Distributed and focused attention: Neuropsychological evidence for separate attentional mechanisms when counting and estimating.

Evidence is presented for 2 modes of attention operating in simultanagnosia. The authors examined visual enumeration in a patient, GK, who has severe impairments in serially scanning across a scene and is unable to count the numbers of items in visual displays. However, GK's ability to judge the relative magnitude of 2 displays was consistently above chance, even when overall luminosity did not vary with the number of items present. In addition, several variables had a differential impact on GK's counting and magnitude estimation. Magnitude estimation but not counting was facilitated by using elements that grouped more easily and by presenting the elements in regular configurations. In contrast, counting was facilitated by placing the elements in different colors while magnitude estimation was disrupted. Also GK's performance on magnitude estimation tasks was disrupted by asking him to count the elements present. The data suggest that GK can process visual stimuli in either a focused or distributed attention mode. When in a focused attention mode, performance is limited by poor serial scanning of attention due to an impaired explicit representation of visual space. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of eye movements in subitizing and counting.

Previous work has suggested that eye movements may be necessary for accurate enumeration beyond the subitization range of about 4 items. This study determined the frequency of eye movements normally made during enumeration, their relationship to response times, and whether they are required for accurate performance. This was achieved by monitoring eye movements and comparing performance when observers were allowed to saccade and when they were not. The results showed that (a) there was a sharp increase in saccadic frequency beyond about 4 items (from = 0.2 saccades per item to about 1 per item), and (b) enumeration of fewer than 4 items remained rapid and accurate even when eye movements were prevented, whereas enumeration beyond this became less efficient and sometimes less accurate. The results are discussed in relation to the memory and processing requirements of enumeration tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fractionating the binding process: Neuropsychological evidence from reversed search efficiencies.

The authors present neuropsychological evidence distinguishing binding between form, color, and size (cross-domain binding) and binding between form elements. They contrasted conjunctive search with difficult feature search using control participants and patients with unilateral parietal or fronto/temporal lesions. To rule out effects of task difficulty or loss of top-down guidance of search, the authors made conjunction search easier than feature search. Despite this, parietal patients were selectively impaired at detecting conjunction targets in their contralateral field. In contrast, the parietal patients performed like the other participants with form conjunctions, with form conjunctions being easier to detect than difficult feature targets. These data indicate a qualitative difference between binding in the form domain and binding across form, color, and size, consistent with theories that propose distinct binding processes in vision. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological impairment in patients with schizophrenia and evidence of hyponatremia and polydipsia.

Patients with schizophrenia and water imbalance may represent a subset of patients with distinct pathophysiological abnormalities and susceptibility to cognitive impairment. Specifically, patients with polydipsia and hyponatremia have been shown to have smaller anterior hippocampal volumes, which are also associated with various impairments in neuroendocrine function. To determine whether abnormalities in patients with water imbalance extend to the cognitive realm, the present study evaluated neuropsychological functioning in three groups of patients with schizophrenia: polydipsic hyponatremic, polydipsic normonatremic, and nonpolydipsic normonatremic. Participants were administered cognitive tests assessing intelligence, attention, learning/memory (verbal, nonverbal, emotional), and facial discrimination. Hyponatremic patients showed poorer overall neuropsychological functioning relative to all other patients, and polydipsic normonatremic patients performed intermediate to the other two groups. Results indicate that patients with schizophrenia and polydipsia, and particularly those with hyponatremia, show prominent cognitive deficits relative to patients without water imbalance. The clinical, neuroendocrine, and cognitive abnormalities in these patients may arise from pathology within the anterior hippocampus and associated prefrontal/limbic brain regions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation between recency and span: Neuropsychological and experimental evidence.

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subitizing speed, subitizing range, counting speed, the Stroop effect, and aging: Capacity differences and speed equivalence.

Thirty younger and 29 older adults were tested on reaction times for set size of a display of 1 to 9 digits. On half of the trials, the nominal value of the digits was equal to the size of the set displayed; on the other half, the value differed by 1 from the set size (Stroop interference). We found evidence for age differences in subitizing span (2.83 vs. 2.07). Once individual differences in subitizing range were taken into account, no age differences were found in the rate of either subitizing or counting, and no individual differences were apparent in subitizing speed. There was no age difference in the susceptibility to the Stroop effect. The results suggest that, with advancing age, the size of the focus of attention may shrink, but speed of access to elements in the focus of attention may remain constant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological mechanisms of individual differences in emotion, personality, and arousal.

