Selective attention deficits and subjective fatigue following traumatic brain injury.

The present study aimed to investigate the relationship between subjective fatigue and selective attention deficits following traumatic brain injury (TBI). Forty-six participants with mild-severe TBI and 46 healthy controls completed fatigue scales (Visual Analogue Scale--Fatigue, Fatigue Severity Scale [FSS] and Causes of Fatigue Questionnaire [COF]), and attentional measures including subtests from the Test of Everyday Attention, and the Complex Selective Attention Task (C-SAT). TBI participants reported greater fatigue on the FSS and COF, performed more slowly on attentional measures, and made more errors on the C-SAT. After controlling for anxiety and depression, fatigue was significantly correlated with performance only on the C-SAT. Findings suggest a relationship between subjective fatigue and impairment on tasks requiring higher order attentional processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Executive Functioning, Memory, and Learning in Phenylketonuria.

The executive deficit hypothesis of treated phenylketonuria (PKU) suggests that dopaminergic depletion in the lateral prefrontal cortex leads to selective executive impairment. This was examined by comparing adults with PKU on a lifelong diet with a matched healthy control group. Those with PKU were impaired on selective and sustained attention, working memory (Self-Ordered Pointing), and letter fluency. However, they failed to show differential sensitivity to increased cognitive load on the attentional and working memory tasks, and they did not differ significantly on the remaining executive tasks (rule finding, inhibition, and multitasking). Nor did they differ significantly on recall or recognition memory. Overall, the findings provided little support for the executive deficit hypothesis. A possible explanation in terms of slowed information processing speed is explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive functioning ten years following traumatic brain injury and rehabilitation.

Many previous studies investigating long-term cognitive impairments following traumatic brain injury (TBI) have focused on extremely severely injured patients, relied on subjective reports of change and failed to use demographically relevant control data. The aim of this study was to investigate cognitive impairments 10 years following TBI and their association with injury severity. Sixty TBI and 43 control participants were assessed on tests of attention, processing speed, memory, and executive function. The TBI group demonstrated significant cognitive impairment on measures of processing speed (Symbol Digit Modalities Test [SDMT], Smith, 1973; Digit Symbol Coding, Wechsler, 1997), memory (Rey Auditory Verbal Learning Test [RAVLT]; Rey, 1958; Lezak, 1976), Doors and People tests; Baddeley, Emslie & Nimmo-Smith, 1994) and executive function (Hayling C [Burgess & Shallice, 1997] and SART errors, Robertson, Manly, Andrade, Baddeley & Yiend, 1997). Logistic Regression analyses indicated that the SDMT, Rey AVLT and Hayling C and SART errors most strongly differentiated the groups in the domains of attention/processing speed, memory and executive function, respectively. Greater injury severity was significantly correlated with poorer test performances across all domains. This study shows that cognitive impairments are present many years following TBI and are associated with injury severity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How well do patients with schizophrenia track multiple moving targets?

It has been demonstrated that patients with schizophrenia perform poorly on tasks that require orienting, focusing, maintaining, and shifting attention. However, it is unknown how patients with schizophrenia can track multiple moving targets. To elucidate this issue, the authors investigated fast and slow multiple-object tracking in patients with schizophrenia (n = 30) and in matched healthy control participants (n = 30) and assessed their relationship with motion perception (velocity discrimination), sustained attention and context processing (Continuous Performance Test, 1-9 version; J. R. Finkelstein, T. D. Cannon, R. E. Gur, R. C. Gur, & P. Moberg, 1997), and object and spatial working memory. Results revealed that patients with schizophrenia displayed impaired performances on multiple-object tracking tasks. Linear regression analysis revealed a specific relationship among object tracking, velocity discrimination, and spatial working memory. In patients with schizophrenia, velocity discrimination and spatial working memory were the predictive factors of multiple-object tracking, whereas in healthy control participants, the single predictive factor was velocity discrimination. Probabilistic regression analysis revealed that only the Continuous Performance Test made significant contribution to discriminating between patients and control participants. These results suggest that multiple-object tracking is impaired in schizophrenia, and that it is specifically associated with motion perception and spatial working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disentangling the adult attention-deficit hyperactivity disorder endophenotype: Parametric measurement of attention.

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a “theory of visual attention.” These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Depressed mood in multiple sclerosis: Relationship to capacity-demanding memory and attentional functioning.

