Traumatic brain injury (TBI) is associated with impairments of attention, most typically measured through tests of information processing, or by subjective symptom endorsement by patients, families, and clinicians. We have previously shown increased rates of off-task behavior among patients with TBI versus controls as defined by videotaped records of independent work in distracting environments. In this research, we report on a more detailed method of coding such videotaped records which allows measurement of the precise number of off-task behaviors, their durations, and their relationship to distracting events. Using this method, we studied 20 patients with recent moderate-to-severe TBI and 20 demographically comparable controls as they performed independent work tasks while being subjected to controlled distracting events. This research confirms that patients are markedly less attentive than controls both in the presence of distractions and in their absence, that distractions have an influence on off-task behavior in both groups, and that the disruptive impact of distractors wanes relatively quickly for controls but not for patients. The duration of distraction produced by various classes of distracting events appeared similar for patients and controls, although the power to detect differences in behavioral duration between groups was limited. The pattern of inattentiveness among patients showed minimal relationship to measures of injury severity within this sample. (JINS, 2000, 6, 1–11.)

This study was undertaken to investigate whether alcoholics differ qualitatively from controls in their organizational approach to the Rey–Osterrieth Complex Figure (ROCF) and to examine the effects of problem-solving and organizational ability on learning and retention. Data were collected on 3 groups of neuromedically healthy, middle-aged men: 29 recently detoxified alcoholics (RDA) abstinent at least 2 weeks, 29 long-term abstinent alcoholics (LTA) abstinent at least 18 months, and 29 nonalcoholic controls (NAC). Groups were comparable in age, education, WAIS–R Vocabulary score, and ANART IQ. Three indices of problem-solving approach were used to score how participants produce the ROCF during the copy condition: perceptual clustering, organization, and constructional accuracy. Learning and retention were measured by immediate recall, 20-min delayed recall, and recognition performance. RDAs had significantly impaired immediate recall, delayed recall, and recognition scores compared to NACs. RDAs also had significantly lower perceptual clustering, organization, and constructional accuracy scores than their long-term abstinent and nonalcoholic counterparts. Multiple regression analyses revealed that problem-solving ability at copy accounted for a significant proportion of the variance in immediate recall, delayed recall, and recognition. Further investigation of memory performance using a repeated measures design revealed that across the 3 groups, little forgetting occurred between immediate and delayed recall, while performance improved significantly on the recognition trial. Use of less efficient problem-solving strategies appears to affect RDAs' ability to learn and retrieve complex figural information. (JINS, 2000, 6, 12–19.)

Chronic exposure to elevated glucocorticoid levels in Cushing's syndrome (CS), is associated with deficits in cognitive function and in emotion. The hippocampus plays a crucial role in the behavioral manifestations of the syndrome as it is richest in glucocorticoid receptors and is thus particularly vulnerable to glucocorticoid excess. The wide distribution of glucocorticoid receptors throughout the cerebral cortex, however, suggests that several cognitive functions can also be affected by the dysregulation of glucocorticoids. In this study, we investigated how an excess of glucocorticoid hormones affects cognitive processes. Nineteen patients with chronic hypercortisolemia due to CS were compared to healthy controls matched for age, sex, education, and occupation in tests of processing of visual and spatial information, memory, reasoning and concept formation, language and verbal functions, and attention. Multivariate and univariate analyses revealed overall differences in tests of treatment of visual and spatial information, reasoning and concept formation as well as in verbal and language performance, with poorer performance from CS patients. Differences were also observed in nonverbal aspects of memory and in attention tasks. The results suggest that chronic exposure to elevated levels of cortisol is associated with deficits in several areas of cognition, particularly those involving processing of selective attention and visual components. This study also shows that hormones play an important role in the modulation of cognitive function and that their influence on cerebral structure and function merits closer scrutiny. (JINS, 2000, 6, 20–29.)

Cognitive impairment in schizophrenia may be related to reduced availability of information-processing resources (resource limitations hypothesis). An abnormally accelerated age-related decline in processing resource availability may also occur in older patients with schizophrenia (neurodegeneration hypothesis). To test these hypotheses, pupillary responses were recorded as an index of processing resource availability during performance of the span of apprehension (SOA) task in 33 middle-aged and older patients with schizophrenia and 37 age-comparable nonpsychiatric participants. Consistent with the resource-limitations hypothesis, the patients with schizophrenia showed impaired detection accuracy and abnormally small pupillary responses (reduced resource allocation) only in the higher processing load SOA conditions. This pattern of results suggests that the patients depleted their available processing resources at lower processing loads than the nonpsychiatric participants. Consistent with the neurodegeneration hypothesis, cross-sectional analyses showed abnormally accelerated rates of age-related decline in SOA performance and pupillary responses in the patients with schizophrenia relative to age-comparable normal participants. (JINS, 2000, 6, 30–43.)

