethnicity. Demographically corrected Recognition Discriminability cutoff scores were calculated for age and education levels. In order to provide some indices of important memory processes, we also computed indices of retrieval, Short-Delay forgetting and Long-Delay forgetting and present normative information for them.

Demographically corrected norms for African Americans and Caucasians on the Hopkins Verbal Learning Test–Revised, Brief Visuospatial Memory Test–Revised, Stroop Color and Word Test, and Wisconsin Card Sorting Test 64-Card Version

Memory and executive functioning are two important components of clinical neuropsychological (NP) practice and research. Multiple demographic factors are known to affect performance differentially on most NP tests, but adequate normative corrections, inclusive of race/ethnicity, are not available for many widely used instruments. This study compared demographic contributions for widely used tests of verbal and visual learning and memory (Brief Visual Memory Test–Revised, Hopkins Verbal Memory Test–Revised) and executive functioning (Stroop Color and Word Test, Wisconsin Card Sorting Test–64) in groups of healthy Caucasians (n = 143) and African Americans (n = 103). Demographic factors of age, education, gender, and race/ethnicity were found to be significant factors on some indices of all four tests. The magnitude of demographic contributions (especially age) was greater for African Americans than for Caucasians on most measures. New, demographically corrected T-score formulas were calculated for each race/ethnicity. The rates of NP impairment using previously published normative standards significantly overestimated NP impairment in African Americans. Utilizing the new demographic corrections developed and presented herein, NP impairment rates were comparable between the two race/ethnicities and were unrelated to the other demographic characteristics (age, education, gender) in either race/ethnicity group. Findings support the need to consider extended demographic contributions to neuropsychological test performance in clinical and research settings.

Response inhibition and set shifting in patients with frontal lobe epilepsy or temporal lobe epilepsy

Patients with frontal lobe epilepsy (FLE), patients with temporal lobe epilepsy (TLE), and matched controls were administered a test of response inhibition and set shifting (switching) (Color Word Interference Test, CWIT). Patients with FLE were impaired relative to the controls across all conditions of the CWIT, with the FLE patients showing disproportionate impairment in the Inhibition and Inhibition/Switching conditions. In contrast, the TLE patients did not differ from controls. Further analysis of the patient groups revealed that patients with left FLE were impaired relative to those with right FLE, left TLE, and right TLE in the Inhibition condition. In the Inhibition/Switching condition, patients with left FLE and left TLE were impaired relative to their right-sided counterparts. Finally, performance by the TLE group in the Inhibition/Switching condition was correlated with seizure frequency. These data suggest that patients with FLE, but not TLE, show impaired inhibition and set shifting relative to controls. In addition, side of the seizure focus and seizure frequency may contribute to executive dysfunction in patients with epilepsy.

Is impairment in set-shifting specific to frontal-lobe dysfunction? Evidence from patients with frontal-lobe or temporal-lobe epilepsy

Frontal-lobe epilepsy (FLE), temporal-lobe epilepsy (TLE), and matched-control subjects were administered the Trail Making Test (TMT) of the Delis-Kaplan Executive Function System (D-KEFS; Delis et al., 2001), which assesses set-shifting on a visuomotor sequencing task. Results indicated that patients with FLE were impaired in both speed and accuracy on the switching condition relative to patients with TLE and controls. The two patient groups did not differ from controls on the four baseline conditions of the test, which assess visual scanning, motor speed, number sequencing, and letter sequencing. In addition, seizure-related variables (i.e., age of seizure onset, duration of epilepsy, and seizure frequency) failed to correlate with set-shifting performance in patients with FLE. These results suggest that patients with FLE can be reliably distinguished from those with TLE and control subjects on set-shifting as measured by the DKEFS TMT.

Discriminating patients with frontal-lobe epilepsy and temporal-lobe epilepsy: utility of a multilevel design fluency test.

Patients with frontal-lobe epilepsy (FLE) or temporal-lobe epilepsy (TLE) and matched control participants were given a design fluency test that assessed nonverbal fluency and switching ability. Patients with FLE generated fewer designs in the switching condition relative to the TLE patients and controls, whereas group differences did not emerge in the basic fluency conditions. When the side of the seizure focus and the presence or absence of a structural lesion were considered in patients with FLE, only those with left-lesional FLE generated fewer designs than controls did in the switching condition. Furthermore, patients with left-lesional and nonlesional FLE produced a greater proportion of set-loss errors than did controls. These results indicate that patients with FLE are impaired when they must simultaneously generate new designs and engage in cognitive switching; however, the pattern of impairment may depend on the side of the seizure focus and the presence of a structural lesion.

