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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Verbal learning and memory in children with myelomeningocele

Examined verbal learning and memory in children with myelomeningocele using the California Verbal Learning Test (CVLT). Participants included 41 children with myelomeningocele, 8 to 15 years of age, 33 of whom had a history of shunted hydrocephalus, and 41 matched, unaffected controls. Children with myelomeningocele and shunted hydrocephalus performed worse than controls on the CVLT. They recalled as many words as controls on the first learning trial, but acquired words more slowly across trials, so that their overall recall was lower. Their learning was characterized by a pronounced recency effect. Their delayed recall of the original list was worse than controls, but not their recognition. Performance of children with myelomeningocele but without shunts was generally not significantly different from that of the other two groups, although they did demonstrate better long-delay free recall than children with shunts. Myelomeningocele is associated with significant retrieval problems when accompanied by shunted hydrocephalus.

Decline in working memory associated with HIV infection. HNRC Group

HIV infection has been associated with decline in a number of cognitive functions that are components of 'working memory'. Thus, tests of working memory that require the interaction of these components may be particularly sensitive to cognitive dysfunction that arises from HIV infection. To assess this possibility, working memory was examined in 147 HIV-seropositive (HIV+) and 38 HIV-seronegative (HIV-) males using the Reading Span Test and the Digit Span subtest from the Wechsler Memory Scale-Revised (WMS-R). Speed of information processing, a component of some working memory tasks, was assessed with a version of the Sternberg Memory Scanning task. Results indicated that symptomatic HIV+ subjects were impaired relative to HIV- control subjects on the Reading Span and Digit Span tests. Asymptomatic and mildly symptomatic HIV+ groups exhibited a trend toward impairment on these tests, and on the whole, a greater proportion of HIV+ subjects than HIV- subjects were impaired. The groups did not differ significantly in information processing speed. These results indicate that deficits in working memory are apparent in at least a subset of HIV-infected individuals. These deficits are most apparent in symptomatic HIV+ individuals, but the decline may begin during the asymptomatic phase of infection.

Visual attention and perception in patients with Huntington's disease: comparisons with other subcortical and cortical dementias

Shifts in attention were examined in patients with Huntington's disease (HD) using a divided attention paradigm that involved the presentation of global-local stimuli. The HD patients' pattern of performance was compared to the previously reported results of groups of patients with Alzheimer's disease (AD; Filoteo et al., 1992) or Parkinson's disease (PD; Filoteo et al., 1994). Across consecutive trials of the divided attention task, a visual target could appear at either the same global-local level or at a different level. When the target changed levels across consecutive trials, the AD patients demonstrated an impairment in disengaging attention from the level at which the last target appeared, whereas the PD patients were impaired in maintaining their attention at the previously attended level. In contrast to these patterns of performances, the HD patients did not demonstrate a significant impairment in shifting attention between hierarchical levels. Both the AD and the PD patients' abnormal shifting ability was significantly related to the number of errors they made in identifying target stimuli; however, the pattern of the relationship was qualitatively distinct. These results suggest that different attentional mechanisms may underlie AD and PD patients' visual-perceptual deficits. The HD patients' shifting ability was not related to the number of errors they made in identifying target stimuli, suggesting that a different mechanism may account for the visual-perceptual impairments exhibited by these patients.

Verbal learning and memory following pediatric closed-head injury

In this study, verbal learning and memory following pediatric closed-head injuries (CHI) using the children's version of the California Verbal Learning Test (CVLT). Participants included 47 children, ages 5-16 yr, with a history of CHI, and 47 matched, noninjured controls. Children with CHI performed more poorly than controls on the CVLT, although their deficits varied qualitatively as a function of injury severity. Those with mild/moderate injuries performed as well as controls on learning trials, but they recalled proportionally fewer words after a delay (although their recognition was intact). Severely injured children demonstrated deficits in learning, delayed recall, and recognition, compared to controls. The groups did not differ in learning characteristics, but children with severe CHI exhibited more intrusions than controls. Pediatric CHI are associated with specific disturbances in verbal learning and memory similar to those of adults with CHI but different from those of children with other developmental and neurological disorders.

