Processing speed versus working memory: contributions to an information-processing task in multiple sclerosis

Effects of exergaming on cognition, lower limb functional coordination, and stepping time in people with multiple sclerosis: a randomized controlled trial

PURPOSE

To compare the effects of exergaming versus conventional exercises on cognition, lower-limb functional coordination, and stepping time in people with multiple sclerosis (PwMS).

METHODS

Thirty-six PwMS were randomly assigned to either intervention (n = 18) or control (n = 18) group and received 18 training sessions during six weeks. The intervention group performed exergames that required multidirectional timed-stepping, weight-shifting, and walking while the control group performed conventional matched exercises. Trail making test (TMT part A, B; TMT-A, TMT-B, TMT B-A), six-spot step test (SSST), and choice stepping reaction time (CSRT-including reaction time (RT), movement time (MVT), and total response time (TRT)) were assessed pre- and post-intervention (short-term), and after three-month follow-up (mid-term).

RESULTS

The intervention group showed faster TMT-B (p = 0.003) and TMT B-A (p = 0.002) at post-intervention and faster SSST at both post-intervention (p = 0.002) and follow-up (p = 0.04). The CSRT components showed no between-group differences at post-intervention; however, at follow-up, the intervention group had lower TRT (p = 0.046) and MVT (p = 0.015). TMT-A and RT had no significant between-group differences.

CONCLUSIONS

In short-term, exergames led to more improvements in complex attention, executive function, and lower-limb functional coordination comparing to the matched conventional exercises. In mid-term, exergaming was more effective for improving stepping time and lower-limb functional coordination. However, the two approaches did not show any superiority over each other for improving simple attention and RT.Implications for rehabilitationWhen designed properly, exergames have great potential to improve attention and executive function of people with multiple sclerosis (PwMS), at least in the short-term.Exergames seem like an appropriate option for improving lower limb coordination and decreasing choice stepping response time among PwMS in the mid-term.Exergames do not have superiority in improving the choice stepping reaction time compared to their matched conventional treatment.

Effect of deep gray matter atrophy on information processing speed in early relapsing-remitting multiple sclerosis

BACKGROUND

Cognitive dysfunction, including reduced Information processing speed (IPS), is relatively common in multiple sclerosis(MS). IPS deficits have profound effects on several aspects of patients' life. Previous studies showed that deep gray matter atrophy is highly correlated with overall cognitive impairment in MS. However, the effect of deep gray matter atrophy on IPS deficits is not well understood. In this study, we evaluated the effects of deep gray matter volume changes on IPS in people with early relapse-remitting MS (RRMS) compared to healthy control.

METHODS

In this case-control study, we enrolled 63 case with RRMS and 36 healthy controls. All patients were diagnosed within 6 years. IPS was evaluated using the Integrated Cognitive Assessment (ICA) test. We also performed a 1.5T MRI to evaluate deep gray matter structures.

RESULTS

People with RRMS had lower accuracy in the ICA test (p = .01). However, the reaction time did not significantly differ between RRMS and control groups (p = .6). Thalamus volume was significantly lower in the RRMS group with impaired IPS compared to the RRMS with normal IPS and control groups (p < 10-4). Other deep gray matter structures were not significantly different between the RRMS with impaired IPS group and the RRMS with normal IPS group.

CONCLUSION

Some people with MS are impaired in IPS even in the early stages of the disease. Thalamic atrophy affected IPS in these patients, however atrophy in other deep gray matter structures, including caudate, putamen, globus pallidus, hippocampus, amygdala, accumbens, and cerebellum, were not significantly correlated with IPS impairment in early RRMS.

Interpreting the clinical importance of the relationship between subjective fatigue and cognitive impairment in multiple sclerosis (MS): How BICAMS performance is affected by MS-related fatigue

BACKGROUND

There is evidence that subjective fatigue can influence cognitive functioning in multiple sclerosis (MS). DeLuca et al.'s (2004) Relative Consequence Model proposes that impairments to other high-level cognitive functions, such as memory, result from the disease's effect on information processing speed.

