There are dramatic changes in the electroencephalogram of the inactivated hemisphere in the intracarotid sodium amobarbital test. One of the more profound behavioral changes during this procedure is left hemispatial neglect accompanying right hemisphere inactivation. The present study was designed to ascertain whether there was a clear relationship between the degree of hemispheric inactivation (as measured by the electroencephalogram) and the degree of left hemispatial neglect during this procedure. Sixty-nine participants undergoing right hemisphere intracarotid sodium amobarbital testing were presented with a random letter cancellation test at various points during the procedure. Neglect was quantified as significant, moderate, minimal, or none, based on how many target letters the patients missed. The simultaneous electroencephalogram from each of these testing points was spectrally analyzed and topographic maps were generated. The degree of neglect was then compared with the comparable topographic map. It was found that as the amobarbital-induced right hemispheric dysfunction regressed, the degree of neglect lessened in a systematic fashion, as did the profound electroencephalographic changes induced by the drug. Thus, there is a clear relation between the degree of hemispheric inactivation induced by the amobarbital and the degree of left hemispatial neglect. This relationship held regardless of side of hemispheric language dominance or epileptic focus. These results replicate previous findings that right hemisphere inactivation during the intracarotid sodium amobarbital test results in left hemispatial neglect. They extend these findings by clearly showing that neglect changes in a quantitative fashion (rather than being an all-or-none phenomenon) and further, show that there is a clear relationship between the severity of neglect and the degree of hemispheric dysfunction. (JINS, 1998, 4, 99–105.)

Neuroimaging and lesion studies have demonstrated that hippocampal volume correlates with memory performance, but material-specific lateralization of this structure-function relationship has been inconsistent. This MRI study examined the relative contributions of left and right temporal lobe volumes to verbal and nonverbal recognition memory in a group of 20 Alzheimer's disease (AD) patients. There was a significant relationship between extent of right hippocampal and right temporal gray matter tissue volume deficit and performance on the face recognition subtest of the Warrington Recognition Memory Test. The face recognition test correlated with right hemisphere volume but not to left, indicating a material-specific relationship between brain structure and function in this patient group. Right temporal horn volume did not account for a significant proportion of variance in face recognition memory. Although word recognition was not significantly correlated with either left or right hippocampal volume in the total group, there was a strong correlation between left hippocampal volume and word recognition memory in the female AD patients. Thus, face recognition shows a material specific relationship with select lateralized hippocampal and temporal cortical volumes in AD patients, regardless of gender, whereas the verbal recognition–left-hippocampal volume relationship may be mediated by gender. (JINS, 1998, 4, 106–114.)

We compared the verbal learning and memory performance of 57 inpatients with unipolar major depression and 30 nondepressed control participants using the California Verbal Learning Test. The effect of age within this elderly sample was also examined, controlling for sex, educational attainment, and estimated level of intelligence. Except for verbal retention, the depressives had deficits in most aspects of performance, including cued and uncued recall and delayed recognition memory. As well, there were interactions between depression effects and age effects on some measures such that depressives' performance declined more rapidly with age than did the performance of controls. The results are discussed in the context of recent contradictory reports about the integrity of learning and memory functions in late-life depression. We conclude that there is consistent evidence, from this and other studies, that elderly depressed inpatients have significant deficits in a range of explicit verbal learning functions. (JINS, 1998, 4, 115–126.)

Clinical assessments of individuals with traumatic brain injury (TBI) typically report attentional difficulties, with distractibility prominent among these complaints. However, laboratory-based measures have often failed to find disproportionate distraction among patients with TBI, as compared to control participants. In this experiment, we tested 21 patients hospitalized for rehabilitation following recent TBI and 21 demographically comparable control subjects on a visual reaction time go–no-go task in which the target was preceded or followed by a brightly colored moving visual stimulus, appearing above the target location. Early distractors actually served as warning stimuli, improving accuracy and speed for both participant groups. Distractors occurring at or shortly after the time of target presentation had no significant impact on accuracy or response bias in either group, but did produce slowing of RT that was significantly greater for patients than for controls. The distractor that produced maximal slowing occurred 100 ms after the presentation of the target or foil. Repeated testing sessions led to reduction in the impact of the distractor and loss of the group difference in RT impact. The degree of RT slowing induced by distraction was modestly related to injury severity, as measured by the current score on the Disability Rating Scale, and the time until the patient first followed verbal commands. There was also a trend of greater RT slowing among individuals with focal orbitofrontal lesions, as assessed on neuroimaging studies. These results document a greater susceptibility to extraneous visual distraction among patients with TBI in comparison to controls. The fact that this difference appears only in the RT domain, and is greatest when the distractor follows the target, suggests that the primary impact of visual distractors is on response preparation and execution rather than target detection. (JINS, 1998, 4, 127–136).

Two components of verbal fluency performance—clustering (i.e., generating words within subcategories) and switching (i.e., shifting between subcategories)—were examined in patients with dementia of the Alzheimer type (DAT), patients with dementia with Parkinson's disease (DPD), nondemented patients with Parkinson's disease (NPD), and demographically matched controls. The DAT and DPD groups were impaired in the number of words generated on both phonemic and semantic fluency. The DAT group produced smaller clusters on both tasks and switched less often on semantic fluency than controls. The DPD group switched less often on both tasks and produced smaller clusters on phonemic fluency than controls. The NPD group was not impaired on any fluency variable. Thus, the total number of words generated on phonemic and semantic fluency did not discriminate the dementia groups from their respective control groups, but measures of clustering and switching did. This differential pattern of performance provides evidence for the potential usefulness of measures of switching and clustering in the assessment of dementia. (JINS, 1998, 4, 137–143.)