Because it is theorized that depression results in reduced available attentional capacity that, in turn, can explain the impaired performance on capacity-demanding tasks in depressed individuals, the authors predicted that multiple sclerosis (MS) patients with depressed mood would have difficulty with these types of tasks. Twenty depressed mood MS participants were compared with 41 nondepressed mood MS participants and 8 nondepressed mood controls on 5 attentional capacity-demanding clinical memory and attentional tasks and 3 tasks with minimal capacity demands. Depressed mood MS patients performed significantly worse than both nondepressed mood groups on the 3 speeded capacity-demanding attentional measures but not on any of the tasks requiring few capacity demands, supporting the authors' predictions. The possibility that the impaired performance of depressed mood MS patients on speeded attentional tasks was mediated by reduced verbal working memory capacity, impaired deployment of executive strategies that access working memory capacity, or psychomotor slowing is explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anoxic Versus Traumatic Brain Injury: Amount of Tissue Loss, Not Etiology, Alters Cognitive and Emotional Function.

Research in neuropsychology suggests that the etiology of a neurologic injury determines the neuropathological and neuropsychological changes. This study compared neuropsychological outcome in subjects who had traumatic brain injury (TBI) with subjects who had anoxic brain injury (ABI), who were matched for age, gender, and ventricle-to-brain ratio. There were no group differences for morphologic or neuropsychological measures. Both groups exhibited impaired memory, attention, and executive function, as well as slowed mental processing speed. Intelligence correlated with whole brain volume, and measures of memory correlated with hippocampal atrophy. There was no unique contribution of hippocampal atrophy on neuropsychological outcome between the groups. In the absence of localized lesions, the amount of neural tissue loss, rather than etiology, may be the critical factor in neuropsychological outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional skills following traumatic brain injury in childhood: a componential analysis

Recent research has documented residual deficits in attention following traumatic brain injury in childhood. The present study aimed to investigate whether such deficits are global, or affect specific components of attention differentially. Four attentional domains were examined using a newly developed test of attention, the Test of Everyday Attention for Children: sustained attention, focussed attention, divided attention, and response inhibition. Eighteen children with a history of traumatic brain injury, aged between 8 and 14 years, and 18 non-injured matched controls participated in the study. Results indicated that attentional skills may be differentially impaired after TBI, with children who have sustained moderate-to-severe TBI exhibiting significant deficits for sustained and divided attention, and response inhibition, but relatively intact focussed attention.     

Immediate memory capacity for nonsequential information: The configural attention test.

Performance data on a newly developed, nonsequential measure of immediate memory capacity (the Configural Attention Test) were collected on groups of elementary schoolchildren aged 7 to 14 and on a young adult sample (mean age = 21.6). The data indicated increasingly proficient performances with advancing age in a generally linear manner. Overall, boys and men performed modestly better than girls and women. Performance on the Configural Attention Test was not meaningfully related to socioeconomic status. However, as expected, there were relationships with performance on another spatial attentional measure and with overall intellectual ability. Internal consistency for the instrument was quite acceptable (Cronbach's α?=?.92). These data provide developmental standards for this new instrument and suggest that it may be a selective measure of nonsequential, spatial information processing with clinical and experimental utility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prospective memory in Parkinson disease across laboratory and self-reported everyday performance.

Prospective memory is a complex cognitive construct ubiquitous in everyday life that is thought to sometimes rely on executive skills commonly affected by Parkinson’s disease (PD). The present study investigated the effect of PD on prospective memory tasks with varying demand on executive control processes, namely on the amount of strategic attentional monitoring required for intention retrieval. Individuals with PD but without dementia and healthy adults performed laboratory event-based prospective memory tasks that varied in whether strategic attentional monitoring (nonfocal condition) or spontaneous processes (focal condition) were primarily involved in intention retrieval. Participants also completed a questionnaire rating their frequency of prospective memory failures in everyday life for both self-cued and environment-cued tasks. PD participants performed worse than non-PD participants in the nonfocal, but not focal, condition of the laboratory task. They also reported more everyday failures than non-PD participants for self-cued, but not environment-cued, prospective memory tasks. Thus, nondemented individuals with PD are preferentially impaired on prospective memory tasks for which higher levels of executive control are needed to support intention retrieval. This pattern is consistent across laboratory and reported real-world performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Diffuse Axonal Injury on Speed of Information Processing Following Severe Traumatic Brain Injury.