OBJECTIVE

The primary aims of the study were to investigate both 1) the relationship between subjective fatigue and cognitive functioning, as measured by the widely used Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) in MS; and 2) the consequential effect of fatigue on information processing speed as predicted by the Relative Consequence Model.

METHODS

192 participants with MS attending tertiary referral MS centre completed the Modified Fatigue Impact Scale and BICAMS.

RESULTS

Multiple correlation analyses determined that there were statistically significant relationships between all domains assessed by the BICAMS and levels of fatigue, such that higher levels of self-reported fatigue were associated with lower performance on information-processing, and visual and verbal learning. After controlling for information processing speed, the strength of correlation between fatigue and learning performance weakened. Linear regression analysis showed that fatigue predicted the most variance in verbal learning and 11.7% of the overall variance in BICAMS performance.

CONCLUSION

Subjective fatigue and objective cognitive performance in MS are related. Caution is advised in the interpretation of BICAMS scores in cases where high levels of fatigue are present, and more detailed neuropsychological assessments may be required in order to accurately identify objective cognitive impairment independent of subjective fatigue.

The efficacy of speed of processing training for improving processing speed in individuals with multiple sclerosis: a randomized clinical trial

OBJECTIVE

The current study examines the efficacy of speed of processing training (SOPT) to improve processing speed (PS) in individuals with multiple sclerosis (MS). Outcomes included changes in the useful field of view (UFOV) and neuropsychological evaluation (NPE).

METHODS

This double-blind, placebo-controlled randomized clinical trial included 84 participants with clinically definite MS and impaired PS, 43 in the treatment group and 41 in the placebo control group. Participants completed a baseline NPE and a repeat NPE post-treatment. The treatment group was randomized to booster sessions or no contact. Long-term follow-up assessments were completed 6 months after treatment.

RESULTS

A significant effect of SOPT was observed on both the UFOV (large effect) and pattern comparison with a similar pattern of results noted on letter comparison, albeit at a trend level. The treatment effect was maintained 6 months later. The impact of booster sessions was not significant. Correlations between degree of improvement on the UFOV and the number of levels completed within each training task were significant for both speed and divided attention indicating that completion of more levels of training correlated with greater benefit.

CONCLUSION

SOPT is effective for treating PS deficits in MS with benefit documented on both the UFOV and a neuropsychological measure of PS. Less benefit was observed as the outcome measures became more distinct in cognitive demands from the treatment. Long-term maintenance was observed. The number of training levels completed within the 10-sessions exerted a significant impact on treatment benefit, with more levels completed resulting in greater benefit.

Understanding visual-spatial perceptual deficits in individuals with multiple sclerosis: an analysis of patient performance on the Hooper Visual Organization Test and Visual Form Discrimination

Purpose: Although the cognitive sequelae of multiple sclerosis have been recognized for more than four decades, the focus of research has been on studying the more common deficits of the disease, including those involving memory and information processing speed. Less understood and investigated are the visual-spatial perceptual disturbances of multiple sclerosis, which can be difficult to assess and interpret given the potential confounds associated with the physical problems and other cognitive disturbances of the disorder.Materials and methods: This study examined the visual-spatial perceptual deficits of multiple sclerosis in 40 participants diagnosed with this condition using two measures generally unaffected by the aforementioned confounds, the Hooper Visual Organization Test and Visual Form Discrimination.Results: Results revealed both measures to be sensitive to the impairments of multiple sclerosis but suggested that they are assessing somewhat different aspects of visual-spatial perception in this population, given their relationship with one another and with disease-related variables.Conclusions: In this light, findings indicate that a complete and accurate understanding of the visual-spatial perceptual sequelae of multiple sclerosis requires the administration of more than a single measure.