Evidence is reviewed to suggest that parietotemporal regions of the right hemisphere not only are specialized for the processing of emotional information but also play a critical role in the experience of emotion. In particular, it is argued that these regions of the right hemisphere constitute a system involved in modulating autonomic and behavioral arousal in emotional states. This system is characterized by a set of cognitive and attentional qualities that make it uniquely suited to respond to environmental events in an adaptive fashion. The current proposal is an elaboration of a model of emotion and brain organization (W. Heller, 1990) that incorporates several aspects of emotional function: (1) perception and production of emotional information, (2) mood and emotional experience, and (3) autonomic arousal. In the context of this model, it is suggested that the right-hemisphere system operates in conjunction with a system localized to the frontal lobes that is involved in modulating the emotional valence of experience. The interaction of these 2 systems is hypothesized to be conditioned by individual differences and developmental tendencies that contribute to the production of a unique and stable pattern of personality traits and emotional characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple mechanisms of visual-spatial attention: recent evidence from human electrophysiology

Natural visual scenes contain vast quantities of information--far more than the visual system can process in a short period of time-and spatial attention is therefore used to focus the visual system's processing resources onto a subset of the incoming visual information. Most psychological theories of attention posit a single mechanism for this focusing of attention, but recent electrophysiological studies have provided evidence that the visual system employs several separable neural mechanisms of spatial attention. This paper describes the evidence for multiple attentional mechanisms and suggests links between these neurophysiologically defined mechanisms and specific functional processes that have been proposed in psychological theories of attention.     

Neuropsychological evidence for visual- and motor-based affordance: Effects of reference frame and object–hand congruence.

Two experiments are reported that use patients with visual extinction to examine how visual attention is influenced by action information in images. In Experiment 1 patients saw images of objects that were either correctly or incorrectly colocated for action, with the objects held by hands that were congruent or incongruent with those used premorbidly by the patients. The images were also shown from a 1st- and 3rd-person perspective. There was an overall reduction in extinction for objects colocated for action. In addition, there was an extra benefit when the objects were held in hands congruent with those used by the patients and when the objects were seen from a 1st-person perspective. This last result fits with an effect of motor simulation, over and above a purely visual effect based on positioning objects correctly for action. Experiment 2 showed that effects of hand congruence could emerge with images depicted from a 3rd-person perspective when patients saw themselves holding the objects. The data indicate 2 effects of action information on extinction: (a) an effect of colocating objects for action, which does not depend on a self-reference frame (a visual effect), and (b) an effect sensitive to object–hand congruence, which does depend on a self-reference frame (a motor-based effect). The self-reference frame is induced when stimuli are viewed from a 1st-person perspective and when an image of the self is seen from a 3rd-person perspective. Both visual and motor-based effects of action information facilitate the spread of attention across objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early neuropsychological impairment in HIV-seropositive intravenous drug users: evidence from the Italian Multicentre Neuropsychological HIV Study

The purpose of this study was to document the emetogenic potential of intrathecal chemotherapy (IC) in children and to evaluate the efficacy of ondansetron in reducing nausea and vomiting with this chemotherapy treatment. Patients less than 18 years of age with acute lymphoblastic leukemia were eligible to participate in a survey project measuring the emetogenic potential of various chemotherapy treatments. Patients surveyed for 1 or more IC treatments were included in this report. The IC consisted of methotrexate, hydrocortisone and cytarabine, dosed according to patient age. A nausea/vomiting survey instrument was completed by each patient and/or parent following IC treatment. The instrument rated nausea, vomiting and daily activity interference (DAI) on a 4-point scale of 0 = none, 1 = mild, 2 = moderate and 3 = severe, and collected data on the number of vomiting and/or retching episodes in addition to the child's appetite following the chemotherapy treatment. When ondansetron was employed, it was administered in an i.v. infusion at a dose of 0.15 mg/kg before and after chemotherapy or as an oral dose of 4 mg or 8 mg before chemotherapy. Courses of IC without antiemetics were analyzed to determine the emetogenic potential of IC. For patients receiving IC both with and without ondansetron, courses were compared with each patient used as their own control to determine the influence of ondansetron upon survey responses. Statistical analysis consisted of nonparametric Friedman 2-way ANOVA for ordinal variables and a paired t-test for continuous variables. The binomial test was employed to analyze for differences between ondansetron and no antiemetic in the number of patients with complete control of both nausea and vomiting or vomiting alone. A total of 63 children with a mean age of 7.6 +/- 4.2 years were each studied on one or more occasions. Thirty-seven children were surveyed for 87 IC treatments without antiemetics (group I), and 17 children from this group were surveyed for 48 IC courses with i.v. ondansetron (group IA). An additional 18 children were subsequently surveyed for 39 IC courses with i.v. ondansetron (group II). Fifteen patients (7 of whom were members of group I) were surveyed following 33 IC courses with oral ondansetron (group III). The survey scores for group I patients were: nausea severity 1.3 +/- 1.1, vomiting severity 1.2 +/- 1.1, DAI 1.2 +/- 1.0 and mean number of emetic episodes 4.7 +/- 8.4. The mean appetite score was 1.5 +/- 1.1. For patients in group IA, nausea severity (0.8 +/- 0.9), vomiting severity (0.5 +/- 0.8), DAI (0.7 +/- 0.8), and the number of emetic episodes (1.4 +/- 2.8) were all significantly lower than with prior IC treatments without ondansetron. For complete protection, children receiving i.v. ondansetron had greater complete protection rates from both nausea and vomiting or vomiting alone than did patients receiving no antiemetic. Survey responses were also lower for patients receiving oral ondansetron, but insufficient control data did not allow for statistical analysis. IC results in mild to moderate nausea and vomiting in children. The emetogenic potential of IC is significantly reduced by i.v. ondansetron.     