To test the hypothesis that slowed information processing in traumatic brain injury is related to diffuse axonal injury (DAI), the authors compared 10 patients with predominant DAI (diffuse group) and minimal DAI (mixed injury group) on the Symbol Digit Modalities Test, simple and choice reaction time, Trail Making Tests A and B, and the Stroop Neuropsychological Screening Test. The diffuse group was slower than the mixed injury and control groups on basic speed of processing tasks. This difference was not apparent on complex speeded tasks once basic speed of processing was controlled for. The diffuse group's slower speed of processing was not accounted for by differences in injury severity, age, or time postinjury. The diffuse group showed greater recovery over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-related decay or interference-based forgetting in working memory?

The time-based resource-sharing model of working memory assumes that memory traces suffer from a time-related decay when attention is occupied by concurrent activities. Using complex continuous span tasks in which temporal parameters are carefully controlled, P. Barrouillet, S. Bernardin, S. Portrat, E. Vergauwe, & V. Camos (2007) recently provided evidence that any increase in time of the processing component of these tasks results in lower recall performance. However, K. Oberauer and R. Kliegl (2006) pointed out that, in this paradigm, increased processing times are accompanied by a corollary decrease of the remaining time during which attention is available to refresh memory traces. As a consequence, the main determinant of recall performance in complex span tasks would not be the duration of attentional capture inducing time-related decay, as Barrouillet et al. (2007) claimed, but the time available to repair memory traces, and thus would be compatible with an interference account of forgetting. The authors demonstrate here that even when the time available to refresh memory traces is kept constant, increasing the processing time still results in poorer recall, confirming that time-related decay is the source of forgetting within working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategic processing and episodic memory impairment in obsessive compulsive disorder.

There is evidence that nonverbal memory problems in obsessive compulsive disorder (OCD) are mediated by impaired strategic processing. Although many studies have found verbal memory to be normal in OCD, these studies did not use tests designed to stress organizational strategies. This study examined verbal and nonverbal memory performance in 33 OCD patients and 30 normal control participants with the Rey-Osterrieth Complex Figure Test and the California Verbal Learning Test. OCD patients were impaired on verbal and nonverbal measures of organizational strategy and free recall. Multiple regression modeling indicated that free recall problems in OCD were mediated by impaired organizational strategies used during learning trials. Therefore, verbal and nonverbal episodic memory deficits in OCD are affected by impaired strategic processing. Results are consistent with neurobiological models proposing frontal-striatal system dysfunction in OCD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of reducing attentional resources on implicit and explicit memory after severe traumatic brain injury.

Implicit and explicit memory were examined in individuals with severe traumatic brain injury (TBI) under conditions of full and divided attention. Participants included 12 individuals with severe TBI and 12 matched controls. In Experiment 1, participants carried out an implicit test of word-stem completion and an explicit test of cued recall. Results demonstrated that TBI participants exhibited impaired explicit memory but preserved implicit memory. In Experiment 2, a significant reduction in the explicit memory performance of both TBI and control participants, as well as a significant decrease in the implicit memory performance of TBI participants, was achieved by reducing attentional resources at encoding. These results indicated that performance on an implicit task of word-stem completion may require the availability of additional attentional resources that are not preserved after severe TBI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychopathic personality traits associated with abnormal selective attention and impaired cognitive control.

The current study investigated how mechanisms of attention that have been well-characterized in the cognitive psychology literature (Lavie, Hirst, De Fockert, & Viding, 2004; Maylor & Lavie, 1998) may be differentially associated with psychopathic traits in nonincarcerated men. Previous research on cognition and psychopathy indicated that primary psychopathic traits were associated with overfocused attention and/or reduced processing of information peripheral to the focus of attention. Conversely, deficits in executive functioning, such as working memory and cognitive control, were implicated in secondary psychopathic traits. Results revealed a significant relationship between traits typically associated with primary psychopathy (e.g., low anxiety, social dominance, fearlessness, callousness) and reduced processing of task-irrelevant distractors, suggesting diminished basic attentional capacity among individuals high on these traits. In contrast, some characteristics linked to secondary psychopathy (e.g., social alienation, cynicism) showed a positive relationship with impaired working memory functioning, indicative of deficits in cognitive control, whereas other traits (i.e., self-centeredness, antagonism) did not. These results suggest that psychopathic traits are differentially related to selective impairments in attentional functioning, which may help explain the observed heterogeneity in psychopathic manifestations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in the efficiency of word recognition.

