Reaction time (RT) is often used in the assessment of patients with traumatic brain injury (TBI), presumably because it reflects either information processing speed or attentional capacity. To clarify this distinction, we examined behavioral RT and the within-subject variability of RT as they relate to electrophysiological measures of attention and information processing. These include the P300 latency, which reflects stimulus evaluation time, P300 amplitude, which reflects attentional allocation, and the preresponse component of the contingent negative variation (CNV), which reflects sustained attention. We found that the latency and variability in behavioral RT were not correlated with the latency or variability of the P300, suggesting that stimulus evaluation time is not a major contributor to RT and its variability in this paradigm. However, among normal controls, RT was related to P300 amplitude, and therefore to attentional allocation. For the TBI subjects, it was the variability, not the speed, of RT that was related to P300 amplitude and to the preresponse component of the CNV. These data suggest that, while in normal controls RT reflects attentional allocation, among TBI subjects it is the variability in RT that is sensitive to the ability to allocate and sustain attention. (JINS, 1997, 3, 95–107.)

Emotion processing deficits may have an important effect on the quality of life of Alzheimer's disease (AD) patients and their families, yet there are few studies in this area and little is known about the cause of such deficits in AD. This study sought to determine if some AD patients have a disruption in a specific right hemisphere emotion processing system, and to determine if the processing of emotional facial expression is more vulnerable to the pathology of AD than is the perception of emotional prosody. It was specifically hypothesized that patients with greater right hemisphere dysfunction (low spatial AD patients) would be impaired on emotion processing tasks relative to those with predominantly left hemisphere dysfunction (low verbal AD patients). Both groups showed impairment on emotion processing tasks but for different reasons. The low verbal patients performed poorly on the affect processing measures because they had difficulty comprehending and/or remembering the task instructions. In contrast, low spatial AD patients have emotion processing deficits that are independent of language and/or memory and may be due to a more general visuoperceptual deficit that affects the perception of static but not dynamic affective stimuli. (JINS, 1997, 3, 411–419.)

Neurobehavioral theories of autism have hypothesized core deficits in sensory input or perception, basic attentional abilities or generalized attention to extrapersonal space, anterograde memory, auditory information processing, higher order memory abilities, conceptual reasoning abilities, executive function, control mechanisms of attention, and higher order abilities across domains. A neuropsychologic battery designed to investigate these hypotheses was administered to 33 rigorously diagnosed autistic individuals with IQ scores greater than 80, and 33 individually matched normal controls. Stepwise discriminant function was used to define the profile of neuropsychologic functioning across domains. The neuropsychologic profile in these autistic individuals was defined by impairments in skilled motor, complex memory, complex language, and reasoning domains, and by intact or superior performance in the attention, simple memory, simple language, and visual–spatial domains. This profile is not consistent with mental retardation or with a general deficit syndrome, but rather with a selective impairment in complex information processing that does not involve visual–spatial processing. This profile is not consistent with a single primary deficit, but with a multiple primary deficit model in which the deficit pattern within and across domains is reflective of the complexity of the information processing demands. This neuropsychologic profile is furthermore consistent with the neurophysiologic characterization of autism as a late information processing disorder with sparing of early information processing. (JINS, 1997, 3, 303–316)

Previous studies of the neuropsychological consequences of insulin dependent diabetes mellitus (IDDM) have had mixed and often contradictory results, possibly due to the heterogeneity of the samples and neuropsychological measures, and a lack of specific hypotheses. In order to address this problem, we focused on the effect of severe hypoglycemia on memory functioning in a relatively homogeneous sample of childhood-onset IDDM patients. Given the deleterious effects of hypoglycemia on medial temporal lobe structures (e.g., hippocampus) and the relationship between medial temporal damage and declarative memory functioning, we hypothesized that those patients who had experienced severe hypoglycemia would demonstrate impaired declarative memory and spared nondeclarative memory functioning. Results of the study were generally consistent with this hypothesis, although some impact of hypoglycemia was observed on perceptual priming ability. (JINS, 1997, 3, 509–520.)

