Executive functions in multiple sclerosis: an analysis of temporal ordering, semantic encoding, and planning abilities

The Relationship between Executive Functions and Metacognition in College Students

This study investigated the relationship between executive functions and metacognition. Both constructs have been well-studied, but little research has focused on their connections. The goal of the current investigation was to increase the understanding of the relationship between metacognition and executive functions by assessing the relationships between metacognitive monitoring accuracy and the three component executive functions (updating, inhibition, and shifting) among college students. Metacognitive monitoring accuracy was measured using a knowledge monitoring accuracy (KMA) test. The three components of executive functions, updating, inhibition, and shifting were measured, respectively, using the ABCD updating task, the Stroop color-word interference test, and the letter-number task. The Tower of Hanoi task was used to measure the complex executive functions (inhibition and updating). Correlation and regression analyses were performed to examine the relationships. The results indicate that updating is the only component executive function that significantly correlated with metacognitive monitoring, suggesting that metacognition-specifically, metacognitive monitoring-is associated with at least one component of executive functioning.

Deficits in psychological resilience and problem-solving ability in adolescents with suicidal ideation

OBJECTIVES

This study aimed to explore differences between psychological resilience and problem-solving ability in grade one junior middle school adolescents with and without suicidal ideation, focusing on the relationship between these factors and suicidal ideation.

METHODS

Ninety-nine adolescents (aged 10 to 14) were divided into Suicidal Ideation (SI, n = 49) and Non-Suicidal Ideation (NSI, n = 50) grouped by the Self-rating Idea of Suicide Scale (SIOSS). The Psychological Resilience Scale (PRS) and Tower of Hanoi task (TOH) were applied to assess psychological resilience and problem-solving ability, respectively.

RESULTS

The SI group scored significantly lower than the NSI group on PRS (p < 0.001) and performed more poorly on TOH than the NSI group, with more mistakes in the number of errors index (p < 0.001) and requiring a longer time in the task completion time index (p < 0.05). Among all the participants in this study, a significant negative correlation was observed between PRS and SIOSS (r = - 0.413, p < 0.01). The sub-dimensions of PRS including emotional control, family support, and interpersonal assistance were significantly negatively correlated with the SIOSS total score (r = - 0.361, - 0.360, - 0.382; p < 0.01).

CONCLUSIONS

This study profiled the characteristics and differences in psychological resilience and problem-solving ability between adolescents with and without suicidal ideation. The data suggested adolescents with SI might have deficits in psychological resilience and problem-solving ability, which may serve as potential targets for suicide intervention.

Executive functions in primary progressive aphasia: A meta-analysis

Executive functions (EFs) refer to a set of cognitive processes, specifically shifting, inhibition, updating of working memory, and are involved in the cognitive control of behavior. Conflicting results have been reported regarding impairments of EFs in Primary Progressive Aphasia (PPA). We performed a multi-level meta-analysis to confirm whether deficits of EFs exist in this population, focusing on a common EFs composite, and the components shifting, inhibition and updating separately. We included 141 studies that report on 294 EFs tasks. The overall mean weighted effect size was large (d = -1,28), indicating poorer EFs in PPA as compared to age-matched cognitively healthy controls. Differences between effect sizes of the EFs components were not significant, indicating all components are affected similarly. Overall, moderator analysis revealed that PPA variant and disease duration were significant moderators of performance, while task modality and years of education were not. The non-fluent/agrammatic PPA and the logopenic PPA variants were similarly affected, but the semantic variant was affected to a lesser extent. We discuss implications for clinical and research settings, and future research.

The relationship between processing speed and verbal and non-verbal new learning and memory in progressive multiple sclerosis

Objective:

Processing speed (PS) deficits are the most common cognitive deficits in multiple sclerosis (MS), followed by learning and memory deficits, and are often an early cognitive problem. It has been argued that impaired PS is a primary consequence of MS, which in turn decreases learning. The current analysis examined the association between PS and learning in a large cohort of individuals with progressive MS.

Methods:

Baseline data from a randomized clinical trial on rehabilitation taking place at 11 centers across North America and Europe were analyzed. Participants included 275 individuals with clinically definite progressive MS (primary, secondary) consented into the trial.

