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.)

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 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.)

Arithmetical reasoning ability has been investigated in a group study of patients with unilateral cerebral lesions. Two series of 38 and 39 patients, who had suffered unilateral cerebral lesions of the right and left cerebral hemisphere, respectively, were investigated. They completed a neuropsychological battery that included a test of computation (Graded Difficulty Arithmetic, GDA; Jackson & Warrington, 1986), and a new test of numerical series completion (Arithmetical Reasoning Test, ART). Whereas the left-hemisphere lesion group were markedly more impaired on the GDA compared to both the right-hemisphere lesion group and a standardization sample, both lesion groups were equally severely impaired on the ART. It is suggested that the abstraction of numerical relations, which is essential to numerical series completion, relies on the integrity of the right hemisphere. A global model of arithmetic processing that incorporates these findings is proposed. (JINS, 1997, 3, 260–268.)

Journeymen painters were evaluated with a comprehensive battery of neuropsychological tests and compared to demographically similar nonexposed controls. For painters, a cumulative exposure to solvents was estimated from a structured interview that derived an index based on lifetime exposure and exposure in the past year. Painters were tested either shortly after having painted or after an exposure-free interval. Significant between-group differences were found on a cluster of tests measuring learning and memory. Within the painter group, scores on the learning and memory tests were significantly related to the interaction of condition and exposure. That is, those painters who were tested soon after painting and who also had a higher overall lifetime exposure, performed worst on tests of learning and memory. These results are consistent with the view that neuropsychological function — particularly learning and memory — may be compromised in active workers with a history of chronic solvent exposure. Furthermore, both the chronicity of solvent exposure, as well as the acuteness of the exposure, are significant factors in cognitive performance. (JINS, 1997, 3, 269–275.)

HIV infection often results in MRI-detectable brain atrophy and white matter signal hyperintensities (WMSHs). Magnetic resonance images were obtained from 31 HIV+ male patients and 10 high-risk controls. Variation within the HIV+ group on neuropsychological (NP) impairment and stage of systemic disease were relatively independent, allowing examination of the relative association of MRI measures with NP impairment versus with systemic stage of disease. HIV+ patients compared to high-risk controls evidenced global atrophy, reduced caudate nuclei volume, and a trend to gray matter volume loss but no difference in white matter volume or in WMSHs. These effects were progressive with CDC clinical stage such that patients at CDC stage A had values very close to those of controls, while patients at CDC stage C had the most abnormal values. In contrast, the relationship between these MRI variables and severity of NP impairment was much less dramatic, with the mildly to moderately impaired HIV+ subjects showing MRI volume effects greater than or equal to those of the severely impaired HIV+ subjects. These results suggest that MRI-detectable brain atrophy secondary to HIV infection is not the primary substrate underlying the progressive NP impairment in HIV disease. (JINS, 1997, 3, 276–287.)

There have been several proposals for the mechanism by which we are able to recognize an object across a number of viewpoints. Viewpoint-dependent accounts suggest that recognition may be based on an incremental transformation (e.g., mental rotation) strategy, while a variety of viewpoint-independent mechanisms for object recognition have also been proposed. Recent research in neurobiology, based on the two cortical visual systems account, suggest that the processes of viewpoint-dependent and viewpoint-independent object recognition may rely on separate anatomical regions, and that brain lesions may leave patients with selective access to particular types of representation. Evidence from a variety of neuropsychological disorders are reviewed to support the position that viewpoint-independent object recognition depends upon the integrity of occipitotemporal structures. In addition, it is suggested that viewpoint-dependent processes (perhaps depending on occipitoparietal structures) may supplement this primary system under nonoptimal circumstances. (JINS, 1997, 3, 288–298.)