Associate learning for visual nonverbal and auditory verbal items was examined in 21 children with spastic diplegic cerebral palsy (SDCP) and 28 healthy children using four paired associate tasks. SDCP children showed poorer performance than the comparison group for learning pairs that required visual nonverbal responses, regardless of the stimulus modality. Within the SDCP group, lesion severity was assessed in 17 of the children. Lesion severity was related to the level of performance on paired associate tasks requiring visual nonverbal responses; lesion severity did not reach statistical significance for tasks requiring auditory verbal responses. The study suggests: (1) periventricular white matter regions are important for the development of basic learning processes, such as associative learning, and (2) learning of visual nonverbal material is disproportionately affected following white matter injury early in life. (JINS, 1997, 3, 521–527.)

Clinically, tests of executive functions tend to be chosen on face validity. If such tests are to be used to evaluate a clinical population, their ability to measure executive functions should be reliably demonstrated in a normal population. In order to investigate the reliability of such tests, a sample of 130 normal adults (74 women, 56 men) ages 17 to 55 years were administered 4 tests purporting to measure planning/problem-solving: the Tower of London Test, the Six Element Test, the Twenty Questions Test, and the Rey Complex Figure Test. A structural equation modeling approach provided by the LISREL 8 program was used to evaluate three models hypothesized to explain the relationship among the test variables and the latent construct of planning/problem-solving. An adequate model was unable to be estimated, thus raising questions about the meaning of the latent construct planning/problem-solving and the psychometric structure of the Tower of London Test. (JINS, 1997, 3, 108–119.)

Robust comparative and diagnostic norms for the elderly are provided for the Selective Reminding Test (Buschke, 1973). Correcting for factors such as age and education level are appropriate for comparative norms, which are intended for ranking individuals with respect to their age and education matched peers. However, because age and education are both risk factors for dementia, correcting for these factors decreases test sensitivity for detecting dementia. Age- and education-corrected Selective Reminding scores have a sensitivity for detecting dementia that is 28% lower than uncorrected scores. Using information about age in combination with memory scores provided optimal discrimination of dementia. It is concluded that statistically removing the contribution of dementia risk factors from memory test scores can severely decrease discriminative validity for detecting dementia in the elderly. (JINS, 1997, 3, 317–326.)

The incidence of clinically apparent asymmetric profiles of neuropsychological deficits in Alzheimer's disease (AD) patients similar to those reported in the PET literature is currently unclear. This study investigated lateral neuropsychological asymmetry using principal component factor analysis in a sample of 153 patients diagnosed with probable AD. Using factor scores, patients were classified into groups exhibiting asymmetric or symmetric profiles of neuropsychological deficits. In the analysis of lateral asymmetry, 27.5% of patients were classified as asymmetric (10% verbally and 17% visuospatially). Consistent with reports of continued asymmetry beyond the mild dementia stage, asymmetry was exhibited in the mild, moderate, and severely demented groups. These findings of neuropsychological asymmetry across stages of dementia are consistent with the picture of significant neuropsychological heterogeneity in AD that has been emerging in the decade. (JINS, 1997, 3, 420–427.)

With this January 1997 issue, the Journal of the International Neuropsychological Society (JINS) celebrates its 2nd birthday. As we enter into our third year of publication as the official journal of the INS, it is appropriate to review briefly what has been accomplished, and look at what lies ahead.