Alcohol and the brain: Neuropsychological correlates.

This review considers neuropsychological changes associated with alcohol abuse and touches on related neuropathological and neuroradiological research. Most neuropsychological research has been conducted with recently detoxified (1 month sober) alcoholic men, many of whom manifest deficits in abstracting ability, complex perceptual-motor skills, and learning and recall but demonstrate preserved verbal intelligence. Long-term abstinence (months to years) can be associated with slow recovery, suggesting the presence of intermediate-duration organic mental disorder. Animal research indicates that dendritic rearborization can occur after cessation of chronic ethanol exposure. A dose-effect relation between alcohol consumption variables and human neuropsychological performance has not been established. Sources of neuropsychological variability that might precede, coexist with, or be effects of excessive drinking include family history of alcoholism, developmental and neuromedical risk events, nutritional status, age, and education. A model illustrating the possible interrelations of these variables is presented, and a plea is made for assiduous care in subject selection and characterization as a prerequisite for further progress in understanding the long-term effects of alcohol on the brain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological test feedback to patients with brain dysfunction.

The provision of neuropsychological test feedback is of central importance in helping patients and their families cope with the consequences of brain injury. A general framework for presenting feedback is described, with an emphasis on techniques designed to maximize patient benefit. Special issues involving test-related limitations, patient characteristics, and family involvement in the feedback process are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retinotopic organisation of cortical mechanisms responsive to colour: evidence from patient studies

This paper deals with the visual responses of three patients who have impaired colour vision consequent on cortical dysfunction which, in two of them, is associated with demonstrable neuronal damage. The studies to be described are concerned particularly with the spatial attributes of their chromatic response mechanisms. Data are presented which establish that a hemianope GY has coarse chromatic discrimination for large stimuli located within his 'blind' hemifield. GY responds to stimuli containing differently coloured equiluminant components as if the coloured components were averaged over the whole field and it is speculated that such spatial averaging may correspond to the process which, in normal vision, provides compensation for change of illuminant in order to achieve colour constancy. Colour constancy is impaired in a second patient, BL, who has cortical lesions involving the lingual and fusiform gyri, areas which are partially spared in GY. It is shown that movement, but not colour, presented to GY's normal hemifield generates a response localised in his blind hemifield and disinhibitory interaction between movement and colour is illustrated for a patient MW, in whom colour chromatic stimuli generate spreading inhibition of visual responses. This inhibitory interaction is propagated between widely separated stimuli, including those which are located on opposite sides of the vertical meridian. We discuss these experimental results in relation to anatomical and physiological mechanisms of the primate visual cortex.     

Neuropsychological correlates of decision making in patients with bulimia nervosa.

In addition to the core psychopathology of bulimia nervosa (BN), patients with BN often show impulsive behavior that has been related to decision making deficits in other patient groups, such as individuals with anorexia nervosa and pathological gamblers. However, it remains unclear whether BN patients also show difficulties in decision making. In this study, 14 patients with BN and 14 healthy comparison subjects, matched for age, gender, education, body mass index, and intelligence, were examined with the Game of Dice Task (M. Brand, E. Fujiwara, et al., 2005), a gambling task that has fixed winning probabilities and explicit rules for gains and losses, as well as with a neuropsychological test battery and personality questionnaires. On the task, the patients with BN chose the disadvantageous alternatives more frequently than did the comparison subjects. Performance on the Game of Dice Task was related to executive functioning but not to other neuropsychological functions, personality, or disease-specific variables in the BN group. Thus, in patients with BN, decision making abnormalities and executive reductions can be demonstrated and might be neuropsychological correlates of the patients' dysfunctional everyday-life decision making behavior. Neurocognitive functions should be considered in the treatment of BN. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological functioning among the nonpsychotic relatives of schizophrenic patients: A diagnostic efficiency analysis.