Many retrospective analyses of remote memory have demonstrated recency effects in that memory for events proximal to the time of testing is superior to memory for events from remote time periods. However, the rate at which information decays over time and the specific pattern of forgetting may vary depending upon the distinct attributes of stimuli used as indices of memory. Studies examining long-term forgetting of well rehearsed, conceptually integrated information underscore preservation of remote events, some of which are thought to be permanently stored in memory. A different pattern of forgetting emerges in relation to recall of discrete facts whereby recall declines according to a negatively accelerated decay curve. In the current study long-term retention of transient news events was examined. Results were examined in relation to the effects of age and sex. All age groups demonstrated recency effects in that events from the recent past were recalled better than remote events. Age did not exert a negative influence on recall of remote or recent events with the exception of younger participants who did not recall items predating their dates of birth. Older female participants were less adept at recalling very old events than their male counterparts. (JINS, 2000, 6, 44–51.)

One theory of normal cognitive aging asserts that decreases in simple processing speed mediate the age-related decline of fluid intelligence. Another possibility is that age-related atrophic changes in frontal brain structures undermine the functioning of executive abilities, thereby producing the same decline. In this study, we used principal components analysis to derive a measure of fluid–spatial intelligence in 197 normal adults between 20 and 92 years of age. Measures of perceptual comparison speed, working memory, and executive ability, as well as regional brain volumes based on high resolution magnetic resonance imaging were obtained from a subsample of 112 participants. We then conducted a series of hierarchical multiple regression analyses to test whether (1) the processing speed theory, (2) frontal–executive theory, or (3) some combination of these best accounted for age-related variation in fluid intelligence. The results showed that perceptual comparison speed, executive ability, and frontal lobe volume each made significant contributions to a regression equation that explained 57% of the variance in fluid intelligence. These findings suggest that both the processing speed and frontal–executive theory of cognitive aging are partially correct and complement one another. (JINS, 2000, 6, 52–61.)

Prospective memory can be defined as the timely execution of a previously formed intention, and is critical in daily life because of its inherent involvement in goal-directed behavior. Cognitive systems involved in prospective memory have been hypothesized as involving the frontal cortex, and in adults, associated with working memory and executive functions. This study introduces a new computerized measure of prospective memory designed for children. In this study prospective memory is examined in a driving game task called the CyberCruiser. In a sample of 80 children ages 6–12 years, variables from this task demonstrated a significant age effect and were significantly correlated with other well known measures of executive function, even after controlling for chronological age. Performance on this task also demonstrated the anticipated pattern of strategic monitoring that has been demonstrated in other studies of prospective memory. (JINS, 2000, 6, 62–70.)

In a previous study, we demonstrated that unilateral cerebral lesions produce hypometric limb movements of the contralateral arm and hemispatial (i.e., directional) hypometria for movements towards contralateral hemispace. In the present study, we investigated 10 patients with right cerebral lesions and 25 healthy controls using a task to uncouple deficits in sensory perceptual systems and motor-action output systems on directional hypometria. This task required participants, with their eyes closed, to reproduce lateral and medial horizontal displacements (15–27 cm) with each arm. Each participant was seated at a waist high table and had their hand placed at an origin point aligned with the axillary fold on the same side. Their hand was moved by the investigator from the origin point to a target point and brought back to the point of origin (input displacement). The participant was then asked to return their hand to either the same target point or to an equidistant target point in the opposite direction. Healthy dextral participants were significantly more hypometric with their right arm, but patients with right cerebral lesions exhibited an opposite pattern with overall left arm hypometria. In addition, patients were significantly more hypometric for movements when output displacements were toward left hemispace. No effect was found for direction of sensory input. The results suggest that the directional hypometria is predominantly produced by hemispatial output deficits. (JINS, 2000, 6, 71–75.)

Age-related declines in executive abilities have been widely reported and are thought to result from neuropathological changes in the prefrontal cortex. Some investigators have suggested that age-related changes in cognition may be the result of slowed information processing speed rather than declines in specific cognitive abilities. We examined the relationships among age, executive abilities, and psychomotor speed in 40 older adults and 46 young adults. Both verbal and nonverbal tasks were administered that measured 2 aspects of executive ability: set formation and set shifting. Executive and psychomotor speed tasks were paired based on similarities in basic task demands. Our results revealed that poorer executive performance was associated with increasing age. Further, although psychomotor speed attenuated the relationship, age accounted for a unique and significant proportion of variance in executive performance after controlling for psychomotor speed. These results suggest that age has an effect on prefrontally mediated executive abilities that cannot be explained solely in terms of psychomotor slowing. (JINS, 2000, 6, 76–82.)