Evaluating the relationship between working memory and information processing speed in multiple sclerosis

The aim of the present study was to evaluate the effect of information processing speed on the functioning of specific working memory components, i.e. phonological loop, visuospatial sketchpad, central executive and episodic buffer. Cognitive tasks that assess working memory ("word lists recall" for the phonological loop, "block recall" for the spatial component of visuospatial sketchpad, "listening recall" for the central executive and "immediate story recall" for the episodic buffer) and information processing speed (symbol digit modalities test- oral form) were administered to 38 patients with multiple sclerosis. Results showed that the central executive and episodic buffer components were significantly related to information processing speed. However, when age was included in the regression model, information processing speed significantly predicted only the episodic buffer scores. Further research on the relationship between the episodic buffer and information processing speed is recommended.

Effects of Age, Cognition, and Neural Encoding on the Perception of Temporal Speech Cues

Older adults commonly report difficulty understanding speech, particularly in adverse listening environments. These communication difficulties may exist in the absence of peripheral hearing loss. Older adults, both with normal hearing and with hearing loss, demonstrate temporal processing deficits that affect speech perception. The purpose of the present study is to investigate aging, cognition, and neural processing factors that may lead to deficits on perceptual tasks that rely on phoneme identification based on a temporal cue - vowel duration. A better understanding of the neural and cognitive impairments underlying temporal processing deficits could lead to more focused aural rehabilitation for improved speech understanding for older adults. This investigation was conducted in younger (YNH) and older normal-hearing (ONH) participants who completed three measures of cognitive functioning known to decline with age: working memory, processing speed, and inhibitory control. To evaluate perceptual and neural processing of auditory temporal contrasts, identification functions for the contrasting word-pair WHEAT and WEED were obtained on a nine-step continuum of vowel duration, and frequency-following responses (FFRs) and cortical auditory-evoked potentials (CAEPs) were recorded to the two endpoints of the continuum. Multiple linear regression analyses were conducted to determine the cognitive, peripheral, and/or central mechanisms that may contribute to perceptual performance. YNH participants demonstrated higher cognitive functioning on all three measures compared to ONH participants. The slope of the identification function was steeper in YNH than in ONH participants, suggesting a clearer distinction between the contrasting words in the YNH participants. FFRs revealed better response waveform morphology and more robust phase-locking in YNH compared to ONH participants. ONH participants also exhibited earlier latencies for CAEP components compared to the YNH participants. Linear regression analyses revealed that cortical processing significantly contributed to the variance in perceptual performance in the WHEAT/WEED identification functions. These results suggest that reduced neural precision contributes to age-related speech perception difficulties that arise from temporal processing deficits.

The Role of Premotor Areas in Dual Tasking in Healthy Controls and Persons With Multiple Sclerosis: An fNIRS Imaging Study

Persons with multiple sclerosis (pwMS) experience declines in physical and cognitive abilities and are challenged by dual-tasks. Dual-tasking causes a drop in performance, or what is known as dual-task cost (DTC). This study examined DTC of walking speed (WS) and cognitive performance (CP) in pwMS and healthy controls (HCs) and the effect of dual-tasking on cortical activation of bilateral premotor cortices (PMC) and bilateral supplementary motor area (SMA). Fourteen pwMS and 14 HCs performed three experimental tasks: (1) single cognitive task while standing (SingCog); (2) single walking task (SingWalk); and (3) dual-task (DualT) that included concurrent performance of the SingCog and SingWalk. Six trials were collected for each condition and included measures of cortical activation, WS and CP. WS of pwMS was significantly lower than HC, but neuropsychological (NP) measures were not significantly different. pwMS and HC groups had similar DTC of WS, while DTC of CP was only significant in the MS group; processing speed and visual memory predicted 55% of this DTC. DualT vs. SingWalk recruited more right-PMC activation only in HCs and was associated with better processing speed. DualT vs. SingCog recruited more right-PMC activation and bilateral-SMA activation in both HC and pwMS. Lower baseline WS and worse processing speed measures in pwMS predicted higher recruitment of right-SMA (rSMA) activation suggesting maladaptive recruitment. Lack of significant difference in NP measures between groups does not rule out the influence of cognitive factors on dual-tasking performance and cortical activations in pwMS, which might have a negative impact on quality of life.