Results:

Symbol Digit Modalities Test (SDMT) significantly correlated with California Verbal Learning Test-II (CVLT-II) ( r = 0.21, p = 0.0003) and Brief Visuospatial Memory Test–Revised (BVMT-R) ( r = 0.516, p < 0.0001). Receiver operating characteristic (ROC) analysis of the SDMT z score to distinguish between impaired and non-impaired CVLT-II performance demonstrated an area under the curve (AUC) of 0.61 (95% confidence interval (CI): 0.55–0.68) and a threshold of −1.62. ROC analysis between SDMT and BVMT-R resulted in an AUC of 0.77 (95% CI: 0.71–0.83) and threshold of −1.75 for the SDMT z score to predict impaired BVMT-R.

Conclusion:

Results indicate little ability beyond chance to predict CVLT-II from SDMT (61%), albeit statistically significant. In contrast, there was a 77% chance that the model could distinguish between impaired and non-impaired BVMT-R. Several potential explanations are discussed.

Problem-solving deficits in methcathinone use disorder

RATIONALE

The use of methcathinone (MCAT), a psychostimulant drug that can lead to long-term health risks and executive dysfunction, increased to an alarming rate in recent years. Impairments in low-level executive function have been reported in substance use disorder. However, little empirical evidence is available regarding high-level executive function (e.g., problem solving), which may act as a risk factor for relapse.

OBJECTIVES

The present study aimed to investigate whether the problem-solving ability was altered in abstinent individuals with methcathinone use disorder (MCUD). Here, we tested fifty male MCUD individuals (short-term MCUD group: twenty-nine patients with MCAT use less than 3 years, long-term MCUD group: twenty-one patients with MCAT use longer than 3 years, which were split by medium years of drug use) and twenty-four well-matched healthy controls (HC) in the Tower of Hanoi task (TOH) to assess the impact of task difficulty on drug-related changes in problem-solving performance. We used several measures to characterize problem-solving performance: the number of mistakes made, the completion time of the task, and the thinking time before the first move.

RESULTS

In the low task difficulty condition, the MCUD group and HC group showed similar levels of mistakes and completion time, while in the high task difficulty condition, the MCUD group reported more mistakes (the mean number of mistakes in each trial: 1.41 ± 1.15 vs 0.79 ± 0.76, P = 0.019, Cohen's d = 0.635) and longer completion time in the task (the mean completion time in each trial: 45.83 ± 20.51 s vs 33.40 ± 15.10 s, P = 0.010, Cohen's d = 0.690) than the HC group. The thinking time before the first move did not differ significantly between groups (P = 0.257). We further found that the long-term (more than 3 years) MCUD group made more mistakes than the short-term MCUD group and HC group, mainly in the highly difficult subtasks. The longer time than HCs was reported in the long-term MCUD group among high task difficulty of subtasks. In addition, there was a positive correlation between years of MCAT use and the number of mistakes made in high task difficulty TOH task (r = 0.326, P = 0.021).

CONCLUSIONS

Chronic methcathinone use was associated with deficits in problem-solving performance, which depended on the degree of task difficulty. The impairment was more evident in the long-term (> 3 years) MCAT group.

Training the brain: could it improve multiple sclerosis treatment?

Multiple sclerosis (MS) is a neurological disease characterized by neuroinflammation, demyelination and axonal degeneration along with loss of function in the central nervous system. For many years, research in MS has focused on the efficacy of pharmacological treatments. However, during the last years, many publications have been dedicated to the study of the efficacy of non-pharmacological strategies, such as physical exercise and cognitive training. Beneficial effects of the combination of both strategies on cognitive function have been described in both ageing adults and patients with neurodegenerative diseases, such as MS. The analysis of combining both physical and cognitive stimulation can be summarized by the environmental enrichment (EE) experiments, which are more suitable for animal models. EE refers to housing conditions consisting of exercise and cognitive and social stimulation. In this review, we will summarize the available studies that describe the influence of EE in both MS patients and MS animal models.

