D-KEFS trail making test as an embedded performance validity measure.

OBJECTIVE: The Delis-Kaplan Executive Function System (D-KEFS) Trail Making Test (TMT) is a commonly used measure of processing speed and executive functioning that may also be useful as an embedded performance validity test (PVT). We evaluated the utility of several multi-condition indices on the D-KEFS TMT in three independent samples to determine an optimal multi-condition index and cutoff on the D-KEFS TMT. METHOD: Classification accuracy statistics for multiple multi-condition indices on the D-KEFS TMT were evaluated in three independent samples, including a sample with history of mild traumatic brain injury (TBI; n = 267) classified into psychometrically defined performance-valid and performance-invalid subgroups, the D-KEFS national normative sample (n = 1713), and a sample of middle- and older-aged adults diagnosed with mild cognitive impairment (MCI; n = 70). RESULTS: The D-KEFS TMT Conditions 1-5 summation index maximized sensitivity at .31 while maintaining adequate specificity at ≥.9. This index also had acceptable classification accuracy in both the D-KEFS national normative and MCI cross-validation samples, with the exception of the oldest subgroup of the national norming sample (i.e., individuals' ages 80-89), in which the observed failure rates for all multi-condition indices tested were greater than 10%. CONCLUSION: Our study provides support for the use the D-KEFS TMT Conditions 1-5 summation index as an embedded PVT among individuals younger than 80 years-old and from a range of conditions spanning from cognitively normal to mildly impaired; however, further validation is necessary.

Elevated pulse pressure is associated with age-related decline in language ability.

Recent research suggests that pulse pressure (PP), a putative marker of vascular integrity, may be associated with brain microvascular damage and age-related cognitive decline. Thus, the present study examined the relationship between PP and cognition in a sample of healthy nondemented older adults. One hundred nine participants were administered neurological and neuropsychological evaluations and determined to be nondemented. Regression analyses were used to examine the relationships among pulse pressure (PP) [systolic blood pressure (SBP)--diastolic blood pressure (DBP)], age, and cognition. PP and related measures were inversely correlated with global cognitive functioning and scores on a composite measure of language function, even after adjusting for age, education, and relevant vascular risk factors. Results indicate that increases in the pulsatile component of blood pressure may convey added risk of global cognitive decline and specific impairment in language abilities.

Detection of mild cognitive deficits in Parkinson's disease patients with the WAIS-R NI.

The relative insensitivity of traditional IQ tests to mild cognitive deficits has led investigators to develop a version of the widely used Wechsler intelligence scales that allows quantitative analysis of underlying qualitative responses. This instrument, the Wechsler Adult Intelligence Scale-Revised as a Neuropsychological Instrument (WAIS-R NI) was administered to 16 Parkinson's disease (PD) patients and 30 normal controls (NC). The 2 groups did not differ significantly in mean age or education, or on their mean Mattis Dementia Rating Scale score. Relative to NC participants, PD patients showed decreased visual attention span, longer response latencies, slower visuomotor processing, and more stimulus-bound errors. Many of the WAIS-R NI measures were able to detect cognitive impairment in a greater percentage of patients than the traditional WAIS-R measures, making it easier to identify deficits that could affect quality of life early in the course of the disease.

Verbal and design fluency in patients with frontal lobe lesions.

The ability to generate items belonging to categories in verbal fluency tasks has been attributed to frontal cortex. Nonverbal fluency (e.g., design fluency) has been assessed separately and found to rely on the right hemisphere or right frontal cortex. The current study assessed both verbal and nonverbal fluency in a single group of patients with focal, frontal lobe lesions and age- and education-matched control participants. In the verbal fluency task, participants generated items belonging to both letter cues (F, A, and S) and category cues (animals and boys' names). In the design fluency task, participants generated novel designs by connecting dot arrays with 4 straight lines. A switching condition was included in both verbal and design fluency tasks and required participants to switch back and forth between different sets (e.g., between naming fruits and furniture). As a group, patients with frontal lobe lesions were impaired, compared to control participants, on both verbal and design fluency tasks. Patients with left frontal lesions performed worse than patients with right frontal lesions on the verbal fluency task, but the 2 groups performed comparably on the design fluency task. Both patients and control participants were impacted similarly by the switching conditions. These results suggest that verbal fluency is more dependent on left frontal cortex, while nonverbal fluency tasks, such as design fluency, recruit both right and left frontal processes.

