The relation between working memory components and ADHD symptoms from a developmental perspective

The objective was to examine the relations between attention deficit hyperactivity disorder (ADHD) symptoms and four working memory (WM) components (short-term memory and central executive in verbal and visuospatial domains) in 284 6-16-year-old children from the general population. The results showed that verbal and visuospatial short-term memory and verbal central executive uniquely contributed to inattention symptoms. Age interacted with verbal short-term memory in predicting inattention, with the relation being stronger in older children. These findings support the notion of ADHD as a developmental disorder, with changes in associated neuropsychological deficits across time. The results further indicate ADHD-related deficits in several specific WM components.     

Longitudinal changes in cognition, gait, and balance in abstinent and relapsed alcoholic men: relationships to changes in brain structure

Chronic alcoholism is associated with cognitive and motor deficits, and there is evidence for reversibility with sobriety. Alcoholic men were examined after 1 month of sobriety and 2 to 12 months later with cognitive and motor tests and magnetic resonance imaging. In this naturalistic study, 20 alcoholic participants had abstained and 22 had resumed drinking at retesting. Abstainers sustained greater improvement than relapsers on tests of delayed recall of drawings, visuospatial function, attention, gait, and balance. Shrinkage in 3rd ventricle volume across all participants significantly correlated with improvement in nonverbal short-term memory. Additional brain structure-function relationships, most involving short-term memory, were observed when analyses were restricted to alcoholic men who had maintained complete abstinence, were light relapsers for at least 3 months, or had consumed no more than 10 drinks prior to follow-up testing. Thus, alcoholic men who maintain abstinence can show substantial functional improvement that is related to improvement in brain structure condition.     

Cognitive profile of fragile X premutation carriers with and without fragile X-associated tremor/ataxia syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS) develops in a subset of fragile X premutation carriers and involves gait ataxia, action tremor, Parkinsonism, peripheral neuropathy, autonomic disorders, and cognitive impairment. The study was designed to define the nature of cognitive deficits affecting male premutation carriers with and without FXTAS. A sample of 109 men underwent motor, cognitive, genetic, and neurologic testing, as well as brain magnetic resonance imaging. Subjects were classified into 3 groups: (a) asymptomatic premutation carriers, (b) premutation carriers with FXTAS, and (c) normal controls. Men with FXTAS performed worse than controls on mental status, intelligence, executive cognitive functioning (ECF), working memory, remote recall of information, declarative learning and memory, information processing speed, and temporal sequencing, as well as 1 measure of visuospatial functioning. Language and verbal comprehension were spared. Asymptomatic carriers performed worse than controls on ECF and declarative learning and memory. This comprehensive examination of cognitive impairment in male premutation carriers suggests that FXTAS involves substantial executive impairment and diffuse deficits in other cognitive functions. Longitudinal research currently underway will provide insight into the progression of the disorder.     

Working memory capacity, indirect semantic priming, and stroop interference: pattern of interindividual prefrontal performance differences in healthy volunteers

Using neuropsychological models of prefrontal function, the authors investigated the pattern of interindividual prefrontal performance differences in healthy volunteers. Using a correlation and an extreme group approach, they compared verbal and visuospatial working memory capacity with performance on the Stroop interference task as a measure of executive control and on the direct and indirect semantic priming tasks as a measure of semantic access. Subjects with low visuospatial working memory capacity exhibited increased Stroop interference Subjects with low verbal memory capacity showed increased priming and Stroop interference only. The study shows that prefrontal functioning varies interindividually, forming patterns of performance differences. These findings suggest that working memory, executive control, and semantic retrieval are functionally related to some extent.     

Sex differences favoring women in verbal but not in visuospatial episodic memory

Sex differences favoring women have been found in a number of studies of episodic memory. This study examined sex differences in verbal, nonverbal, and visuospatial episodic memory tasks. Results showed that although women performed at a higher level on a composite verbal and nonverbal episodic memory score, men performed at a higher level on a composite score of episodic memory tasks requiring visuospatial processing. Thus, men can use their superior visuospatial abilities to excel in highly visuospatial episodic memory tasks, whereas women seem to excel in episodic memory tasks in which a verbalization of the material is possible.     