Cognitive and behavioral outcome of stereotactic laser amydalohippocampotomy in a pediatric setting

We present neuropsychological and functional outcome data in a teenager undergoing stereotactic laser amygdalohippocampotomy (SLAH) who had drug-resistant mesial temporal lobe epilepsy due to left hippocampal sclerosis. Given strong baseline cognitive performance, there was concern for post-operative declines in language and verbal memory were this patient to undergo open resection. She was evaluated pre- and post-ablation with clinical and experimental neuropsychological measures including semantic memory, category-specific object/face recognition and naming, spatial learning, and socio-emotional processing. The patient became seizure-free following SLAH and experienced significant improvements in school performance and social engagement. She experienced improvement in recognition and naming of multiple object categories, memory functions, and verbal fluency. In contrast, the patient declined significantly in her ability to recognize emotional tone from facial expressions, a socio-emotional process that had been normal prior to surgery. We believe this decline was related to surgical disruption of the limbic system, an area highly involved in emotional processing, and suspect such deficits are an under-assessed and unrecognized risk for all surgeries involving the amygdalohippocampal complex and broader limbic system regions. We hope this positive SLAH outcome will serve as impetus for group level research to establish its safety and efficacy in the pediatric setting.

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Stereotactic laser ablation can be used successfully in pediatric epilepsy.

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At risk cognitive abilities did not decline after focal ablation in this teenager.

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Functional improvement was observed that paralleled gains in seizure status and cognition.

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Deficits still occurred in select areas related to focal structures ablated.

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Socio-emotional deficits can result from surgeries restricted to the amygdalohippocampal complex.

[Methodological issues of cognitive impairment studies in pediatric multiple sclerosis patients]

The article provides a review of the characteristics of cognitive impairment in multiple sclerosis (MS) and methods for its assessment in children. The features of the most frequently used neuropsychological batteries, with consideration of specifics of cognitive impairment in MS, and data on assessment of a state of cognitive functions obtained using neuropsychological tests are presented. The authors also discuss the issue of a long-term impact of the disease on a state of cognitive functions. Clinical factors, which can lead to cognitive impairment (type of multiple sclerosis, age at manifestation, number of relapses), are described.

The weekly calendar planning activity in multiple sclerosis: A top-down assessment of executive functions

Deficits in executive functioning are detrimental to employment, daily functioning and quality of life, however their precise nature in multiple sclerosis (MS) remains underspecified. The aims of this study were to: (1) describe the executive processes affected in MS, using a top-down (Weekly Calendar Planning Activity; WCPA) and bottom-up (Delis-Kaplan Executive Function System; DKEFS) assessment tools; (2) explore relationships between performance on the WCPA and DKEFS with a test of everyday functional performance, Actual Reality^TM (AR). Methods: Sixty two participants with MS with and without cognitive impairments (n = 21 and 41, respectively) and 38 Healthy Controls (HC) completed the WCPA, two selected subtests of the DKEFS, and AR. Results: The MS group with cognitive impairments performed worse compared with the MS with no cognitive impairments and HC on both the WCPA and DKEFS. Better scores on the DKEFS were associated with better performance of the WCPA. WCPA was a significant predictor of three of the four AR variables. The DKEFS was a significant predictor of time to perform the AR. The results support the use of the WCPA as an assessment of executive functions in persons with MS. It embodies processes such as environmental monitoring, planning and problem solving, and self-regulation.

Validity of the Verbal Concept Attainment Test in multiple sclerosis

OBJECTIVE

As many as 70% of people with multiple sclerosis (MS) have clinically significant cognitive impairment, and most of these individuals exhibit executive dysfunction. Most research concerning executive dysfunction in MS has focused upon nonverbal measures. The Verbal Concept Attainment Test (VCAT) has demonstrated construct validity as an executive function measure in people infected with HIV and in people with focal brain lesions, but its validity among people with MS is unknown. The current study evaluated the VCAT's criterion, diagnostic, and ecological validity in people with MS.

METHOD

A comprehensive neuropsychological battery was administered to 44 healthy individuals and 97 people with MS. Based on existing norms, they were classified as impaired or unimpaired, resulting in 65 people with MS categorized as unimpaired and 32 as impaired. They were administered a battery assessing neuropsychological impairment and disability status.

RESULTS

The VCAT correlated with most measures of neuropsychological function, but its largest correlations occurred with measures of executive function, working memory, and verbal memory. Regarding classification accuracy, the VCAT achieved satisfactory sensitivity and specificity in identifying neuropsychological impairment in people with MS. The VCAT achieved moderate correlations with measures of disability status.

CONCLUSIONS

The data provide evidence for an optimal VCAT cutoff score for establishing neuropsychological impairment in people with MS, and they demonstrate that the VCAT possesses acceptable criterion, diagnostic, and ecological validity. As such, these data support the inclusion of the VCAT in research and clinical practice involving people with MS.