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.

Validity of a Novel Touch Screen Tablet-Based Assessment for Mild Cognitive Impairment and Probable AD in Older Adults

This study aimed to develop a psychometrically valid touch screen tablet-based cognitive test battery to identify early cognitive impairment due to dementia in older adults. The battery includes eight tests with 13 subscores, evaluating visual attention, auditory attention, information processing speed, visual memory, motor control, and visuospatial perception. Among the participants, 43 had been diagnosed with mild cognitive impairment (MCI) and 36 with probable Alzheimer’s disease (AD); 41 had no cognitive impairment. The average time to administer the tablet-based tests was 10 minutes. Significant correlations with the Mini-Mental State Examination were found in 9 out of 13 subscores. Patients with probable AD scored significantly lower than controls in 8 out of 13 subscores, whereas those with MCI scored significantly lower in 4 out of 13 subscores. Confirmatory factor analysis using Promax rotation showed that four factors caused lower subscores in the MCI group compared with the controls: information processing speed, memory, visuospatial perception, and motor control. All four factors significantly discriminated the controls from the MCI and probable AD groups, and in the expected direction. The touch screen tablet-based cognitive test battery is psychometrically valid for evaluating cognition in older adults.

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.

Effects of cognitive impairment on prosodic parameters of speech production planning in multiple sclerosis

Cognitive impairment (CI) affects 40-65% of patients with multiple sclerosis (MS). CI can have a negative impact on a patient's everyday activities, such as engaging in conversations. Speech production planning ability is crucial for successful verbal interactions and thus for preserving social and occupational skills. This study investigates the effect of cognitive-linguistic demand and CI on speech production planning in MS, as reflected in speech prosody. A secondary aim is to explore the clinical potential of prosodic features for the prediction of an individual's cognitive status in MS. A total of 45 subjects, that is 22 healthy controls (HC) and 23 patients in early stages of relapsing-remitting MS, underwent neuropsychological tests probing specific cognitive processes involved in speech production planning. All subjects also performed a read speech task, in which they had to read isolated sentences manipulated as for phonological length. Results show that the speech of MS patients with CI is mainly affected at the temporal level (articulation and speech rate, pause duration). Regression analyses further indicate that rate measures are correlated with working memory scores. In addition, linear discriminant analysis shows the ROC AUC of identifying MS patients with CI is 0.70 (95% confidence interval: 0.68-0.73). Our findings indicate that prosodic planning is deficient in patients with MS-CI and that the scope of planning depends on patients' cognitive abilities. We discuss how speech-based approaches could be used as an ecological method for the assessment and monitoring of CI in MS.

Validity of the Symbol Digit Modalities Test as a cognition performance outcome measure for multiple sclerosis

Cognitive and motor performance measures are commonly employed in multiple sclerosis (MS) research, particularly when the purpose is to determine the efficacy of treatment. The increasing focus of new therapies on slowing progression or reversing neurological disability makes the utilization of sensitive, reproducible, and valid measures essential. Processing speed is a basic elemental cognitive function that likely influences downstream processes such as memory. The Multiple Sclerosis Outcome Assessments Consortium (MSOAC) includes representatives from advocacy organizations, Food and Drug Administration (FDA), European Medicines Agency (EMA), National Institute of Neurological Disorders and Stroke (NINDS), academic institutions, and industry partners along with persons living with MS. Among the MSOAC goals is acceptance and qualification by regulators of performance outcomes that are highly reliable and valid, practical, cost-effective, and meaningful to persons with MS. A critical step for these neuroperformance metrics is elucidation of clinically relevant benchmarks, well-defined degrees of disability, and gradients of change that are deemed clinically meaningful. This topical review provides an overview of research on one particular cognitive measure, the Symbol Digit Modalities Test (SDMT), recognized as being particularly sensitive to slowed processing of information that is commonly seen in MS. The research in MS clearly supports the reliability and validity of this test and recently has supported a responder definition of SDMT change approximating 4 points or 10% in magnitude.