Neuropsychological change following gamma knife surgery in patients with left temporal lobe epilepsy: a review of three cases

Gamma knife surgery (GKS) is a radiation procedure recently used in the treatment of temporal lobe epilepsy (TLE). Preliminary studies have shown significant seizure reductions in patients 8-26 months postprocedure; however, little is known about the effect of GKS on cognitive functioning in TLE. We report neuropsychological data on three patients with left TLE and MRI evidence of hippocampal sclerosis who underwent GKS. Two models for assessing cognitive change, reliable change indices and regression-based norms for change, were used to measure preoperative versus 13- to 27-month postoperative cognitive change. Results revealed a significantly long delayed verbal memory decline on one measure following GKS. No patient declined on measures of IQ, visual memory, or language. Radiation-induced edema was present at the time of testing in all three patients, which may have affected verbal memory performance. While preliminary, these data suggest that GKS offers a less invasive option to anterior temporal lobectomy, but may produce neuropsychological changes similar to those produced by left anterior temperol lobectomy up to 2 years post-GKS treatment.

Demographically Adjusted Normative Standards for New Indices of Performance on the Paced Auditory Serial Addition Task (PASAT)

The Paced Auditory Serial Addition Task (PASAT) is a complex cognitive test sensitive to neuropsychological disorders. Its traditional Total Correct score seemingly reflects multiple cognitive abilities, including attention, working memory, and processing speed. Snyder, Aniskiewicz, and Snyder (1993) modified scoring guidelines for the PASAT to give credit only for “dyads.” This method emphasizes working memory operations and has been found superior to Total Correct scores at detecting cognitive impairments in several investigations. To date, normative standards are not available for the “dyad” scoring method, thus limiting its utility in clinical and research settings. The current investigation provides demographically adjusted normative data based on a sample of 500 healthy adults of varied age, education, sex, and race (African American and Caucasian) for various indices of performance on the PASAT, including “Total Dyads” obtained across the four PASAT trials. In addition, we describe and present normative data on four other indices designed to quantify various aspects of performance on the PASAT: invalid responding, effects of varied information processing speed demands, and tendency to omit responses and to make arithmetic errors.

Racial and ethnic diversity among trainees and professionals in psychology and neuropsychology: needs, trends, and challenges.

The United States is rapidly becoming a more racially and ethnically diverse nation, bringing the challenge of ensuring that health care specialties, including neuropsychology, are representative of and competent to serve the needs of this population. Initiatives have been undertaken to increase minority representation in training for psychology and neuropsychology. However, tracking progress requires reliable race/ethnicity data collection and reporting. On the 2002 American Psychological Association (APA) Directory Survey (APA Research Office, 2002), up to 42% of the APA membership and up to 25% of the Division 40 membership did not specify race/ethnicity status. Within Division 40, data for members who did report race/ethnicity suggest that representation of Hispanic, Asian, Black/African American, and Native American members lags substantially behind that of White members. Improved methods for collecting information on race/ethnicity are needed to meet diversity objectives.

Association between dyads and correct responses on the Paced Auditory Serial Addition Task (PASAT).

The sensitivity of the Paced Auditory Serial Addition Task (PASAT) to working memory deficits may be enhanced by examining “dyads” (i.e., correct responses immediately preceded by a correct response) as a complement to the traditional total correct summary score. In a sample of 397 mostly African American (79%) healthy adults, total dyad and total correct scores were highly correlated (r = .96, p < .001); however, the magnitude of this association diminished in faster stimulus presentation trials, particularly among participants with impaired working memory abilities.

Multimodal imaging of language reorganization in patients with left temporal lobe epilepsy

HighlightsMultimodal imaging can help to localize language networks in LTLE.Interhemispheric language reorganization is associated with alternations to the ARC.Structural and functional shifts mitigate language impairment in LTLE. ABSTRACT This study explored the relationships among multimodal imaging, clinical features, and language impairment in patients with left temporal lobe epilepsy (LTLE). Fourteen patients with LTLE and 26 controls underwent structural MRI, functional MRI, diffusion tensor imaging, and neuropsychological language tasks. Laterality indices were calculated for each imaging modality and a principal component (PC) was derived from language measures. Correlations were performed among imaging measures, as well as to the language PC. In controls, better language performance was associated with stronger left‐lateralized temporo‐parietal and temporo‐occipital activations. In LTLE, better language performance was associated with stronger right‐lateralized inferior frontal, temporo‐parietal, and temporo‐occipital activations. These right‐lateralized activations in LTLE were associated with right‐lateralized arcuate fasciculus fractional anisotropy. These data suggest that interhemispheric language reorganization in LTLE is associated with alterations to perisylvian white matter. These concurrent structural and functional shifts from left to right may help to mitigate language impairment in LTLE.