Verbal and nonverbal fluency in children with heavy prenatal alcohol exposure.

OBJECTIVE: Executive function deficits, including verbal fluency, have been documented in children with histories of prenatal alcohol exposure. Whereas nonverbal fluency impairments have been reported in adults with such exposure, these abilities have not been tested in children. Deficits in both verbal and nonverbal fluency were predicted and assessed in children and adolescents with histories of heavy prenatal alcohol exposure. METHOD: There was a total of 28 (54% female) subjects; children with heavy prenatal alcohol exposure with (n = 10) and without (n = 8) fetal alcohol syndrome (FAS) were compared to nonexposed controls (n = 10) on the design and verbal fluency measures from the Delis-Kaplan Executive Function System. Both fluency measures consist of three conditions, including a new set-shifting task. All tests require the generation of multiple responses within both rule and time constraints. RESULTS: Data were analyzed using repeated measures analyses of variance and hierarchical regression analyses. Compared to controls, children with heavy prenatal alcohol exposure with and without FAS displayed deficits in both fluency domains, but did not differ from each other. In addition, prenatal alcohol exposure was a significant predictor of performance on the set-shifting design fluency task above and beyond performance on more traditional fluency tasks. IQ was not a significant predictor for the traditional or set-shifting fluency measures, whereas diagnostic group remained a significant predictor when IQ was included in the model. CONCLUSIONS: This study adds to the literature on the integrity of executive functions in children with heavy prenatal alcohol exposure, documenting fluency impairment in both verbal and nonverbal domains. It is important to note that these impairments were demonstrated in higher functioning alcohol-exposed children, both with and without FAS, and that diagnostic group explained such deficiencies above and beyond general intellectual ability.

Do subgroups of patients with Alzheimer's disease exhibit asymmetric deficits on memory tests?

Several studies have reported asymmetric cognitive profiles in patients with Alzheimer's disease (AD), but these results have almost exclusively been found using non-memory cognitive instruments. The present study investigated whether AD patients who display lateralized profiles on non-memory cognitive instruments also exhibit asymmetric deficits on verbal versus spatial memory tests. Sixty-eight AD patients participated in the study: 36 with a "High Verbal" cognitive profile, and 32 with a "High Spatial" profile. The results indicated that the High Verbal AD patients performed significantly better than the High Spatial AD patients on verbal memory tests, but the two subgroups failed to differ on spatial memory tests. Implications of these findings for understanding the heterogeneous nature of cognitive profiles in AD patients are discussed.

Age effects on executive ability.

Heterogeneity of executive tasks has made it difficult to determine whether there are age-related declines in executive functioning. To address this issue, 112 individuals, 20-79 years old, took the California Trail Making Test (CTMT) and the California Stroop Test (CST), subtests of the Delis-Kaplan Executive Function Scale (D. C. Delis, E. Kaplan, & J. H. Kramer, in press) that include measurement of component skills embedded in the executive function tasks. Multiple regression analyses revealed that after controlling for component skills, age had a significant effect on the executive requirement of the CST, namely speed on the interference condition. Age did not affect switching performance on the letter-number condition of the CTMT. Additional analyses revealed that age was significantly associated with commission of certain types of errors. This study confirms the importance of partialing out components in the assessment of multidimensional cognitive tasks, particularly when making age comparisons. It also emphasizes specificity over generalizability when examining the impact of age on cognition.

Comparison of the serial position effect in very mild Alzheimer's disease, mild Alzheimer's disease, and amnesia associated with electroconvulsive therapy.