This study investigated the nature of selective attention deficits after severe closed head injury (CHI). Twenty participants with severe CHI (greater than 1 year postinjury) and 20 matched controls completed search and nonsearch visual selective attention tasks under conditions of low (Experiment 1) and high (Experiment 2) target–distractor similarity. In the search situations, participants searched visual displays that contained 1, 4, or 8 items for the targets. In the nonsearch situations, the location of the targets was visually cued with a peripheral arrow. The results revealed that in both the low and high target–distractor similarity search conditions, CHI participants required a longer time than controls to locate and identify the target. In contrast, in the nonsearch condition, CHI participants were able to successfully ignore irrelevant task information when target–distractor similarity was low. However, when target–distractor similarity was high, CHI participants had more difficulty than controls ignoring the irrelevant information. These results suggest that, in comparison to controls, CHI participants may be at a disadvantage in selective attention situations when visual search is required and when the discriminability between targets and distractors is difficult. (JINS, 1998, 4, 144–159.)

The purpose of this study was to examine regional cerebral blood flow using positron emission tomography (PET) during the performance of tasks related to visual confrontation naming. Ten healthy, young participants were scanned twice in each of 5 conditions; blood flow was measured using standard PET [15O]-water technology. Two major findings have replicated previous studies. First, the naming of visually presented objects, whether covert or overt, requires a region of the left inferior cortex including the fusiform gyrus. Second, during overt naming, there is an increase in activity in the inferior or frontal cortex and insula as a consequence of generating speech code. These data are consistent with other studies demonstrating the importance of the inferior temporal regions for semantic processing, and the frontal cortex for word form generation. (JINS, 1998, 4, 160–166.)

Fourteen patients with body dysmorphic disorder (BDD) were assessed with neuropsychological measures, including tests of executive, mnestic, and motor functions. Performance in these patients was compared to 10 patients with obsessive-compulsive disorder (OCD), 14 patients with schizophrenia, and 24 normal controls. Findings indicated normal performance of the BDD group on measures of mnestic and motor function, but poor performance of this group on tests of executive function (p < .05). The overall performance of the BDD and OCD groups on the neuropsychological measures was similar, while the schizophrenic groups showed a wider spectrum of neuropsychological deficits to these groups. These findings are discussed in terms of current theories of executive functions and the possible relationship between BDD and OCD. (JINS, 1998, 4, 167–171.)

Numerous reports have assessed the neuropsychological functioning of medically asymptomatic HIV-1 infected men. However, to date there have been no published studies of the neuropsychological functioning of asymptomatic HIV-1 infected women, even though women represent the fastest-growing demographic group of HIV-1 infected individuals. In this investigation, 31 women (17 asymptomatic HIV-1 seropositive, 14 seronegative) were administered a battery of neurocognitive and neuropsychiatric instruments. Participants in both groups were matched for age, education, months since injection drug use, and substance use. Group comparisons revealed no significant differences in any of the neurocognitive or neuropsychiatric measures. The results of this preliminary study suggest that clinically significant differences in neurobehavioral function are unlikely in medically asymptomatic HIV-1 infected women compared to seronegative controls. However, additional studies are needed with larger sample sizes and with careful attention to possible confounding or masking variables. (JINS, 1998, 4, 172–178.)

While the neuropsychological literature includes few cases of child-onset amnesia, 2 previous case studies suggest that these patients may be able to learn new information of a semantic or academic nature. The previous studies were, in large part, based on neuropsychological testing performed during adulthood and a retrospective review of academic achievement test scores during childhood. We present patient A.C., who acquired severe anterograde amnesia at age 10 years but demonstrated average levels of performance on tests of reading, spelling and arithmetic upon examination at age 19 years. Episodic and semantic memory test scores were severely impaired, but near normal performances were found on tests of implicit and procedural memory. In a prospective study, A.C. learned to read new irregular and pseudowords and retained this learning over a 1-month period, similar to the performance of age-matched controls. This demonstration of postmorbid, acquired oral reading vocabulary supports a previous conclusion that oral reading can progress in childhood following the onset of severe anterograde amnesia. The data also suggest that this new learning probably reflects nondeclarative memory processes rather than preservation of semantic memory, as was proposed in an earlier case study. (JINS, 1998, 4, 179–189.)

Recently an outbreak of acute respiratory infection associated with the hantavirus occurred in the southwestern United States. Hantavirus pulmonary syndrome (HPS) is a life threatening illness that carries with it a high mortality rate. Patients with HPS experience prolonged periods of hypoxemia requiring mechanical ventilation and treatment in intensive care units. We have recently seen 2 survivors of HPS. A neuropsychological test battery was administered immediately following their acute hospitalization and at 1 year postrecovery from HPS. Both patients exhibited cognitive impairments immediately following HPS as well as persistent cognitive impairments at 1 year. The cognitive impairments seen in these two HPS survivors are similar to those seen in other patients who have experienced brain anoxia, including memory impairments. It is also possible that hantavirus may directly cause brain injury with concomitant cognitive impairments. Additional research needs to be carried out in order to determine the extent and severity of the cognitive impairments in survivors of HPS. (JINS, 1998, 4, 190–196.)