Neuropsychology

Numeracy skills in patients with degenerative disorders and focal brain lesions: A neuropsychological investigation.
Objective: To characterize the numerical profile of patients with acquired brain disorders. Method: We investigated numeracy skills in 76 participants—40 healthy controls and 36 patients with neurodegenerative disorders (Alzheimer dementia, frontotemporal dementia, semantic dementia, progressive aphasia) and with focal brain lesions affecting parietal, frontal, and temporal areas as in herpes simplex encephalitis (HSE). All patients were tested with the same comprehensive battery of paper-and-pencil and computerized tasks assessing numerical abilities and calculation. Degenerative and HSE patients also performed nonnumerical semantic tasks. Results: Our results, based on nonparametric group statistics as well as on the analysis of individual patients, and all highly significant, show that: (a) all patients, including those with parietal lesions—a key brain area for numeracy processing—had intact processing of number quantity; (b) patients with impaired semantic knowledge had much better preserved numerical knowledge; and (c) most patients showed impaired calculation skills, with the exception of most semantic dementia and HSE patients. Conclusion: Our results allow us, for the first time, to characterize the numeracy skills in patients with a variety of neurological conditions and to suggest that the pattern of numerical performance can vary considerably across different neurological populations. Moreover, the selective sparing of calculation skills in most semantic dementia and HSE suggest that numerical abilities are an independent component of the semantic system. Finally, our data suggest that, besides the parietal areas, other brain regions might be critical to the understanding and processing of numerical concepts. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Deficits of contralesional awareness: A case study on what paper-and-pencil tests neglect.
Objective: Attentional orienting and awareness for contralesional hemispace were studied longitudinally in a woman (GB) who suffered a right hemispheric stroke without any motor impairment and who presented normal performance on standard paper-and-pencil tests for neglect but manifested difficulties in everyday life. We aimed to test whether computer-based, dual-task paradigms were sufficiently sensitive to detect the presence of subclinical neglect in GB. Method: We assessed the spatial awareness of GB by means of cued-detection tasks, paper-and-pencil tests, attentionally demanding dual tasks, and in several ecological settings after her discharge from the hospital. A group of right brain–damaged patients and an age-matched healthy participant were also tested with the dual tasks. Results: Dramatic awareness deficits for the left contralesional hemispace emerged in GB only under dual-task conditions, both in computer-based and in ecological settings, as if her degree of contralesional space awareness impairment was closely dependent on the quantity of available attentional resources. Our dual-task paradigm was also effective in quantifying awareness improvements over time. The absence of motor impairments, uncommon for a postacute patient with severe albeit hidden neglect, allowed us to ascribe her everyday life impairments for contralesional hemispace to awareness deficits. The performance of the group of patients confirmed the detrimental effects of the dual tasks, whereas the performance of the healthy control we tested was not affected by dual-task manipulation. Conclusions: Our results confirm the well-known lack of sensitivity of standard neuropsychological tests to detect subclinical forms of neglect, which, nonetheless, may result in negative consequences in everyday life. Computer-based, resource-demanding paradigms seem to be a promising solution to uncover subtle awareness deficits that can affect the everyday life of stroke patients. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Time since stroke influences the impact of hemianopia and spatial neglect on visual-spatial tasks.
Objective: Spatial neglect results in an ipsilesional misorientation of attention in visual-spatial tasks. Hemianopia impairs visual perception but its influence on visual-spatial tasks is subject to debate. Here, we investigated the influence of the time since stroke on the respective impacts of hemianopia and spatial neglect. Method: A total of 29 patients with a right hemisphere stroke were included in the study. Nine had severe neglect and hemianopia, six had severe neglect only, four showed hemianopia with little or no neglect after infarction of the posterior cerebral artery, and 10 had neither neglect nor hemianopia. We investigated the spatial bias in the subjective straight ahead (SSA) test and in clinical tests (bell cancellation, line bisection, and scene copy). Each task was administered twice (at S1 and S2: 41.4 and 67.2 days [on average] after the stroke, respectively). Results: At S1, spatial neglect and hemianopia had an additive influence on SSA test performance (rightward translation). Similar rightward biases were observed in the clinical tests. At S2, the influence of hemianopia had disappeared, whereas that of neglect was still present. Furthermore, loss of bias in the SSA test correlated with the improvements seen in most of the clinical tests. Conclusions: In patients with recent stroke, hemianopia aggravates the visual-spatial bias when neglect is present or may lead to visual-neglect-like behavior when classically defined neglect is absent. However, the influence of hemianopia disappears relatively quickly over time, due to compensation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Does attentional training improve numerical processing in developmental dyscalculia?