Individuals given a series of words to memorize normally show better immediate recall for items from the beginning and end of the list than for mid-list items. This phenomenon, known as the serial position effect, is thought to reflect the concurrent contributions of secondary and primary memory, respectively, to recall performance. The present study compared the serial position effects produced on Trial 1 of the California Verbal Learning Test (CVLT) in mildly demented (N = 25; M MMSE = 20.0) and very mildly demented (N = 25; M MMSE = 25.5) patients with Alzheimer's disease (AD), and age- and education-matched normal control (NC) participants (N = 50). In addition, the serial position effects of the very mildly demented AD patients were compared to those of patients with a transient, circumscribed amnesia arising from a prescribed series of electroconvulsive therapy (ECT) treatments for the relief of depressive illness (N = 11). While the NC group exhibited the typical serial position effect, AD patients recalled significantly fewer words than NC participants overall, and exhibited a significantly reduced primacy effect (i.e., recall of the first 2 list items) with a normal recency effect (i.e., recall of the last 2 list items). Patients with circumscribed amnesia due to ECT were as impaired as the very mildly demented AD patients on most standard CVLT measures of learning and memory, but exhibited primacy and recency effects, which were within normal limits. These results suggest that a reduction in the primacy effect, but not the recency effect, is an early and ubiquitous feature of the memory impairment of AD. It is not, however, a necessary feature of all causes of memory impairment.

Neurocognitive functioning of adolescents: effects of protracted alcohol use.

BACKGROUND: The present study examined associations between alcohol involvement in early to middle adolescence and neuropsychological (NP) functioning. METHODS: Alcohol-dependent adolescents (n = 33) with over 100 lifetime alcohol episodes and without dependence on other substances were recruited from alcohol/drug abuse treatment facilities. Comparison (n = 24) adolescents had no histories of alcohol or drug problems and were matched to alcohol-dependent participants on age (15 to 16 years), gender, socioeconomic status, education, and family history of alcohol dependence. NP tests and psychosocial measures were administered to alcohol-dependent participants following 3 weeks of detoxification. RESULTS: Alcohol-dependent and comparison adolescents demonstrated significant differences on several NP scores. Protracted alcohol use was associated with poorer performance on verbal and nonverbal retention in the context of intact learning and recognition discriminability. Recent alcohol withdrawal among adolescents was associated with poor visuospatial functioning, whereas lifetime alcohol withdrawal was associated with poorer retrieval of verbal and nonverbal information. CONCLUSIONS: Deficits in retrieval of verbal and nonverbal information and in visuospatial functioning were evident in youths with histories of heavy drinking during early and middle adolescence.

Verbal memory impairments in dyslexia.

Although verbal memory deficits are frequently reported in reading disabled children, the specific mechanisms underlying these impairments have yet to be clearly defined. The present study used the California Verbal Learning Test-Children's Version (CVLT-C) to assess verbal learning in 57 dyslexic children and 114 controls matched for gender, age, and WISC-R Vocabulary score. Three areas of verbal memory were investigated: Recall and recognition, use of learning strategies, and interference effects. The dyslexic group learned the list items more slowly, recalled fewer words on the last learning trial and the delayed trials, and performed less well on the recognition condition. Dyslexics and controls displayed similar vulnerability to interference, but group differences were evident in serial position effects. Taken together, our data suggest that dyslexics have less efficient rehearsal and encoding mechanisms, resulting in deficient encoding of new information, but normal retention and retrieval.

Executive functioning in children with heavy prenatal alcohol exposure.

BACKGROUND: Children with heavy prenatal alcohol exposure have well documented deficits in overall cognitive ability. Recently, attention has turned to the executive function (EF) domain in this population. Until recently, comprehensive measures of EF have not been available within one test battery. This study used a battery of tests to assess four domains of EF in alcohol-exposed children. METHODS: The Delis-Kaplan Executive Function Scale was used to evaluate EF in 18 children with heavy prenatal alcohol exposure, with and without a diagnosis of fetal alcohol syndrome (FAS), and 10 nonexposed controls. Children ranged in age from 8 to 15 years. Measures from four domains of executive functioning were analyzed: planning ability, cognitive flexibility, selective inhibition, and concept formation and reasoning. Tasks consisted of primary EF measures as well as measures of secondary component skills. RESULTS: Alcohol-exposed children were deficient on EF measures compared with nonexposed controls. Furthermore, in most cases, children with and without the FAS diagnosis did not differ from one another. These deficits were not entirely explainable by concomitant deficits on component skills. Specific impairments were identified within the domains of planning and response inhibition, with additional deficits in abstract thinking and flexibility. CONCLUSIONS: Deficits in executive functioning were observed in alcohol-exposed children with or without the diagnosis of FAS and in the absence of mental retardation. Performance on these EF tasks provides insight into the cognitive processes driving overall performance and has implications for adaptive and daily functions. These results are consistent with anecdotal and empirical reports of deficits in behavioral control and with neuroanatomical evidence of volumetric reductions in structures within the frontal-subcortical system in children with heavy prenatal alcohol exposure.