Brain connectivity and cognitive processing speed in multiple sclerosis: A systematic review

BACKGROUND

Processing speed (PS) decline is the most commonly observed cognitive deficit in people with multiple sclerosis (MS) resulting in a significant impact on quality of life. Despite its importance, knowledge of the underlying neural substrates is lacking.

OBJECTIVE

As MS is increasingly recognised as a disconnection syndrome, our aim was to carry out a systematic literature review to clarify the relationship between PS performance and MRI measures of structural and functional brain connectivity in people with MS.

SEARCH METHODS

A literature search was carried out on PubMed and Web of Science that included publications predating September 2017. Additional articles were added after inspection of the reference lists of all selected papers.

DATA EXTRACTION

All selected papers were categorised in three sections according to the MRI measures investigated, independently or both. Quality assessment was carried out using a customised set of criteria.

RESULTS

Thirty-two articles met the inclusion criteria and were included in the review. Microstructural integrity of the anterior corpus callosum and functional connectivity of frontal areas were more consistently found to correlate with PS performance, though high variability of findings was observed across studies. Several methodological flaws emerged from the reviewed literature.

CONCLUSIONS

Despite the observed trends, no definite conclusions can be drawn on the relationship between brain connectivity and PS decline in MS given the limitations of the current literature. Future investigations may benefit from theoretical and methodological advances to clarify how MS-related brain damage affects patients' cognition.

Neuropsychological Assessment in Multiple Sclerosis

Abstract. Neuropsychological deficits in multiple sclerosis (MS) are common. Over the past decades, many different procedures have been employed in diagnosing these deficits. Even though certain aspects of cognitive performance such as information processing speed and working memory may be affected more frequently than other cognitive functions, no specific deficit profile has been established in MS. This article provides an overview of the neuropsychological diagnostic procedures in MS and allows the reader to reach an informed decision on the applicability of specific procedures and the availability of study data in the context of MS. Additionally, it makes recommendations on the compilation of both screening procedures and extensive test batteries.

An initial investigation of the reliability and validity of the Compensatory Cognitive Strategies Scale

Although many cognitive performance tests and self-reported cognitive concerns scales have been used to evaluate cognitive functioning, fewer measures assess the use of compensatory cognitive strategies for daily activities among those experiencing mild levels of cognitive impairment. The Compensatory Cognitive Strategies Scale was developed to measure frequency of self-reported cognitive strategies to decrease distractions, organise and sequence activities, and to utilise newly available computer aids to assist memory among those with multiple sclerosis (MS). Cronbach's alpha, a measure of internal consistency reliability, was .89 and .90 in two different samples. Concurrent validity was supported by the total score's moderate correlation with the MMQ-Strategy Scale (r_s = .67) and by a statistically significant increase in total scores for those who had participated in an intervention designed to improve their cognitive abilities. Correlations were stronger with another strategy measure than with measures of other constructs such as health-promoting behaviours, thus supporting the scales convergent versus divergent validity. These initial findings suggest that the Compensatory Cognitive Strategies Scale may be useful to both researchers and clinicians working to build compensatory strategies for day-to-day functioning among those with mild cognitive impairment.

Cognitive screening in Multiple Sclerosis: the Five-Point Test as a substitute for the PASAT in measuring executive function

OBJECTIVE

The Paced Auditory Serial Addition Test (PASAT) is frequently employed to measure executive functions in patients with Multiple Sclerosis (MS). In the past, the PASAT has often been criticized because of its stressful and demanding requirements. Continuous utilization might also reduce its validity. The Five-Point Test (FPT) by Regard, Strauss, and Knapp ((1982) Children's production on verbal and non-verbal fluency tasks. Perceptual and Motor Skills, 55, 839-844.) is a short test of figural fluency which might serve as a substitute.

METHOD

116 patients diagnosed with MS were tested with a short version of the Brief Repeatable Battery (BRB) by Rao and the Cognitive Function Study Group of the National Multiple Sclerosis Society including the PASAT, as well as the FPT. A factor analysis was computed and the frequency of cognitive impairment was calculated for both the original short version of the BRB and the alternative version (involving the FPT).

RESULTS

In the factor analysis, PASAT and FPT loaded highest on the same factor (two factors were extracted). The estimation of the frequency of cognitive impairment showed that replacing the PASAT with the FPT did not considerably alter the proportion of patients identified as cognitively impaired.