HIV infection and abuse of central nervous system (CNS) stimulants are both associated with brain damage and dysfunction. CNS stimulant overdose can lead to microinfarction, hemorrhagic lesions, and vasculitis (Bostwick, 1981; Cahill et al., 1981), and may impact frontostriatal systems. Investigations of HIV-infected (HIV+) individuals have demonstrated deficits in attention, speed of information processing, motor functioning, executive functioning, and learning efficiency. These deficits are consistent with frontostriatal involvement (Heaton et al., 1995; Martin, 1994). Given the rise in AIDS cases attributable to drug use at a time when the number of AIDS cases due to sexual transmission is stable or declining, it is critical to determine if drug use, especially CNS stimulants, potentiates HIV-related neuronal injury.

Fifty-eight studies of the neuropathological and neuropsychological outcomes of cerebral anoxia were reviewed. Neuropathological reports were examined for the variety, extent, and specificity of lesions resulting from an anoxic event. While most attention has focused on damage to the hippocampus following anoxic brain injury, the review indicated that watershed cerebral cortex and the basal ganglia were both more frequently damaged than the hippocampus. The hippocampus was the sole affected structure in only 18% of reported cases. Neurological, neuropsychological and psychiatric studies were analyzed. Of 67 individual case reports, a memory disturbance was documented in 36 (54%), but a memory disturbance without report of additional cognitive deficits occurred in only 13 (19.4%). Changes in personality and behavior were noted in 31 (46.2%). Visuospatial or, less frequently, visual recognition problems were noted in 21 individual cases (31.3%) reviewed. Memory deficits were found in all 14 group studies reviewed, while in 9 papers changes in behavior or personality were also documented. Six studies also reported visuospatial deficits. Careful reading of the literature reveals a range of cognitive and behavioral changes that reflect very well the neuropathological outcomes of anoxic episodes. (JINS, 2000, 6, 86–99.)

In his forward to Clinical Neuropsychology Arthur Benton comments, “More aptly than might have been anticipated, clinical neuropsychology is coming of age. I mean by this that it is evolving from what was largely a set of assessment procedures coupled with a diagnostic inference to be drawn from them into a true discipline, conscious of its conceptual bases and concerned with the cognitive and neuromechanisms that mediate the behavior of normal individuals and patients with brain disease.” Dr. Benton's assessment catches the thrust of the book well. It concerns itself with the development and maturation of the field, its relationship to sister disciplines such as behavioral neurology and neuropsychiatry, focuses in on important practice and credentialing issues, and provides cogent reviews of progress in many important content areas.

From the outset, it should be made clear that this book is not a new text on cognitive neuroscience. It does not pretend to cover the whole area comprehensively and is unsuitable for those wanting a thorough introduction or overview of cognitive neuroscience with colored illustrations. Instead, this volume could be considered a companion to such a text. Findings and Current Opinion in Cognitive Neuroscience, contains a set of 46 articles carefully selected from Current Opinion in Neurobiology, which is part of an even wider series offering current opinions on a wide range of scientific–medical topics (e.g., Current Opinion in Neurology and Neurosurgery). Those who browse in medical or academic libraries will be familiar with the series, which is unique. Instead of the traditional journal format, a collection of short review articles are presented, each written by an expert in the particular field. Each article summarizes current thinking in the area or field, and concludes with an annotated bibliography. Six issues of each set of current opinions are published annually. Each issue is dedicated to a particular aspect of an area.

This book contains an introduction by the editors and 15 chapters that are divided into three parts. Part I is entitled “Decoding Speech Sounds and Individual Words”; part II: “Lexical and Sentence-Level Semantics”; and Part III: “Discourse Processing and Problem Solving.” Each part concludes with a commentary by the editors. As these section titles show, the book provides evidence that the right hemisphere is involved with functions more commonly ascribed to the left hemisphere, namely, phonology, morphology, and semantics. In addition, several chapters are devoted to aspects of communicative competence commonly associated with right hemisphere specialization, such as discourse comprehension and the appreciation of emotional verbal messages. Previous works, such as Language, Aphasia, and the Right Hemisphere by Chris Code (1987), provide a more basic introduction to what was then known of right hemisphere communicative competence. The Beeman and Chiarello volume is directed towards a more sophisticated target audience familiar with neurolinguistic models of hemispheric contributions to language comprehension.

Attention-deficit hyperactivity disorder (ADHD) and learning disabilities (LD) are most frequently associated with childhood. This, of course, is because a child's job is to sit in a classroom, pay attention, and learn, and these are disorders that interfere with completing that job. Because these disorders are presumed due to brain dysfunction, it should be no surprise that both LD and ADHD continue to exert effects as children grow, go on to postsecondary education, and enter the job market. That is, developmental learning disorders, including LD and ADHD, do not “go away” when one becomes an adult. Several research groups have followed children with LD or ADHD into adulthood and have shown the persistence of symptoms and cognitive deficits, along with the toll that these difficulties take on psychosocial functioning, later academic performance, and vocational advancement.