Regional cerebral volume loss associated with verbal learning and memory in dementia of the Alzheimer type.

Twenty-seven research participants with dementia of the Alzheimer type were studied with the California Verbal Learning Test (D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1987) and standardized volume measures of the mesial temporal cortical gray matter, neocortical gray matter, thalamus, and caudate nuclei, from magnetic resonance imaging. A pattern of atrophic brain changes in the mesial temporal lobes (MTL) and the thalamus, with relatively less severe atrophy in the neocortical gray matter, was associated with poorer learning of the word list. Similar patterns of brain atrophy were observed for measures of delayed recall and recognition hits. However, for delayed recall, neither contribution was statistically significant, and for recognition hits, MTL was only at the trend level for significance. These results provide evidence that the verbal memory deficit of Alzheimer's disease (AD) is associated not only with the mesial temporal limbic cortex, thought to be the site of earliest and most severe pathology in AD, but also with damage in the thalamus.

Normative data for 4-year-old children on the California Verbal Learning Test-Children's Version.

This study presents normative data for 4-year-old children on the California Verbal Learning Test-Children's Version (CVLT-C), a measure of verbal learning and memory. Norms are currently available for children 5 years and older; however, normative data are unavailable for this younger population. Forty males and 40 females comprise this normative sample of 4-year-old children. The mean number of words recalled increased from the first to the fifth learning trial, and a consistent level of recall was maintained across delay recall trials. Extra-list intrusion responses were common and these responses were more frequent than correct responses on cued but not free recall conditions. Finally, yes/no recognition testing resulted in the greatest mean number of words remembered compared to the other trials. Overall, the pattern of performance across the learning and memory variables in this younger population was similar to that of older children, but at a lower level. These data suggest that 4-year-old children are able to perform this task, making possible the use of the CVLT-C in normal and clinical populations in this age group.

Impact of pediatric traumatic brain injury on components of verbal memory.

This 3-month longitudinal study examined spared and impaired components of verbal learning and memory after pediatric traumatic brain injury (TBI), using the California Verbal Learning Test for Children. School-aged participants with severe or mild-to-moderate TBI were compared to traumatically injured control subjects without head trauma. Participants were initially evaluated approximately 1 month post injury, and again 3 months later. At Times 1 and 2, participants with severe TBI displayed deficits in immediate recall, delayed recall, and recognition accuracy, consistent with a mild encoding deficit. In both evaluations, participants with mild-to-moderate TBI performed similarly to controls. On average, mild verbal encoding deficits appear to be associated with severe, but not mild-to-moderate, pediatric TBI in the first several months post injury.

Neuropsychological comparison of alcohol-exposed children with or without physical features of fetal alcohol syndrome.

Fetal alcohol syndrome (FAS) is associated with behavioral and cognitive deficits. However, the majority of children born to alcohol-abusing women do not meet the formal criteria for FAS and it is not known if the cognitive abilities of these children differ from those of children with FAS. Using a set of neuropsychological tests, 3 groups were compared: (a) children with FAS, (b) children without FAS who were born to alcohol-abusing women (the PEA group), and (c) normal controls. The results indicated that, relative to controls, both the FAS and the PEA groups were impaired on tests of language, verbal learning and memory, academic skills, fine-motor speed, and visual-motor integration. These data suggest that heavy prenatal alcohol exposure is related to a consistent pattern of neuropsychological deficits and the degree of these deficits may be independent of the presence of physical features associated with FAS.

Is there a "subcortical" profile of attentional dysfunction? A comparison of patients with Huntington's and Parkinson's diseases on a global-local focused attention task.

This study investigated focused attention in two subcortical degenerative disorders by examining the performance of patients with Huntington's disease (HD) and Parkinson's disease (PD) on a task utilizing global-local stimuli. Participants were presented with global-local figures and were instructed to focus their attention on either the global or local level. Stimuli were either "consistent", with the same form at the global and local levels, or "inconsistent", with different forms at the global and local levels. It was found that response times (RTs) of patients with PD were comparable to those of similarly-aged controls regardless of stimulus consistency. In contrast, patients with HD demonstrated disproportionately longer RTs to inconsistent stimuli relative to their age-matched control group. Difference scores between RTs for inconsistent versus consistent stimuli were not correlated with overall level of dementia or disease severity for either the HD or PD group. These results provide further evidence for the heterogeneity of attentional dysfunction among subcortical degenerative illnesses.