Objective: Recently, a deficit in attention was found in those with pure developmental dyscalculia (DD). Accordingly, the present study aimed to examine the influence of attentional training on attention abilities, basic numerical abilities, and arithmetic in participants who were diagnosed as having DD. Method: Nine university students diagnosed as having DD (IQ and reading abilities in the normal range and no indication of attention-deficit hyperactivity disorder) and nine matched controls participated in attentional training (i.e., video game training). Results: First, training modulated the orienting system; after training, the size of the validity effect (i.e., effect of valid vs. invalid) decreased. This effect was comparable in the two groups. Training modulated abnormalities in the attention systems of those with DD, that is, it reduced their enlarged congruity effect (i.e., faster responding when flanking arrows pointed to the same location as a center arrow). Second, in relation to the enumeration task, training reduced the reaction time of the DD group in the subitizing range but did not change their smaller-than-normal subitizing range. Finally, training improved performance in addition problems in both the DD and control groups. Conclusions: These results imply that attentional training does improve most of the attentional deficits of those with DD. In contrast, training did not improve the abnormalities of the DD group in arithmetic or basic numerical processing. Thus, in contrast to the domain-general hypothesis, the deficits in attention among those with DD and the deficits in numerical processing appear to originate from different sources. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Deconstructing spatial working memory and attention deficits in multiple sclerosis.
Objective: To investigate whether spatial working memory (WM) is impaired in multiple sclerosis (MS), and, if it is, to localize impairment to specific cognitive subprocess(es). Method: In Experiment 1, MS and control participants performed computerized memory-span and visuomotor tasks. WM subprocesses were taxed by manipulating (1) the requirement to remember serial order, (2) delay duration, and (3) the presence of irrelevant stimuli during target presentation. In Experiment 2, recall and recognition tests varied the difficulty of WM retrieval. In Experiment 3, an attention-cueing task tested the ability to voluntarily and rapidly reorient attention. Results: Performance was worse for MS than for control participants in both spatial recall (Exp. 1 span: 95% CI MS = [5.11, 5.57], 95% CI Controls = [5.58, 6.03], p = .003, 1-tailed; Exp. 2 span: 95% CI MS = [4.44, 5.54], 95% CI Controls = [5.47, 6.57], p = .006, 1-tailed) and recognition (accuracy: 95% CI MS = [0.71, 0.81], 95% CI Controls = [0.79, 0.88], p = .01, 1-tailed) tests. However, there was no evidence for deficits in spatiotemporal binding, maintenance, retrieval, distractor suppression, or visuomotor processing. In contrast, MS participants were abnormally slow to reorient attention (cueing effect (ms): 95% CI MS : [90, 169], 95% CI Controls : [29, 107], p = .015, 1-tailed). Conclusions: Results suggest that, whereas spatial WM is impaired in MS, once spatial information has been adequately encoded into WM, individuals with MS are, on average, able to maintain and retrieve this information. Impoverished encoding of spatial information, however, may be due to inefficient voluntary orienting of attention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Mood and motor trajectories in Parkinson's disease: Multivariate latent growth curve modeling.
Objective: Apathy is a common feature of Parkinson's disease (PD) that can manifest independently of depression, but little is known about its natural progression in medically managed patients. The present study sought to characterize and compare trajectories of apathy, depression, and motor symptoms in PD over 18 months. Method: Data from a sample of 186 PD patients (mean disease duration of 8.2 years) followed by the University of Florida Movement Disorders Center were obtained from a clinical research database. Scores on the Unified Parkinson's disease Rating Scale (motor portion), Apathy Scale, and Beck Depression Inventory at three time-points (baseline, 6 months, 18 months) were analyzed in a structural equation modeling framework. Results: A multivariate growth model controlling for age, sex, education, and disease duration identified linear worsening of both apathy (slope estimate = 0.73; p <.001) and motor symptoms (slope estimate = 1.51; p <.001), and quadratic changes in depression (slope estimate = 1.18; p = .07). All symptoms were positively correlated. Higher education was associated with lower apathy, depression, and motor severity. Advanced age was associated with greater motor and apathy severity. Female sex and longer disease duration were associated with attenuated motor worsening. Antidepressant use was associated only with depression scores. Conclusions: These longitudinal results support the differentiation of apathy and depression in PD. Like motor progression, apathy progression may be linked at least partially to dopaminergic neurodegeneration. Empirically supported treatments for apathy in PD are needed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
The SEA (Social Cognition and Emotional Assessment): A clinical neuropsychological tool for early diagnosis of frontal variant of frontotemporal lobar degeneration.