CONCLUSIONS

The FPT proved to be a viable alternative to the PASAT in this study. It may be recommended as a possible replacement in neuropsychological screening of MS-patients with the advantage of avoiding the indicated limitations of the PASAT.

Cognitive strategies application of multiple sclerosis patients

When performing a novel task, people need to generate and apply a working strategy. The applicatio n of an appro priate working strategy enables patients with cognitive impairment (C I) to perform tasks efficiently, which in turn makes it easier to meet the challenges of daily life tasks. We investigated the strategy application abilities (SAA) of multiple sclerosis (MS) patients and compared these results with data based on healthy subjects’ performance. Seventy-six patients performed a Strategy A pplication Test (SAT) along with other cognitive tests, and completed depression, fatigue, and activity of daily living (A DL) questionnaires. O ur results indicated that 76% of the MS patients included had impaired SAA, and that this impairment was not correlated with their depression, fatigue, Expanded Disability Severity Scale (EDSS), or A DL. These findings may have important implications for the understanding of the capability of MS patients to cope with nonroutine tasks, as well as for the potential of future implementation of cognitive rehabilitation in improving the SAA of patients with MS or other cognitive disorders.

Verbal Learning Processes in Patients with Glioma of the Left and Right Temporal Lobes

Recent research supports the utility of process variables in understanding mechanisms underlying memory impairments. The Hopkins Verbal Learning Test-Revised (HVLT-R) was administered to 84 patients with left (LTL, n = 58) or right temporal lobe glioma (RTL, n = 26) prior to surgical resection. Primary HVLT-R measures of learning and memory and numerous learning process indices were computed. Both groups exhibited frequent memory impairment (>30%), with greater severity in the LTL group. Patients with LTL glioma also exhibited lower semantic clustering scores than RTL patients, which were highly associated with Total Recall (ρ = 0.83) and Delayed Recall (ρ = 0.68). Learning slope and a novel measure of learning efficiency were also significantly associated with primary memory measures, though scores were similar across the LTL and RTL groups. While lesions to either temporal lobe impact verbal memory, semantic encoding appears to depend upon the integrity of LTL structures in particular.

Cognitive Impairment and Community Integration Outcomes in Individuals Living With Multiple Sclerosis

OBJECTIVES

To determine the association between unique domains of cognitive impairment and community integration in individuals with multiple sclerosis (MS), and to determine the contributions of cognitive impairment to community integration beyond the influence of demographic and clinical variables.

DESIGN

Cross-sectional analysis of objective neuropsychological assessment and self-report data. Data were collected during baseline assessment of a randomized, multisite controlled trial of ginkgo biloba for cognitive impairment in MS. Hierarchical regression analyses examined the association between subjective and objective measures of cognitive impairment and 3 domains of community integration, adjusting for relevant covariates.

SETTING

Two Veterans Affairs medical center MS clinics.

PARTICIPANTS

Adults (N=121; ages 24-65y) with a confirmed MS diagnosis.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Primary outcomes were scores on the Home Integration (CIQ-H), Social Integration (CIQ-S), and Productivity (CIQ-P) domains of the Community Integration Questionnaire (CIQ).

RESULTS

Cognitive impairment was associated with lower scores on the CIQ-H and CIQ-S, but not the CIQ-P. Greater levels of subjective cognitive impairment were associated with lower scores on the CIQ-H and CIQ-S. Greater levels of objective cognitive impairment, specifically slower processing speed and poorer inhibitory control, were related to lower CIQ-S scores. Subjective and objective measures of cognitive impairment were significantly and independently associated with CIQ-S.

CONCLUSIONS

Objective cognitive impairment may interfere with participation in social activities. Subjective cognitive impairment is also important to assess, because individuals who perceive themselves to be cognitively impaired may be less likely to participate in both home and social activities. Clinical interventions to enhance community integration in individuals with MS may benefit from addressing objective and subjective cognitive impairment by integrating cognitive rehabilitation approaches with self-efficacy-enhancing strategies.