Previous studies have reported that developmental disruption of dopaminergic systems results in lateralized deficits in visual attention (Posner et al., 1991; Craft et al., 1992). Infants who were prenatally exposed to cocaine were hypothesized to have increased reaction times to targets in the right visual field on measures of visual attention compared with infants who were not exposed to cocaine. Seventeen children without prenatal exposure to cocaine and 14 children who were exposed to cocaine (age range from 8–40 months) completed a visual attention task, the Mental Development Index of the Bayley Scales of Infant Development, Second Edition; and the Preschool Language Scale, Third Edition. Cocaine-exposed children were slower to orient to stimuli in the right visual field after repeated trials, especially after attention was first cued to the left visual field. They were also less likely to orient to the right when given a choice. Results suggest that the left hemisphere visual attention system is disproportionately affected by prenatal exposure to cocaine. (JINS, 1997, 3, 237–245.)

In a descriptive analysis of 158 patients with temporal lobe epilepsy, Taylor (1969) reported that the age of first seizure varied systematically as a function of laterality and sex. We conducted inferential analyses of Taylor's original data which (1) provided support for his proposal of disproportionate left hemisphere vulnerability to seizure onset in early life, but (2) failed to provide evidence of sex differences in age of onset of unilateral seizures. Examination of these effects in a larger sample of 844 patients drawn from the Bozeman Epilepsy Consortium provided some additional support for findings from the inferential analysis. Specifically, the left hemisphere appeared more vulnerable to seizure onset in childhood, this increased vulnerability extending to about age 5 years. Age of onset of seizures was not different when males and females were compared. Thus, reanalysis of Taylor's original data as well as examination of data from a larger, more contemporary sample suggest that seizure onset varies as a function of laterality, but not sex. (JINS, 1997, 3, 428–434.)

This study examined the utility of word recognition scores for estimating actual Verbal IQ scores obtained from 1–5 years earlier. Participants were 271 persons remaining normal and 24 initially normal persons who developed cognitive impairment over longitudinal follow-up. A previously published regression equation based on education and the American modification of the National Adult Reading Test (Nelson, 1982) was used to estimate Mayo Verbal IQ. In spite of correlating well with prior obtained scores (r = .7) the predicted score tended to overestimate the obtained Mayo Verbal IQ. A revised equation was developed in the normal sample, which improved accuracy of prediction. Among the 24 persons who developed cognitive impairment over a 5-year span, the revised predicted scores provided reasonable estimates of initial Mayo Verbal IQ. To aid in clinical interpretation, a table of the normal frequencies of predicted Mayo Verbal IQ minus contemporaneously obtained Mayo Verbal IQ is provided. (JINS, 1997, 3, 528–533.)

Twenty-four closed-head-injured (CHI) and 24 control participants studied two word lists under shallow (i.e., nonsemantic) and deep (i.e., semantic) encoding conditions. They were then tested on free recall, perceptual priming (i.e., perceptual partial word identification) and conceptual priming (i.e., category production) tasks. Previous findings have demonstrated that memory in CHI is characterized by inefficient conceptual processing of information. It was thus hypothesized that the CHI participants would perform more poorly than the control participants on the explicit and on the conceptual priming tasks. On these tasks the CHI group was expected to benefit to a lesser degree from prior deep encoding, as compared to controls. The groups were not expected to significantly differ from each other on the perceptual priming task. Prior deep encoding was not expected to improve the perceptual priming performance of either group. All findings were as predicted, with the exception that a significant effect was not found between groups for deep encoding in the conceptual priming task. The results are discussed (1) in terms of their theoretical contribution in further validating the dissociation between perceptual and conceptual priming; and (2) in terms of the contribution in differentiating between amnesic and CHI patients. Conceptual priming is preserved in amnesics but not in CHI patients. (JINS, 1997, 3, 327–336.)

In this study we applied clustering procedures to a subgroup of 341 participants from the WAIS–R standardization sample. These individuals were selected by virtue of their having full-scale profiles characterized by scatter of greater than 8 scaled scores. Using a hierarchical clustering algorithm, a multistage procedure was used to establish and evaluate a cluster solution. The subject selection and clustering methods were successful in revealing a set of 9 profile types characterized by unique profile shapes. All profiles were associated with FSIQs that were at least in the average range. Seven of the profiles were characterized by specific subtest strengths, only 1 with subtest weaknesses. Examination of the external correlates of profile membership revealed differences among profile groups for age, marital status, education, and occupation. Our findings suggest that variability in and across the 9 profile types in this sample reflects increased contributions of unique abilities in comparison to the influence of the underlying primary and secondary WAIS–R dimensions of cognitive ability. (JINS, 1997, 3, 120–127.)