Objective: The frontal variant of frontotemporal degeneration (fvFTD) is characterized by a predominant behavioral syndrome, which is mostly attributable to an orbital-medial prefrontal dysfunction. The orbital and ventral medial prefrontal functions in humans are difficult to assess in clinical practice. Here, we propose a new tool, the SEA (Social cognition and Emotional Assessment), for use in evaluating the functions of the orbital and ventral-medial portions of the prefrontal cortex. Method: The SEA is composed of five subtests, each assessing a specific orbitofrontal-related function: a test of identification of facial emotions, a reversal/extinction task, a behavioral control task, a theory of mind test, and an apathy scale. The maximum score is 55. Three groups have been tested: 22 fvFTD patients, 22 patients with Alzheimer's disease (AD) or amnesic mild cognitive impairment (aMCI), and 30 healthy control subjects, all matched for age and educational level. Results: FvFTD patients showed significantly lower performances in all subtests of the SEA. A cut-off score of 39.4/55 was proposed to separate normal controls from fvFTD patients, with a maximum sensitivity and specificity of 100%. A very high specificity (88.5%) was obtained using the same cut-off with AD/aMCI patients and normal controls versus fvFTD patients. FvFTD patients' performance in the SEA did not correlate with any other neuropsychological scores, particularly the classical cognitive executive tests. Conclusions: The SEA is a new and useful tool for diagnosing fvFTD and, more generally, all of the diseases affecting the orbital and medial prefrontal functions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Prospective memory after moderate-to-severe traumatic brain injury: A multinomial modeling approach.
Objective: Prospective memory (PM), which can be understood as the processes involved in realizing a delayed intention, is consistently found to be impaired after a traumatic brain injury (TBI). Although PM can be empirically dissociated from retrospective memory, it inherently involves both a prospective component (i.e., remembering that an action needs to be carried out) and retrospective components (i.e., remembering what action needs to be executed and when). This study utilized a multinomial processing tree model to disentangle the prospective (that) and retrospective recognition (when) components underlying PM after moderate-to-severe TBI. Method: Seventeen participants with moderate to severe TBI and 17 age- and education-matched control participants completed an event-based PM task that was embedded within an ongoing computer-based color-matching task. Results: The multinomial processing tree modeling approach revealed a significant group difference in the prospective component, indicating that the control participants allocated greater preparatory attentional resources to the PM task compared to the TBI participants. Participants in the TBI group were also found to be significantly more impaired than controls in the when aspect of the retrospective component. Conclusions: These findings indicated that the TBI participants had greater difficulty allocating the necessary preparatory attentional resources to the PM task and greater difficulty discriminating between PM targets and nontargets during task execution, despite demonstrating intact posttest recall and/or recognition of the PM tasks and targets. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Reduced susceptibility to the attentional blink in psychopathic offenders: Implications for the attention bottleneck hypothesis.
Objective: Newman and Baskin-Sommers (in press) have proposed that psychopathy reflects an attention bottleneck that interferes with processing contextual information, including the timely processing of affective and inhibitory cues that initiate self-regulation. Despite a wealth of evidence that attention moderates the affective, inhibitory, and self-regulation deficits of psychopathic offenders, to date there is little or no evidence that psychopathic offenders perform abnormally on a canonical measure of selective attention. In this study, we address this gap in the literature and clarify the attention-related abnormality in psychopathy. Method: We administered the attentional blink (AB) task to 37 male prisoners assessed with Hare's (2003) Psychopathy Checklist-Revised. In the AB paradigm, participants identify targets in a rapid serial visual presentation. Distracters' temporal proximity to the first target elicits a conflict between attending to the target and attending to the distracters. Greater conflict results in a larger AB (i.e., reduced accuracy for the second target). Results: As predicted, psychopathic offenders displayed a significantly smaller AB (i.e., better accuracy throughout the blink interval) than nonpsychopathic offenders. Conclusions: Consistent with the attentional bottleneck hypothesis, psychopathic participants were less susceptible to distracter effects following presentation of an initial target. The results clarify the nature of the attention bottleneck in psychopathy, the circumstances in which it enhances versus interferes with performance, and its implications for more ecologically valid conditions involving the sequential presentation of goal-relevant and goal-incongruent information. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Dual task performance of working memory and postural control in major depressive disorder.