Executive function is an important consideration for coping strategy use in people with multiple sclerosis

INTRODUCTION

Executive function deficits are prevalent in people with multiple sclerosis (PwMS), and PwMS use less adaptive coping than healthy controls. This cross-sectional study assessed whether there is a relationship between executive function and coping in PwMS.

METHOD

One hundred and seven participants with relapsing remitting or secondary progressive MS (n = 83 and 24, respectively; age M = 48.8 ± 11.1 years) completed measures of coping and executive function.

RESULTS

A positive relationship was found between verbal fluency and use of active, emotional, and instrumental social support coping, and total executive function and substance abuse coping. There was a negative relationship between coping strategies and core (social support, acceptance, religion, restraint, and total coping), higher order (denial and humor), and total executive function indices (acceptance, religion, behavioral disengagement, denial, and total coping).

CONCLUSION

These directional differences provide support for the importance of specific executive functions in coping strategy utilization. Understanding these relationships will assist psychologists and neuropsychologists with patient psychoeducation, adaptive coping strategy intervention and management for PwMS with reduced executive function ability.

What you get from what you see: Parametric assessment of visual processing capacity in multiple sclerosis and its relation to cognitive fatigue

Multiple sclerosis (MS(1)) is a diffusely disseminated inflammatory disease affecting widespread cerebral networks. Major cognitive impairments are a reduction of processing capacity and mental fatigue, i.e., an "abnormal sense of tiredness or lack of energy". Here, the present study provides the first assessment of the distinct components of visual processing capacity based on a 'theory of visual attention' (TVA(2)) in MS patients and relates it to measures of subjective as well as (more) objective fatigue. The performance of 36 relapsing-remitting MS patients in a whole report task of brief letter arrays was compared to healthy control subjects matched for gender, age and education. Additionally, the sustained attention test PASAT-3(3) served as a measure of objective fatigue, and the self-report questionnaire MFIS(4) as a measure of subjective fatigue. Results indicate generally diminished processing speed as well as iconic memory buffers, and increased perceptual thresholds in MS patients compared to healthy controls. Block-wise analysis of attentional parameters shows that the processing speed performance of MS patients declines in the second half of the TVA-based test compared to healthy controls and in particular for patients with high versus low objective fatigue. These findings describe which aspects of processing capacity are impaired in MS, and show that fatigue mainly affects speed of processing. Thus, TVA-based assessment provides a novel approach in the determination of cognitive impairments and fatigue in MS. However, further research is required to elucidate the complex relations of processing capacity and cognitive functions in MS.

Information processing speed in multiple sclerosis: Past, present, and future

BACKGROUND

Information processing speed (IPS) is a prevalent cognitive impairment in multiple sclerosis (MS).

OBJECTIVES

This review aims to summarize the methods applied to assess IPS in MS and its theoretical conceptualization. A PubMed search was performed to select articles published between 1 January 2004 and 31 December 2013, resulting in 157 articles included.

RESULTS

The majority (54%) of studies assessed IPS with heterogeneous samples (several disease courses). Studies often report controlling for presence of other neurological disorders (60.5%), age (58.6%), education (51.6%), alcohol history (47.8%), or use of steroids (39.5%). Potential confounding variables, such as recent relapses (50.3%), history of developmental disorders (19.1%), and visual problems (29.9%), were often neglected. Assessments used to study IPS were heterogeneous (ranging from simple to complex tasks) among the studies under review, with 62 different tasks used. Only 9.6% of articles defined the construct of IPS and 22.3% discussed IPS in relation to a theoretical model.

FUTURE DIRECTIONS

The challenges for the upcoming decade include clarification of the definition of IPS as well as its theoretical conceptualization and a consensus on assessment. Based on the results obtained, we propose a new theoretical model, the tri-factor model of IPS.