The nature of learning and memory impairments in schizophrenia

The California Verbal Learning Test was used to characterize the learning and memory impairment in schizophrenia (SC) and to evaluate potential clinical and demographic factors associated with this impairment. SC patients (n = 175) performed worse than normal comparison (NC) subjects (n = 229) on all learning, recall, and recognition memory measures. The most important clinical correlates of these impairments were earlier age of onset, more negative symptoms, and greater anticholinergic medication dosage. SC patients showed a prominent retrieval deficit as indicated by disproportionate improvement when tested in a recognition, rather than a free recall, format. A residual impairment seen with recognition testing suggests a mild encoding deficit as well. In contrast, the relative absence of a storage deficit is suggested by the lack of rapid forgetting. Using a discriminant function analysis that differentiates cortical dementia [i.e., Alzheimer's disease (AD)], subcortical dementia [i.e., Huntington's disease (HD)], and normals, it was found that 50% of the SC patients were classified as having a subcortical memory profile and 35% were classified as having a normal profile, whereas only 15% were classified as having a cortical memory profile. Although these findings reflect the clinical heterogeneity often found in SC, results suggest that most SC patients demonstrate a pattern of learning and memory impairments that resembles the pattern seen in patients with primary subcortical (specifically striatal) pathology.

Verbal memory performance of patients with human immunodeficiency virus infection: evidence of subcortical dysfunction. The HNRC Group

In the present study, the California Verbal Learning Test (CVLT) was administered to symptomatic HIV+ (n = 31), asymptomatic HIV+ (n = 94), and HIV-normal control (HIV-NC) (n = 40) subjects to assess the prevalence and nature of their verbal memory deficits. Symptomatic HIV+ subjects were significantly impaired relative to HIV-control subjects on CVLT measures of acquisition and retention, and were significantly less likely than control subjects to use a semantic clustering strategy to support recall. The performance of the asymptomatic HIV+ subjects fell between those of the symptomatic HIV+ subjects and HIV-controls on almost every CVLT measure. A linear discriminant function analysis (DFA) was used to compare the performances of these three groups to Alzheimer's disease (AD). Huntington's disease (HD), and normal control (NC) subjects on three CVLT measures, including total recall over five learning trials, intrusion errors, and a derived score of delayed recognition discriminability minus the final learning trial. Significant differences were found between the number of symptomatic HIV+ subjects classified as HD (32%), AD (3%), and normal (65%), the number of asymptomatic HIV+ subjects classified as HD (16%), AD (1%), and normal (83%), and the number of HIV-NC subjects classified as HD (2%), AD (0%), and normal (98%). The profile of verbal memory deficits exhibited by the subgroup of impaired HIV+ subjects was similar to that of patients with HD, a prototypical subcortical dementia, and different from that of patients with AD, a prototypical cortical dementia. This finding is consistent with reports of the predominance of subcortical neuropathological changes associated with HIV infection.

Cognitive impairment in adults with Down's syndrome: similarities to early cognitive changes in Alzheimer's disease

Postmortem studies of brains from adults with Down's syndrome (DS) reveal a dramatic age-dependent increase in the incidence of neuropathology associated with Alzheimer's disease (AD). By the age of 40 years, virtually all DS individuals have AD neuropathology. Documentation of cognitive correlates of this phenomenon has been difficult, partly because of the preexisting mental retardation in DS. In the current study, we compared a group of adults with DS, 22 to 51 years old, with a matched control group on various behavioral measures such as savings scores, which are known to be sensitive in detecting early dementia in AD patients. By using the short delayed savings score from the California Verbal Learning Test (a test of verbal memory), a subgroup of DS adults was identified as memory-impaired. This group demonstrated a decline in performance on various other cognitive tests with advancing age, whereas another group identified as having non-memory-impaired DS, and the non-DS controls, showed no evidence of decline with age. These results provide evidence for the presence of early dementia among adults with DS within an age range in which neuropathologic manifestations of AD are predicted to be developing.

