A French Version of a Voice Recognition Symbol Digit Modalities Test Analog

We previously showed that a fully automated voice recognition analog of the Symbol Digit Modalities Test (VR-SDMT) is sensitive in detecting processing speed deficits in people with multiple sclerosis (pwMS). We subsequently developed a French language version and administered it to 49 French-Canadian pwMS and 29 matched healthy control (HC) subjects. Significant correlations between the VR-SDMT and traditional oral SDMT were found in the MS (r = -0.716, p < 0.001) and HC (r = -0.623, p < 0.001) groups. These findings in French replicate our previous findings and confirm the utility of voice recognition software in assessing cognition in pwMS.

Predictive models of multiple sclerosis-related cognitive performance using routine clinical practice predictors

BACKGROUND

The application of machine learning (ML) to predict cognitive evolution is exceptionally scarce. Computer-based self-administered cognitive tests provide the opportunity to set up large longitudinal datasets to aid in developing ML prediction models of risk for Multiple Sclerosis-related cognitive decline.

OBJECTIVE

to analyze to what extent clinically feasible models can be built with standard clinical practice features and subsequently used for reliable prediction of cognitive evolution.

METHODS

This prospective longitudinal study includes 1184 people with MS who received a Processing Speed (PS) evaluation at 12 months of follow-up measured by the iPad®-based Processing Speed Test (PST). Six of the most potent classification models built with routine clinical practice features were trained and tested to predict the 12-month patient class label (PST worsening (PSTw) versus PST stable). A rigorous scheme of all the preprocessing steps run to obtain reliable generalization performance is detailed.

RESULTS

Based on a 12-month reduction of 10% of the PST raw score, 187/1184 (15.8%) people with MS were classified as PSTw. The trees-based models (random forest and the eXtreme Gradient Boosting) achieved the best performance, with an area under the receiver operating characteristic curve (AUC) of 0.90 and 0.89, respectively. The timing of high-efficacy disease-modifying therapies (heDMTs) was identified as one of the top importance predictors in all the models evaluated.

CONCLUSION

Using trees-based machine learning models to predict individual future information processing speed deterioration in MS could become a reality in clinical practice.

Cortical Thickness and Brain Connectivity Mediate the Relation Between White Matter Hyperintensity and Information Processing Speed in Cerebral Small Vessel Disease

White matter hyperintensities of presumed vascular origin (WMH) are the most common imaging feature of cerebral small vessel disease (cSVD) and are associated with cognitive impairment, especially information processing speed (IPS) deficits. However, it is unclear how WMH can directly impact IPS or whether the cortical thickness and brain connectivity mediate such association. In this study, it was evaluated the possible mediating roles of cortical thickness and brain (structural and functional) connectivity on the relationship between WMH (also considering its topography distribution) and IPS in 389 patients with cSVD from the RUN-DMC (Radboud University Nijmegen Diffusion tensor and Magnetic resonance imaging Cohort) database. Significant (p < 0.05 after multiple comparisons correction) associations of WMH volume and topography with cortical thickness, brain connectivity, and IPS performance in cSVD individuals were found. Additionally, cortical thickness and brain structural and functional connectivity were shown to mediate the association of WMH volume and location with IPS scores. More specifically, frontal cortical thickness, functional sensorimotor network, and posterior thalamic radiation tract were the essential mediators of WMH and IPS in this clinical group. This study provided insight into the mechanisms underlying the clinical relevance of white matter hyperintensities in information processing speed deficits in cSVD through cortical thinning and network disruptions.

Processing speed in temporal lobe epilepsy. A scoping review

BACKGROUND

Impaired processing speed (PS) can affect patients with temporal lobe epilepsy (TLE). However, it is usually considered a nonspecific clinical feature and is not measured, but this raises lexical and methodological problems. This review aims to evaluate the existing terminology and assessment methods of PS in patients with TLE.

METHODS

A scoping review was conducted based on the extended guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. The electronic literature search was conducted on Medline-PubMed, American Psychological Association-PsycINFO, Elton Bryson Stephens Company, and Google Scholar, using the keywords "temporal lobe epilepsy" and "speed" or "slowing" plus "processing," "cognitive," "psychomotor," or "mental." Peer-reviewed articles published before December 2022 were analyzed if they were in English, including patients older than 14 years and at least one neuropsychological measure, reported original research focused on PS and had the selected keywords in the title, keywords, and abstract.

RESULTS

Seven articles published between December 2004 and September 2021 were selected. The terms "processing speed," "psychomotor speed," and "information processing speed," based on similar theoretical constructs, were the most frequently used. Assessment methods included non-computerized or paper-and-pencil tests (WAIS-III Digit Symbol and Symbol Search subtests, Purdue Pegboard and Grooved Pegboard Tests, Trail Making Test and Stroop Color-Word Test) and computerized tests (Sternberg Memory Scanning Test, Pattern Comparison Processing Speed, Computerized Visual Searching). In some studies, impairment was associated with white and gray matter damage in the brain, independent of clinical and treatment variables.