Long-Term Neurocognitive, Psychosocial, and Magnetic Resonance Imaging Outcomes in Pediatric-Onset Acute Disseminated Encephalomyelitis

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is a demyelinating disorder that is usually self-limited. Recent studies have suggested ongoing neurological deficits and neurocognitive impairment in these patients. Little information on the correlation of clinical and neuroimaging markers in ADEM is available. We examined potential clinical factors (e.g., age of onset, acute symptom duration, magnetic resonance imaging [MRI] lesions) and their relation to neurocognitive and psychosocial outcomes.

METHODS

This is a retrospective chart review of consecutive pediatric patients diagnosed with ADEM between 2006 and 2012. Patients were evaluated with standard neurological assessment, MRI of the brain, and neuropsychological evaluation.

RESULTS

Twenty-three patients with ADEM with average age at neuropsychological assessment of 10.1 years (±3.50) were included. Five (22.7%) patients were impaired on three or more neurocognitive measures. Psychosocial problems were reported in 20%-40% of patients. Earlier age of onset was correlated with poorer sustained attention and psychosocial problems, whereas acute symptom duration and Expanded Disability Status Scale were not. MRI outcomes were correlated with psychosocial outcomes but not neuropsychological findings.

CONCLUSIONS

Our findings suggest lingering cognitive and psychosocial deficits in children with a history of ADEM. Clinical features and MRI findings correlated more strongly with psychosocial outcomes than cognitive functioning. Further studies are needed to confirm relationships and other possible contributing factors to lingering deficits.

Altered Effective Connectivity during a Processing Speed Task in Individuals with Multiple Sclerosis

OBJECTIVES

Processing speed impairment is the most prevalent cognitive deficit in individuals with multiple sclerosis (MS). However, the neural mechanisms associated with processing speed remain under debate. The current investigation provides a dynamic representation of the functioning of the brain network involved in processing speed by examining effective connectivity pattern during a processing speed task in healthy adults and in MS individuals with and without processing speed impairment.

METHODS

Group assignment (processing speed impaired vs. intact) was based on participants' performance on the Symbol Digit Modalities test (Parmenter, Testa, Schretlen, Weinstock-Guttman, & Benedict, 2010). First, brain regions involved in the processing speed task were determined in healthy participants. Time series from these functional regions of interest of each group of participants were then subjected to the effective connectivity analysis (Independent Multiple-Sample Greedy Equivalence Search and Linear, Non-Gaussian Orientation, Fixed Structure algorithms) that showed causal influences of one region on another during task performance.

RESULTS

The connectivity pattern of the processing speed impaired group was significantly different from the connectivity pattern of the processing speed intact group and of the healthy control group. Differences in the strength of common connections were also observed.

CONCLUSIONS

Effective connectivity results reveal that MS individuals with processing speed impairment not only have connections that differ from healthy participants and MS individuals without processing speed impairment, but also have increased strengths of connections.

Pain and cognition in multiple sclerosis

There is a high prevalence of pain, depression, and cognitive dysfunction in patients with Multiple Sclerosis (MS). These symptoms affect daily tasks resulting in a significant reduction in quality of life. Pain and cognitive changes have been studied across various animal models of MS. In these models the onset of pain and cognitive dysfunction occur early, and do not coincide with the pattern of motor deficits. This is likely underpinned by a number of different mechanisms including changes in glutamate transmission, glial cell activation, and increased levels of pro-inflammatory cytokines. Changes in pain and cognition have been described as belonging to a cluster of symptoms and have been linked through centrally driven processes. In particular, the overactive immune response can induce a state of "sickness-like behaviours" that can influence both pain and cognition. Investigating the mechanism of inflammatory sickness behaviors in MS could lead to a better understanding of the links between pain and cognition. There are currently few effective treatments for pain and cognition dysfunction in MS. Studying the relationship between these symptoms will allow better management of both symptoms.