Norms for depressed patients for the California verbal learning test: associations with depression severity and self-report of cognitive difficulties

This study provides norms for depressed subjects for a widely used test of verbal memory, the California Verbal Learning Test (CVLT). Subjects were 156 outpatients with major depression tested during a drug washout period. Mean CVLT memory scores for these patients were generally between one-half and one standard deviation below age- and sex-corrected norms for nondepressed populations. Severity of depression in the patients was not associated with memory performance, but was associated with self-report of cognitive difficulties. A table of age-, sex-, and education-specific norms for the CVLT is provided.

Directed and divided attention in Alzheimer's disease: impairment in shifting of attention to global and local stimuli

This study investigated the relative performance of Alzheimer's disease (AD) patients and normal controls on directed and divided attention reaction time (RT) tasks that involved the use of global-local stimuli (e.g., a large '1' made from small '2s'). Relative to normals, AD patients displayed disproportionately greater impairment on the divided attention task compared to the directed attention task. On the divided attention task, when the target remained at the same global-local level across consecutive trials, the AD patients displayed a greater facilitation effect than did the controls when responding to the second stimulus. However, when the target changed levels across consecutive trials (i.e., from the global to the local, or vice versa) the AD patients' RTs to the second stimulus were disproportionately slower than were the controls' RTs. These results demonstrated that AD patients are impaired in disengaging and shifting attention across levels of perceptual organization within the same stimulus.

Fetal alcohol syndrome: a case report of neuropsychological, MRI and EEG assessment of two children

Neuropsychological, neuroanatomical, and electrophysiological data are presented on two subjects with fetal alcohol syndrome (FAS). Both boys had intelligence quotients in the mentally deficient range and were found to have several other severe, specific deficits. Magnetic resonance imaging showed abnormalities of the corpus callosum, and reductions in the size of the basal ganglia and thalamic structures. No focal abnormalities were noted in the electroencephalogram records, although the electroencephalograms of both boys were moderately abnormal for their age group. A multidisciplinary approach to the study of FAS, hopefully will lead to a more unified concept of the disorder and perhaps indicate specific areas of vulnerability.

The subcortical dysfunction hypothesis of memory deficits in depression: neuropsychological validation in a subgroup of patients

The subcortical dysfunction hypothesis of verbal learning and memory deficits in depression was evaluated by comparing the memory test profiles of unipolar depressives (n = 40) and bipolar depressives (n = 9) with those of patients with a prototypical subcortical dementia (Huntington's disease, HD), patients with a prototypical cortical dementia (Alzheimer's disease, AD), and normal controls. In a discriminant function analysis that well-differentiated the HD, AD, and normal subjects, it was found that 28.6% of the depressed patients were classified as HD patients (DEP-HD subjects), 49.0% were classified as normals (DEP-N subjects), none were classified as AD patients, and 22.4% were not well-classified. The DEP-HD group closely resembled the HD group on additional indices of verbal learning and memory, and differed from the DEP-N group, which strongly resembled the normal control group. DEP-N patients also performed significantly better than DEP-HD patients on a number of other neuropsychological tests (e.g., WAIS-R Digit Symbol, category fluency, Trail Making Test Part B). The findings provide support for the subcortical dysfunction hypothesis, but only for a subgroup of depressed patients. Implications for differentiating depressive "pseudodementia" from AD are discussed.