Numerous studies suggest that the relatives of schizophrenic patients exhibit neuropsychological impairments that are milder yet similar to those seen among schizophrenic patients. The authors assessed 35 nonpsychotic relatives of schizophrenic patients and 72 normal controls using a clinical and experimental neuropsychological test battery. Three neuropsychological functions met criteria for risk indicators of the schizophrenia genotype: abstraction, verbal memory, and auditory attention. These findings could not be attributed to parental socioeconomic status, education, general visual-spatial ability, or psychopathology. Furthermore, exploratory analyses were performed to determine whether the diagnostic efficiency of the indicators could be adjusted to meet the needs of genetic linkage analyses. These analyses suggest that psychometric considerations may help to create measures for genetic linkage studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective Attention Impairments in Alzheimer's Disease: Evidence for Dissociable Components.

Tasks emphasizing 3 different aspects of selective attention-inhibition, visuospatial selective attention, and decision making-were administered to subjects with mild Alzheimer's disease (AD) and to healthy elderly control (HEC) subjects to determine which components of selective attention were impaired in AD subjects and whether selective attention could be dissociated into different components. The tasks were administered with easy versus hard levels of difficulty to assess proportional slowing as the key variable across tasks. The results indicated that the inhibitory and visual search tasks showed greater proportional slowing in subjects with AD than in HEC subjects, and that the task involving inhibition was significantly more affected in subjects with AD. Furthermore, there were no significant intertask correlations, and the results cannot be explained simply in terms of generalized cognitive slowing. These results provide evidence that inhibition is the most strikingly affected aspect of selective attention that is observed to be impaired in early stages of AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardinality development and counting.

Cardinality means that the last number word used in counting refers to the entire set of items and is thought to be crucial to correct counting. This research focuses on the cardinality acquisition and on the relation between cardinality and counting. Three groups of 24 children (3 years, 5 months to 5 years, 0 months) each received 4 kinds of tasks. First, they counted forward; then were shown sets that were counted for them backward sequentially, jumping forward in the sequence, or forward and backward; and asked to say how many items were in the set. Empirical evidence is gathered regarding the 6 understanding levels of cardinality proposed by V. Bermejo and M. O. Lago (see record 1990-24931-001) . Likewise, these data provide no empirical support for considering counting as a single prerequisite to cardinality. Finally, a new approach to the relation between counting and cardinality is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological functioning among the nonpsychotic relatives of schizophrenic patients: A 4-year follow-up study.

In a prior study of 54 relatives of patients with schizophrenia and 72 control participants, 3 neuropsychological functions met the criteria for risk indicators of the schizophrenia genotype: executive functioning, memory, and auditory attention. In an assessment of the stability of these findings, the sample was reexamined 4 years after the initial assessment. Three test scores were found to differ between groups (Immediate Verbal Memory, Delayed Verbal Memory, and Dichotic Listening Digits Detected) or to show a significant Group?×?Gender interaction (immediate and delayed verbal and visual memories). None of the test scores showed Group?×?Time interactions, suggesting that the discriminating power of the tests was stable over time. Evidence for deficits in working memory and rule learning on the object alternation test was also found. These results support the idea that neuropsychological dysfunction among relatives of patients with schizophrenia is a stable trait caused by the familial predisposition to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Luria-Nebraska Neuropsychological Battery: Theoretical orientation and comment.

Since the introduction of the Luria-Nebraska Neuropsychological Battery (LNNB), issues related to its understanding, interpretation, and validity have generated much interest. In response to P. A. Spiers's (see record 1981-24833-001) criticism of the battery, the authors suggest that the controversy appears to arise from a divergence in theoretical orientation on the role of quantitative versus qualitative assessment as well as from differences in the understanding of measurement methodology and validity. The present article discusses the theoretical basis from which the LNNB was constructed and describes the process of test interpretation. Previous and current research on use and validity of the battery is presented as it relates to the theoretical and methodological concerns. While basic philosophical differences with other theoretical systems are not likely to be resolved, the authors of the LNNB will continue to emphasize the integration of quantitative and qualitative approaches, both in the use of the LNNB and in the field of neuropsychology in general. It is concluded that the LNNB will continue to be revised on the basis of research findings and experience with the test in different patient populations. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological impairment in female alcoholics: Replication and extension.

In 2 separate studies, female alcoholics (N?=?50) performed significantly poorer on 12 neuropsychological tests (e.g., the WAIS and the Bender-Gestalt Test) than female nonalcoholic controls (N?=?50). The pattern of deficit was consistent across studies and similar to that reported for male alcoholics: intact verbal skills but impaired nonverbal abstracting, visual-spatial, and problem-solving abilities. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)