CONCLUSION

Clinical research on TLE has focused inconsistently on PS. Different evaluation terms and methods have been used while referring to similar theoretical constructs. These findings highlight a gap between the clinical importance of PS and its assessment. Studies are needed to share terms and tools among clinical centers and clarify the position of PS in the TLE phenotype.

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.

Personality factors and cognitive functioning in patients with somatic symptom and related disorders

OBJECTIVE

Somatic symptom and related disorders (SSRD) are often complicated by cognitive symptoms, including reduced information processing speed, memory, and planning. Depression has been related to poor cognitive functioning in SSRD, but the role of underlying personality factors is poorly understood. This study investigates the association between personality factors (neuroticism, extraversion, openness, agreeableness, and conscientiousness) with cognitive functioning in patients with SSRD.

METHODS

Data from 366 patients with SSRD from a tertiary care expert center (mean age = 42.1 years (SD = 13.4), 59.6% women) were analyzed using a cross-sectional design. Neuropsychological assessments included measures of information processing speed, memory, attention, and executive function. Personality factors were assessed using the NEO-FFI and depressive symptoms using the PHQ-9.

RESULTS

Regression analyses showed associations between neuroticism with poorer performance on visual memory (B = -0.09, SE = 0.04, β = -0.14, p = .019), and planning (B = -0.09. SE = 0.02, β = -0.23, p < .001). Extraversion was also inversely associated with visual memory (B = -0.13, SE = 0.05, β = -0.18, p = .011) and planning (B = -0.07, SE = 0.03, β = -0.17, p = .021) and openness was associated with better visual memory (B = 0.17, SE = 0.05, β = 0.19, p = .002). These associations were attenuated but remained significant after adjusting for depressive symptoms.

CONCLUSION

Neuroticism, extraversion, and low openness were associated with lower cognitive functioning (particularly planning and visual memory) in patients with SSRD, which remained significant after taking depressive symptoms into account.

The symbol digit modalities test and the paced auditory serial addition test involve more than processing speed

BACKGROUND

Slowed processing speed is the most frequently reported cognitive deficit for people with multiple sclerosis (MS). However, measures used to assess processing speed may also recruit other cognitive abilities. The present objective was to determine the contributions of different cognitive functions to performance on two commonly used processing speed measures: the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT).

METHODS

Adults with relapsing-remitting MS (n = 70) and controls (n = 72) completed the SDMT, PASAT, and multiple measures assessing processing speed, working memory, and learning. Hierarchical regression analyses were used to examine the contributions of MS, processing speed, working memory, learning, and all possible interactions among factors to SDMT and PASAT scores.

RESULTS

Processing speed and working memory generally contributed to performance on the SDMT and PASAT, with learning additionally contributing to SDMT performance. However, significant interactions revealed processing speed did not influence PASAT performance for individuals with high working memory ability whereas processing speed became increasingly more important as working memory declined to average and low levels. Further, processing speed was associated with SDMT performance for patients with MS but not controls.

CONCLUSIONS

These findings support a multifactorial interpretation of the SDMT and PASAT, which facilitates their usefulness as screening measures for cognitive decline but prevents them from identifying which specific cognitive functions are affected.

Theory of Mind and social functioning among neuropsychiatric disorders: A transdiagnostic study

Social dysfunction is commonly present in neuropsychiatric disorders of schizophrenia (SZ) and Alzheimer's disease (AD). Theory of Mind (ToM) deficits have been linked to social dysfunction in disease-specific studies. Nevertheless, it remains unclear how ToM is related to social functioning across these disorders, and which factors contribute to this relationship. We investigated transdiagnostic associations between ToM and social functioning among SZ/AD patients and healthy controls, and explored to what extent these associations relate to information processing speed or facial emotion recognition capacity. A total of 163 participants were included (SZ: n=56, AD: n=50 and age-matched controls: n=57). Social functioning was assessed with the Social Functioning Scale (SFS) and the De Jong-Gierveld Loneliness Scale (LON). ToM was measured with the Hinting Task. Information processing speed was measured by the Digit Symbol Substitution Test (DSST) and facial emotion recognition capacity by the facial emotion recognition task (FERT). Case-control deficits in Hinting Task performance were larger in AD (rrb = -0.57) compared to SZ (rrb = -0.35). Poorer Hinting Task performance was transdiagnostically associated with the SFS (βHinting-Task = 1.20, p<0.01) and LON (βHinting-Task = -0.27, p<0.05). DSST, but not FERT, reduced the association between the SFS and Hinting Task performance, however the association remained significant (βHinting-Task = 0.95, p<0.05). DSST and FERT performances did not change the association between LON and Hinting Task performance. Taken together, ToM deficits are transdiagnostically associated with social dysfunction and this is partly related to reduced information processing speed.