Verbal and nonverbal memory processing in patients with obsessive-compulsive disorder: its relationship to clinical variables

Memory deficits have been reported in several neuropsychological studies of obsessive-compulsive disorder (OCD). Dysfunction in nonverbal memory has been consistently reported, whereas findings on verbal memory are more heterogeneous. The authors studied 50 patients with OCD who were matched for sex, age, educational level, and hand dominance with 50 healthy controls (HC). Cognitive performance in both groups was assessed on verbal and nonverbal memory tasks, and several clinical variables were also assessed in the patient group. Patients with OCD showed a pattern of cognitive dysfunction with alterations in areas of nonverbal memory (recall and recognition), and verbal memory (learning and recall). Older age at onset of OCD was associated with poorer performance on verbal memory tasks. Low scores on some verbal memory tasks were associated with severity of OCD, and nonverbal memory was influenced by depressive symptoms. The study suggests the existence of dysfunction in the execution of verbal and nonverbal memory tasks in OCD; the influence of clinical variables depends on the specific neuropsychological function.     

Visuospatial and verbal working memory load: effects on visuospatial vigilance

In this study, we examined the impact of concurrent verbal and visuospatial working memory demands on performance of a visuospatial successive target detection task. Three hundred and four participants performed a visuospatial vigilance task while simultaneously performing either a spatial or verbal working memory task that either required a memory load during the vigil or did not require a memory load during the vigil. Perceptual sensitivity A′ to vigilance target stimuli was reduced by concurrent memory load, both verbal and visuospatial. The decline in perceptual sensitivity to vigilance targets, the vigilance decrement, was steeper for a visuospatial memory task than a verbal memory task, regardless of concurrent memory load. Memory performance after vigilance detection trials was much lower for visuospatial than verbal items, even though memory performance before vigilance detection trials was higher for visuospatial than verbal items. Together, this indicates increased interference when a visuospatial vigilance task is paired with a visuospatial memory task, than when paired with a verbal memory task. Overall, the visuospatial and verbal working memory loads both impacted vigilance target detection, suggesting utilization of common executive resources. There may, however, be domain specific interference, and this may be exacerbated for two visuospatial tasks.     

Neuropsychological correlates of ADHD symptoms in preschoolers

The authors examined the neuropsychological status of 22 preschoolers at risk for attention-deficit/hyperactivity disorder (ADHD) and 50 matched control children, using measures of nonverbal working memory, perceptual and motor inhibition, and memory for relative time. All tasks included paired control conditions, which allowed for the isolation of discrete executive function constructs. Group differences were evident on several measures of neuropsychological functioning; however, after accounting for nonexecutive abilities, no deficits could be attributed to specific functions targeted by the tasks. Performance on executive measures was not related to objective indices of activity level or ratings of ADHD symptoms. Yet, the fact that at-risk preschoolers were highly symptomatic casts doubt on whether executive function deficits and/or frontostriatal networks contribute etiologically to early behavioral manifestations of ADHD.     

A meta-analysis of cognitive deficits in euthymic patients with bipolar disorder

BACKGROUND: A number of studies have reported evidence of cognitive deficits in euthymic bipolar patients. Qualitative reviews of the literature have indicated impairments in executive functions and declarative memory are most consistently reported. However, not all primary studies conducted to date have had sufficient power to detect statistically significant differences and there have been few attempts to quantify the magnitude of impairments. This review aims to combine data from available studies to identify the profile of neuropsychological deficits in euthymic bipolar patients and quantify their magnitude. METHOD: Systematic literature review and meta-analysis. RESULTS: Large effect sizes (d>or=0.8) were noted for aspects of executive function (category fluency, mental manipulation) and verbal learning. Medium effect sizes (0.5相似文献   

Role of executive functioning in verbal and visual memory

G. Tremont, S. Halpert, D. J. Javorsky, and R. A. Stern (2000) found that individuals with executive dysfunction were more impaired on less structured versus more structured verbal memory tasks. In the present study, the authors investigated the relationship between executive functions and memory in patients with a history of traumatic brain injury by examining the effect of executive functioning on more structured and less structured verbal and visual memory tasks at baseline and 1-year follow-up. Matched subgroups controlled for differences in severity of neuropsychological impairment unrelated to specific executive functions. The G. Tremont et al. (2000) findings were not replicated. Results showed that when acuteness and severity of injury were controlled, executive impairment played no significant role in performance on either more or less structured memory tasks. However, regardless of structure, executive functions played a role in visual memory performance, suggesting that visual memory may be a more fluid ability than verbal memory.     

Effects of continuous positive airway pressure on cognitition and neuroimaging data in sleep apnea

Obstructive sleep apnea (OSA) has been associated with a broad range of neurocognitive difficulties. The current view is that the neurocognitive impairment in OSA is due to the adverse effects of sleep fragmentation and/or intermittent hypoxia. The overall picture of cognitive deficits in OSA is complex. On balance, there appears to be negative effects of OSA on cognition, most likely in the domains of attention/vigilance, verbal and visual delayed long-term memory, visuospatial/constructional abilities, and executive dysfunction. Continuous positive airway pressure (CPAP) is the most effective and widely used treatment of OSA. In the majority of studies of OSA patients treated with CPAP, attention/vigilance improved, but changes in global functioning, executive functioning, and memory improved in about half of the studies. This may be due, in part, to variability in study design and sampling methodology across studies.     