Objective: Previous studies with patients diagnosed with Major Depressive Disorder (MDD) revealed deficits in working memory and executive functions. In the present study we investigated whether patients with MDD have the ability to allocate cognitive resources in dual task performance of a highly challenging cognitive task (working memory) and a task that is seemingly automatic in nature (postural control). Method: Fifteen young (18–35 years old) patients with MDD and 24 healthy age-matched controls performed a working memory task and two postural control tasks (standing on a stable or on a moving platform) both separately (single task) and concurrently (dual task). Results: Postural stability under single task conditions was similar in the two groups, and in line with earlier studies, MDD patients recalled fewer working memory items than controls. To equate working memory challenges for patients and controls, task difficulty (number of items presented) in dual task was individually adjusted such that accuracy of working memory performance was similar for the two groups under single task conditions. Patients showed greater postural instability in dual task performance on the stable platform, and more importantly when posture task difficulty increased (moving platform) they showed deficits in both working memory accuracy and postural stability compared with healthy controls. Conclusions: We interpret our results as evidence for executive control deficits in MDD patients that affect their task coordination. In multitasking, these deficits affect not only cognitive but also sensorimotor task performance. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Changes in response bias with different study-test delays: Evidence from young adults, older adults, and patients with Alzheimer's disease.
Objective: Along with impaired discrimination, patients with Alzheimer's disease (AD) often show an abnormally liberal response bias (greater tendency to respond “old”). Previously we matched discrimination by varying study-test list length and found that participants' usual bias is maintained, such that patients with AD were more liberal than healthy controls. However, this pattern could be a result of the way in which discrimination was matched. In this experiment, we examined whether matching discrimination with the use of a delay would lead to a liberal response bias in healthy younger and older adults as it might lead to the use of more similar memorial processing to the patients with AD. Method: Younger adults, older adults, and patients with AD were run in 2 study-test sessions, with study and recognition test separated by either a 1-min or 1-day delay. Results: With the 1-min delay, both younger adults and healthy older adults showed a conservative response bias, while patients with AD showed a liberal response bias. When discrimination was matched between patients with AD and controls by the use of a delay, response bias was also matched, with all participants showing a more liberal response bias. Conclusions: The current study suggests that how discrimination is matched between patients with AD and controls matters greatly. Potentially, this liberal bias is a result of healthy younger and older adults relying primarily on familiarity at the longer delay, thus using more similar memorial processes to patients with AD who are dependent on familiarity at any delay. (PsycINFO Database Record (c) 2011 APA, all rights reserved)
Examining frontotemporal connectivity and rTMS in healthy controls: Implications for auditory hallucinations in schizophrenia.
Objective: Repetitive transcranial magnetic stimulation (rTMS) has been shown to have clinically beneficial effects in altering the perception of auditory hallucinations (AH) in patients with schizophrenia. However, the mode of action is not clear. Recent neuroimaging findings indicate that rTMS has the potential to induce not only local effects but also changes in remote, functionally connected brain regions. Frontotemporal dysconnectivity has been proposed as a mechanism leading to psychotic symptoms in schizophrenia. The current study examines functional connectivity between temporal and frontal brain regions after rTMS and the implications for AH in schizophrenia. Method: A connectivity analysis was conducted on the fMRI data of 11 healthy controls receiving rTMS, compared with 11 matched subjects receiving sham TMS, to the temporoparietal junction, before engaging in a task associated with robust frontotemporal activation. Results: Compared to the control group, the rTMS group showed an altered frontotemporal connectivity with stronger connectivity between the right temporoparietal cortex and the dorsolateral prefrontal cortex and the angular gyrus. Conclusion: This finding provides preliminary evidence for the hypothesis that normalizing the functional connectivity between the temporoparietal and frontal brain regions may underlie the therapeutic effect of rTMS on AH in schizophrenia. (PsycINFO Database Record (c) 2011 APA, all rights reserved)

Neuropsychology - Vol 26, Iss 1