Studies have consistently found that patients with multiple sclerosis (MS) are impaired on tests of anterograde memory, but the status of remote memory in MS remains unclear. To better understand remote memory in MS we administered the Autobiographical Memory Interview (AMI) to 44 MS patients and 19 normal controls matched for age, education, and gender. Additionally, a shortened version of the Famous Faces Test, a test of recall of past U.S. presidents, and a 14-word learning list were administered. Patients performed significantly lower than controls on the learning list and Famous Faces Test, but not on recall of past presidents. On the AMI, patients were significantly impaired on recall of semantic but not of episodic memories. These results indicate that MS patients exhibit retrograde amnesia that cannot be attributed to anterograde memory deficits or lack of exposure to task-relevant information. (JINS, 1997, 3, 246–251.)

The construct of nonverbal memory, as assessed by figural reproduction tests, has recently been questioned by a number of investigators. The purpose of this study was to reexamine this construct and its relationship to right temporal lobe dysfunction. Figural reproduction test scores were examined in 757 epilepsy surgery candidates obtained from 8 epilepsy centers participating in the Bozeman Epilepsy Consortium. All participants exhibited unequivocal evidence of left (LTL) or right (RTL) temporal lobe epilepsy observed in ictal and interictal EEG recordings. All subjects also had IQ scores exceeding 70, right-hand preference, and left hemisphere language dominance confirmed by intracarotid sodium amytal testing. Comparisons of LTL and RTL groups showed no significant differences in scores on the Visual Reproduction subtests from the Wechsler Memory Scale (WMS) or Wechsler Memory Scale–Revised (WMS–R) or on the copy and delayed recall conditions of the Rey–Osterrieth Complex Figure Test (ROCFT). Significant differences were observed among centers on WMS and ROCFT scores, which are likely to be a result of variations in administration and/or scoring procedures. The lack of significant differences between LTL and RTL groups in this large sample raise questions about the nature of nonverbal memory and its relationship to right temporal lobe dysfunction. (JINS, 1997, 3, 435–443.)

Whether multiple conscious efforts at word search bring a subject closer to an elusive word and to eventual successful retrieval remains a subject of debate. Previous work with normal participants has shown that multiple attempts eventuating in correct retrieval are not usually associated with a systematic progression toward target word phonology in the intervening attempts. In this study we analyzed the naming errors produced by 30 aphasic patients who had received the Boston Naming Test. The analyses were designed to elucidate the characteristics of responses that led to eventual success. Our data showed that among aphasics, as with normal subjects, the presence of target-initial phonology in the subject's first response was the most important predictor of correct retrieval. Moreover, progression towards target phonology in the course of multiple attempts was unrelated to eventual correct retrieval. (JINS, 1997, 3, 128–138.)

The relationships of medical, developmental, social, and familial variables to intellectual performances (IQ scores) were assessed in a sample of 242 adult patients with intractable lateralized temporal lobe epilepsy. Lower IQ scores were associated with low patient and parent education. In addition to the significant contributions of nonneurological social and familial factors to IQ, early age at onset of regular seizures and presence of primary neurological dysfunction in the left cerebral hemisphere were also both independently related to lower IQ. The obtained results suggest that the occurrence of regular seizures during a critical period in early childhood neural maturation poses the greatest risk to cognitive development in the epilepsy population. Total duration of seizures, history of severe convulsive episodes, and the occurrence of another nonepileptic neurological problem in early childhood do not contribute significantly to delayed cognitive development. (JINS, 1997, 3, 252–259.)