Executive dysfunction and memory in older patients with major and minor depression.

Executive function, known to be impaired during late-life depression, is dependent on frontostriatal pathways. Memory is also frequently observed to be impaired among late-life depressed patients, so we assessed the possibility that executive function mediates the learning and recall deficit as a "downstream" effect of the frontostriatal compromise in executive function. A cross-sectional sample of minor and major depressed patients (N=95) and nondepressed volunteers (N=71), screened for other Axis I disorders, dementia, medical comorbidity, and severity of depression, completed a neuropsychological battery that included the California Verbal Learning Test and other tests selected for convergent and divergent validity testing. Depressed patients differed from controls on learning the word list and on verbal and nonverbal executive tasks. Executive function was a mediator for depressed patients verbal learning scores (z=-2.67, p=.01). A nonverbal executive score also mediated verbal learning (z=-2.18, p=.03) indicating convergent validity of executive dysfunction during verbal learning exercises. In conclusion, the verbal memory deficits typically attributed to late-life depression may result from impaired executive functioning during the learning phase of the recall task.     

Cognitive impairment in preclinical Alzheimer's disease: a meta-analysis

To determine the size of the impairment across different cognitive domains in preclinical Alzheimer's disease (AD), a meta-analysis based on 47 studies involving 9,097 controls and 1,207 preclinical AD cases was conducted. There were marked preclinical deficits in global cognitive ability, episodic memory, perceptual speed, and executive functioning; somewhat smaller deficits in verbal ability, visuospatial skill, and attention; and no preclinical impairment in primary memory. Younger age (< 75 years) and shorter follow-up intervals (< 3 years) were associated with larger effect sizes for both global cognitive ability and episodic memory. For global cognitive ability, studies that used population-based sampling yielded larger effect sizes; for episodic memory, larger differences were seen in studies that preidentified groups in terms of baseline cognitive impairment. Within episodic memory, delayed testing and recall-based assessment resulted in the largest effect sizes. The authors conclude that deficits in multiple cognitive domains are characteristic of AD several years before clinical diagnosis. The generalized nature of the deficit is consistent with recent observations that multiple brain structures and functions are affected long before the AD diagnosis.     

Verbal and nonverbal memory deficits in pure dyslexia

We examined verbal and nonverbal memory in “pure” dyslexies and thoroughly screened controls using a two‐cohort cross‐validation design. There were four important results. First, our dyslexic samples showed short‐term memory deficits for both verbal material and nonverbal material. Second, the verbal and nonverbal memory deficits were separable. Third, although the verbal and nonverbal memory deficits were carried by different children, there were no distinct, compact clusters of the dyslexic sample with verbal or nonverbal memory deficits. Fourth, we found no evidence supporting a relationship between nonverbal memory deficit and the presence of arithmetic disability. Our results suggest either that memory deficits and reading disability are separate and mostly unrelated sequelae of an underlying lesion or that they are related in a very complex manner that may change over time.     

The relationship of theory of mind and executive functions to symptom type and severity in children with autism

Although neurocognitive impairments in theory of mind and in executive functions have both been hypothesized to play a causal role in autism, there has been little research investigating the explanatory power of these impairments with regard to autistic symptomatology. The present study examined the degree to which individual differences in theory of mind and executive functions could explain variations in the severity of autism symptoms. Participants included 31 verbal, school-aged children with autism who were administered a battery of tests assessing the understanding of mental states (knowledge and false belief) and executive control skills (working memory, combined working memory and inhibitory control, and planning) and who were behaviorally evaluated for autism severity in the three core symptom domains. Whereas theory of mind and executive control abilities explained the significant variance beyond that accounted for by language level in communication symptoms, neither explained the significant variance in reciprocal social interaction or repetitive behaviors symptoms. These findings are discussed in terms of a proposed distinction between higher level, cognitive-linguistic aspects of theory of mind and related executive control skills, and more fundamental social-perceptual processes involved in the apprehension of mental state information conveyed through eyes, faces, and voices, which may be more closely linked to autistic deficits in social reciprocity.     