Examined the hypothesis that the attentional demands of word recognition covary with other measures of reading efficiency. Individual differences in efficiency were indexed by (1) speed and accuracy of lexical access, (2) obligatory activation of phonological codes, and (3) working memory capacity. The attentional demands of word recognition were measured with a dual-task technique. Ss performed naming and probe-detection tasks separately (single task) and in combination (dual task). The results showed that single-task to dual-task decrements in performance on the naming and probe tasks were predicted by measures of the speed and accuracy of lexical access, obligatory activation of phonological codes, and efficiency of working memory. These findings provide support for the widespread assumption that the attentional demands of basic reading processes are a source of individual differences in reading skill. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Source memory and divided attention: Reciprocal costs to primary and secondary tasks.

Source memory, in comparison with item memory, is more sensitive to frontal lesions and may require more strategic processing. Divided attention was used to restrict attentional resources and strategic processing on memory tasks. Participants encoded and retrieved items (i.e., words) and source (i.e., voice or spatial location) while concurrently performing a fingertapping (FT) or visual reaction-time (VRT) task. Memory accuracy costs under divided attention were greater for retrieval of source than item and were greater with VRT than FT. Similarly, costs to the secondary task were greater when concurrently retrieving source as opposed to item and were greater for VRT than FT. Effects were stronger when spatial location was used as the source task. Findings support the idea that processing source information requires more attentional resources and effort than processing item information. Furthermore, concurrent performance of VRT produced greater interference with a task that was more dependent on intact frontal functioning and better simulated the performance of patients with frontal dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduced working memory span in Parkinson's disease: Evidence for the role of frontostriatal system in working and strategic memory.

Working and strategic memory were examined in unmedicated patients with Parkinson's disease who had neither depression nor dementia. The patients, relative to control participants, had reduced working memory spans for verbal and arithmetic materials. They also had impairment on strategic memory tests of fee recall, temporal ordering, and self-ordered pointing, but no impairment on tests of recognition memory and semantic memory. Impairments in working memory capacity correlated with impairments in strategic memory and with a measure of perceptual-motor speed, but not with motor speed. It is hypothesized that a frontostriatal memory system, in which dopamine plays a critical role, mediates perceptual-motor processing speed that contributes to working memory capacity, which in turn, contributes to strategic memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in spatial memory and striatal ChAT activity among young and aged rats

Individual differences in spatial memory among young and aged rats were assessed using memory tasks related to integrity of the hippocampus and the neostriatum. Relationships were then examined between measures of spatial memory and regional choline acetyltransferase (ChAT) activity, a marker for cholinergic integrity. Twenty-four-month-old Long-Evans rats were impaired in comparisons with 6-month-old rats on measures of place learning, working memory, reference memory, and perseveration in water-maze tasks. Aged rats that were impaired on one measure of memory, however, were not necessarily impaired on other measures. ChAT activity in the ventromedial and dorsolateral neostriatum of aged rats was significantly reduced in comparisons with young rats whereas no difference was found in the hippocampus. Aged rats with the most ChAT activity in the anterior ventromedial neostriatum performed best on the place-learning and reference memory tasks but also made the most perseverative errors on the working memory task. In addition, young and aged rats with the most ChAT activity in the anterior dorsolateral neostriatum were those with the least accurate working memory. No relationships were found between ChAT activity in the hippocampus and spatial memory. Thus age-related memory impairment has components that can be segregated by measuring relationships between cholinergic integrity in subregions of the anterior neostriatum and memory tasks with different strategic requirements.     

Selective interference on the holistic processing of faces in working memory.

Faces and objects of expertise compete for early perceptual processes and holistic processing resources (Gauthier, Curran, Curby, & Collins, 2003). Here, we examined the nature of interference on holistic face processing in working memory by comparing how various types of loads affect selective attention to parts of face composites. In dual tasks, all loads impaired overall performance on face judgment compared with no load. However, a face load reduced holistic face processing (Experiment 1) whereas an object load did not, regardless of expertise (Experiments 2 and 3). Also, 2 types of faces produced asymmetrical interference on each other (Experiment 4), refuting the hypothesis that any faces would produce equal interference. Thus, the interference on holistic face processing in working memory does not depend on overlap in expertise or face processing, but may be modulated by limitations in encoding or maintenance of highly similar representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)