Neuropsychological correlates of multiple sclerosis across the lifespan

Multiple sclerosis can adversely affect cognitive functioning whether the disease has an adult or pediatric onset. The research thus far suggests that pediatric MS shares many features with adult MS but is also unique in several respects. One particular characteristic of pediatric MS is that, while physical disability develops more slowly as compared with adult patients, the impact of cognitive deficits in children may be more substantial as they are in a period of life during which they acquire many skills that are needed to transition into independently functioning adults. Our review takes a lifespan approach to MS, comparing and contrasting the neuropsychology (i.e., cognitive, psychological, and psychosocial factors) of these two populations. Understanding how MS manifests across the lifespan has important implications for tailoring assessment and treatment for individuals with MS as they transition from childhood to adulthood, and later life.

Information processing and magnetic resonance imaging indices of brain pathology in multiple sclerosis

Accumulation of central nervous system (CNS) pathology affects cognitive processing speed and efficiency and is thought to underlie attentional and executive deficits in multiple sclerosis (MS). Most clinical neuropsychological tests are multifactorial and are limited in their sensitivity to specific cognitive processes. This may, in part, account for the low to moderate correlations between clinical test results and magnetic resonance imaging (MRI) indices of brain pathology. We compared the ability of a clinical and an experimental test of cognitive processing speed to differentiate domain-specific cognitive changes in MS, and examined relations between test performance and MRI measures of brain pathology. Twelve MS patients and 12 controls completed the Paced Auditory Serial Addition Test (PASAT) and the Attention Networks Test-Interactions (ANT-I), a computerized response latency task. Subjects also had MRI scans that included T1, T2, and fluid-attenuated inversion recovery (FLAIR) sequences that provided global and localized volumetric measures. Patients made more errors on the PASAT and were slower on the ANT-I. The ANT-I also revealed specific deficits in response inhibition. In addition, ANT-I performance was associated with changes in a number of MRI measures, which was not the case for the PASAT. Reaction time paradigms that manipulate within-task demands on distinct cognitive functions may provide meaningful markers of brain disease burden in MS.

NIH EXAMINER: conceptualization and development of an executive function battery

Executive functioning is widely targeted when human cognition is assessed, but there is little consensus on how it should be operationalized and measured. Recognizing the difficulties associated with establishing standard operational definitions of executive functioning, the National Institute of Neurological Disorders and Stroke entered into a contract with the University of California-San Francisco to develop psychometrically robust executive measurement tools that would be accepted by the neurology clinical trials and clinical research communities. This effort, entitled Executive Abilities: Measures and Instruments for Neurobehavioral Evaluation and Research (EXAMINER), resulted in a series of tasks targeting working memory, inhibition, set shifting, fluency, insight, planning, social cognition and behavior. We describe battery conceptualization and development, data collection, scale construction based on item response theory, and lay the foundation for studying the battery's utility and validity for specific assessment and research goals.

Recall strategies for the verbal fluency test in patients with multiple sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease characterised by inflammation and demyelination. It generates irreversible myelin changes, which in turn give rise to physical and cognitive disorders. The verbal fluency test (VF) has been shown to be a sensitive tool for detecting cognitive impairment in these patients.

OBJECTIVE

To compare quantitative and qualitative aspects of performance on semantic and phonological fluency tests between MS patients and healthy controls by analysing total words produced and strategies used (clusters and switching).

METHOD

We evaluated 46 patients with MS and 33 healthy controls using the VF test.

RESULTS

The semantic VF task revealed no significant differences between groups; for the phonological task, patients demonstrated reduced word production (F [77]=2.286 P<.001) and poorer use of grouping strategies, resulting in more frequent switching (F [77]=3.808 P<.005).

CONCLUSIONS

These results support using qualitative analysis for recall strategies, since the technique provides data about which components of the task are affected by brain damage. Clusters depend on the integrity of semantic memory, while switching has to do with developing effective search strategies, cognitive flexibility, and the ability to modify responses. Frontal lobe damage has been reported in MS, and this is consistent with results from the phonological VF test.