Componential analysis of problem-solving ability: performance of patients with frontal lobe damage and amnesic patients on a new sorting test

A new sorting task designed to isolate and measure specific components of problem-solving ability was administered to four subject groups: patients with focal frontal lobe lesions, patients with both frontal dysfunction and amnesia (Korsakoff's syndrome), patients with circumscribed (non-Korsakoff) amnesia, and normal control subjects. The patients with circumscribed (non-Korsakoff) amnesia, and normal control subjects. The patients with frontal lobe lesions and patients with Korsakoff's syndrome were impaired on eight of the nine components of the task. The findings run counter to theories of a single or primary impairment in patients with frontal lobe dysfunction. Rather, the results suggest that a wide spectrum of deficits in abstract thinking, cognitive flexibility, and use of knowledge to regulate behavior contributes to the problem-solving impairment of these patients. Although the (non-Korsakoff) amnesic patients performed similarly to normal subjects on most measures, a finer analysis suggested that successful performance on this complex sorting task, in addition to being strongly dependent upon frontal lobe function, is mildly dependent upon memory function.

Spatial cognition in Alzheimer's disease: subtypes of global-local impairment

This study investigated whether subgroups of AD patients exhibit different patterns of impairment in analyzing global (configural) and local (detail) features of complex visual stimuli. A High Spatial AD subgroup (i.e., patients with better block constructions than naming) and a High Verbal AD subgroup (i.e., patients with better naming than block constructions) were impaired in analyzing both global and local forms. As predicted, however, the High Spatial AD patients exhibited greater impairment in analyzing the local forms than the High Verbal AD patients and normal controls. In contrast, the High Verbal AD patients exhibited greater impairment in analyzing the global forms than the High Spatial AD patients and normal controls. There was a striking separation of the subgroups: Using the local-global difference score, the hit rate for classifying these patients into the two subgroups was 91%. Robust correlations were found between the AD patients' ability to construct global and local forms and their scores on traditional visuospatial and verbal tests, respectively. The findings suggest that it may be misleading to subdivide AD patients using a verbal/spatial dichotomy, because even those AD patients who appear to have relative strengths on traditional visuospatial tests are likely to exhibit a primary impairment in analyzing local features of complex visual stimuli. The results underscore the importance of a process (qualitative) approach to neuropsychological assessment for a more valid understanding of the behavioral subtypes of Alzheimer's disease.

Verbal learning and memory in language impaired children

The present study investigated patterns of verbal learning and memory in Language Impaired (LI) and normal children, using the California Verbal Learning Test--Children's Version. The LI children showed a normal immediate memory span; however, they were impaired in the total number of correct responses that they generated across repeated trials. They reported significantly more perseverations, but not intrusions, relative to the controls. The LI children were not impaired on a delayed free recall task, but they were significantly impaired relative to the controls on semantically cued recall. The implications of these findings for future research and for remediation are discussed.

Global-local processing in preschool children

The tendency of young children to attend to global and/or local levels of hierarchically structured patterns was examined using an orientation judgment task. 3- and 4-year-old children and adults were asked to judge which way an equilateral triangle was pointing under different contextual conditions. In Experiment 1, contextual variations included overall pattern orientation, configuration alignment type, presence or absence of an immediate frame of reference, and type of local element context. The results showed that, contrary to previous reports in the literature, young children, like adults, attend to both global and local levels of a pattern. Both pattern orientation and the introduction of contextual cues affected children's judgments, and the magnitude of that effect varied with the particular contextual cue present in the stimulus array. In Experiment 2, contextual variations included overall pattern orientation and presence or absence of an internal local level element. Consistent with the results of Experiment 1, young children's orientation judgements were influenced by the addition of local level factors.

Visuoconstructive performance and regional cerebral glucose metabolism in Alzheimer's disease