Impact of comorbid depressive symptoms on nonverbal memory and visuospatial performance in obsessive-compulsive disorder

Introduction. Recent research has suggested that some executive dysfunctions in obsessive-compulsive disorder (OCD) represent an epiphenomenon of comorbid depressive symptoms. The present study investigated whether the impact of comorbid depressive symptoms on cognitive dysfunction in OCD extends to nonverbal memory impairment. Methods. A total of 32 OCD patients and 20 healthy controls took part in the study. Participants were administered a neurocognitive battery with a focus on nonverbal memory and visuospatial functions. Results. While evidence was provided that neurocognitive processes necessitating visuospatial transformation and visuoconstruction are deficient in OCD patients regardless of comorbid depressive symptoms, nonverbal memory dysfunctions were only apparent for patients with elevated scores in the Hamilton Depression (HDRS) Rating Scale (total score S 8). Correlations with subscores of the HDRS revealed that core depressive symptoms are related to nonverbal memory deficits in OCD. Mental rotation, middle discrimination, and position discrimination were found to be unaffected in OCD. Y-BOCS scores, length of illness, onset of illness, number of hospital admissions, and checking compulsions were not associated with neurocognitive disturbances. Conclusions. Nonverbal memory is disturbed in only a subgroup of OCD patients displaying elevated HDRS scores (HDRS S 8). It is claimed but awaits further empirical testing that differences in depression profile across OCD studies have contributed to inconsistencies in prior investigations on neurocognitive functioning in OCD. Our results are questioning the hypothesis that nonverbal deficits are a causal factor for the development of checking compulsions.     

Impaired memory for faces and social scenes in autism: clinical implications of memory dysfunction.

A clinical memory test, the Wechsler Memory Scale-III (WMS-III), was used to study the auditory and visual memory of 29 high-functioning adults with autism and 34 group-matched normal controls. The individuals with autism performed as well as the controls on immediate and delayed memory for word pairs and stories and on a verbal working memory task. The autism group was impaired on immediate and delayed recall of faces and of family scenes and had impaired spatial working memory. The integrity of verbal working memory and impaired spatial working memory is consistent with the findings of other studies and may reflect the greater computational demands of the spatial task. Most importantly, the deficits in memory for faces and common social scenes, complex visual/spatial stimuli, demonstrate the contribution of memory dysfunction in autism to deficits in real life function.     

Meta-analyses of cognitive functioning in euthymic bipolar patients and their first-degree relatives

BACKGROUND: Previous work suggests that impairments in executive function and verbal memory in particular may persist in euthymic bipolar patients and serve as an indicator of genetic risk (endophenotype). METHOD: A systematic review of the literature was undertaken. Effects sizes were extracted from selected papers and pooled using meta-analytical techniques. RESULTS: In bipolar patients, large effect sizes (d>0.8) were noted for executive functions (working memory, executive control, fluency) and verbal memory. Medium effect sizes (0.5相似文献   

Fronto-parietal EEG coherence in theta and upper alpha reflect central executive functions of working memory.

For human working memory the neural correlates of the phonological loop and the visuospatial sketch pad are well explored. In contrast, less is known about central executive processes. Neuroimaging studies suggest that central executive processes are related to a complex fronto-parietal network. In the present study we investigate the question whether varying demands on central executive processes are reflected by differences in coherent activity between and within a fronto-parietal network. We calculated coherence during a visuospatial working memory task. Under an easy executive condition subjects had to mentally imagine previously studied abstract patterns, whereas in the difficult condition, subjects had to mentally manipulate these patterns. The results indicate the involvement of prefrontal areas in executive functions reflected by a decrease of anterior upper alpha short-range connectivity and a parallel increase of fronto-parietal long-range coherence mirroring activation of a fronto-parietal network.     

Executive dysfunction and its relation to language ability in verbal school-age children with autism

This study examined executive dysfunction and its relation to language ability in verbal school-age children with autism. Participants were 37 children with autism and 31 nonautistic comparison participants who were matched on age and on verbal and nonverbal IQ but not on language ability, which was lower in the autism group. Children with autism exhibited deficits compared to the comparison group across all 3 domains of executive function that were assessed including working memory (Block Span Backward; Isaacs & Vargha-Khadem, 1989), working memory and inhibitory control (NEPSY Knock-Tap; Korkman, Kirk, & Kemp, 1998), and planning (NEPSY Tower; Korkman et al., 1998). Children with autism were less developed than the comparison group in their language skills, but correlational analyses revealed no specific association between language ability and executive performance in the autism group. In contrast, executive performance was positively correlated with language ability in the comparison group. This pattern of findings suggest that executive dysfunction in autism is not directly related to language impairment per se but rather involves an executive failure to use of language for self-regulation.