Difficulties in planning among patients with multiple sclerosis: a relative consequence of deficits in information processing speed

Previous studies show that MS patients take longer than healthy controls to plan their solutions to Tower of London (TOL) problems but yield conflicting results regarding the quality of their solutions. The present study evaluated performance under untimed or timed conditions to assess the possibility that differences in planning ability only occur when restrictions in solution times are imposed. MS patients (n = 39) and healthy controls (n = 43) completed a computerized version of the TOL under one of two conditions. In the untimed condition, participants were allowed as much time as needed on each problem. In the timed condition, limits were imposed on solution times and time remaining was displayed with each problem. Patients exhibited longer planning times than controls, and the disparity between groups increased with problem difficulty. Planning performance depended upon condition. In the untimed condition, patients and controls performed equally well. When solution times were restricted, however, patients solved fewer problems than controls. MS patients' planning ability is intact when permitted sufficient time to formulate the required plan. Deficiencies in planning are only evident when time is restricted, and, therefore, are more accurately considered a relative consequence of disease-related problems in information processing speed.

The role of speed versus working memory in predicting learning new information in multiple sclerosis

The most common cognitive impairments in multiple sclerosis (MS) have been documented in specific domains, including new learning and memory, working memory, and information processing speed. However, little attempt has been made to increase our understanding of their relationship to one another. While recent studies have shown that processing speed impacts new learning and memory abilities in MS, the role of working memory in this relationship has received less attention. The present study examines the relative contribution of impaired working memory versus processing speed in new learning and memory functions in MS. Participants consisted of 51 individuals with clinically definite MS. Participants completed two measures of processing speed, two measures of working memory, and two measures of episodic memory. Data were analyzed via correlational and multiple regression analysis. Results indicate that the variance in new learning abilities in this sample was primarily associated with processing speed, with working memory exerting much less of an influence. Results are discussed in terms of the role of cognitive rehabilitation of new learning and memory abilities in persons with MS.

Comparison of neuropsychological impairment and vocational outcomes in systemic lupus erythematosus and multiple sclerosis patients

Systemic lupus erythematosus (SLE) and multiple sclerosis (MS) are chronic immunologic diseases that can cause cognitive dysfunction. MS is a central nervous system (CNS) disease characterized by demyelination and progressive brain atrophy. SLE is an autoimmune disease capable of damaging multiple organ systems, including the CNS. Cognitive disturbances are seen in both SLE and MS. The present study is concerned with understanding the similarities and differences between the cognitive profiles of SLE and MS as well as the relationship between cognitive impairment and vocational disability in these patients. We examined 47 SLE patients, 47 MS patients, and 44 healthy controls. The groups were well matched on demographics and the patient groups were also matched on disease duration and severity. Group comparisons revealed that generative verbal fluency and visual-spatial memory are more profoundly affected in MS than SLE; whereas depression, fatigue, and working memory deficits are similarly involved in both diseases. Logistic regression analysis revealed that executive function, in particular, was predictive of vocational outcomes in SLE and MS patients.

A Review of Virtual Week for Prospective Memory Assessment: Clinical Implications

It is now recognised that prospective memory (PM) failures are commonly observed in clinical groups, and have important implications for functional independence. However, well-validated measures of PM have traditionally been lacking, making this construct difficult to assess in clinical practice. Rendell and Craik's (2000) Virtual Week measure was developed as an indicator of PM, and has been shown to have good psychometric properties and be sensitive to the effects of normal and abnormal adult ageing, as well as various forms of pathology. In this article, an overview of Virtual Week's characteristics is presented, and the literature relating to use of this measure in various populations reviewed. The potential implications of the development of a new computerised version of Virtual Week for clinical practice are discussed.

Altered functional adaptation to attention and working memory tasks with increasing complexity in relapsing-remitting multiple sclerosis patients

As attention, processing speed, and working memory seem to be fundamental for a broad range of cognitive performance, the present study on patients with mild forms of relapsing-remitting multiple sclerosis (RR-MS) focused on these domains. To explore subtle neuropsychological changes in either the clinical or fMRI domain, we applied a multistep experimental design with increasing task complexity to investigate global brain activity, functional adaptation, and behavioral responses to typical cognitive processes related to attention and working memory. Fifteen patients with RR-MS (mean age 38 years, 22-49 years, 9 females, mean disease duration 5.9 years (SD = 3.6 years), mean Expanded Disability Status Scale score, 2.3 (SD = 1.3) but without reported cognitive impairment), and 15 age-matched healthy controls (HC; mean age, 34 years, 23-50 years, 6 women) participated. After a comprehensive neuropsychological assessment, participants performed different fMRI experiments testing attention and working memory. In the neuropsychological assessment, patients showed only subtle reduction in learning and memory abilities. In the fMRI experiments, both groups activated the brain areas typically involved in attention and working memory. HC showed a linear in- or decrease in activation paralleling the changing task complexity. Patients showed stronger activation change at the level of the simple tasks and a subsequent saturation effect of (de-)activation at the highest task load. These group/task interaction differences were found in the right parahippocampal cortex and in the middle and medial frontal regions. Our results indicate that, in MS, functional adaptation patterns can be found which precede clinical evidence of apparent cognitive decline.