The drawings of Alzheimer's disease (AD) patients and elderly control subjects were rated on a number of specific performance scales, such as attention to configuration, attention to detail, and stimulus boundedness. AD patients showed significantly poorer performance than controls on most drawing scales, and the drawing measures were differentially affected by disease severity. Regional cerebral glucose metabolism (rCMRglc) was assessed via positron emission tomography (PET, with 18FDG) in a subgroup of the AD patients. Partial correlations of rCMRglc with drawing measures (age, sex, and education served as control variables) were conducted. Five out of eight of the drawing measures were significantly correlated (p less than .005) with rCMRglc in occipital and/or temporal-parietal regions, for both left and right hemispheres. Only one of the eight drawing measures, attention to detail, was significantly correlated with rCMRglc in both frontal and posterior regions of interest, again for both hemispheres. Overall dementia severity showed no significant correlations with rCMRglc in any of the regions. These findings are suggestive of a posterior-anterior differentiation, but no left-right hemisphere differentiation, in the relationship between drawing performance and cerebral metabolism in AD, which cannot be accounted for by overall dementia severity. Differences between the drawing performance of AD and unilateral brain damaged patients are discussed, and further applications of the rating scales (provided in the Appendix) are suggested.

Neuropsychological presentation of Ganser symptoms

We describe a patient with memory complaints whose history of head injury, polysubstance abuse and positive neurological findings suggested the presence of dementia. Neuropsychological testing revealed inconsistent performance plus multiple verbal and visuospatial approximate answers leading to the diagnosis of a Ganser episode. This case illustrates the importance of neuropsychological assessment in diagnosing Ganser symptoms and in differentiating this disorder from organic conditions and malingering.

Are all subcortical dementias alike? Verbal learning and memory in Parkinson's and Huntington's disease patients

The utility of the concept of 'subcortical dementia' was investigated by comparing the verbal learning and memory abilities of Parkinson's disease (PD) patients with those of Huntington's disease (HD) patients. Many similarities between the PD and HD groups emerged, including impaired immediate memory spans, inconsistency of recall across learning trials, deficient use of a semantic clustering learning strategy, elevated intrusion rates on delayed recall, impaired recognition memory performance, normal retention of information over delay periods, normal vulnerability to proactive or retroactive interference, and normal types of intrusion errors. The HD subjects, however, displayed inferior free recall, deficient improvement across learning trials, abnormal serial position recall effects, higher perseveration rates, and supranormal improvement on recognition testing compared with free recall. Implications of these results for characterizing memory deficits associated with subcortical system dysfunction are discussed.

Block constructions of chronic alcoholic and unilateral brain-damaged patients: a test of the right hemisphere vulnerability hypothesis of alcoholism

A detailed analysis of the block construction performance of chronic alcoholics, unilateral brain-damaged patients, and normal control subjects was conducted to test two hypotheses: (a) that alcoholics perform similarly to right-hemisphere damaged (RHD) patients but not left-hemisphere damaged (LHD) patients; and (b) that unilateral brain-damaged patients display qualitatively different strategies and errors. Differences in performance without a time limit and broken configuration errors suggest that the alcoholics have not incurred the type of visuospatial impairment characteristic of RHD patients. The LHD and RHD patients showed qualitative differences in their strategies and errors. Implications of the findings for research and clinical assessment of visuospatial dysfunction are discussed.

Visuospatial dysfunction following unilateral brain damage: dissociations in hierarchical and hemispatial analysis

Unlike the aphasias, visuospatial dysfunction has resisted fractionation into meaningful spared and impaired component functions. In this study, we show that unilateral brain damage results in pronounced dissociations in both hierarchical and hemispatial processing. Patients with left-hemisphere damage showed the greatest impairment in drawing forms at the lower level of hierarchical stimuli presented in right hemispace, whereas patients with right-hemisphere compromise displayed the opposite pattern. We discuss implications of these results for research in visuospatial function and clinical assessment of visuospatial dysfunction.

Visuospatial functioning before and after commissurotomy. Disconnection in hierarchical processing

A patient who underwent complete cerebral commissurotomy was tested before and after surgery on tasks involving drawing and recognition memory for visual hierarchical stimuli. These stimuli consisted of a large, higher-level form constructed from smaller, lower-level forms. Postoperatively, the patient was more accurate in drawing and recognizing higher-level forms relative to lower-level forms when responding with his left hand and primarily right hemisphere, whereas he showed the opposite pattern when responding with his right hand and primarily left hemisphere. Implications of these findings for theories of the cerebral organization of visuospatial processing are discussed.