Heavy prenatal alcohol exposure with or without physical features of fetal alcohol syndrome leads to IQ deficits.

OBJECTIVE: To assess general intellectual functioning in children with histories of heavy prenatal alcohol exposure, with or without the facial features and growth deficiencies characteristic of fetal alcohol syndrome (FAS). DESIGN: Forty-seven alcohol-exposed children were recruited on evaluation at a dysmorphology clinic and evaluated as part of a university research project using standard tests of IQ. Thirty-four of the alcohol-exposed patients met the traditional diagnostic criteria for FAS. The other 13 alcohol-exposed children lacked both the pattern of facial features and prenatal or postnatal growth deficiency characteristic of the diagnosis. RESULTS: Compared with normal control subjects matched for age, sex, and ethnicity, both groups of alcohol-exposed children displayed significant deficits in overall IQ measures and deficits on most of the subtest scores. Although those in the nondysmorphic group usually obtained marginally higher IQ scores than those in the FAS group, few significant differences were found between the two alcohol-exposed groups. CONCLUSIONS: These results indicate that high levels of prenatal alcohol exposure are related to an increased risk for deficits in intellectual functioning and that these can occur in children without all of the physical features required for a diagnosis of FAS. They also emphasize the need for conducting a thorough history of prenatal alcohol exposure in children with intellectual deficits.

Developmental sex differences in verbal learning.

Although sex differences in verbal learning and memory have been reported in adults, much less is known about when these sex differences emerge and how they develop. In this study, 401 boys and 410 girls between the ages of 5 and 16 years were administered the California Verbal Learning Test--Children's Version. Sex differences were found at all age levels. Girls performed better than boys on all of the immediate and delayed recall trials and on the delayed recognition trial. Girls were also more likely than boys to use a semantic clustering strategy and displayed more effective long-term memory mechanisms. Boys made more intrusion errors and displayed greater vulnerability to interference between the 2 test lists. Because boys had higher mean scores on Wechsler Intelligence Scale for Children--Revised Vocabulary, the observed female superiority in verbal learning could not be attributed to sex differences in overall word knowledge.

An examination of the nature of attentional deficits in patients with Parkinson's disease: evidence from a spatial orienting task.

Endogenous and exogenous shifts of attention were examined in nondemented patients with Parkinson's disease (PD). In the endogenous condition, an arrow was used to cue participants' attention to the possible location of an impending target, whereas in the exogenous condition, a brightened box was used to cue attention. Cues were either valid (i.e., the target appeared in the cued location) or invalid (i.e., the target appeared in a noncued location). The time between cue onset and target onset (stimulus onset asynchrony or SOA) was varied in each condition. The results indicated that PD patients were not differentially impaired in shifting attention at the shorter SOAs relative to normal controls. However, at longer SOAs, the PD patients demonstrated less of an effect from cueing than did the normal control participants. PD patients' differential effect from cueing was evident in both exogenous and endogenous conditions. These results suggest that PD patients may experience a rapid decay of attentional inhibition and do not support the notion that a decrement in processing resources underlies their attentional deficits. Moreover, these findings further support the notion that the basal ganglia may play an important role in attentional functions.

Verbal learning and memory in children with fetal alcohol syndrome.

Children with fetal alcohol syndrome (FAS) were administered the California Verbal Learning Test-Children's Version, a word list learning task that assesses immediate and delayed recall and recognition memory. When compared with matched control children, the children with FAS had difficulty learning and recalling the words after a delay period and tended to make an increased number of intrusion and perseverative errors. In addition, they had difficulty discriminating target words from distracter words and made more false-positive errors on recognition testing. Some of these deficits persisted even when mental age was controlled. The results suggest that children with FAS have profound verbal learning and memory deficits, and that some of these deficits cannot be accounted for even when mental age is considered. Furthermore, the results are consistent with deficits in encoding verbal information and impairment in response inhibition capabilities.