Verbal memory impairment in severe closed head injury: the role of encoding and consolidation

We applied the item-specific deficit approach (ISDA) to California Verbal Learning Test data obtained from 56 severe, acceleration-deceleration closed head injury (CHI) participants and 62 controls. The CHI group demonstrated deficits on all ISDA indices in comparison to controls. Regression analyses indicated that encoding deficits, followed by consolidation deficits, accounted for most of the variance in delayed recall. Additionally, level of acquisition played a partial role in CHI-associated consolidation difficulties. Finally, CHI encoding deficits were largely driven by low semantic clustering during list learning. These results suggest that encoding (primary) and consolidation (secondary) deficits account for CHI-associated verbal memory impairment.

Temporal order memory differences in Alzheimer's disease and vascular dementia

Determining the order of events is essential for accurate memory recollection: an ability previously linked to both frontal and medial temporal functioning. Frontal-subcortical and medial temporal dysfunction typify vascular dementia (VaD) and Alzheimer's disease (AD), respectively. Therefore, we assessed patients' ordering abilities using a novel sequencing task that progressively increased memory load. VaD patients made more errors and selected more previously encountered stimuli than did AD. Curve analysis revealed a general decline in ordering for VaD whereas error production in AD is more dependent on memory load. These findings generally support the role of frontal-subcortical functioning in temporal order memory.

Individual differences in control of language interference in late bilinguals are mainly related to general executive abilities

BACKGROUND

Recent research based on comparisons between bilinguals and monolinguals postulates that bilingualism enhances cognitive control functions, because the parallel activation of languages necessitates control of interference. In a novel approach we investigated two groups of bilinguals, distinguished by their susceptibility to cross-language interference, asking whether bilinguals with strong language control abilities ("non-switchers") have an advantage in executive functions (inhibition of irrelevant information, problem solving, planning efficiency, generative fluency and self-monitoring) compared to those bilinguals showing weaker language control abilities ("switchers").

METHODS

29 late bilinguals (21 women) were evaluated using various cognitive control neuropsychological tests [e.g., Tower of Hanoi, Ruff Figural Fluency Task, Divided Attention, Go/noGo] tapping executive functions as well as four subtests of the Wechsler Adult Intelligence Scale. The analysis involved t-tests (two independent samples). Non-switchers (n = 16) were distinguished from switchers (n = 13) by their performance observed in a bilingual picture-naming task.

RESULTS

The non-switcher group demonstrated a better performance on the Tower of Hanoi and Ruff Figural Fluency task, faster reaction time in a Go/noGo and Divided Attention task, and produced significantly fewer errors in the Tower of Hanoi, Go/noGo, and Divided Attention tasks when compared to the switchers. Non-switchers performed significantly better on two verbal subtests of the Wechsler Adult Intelligence Scale (Information and Similarity), but not on the Performance subtests (Picture Completion, Block Design).

CONCLUSIONS

The present results suggest that bilinguals with stronger language control have indeed a cognitive advantage in the administered tests involving executive functions, in particular inhibition, self-monitoring, problem solving, and generative fluency, and in two of the intelligence tests. What remains unclear is the direction of the relationship between executive functions and language control abilities.

Concurrent validity of the tower tasks as measures of executive function in adults: a meta-analysis

Executive function refers to a variety of behaviors and abilities related to planning and strategy use, as well as to the maintenance of attention and behavior in the pursuit of some goal. Many instruments have been designed for the purpose of assessing executive function, and the tower tasks represent a specific group of measures commonly used in the assessment of this construct. This review and meta-analysis examines the theoretical and psychometric basis for the use of the various tower tasks in neuropsychological assessment of adults. Neuroimaging and electrophysiological evidence are consistent with theoretical hypotheses of frontal involvement (e.g., planning and strategy use) in tower task performance. Further, adults with various disorders of presumed neurological basis demonstrate impaired performance on tower tasks. Implications for the use of tower tasks in practice and research are discussed.