Task-switching abilities in episodic and chronic migraine

Migraineurs show impaired cognitive functions interictally, mainly involving information processing speed, basic attention, and executive functions. We aimed to assess executive impairment in migraine patients with different attack frequencies through a task-switching protocol designed to assess different sub-processes of executive functioning. We enrolled 42 migraine patients and divided them into three groups based on the attack frequency: 13 subjects had episodic migraine with a low frequency (LFEM, 4-7 migraine days per month), 14 subjects had high-frequency episodic migraine (HFEM, 8-14 days) and, finally, 15 subjects presented chronic migraine (≥ 15 headache days/month, CM); we compared them to 20 healthy control (HC), matched to both gender and education. Patients with high headache frequencies (CM and HFEM) showed worse performance than LFEM and HC controls, as indicated by poor accuracy, increased switch cost, and reaction times. Our study demonstrated a difference in task-switching abilities in patients with high frequency or chronic migraine compared with low-frequency episodic migraine and healthy controls. These difficulties in executive control processes could be related to altered functioning of the frontal cortex and its cortical and subcortical connections.

Targeted cognitive game training enhances cognitive performance in multiple sclerosis patients treated with interferon beta 1-a

Background

Prevention of cognitive decline in Multiple Sclerosis (MS) is of major importance. We explored the effect of a 6 months computerized game training program on cognitive performance in MS patients with mild cognitive impairment.

Methods

This was a single-center, randomized prospective study. We enrolled in this study 100 eligible MS patients treated with Interferon-beta-1a (Rebif). All had mild cognitive impairment in either executive function or information processing speed. Patients were randomized 1:1 to either use the cognitive games platform by HappyNeuron (HN) or receive no intervention. Executive function and information processing speed scores were measured at 3 and 6 months from baseline to evaluate the effect of game training on cognitive scores.

Results

In both executive function and information processing speed, the game Training group showed significant improvement after 3 and 6 months. The Non-Training group showed mild deterioration in both domains at 3 months, and further deterioration that became significant at 6 months in executive function. Furthermore, at 6 months, the percent of patients in the Training group that improved or remained stable in both cognitive domains was significantly higher compared to the Non-Training group.

Conclusions

Our findings suggest that cognitive game training has a beneficial effect on cognitive performance in MS patients suffering from mild cognitive impairment. While further evaluation is required to assess the longevity of that effect, we nonetheless recommend to MS patients to be engaged in cognitive gaming practice as part of a holistic approach to treating their condition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-021-00968-3.

Predictors of cognitive fatigue and fatigability in multiple sclerosis

BACKGROUND

Persons with multiple sclerosis (PwMS) commonly experience cognitive fatigue (CF), defined as a decrease in cognitive performance with sustained activity, yet CF remains understudied. Further, the relationship between subjective CF and objective CF, or cognitive fatiguability, has not been fully elucidated in previous studies. Understanding the predictors of cognitive fatigue may scaffold the development of interventions that target this symptom. The objective of this prospective study was to evaluate the extent to which depression, anxiety, information processing speed, and sleep quality predict subjective and objective CF.

METHODS

PwMS were recruited from one academic MS clinic in London (ON) Canada. Objective CF was measured by the Paced Auditory Serial Addition Test (PASAT), where performance on the last third of the PASAT is compared to performance on the 1st third, a validated measurement of objective CF. Subjective CF was measured by the cognitive component of the Modified Fatigue Impact Scale (MFIS). Additionally, depression, anxiety, information processing speed, and sleep quality data was collected. All assessments took place on the same day. Pearson's r was calculated to examine the relationship among all continuous outcome measures while linear regression analyses were used to examine predictors of subjective and objective CF.

RESULTS

The sample consisted of 53 subjects who were mostly female (37; 69.8%) with a mean age of 44.2 years; the majority (47; 88.7%) had relapsing MS. Objective CF and subjective CF were not significantly related (r = - 0.16). Further, there was no statistically significant predictors of objective CF noted. In contrast, subjective CF demonstrated a statistically significant relationship with the Symbol Digit Modalities Test (SDMT; r = - 0.29, p = .05), Hospital Anxiety and Depression Scale (HADS), depression subscale (r = 0.61, p < .001), HADS anxiety subscale (r = 0.54, p < .001), and sleep quality (r = 0.33, p = .02). Additionally, all variables predicted subjective CF, R²_adj = 0.384 [F (6, 40) = 5.783, p = .0002]. In particular, anxiety significantly predicted subjective CF when controlling for depression, information speed, and sleep quality.

CONCLUSION

This study demonstrated that subjective CF is significantly predicted by anxiety, and strongly influenced by information processing impairment and depression. Addressing underlying affective factors, such as anxiety or depression, may help alleviate perceived or subjective CF among PwMS, thus improving their function and quality of life. Further studies with a larger sample size or longitudinal follow up may help define predictors of objective CF.

Cognitive deficits and clinical symptoms in patients with treatment-refractory obsessive-compulsive disorder: The role of slowness in information processing

Patients with Obsessive-Compulsive Disorder (OCD) present neuropsychological deficits across different cognitive domains, especially in executive functioning and information processing speed. Some studies have even suggested that speed deficits may underlie poor neuropsychological performance. However, this hypothesis remains unanswered in both OCD general population and OCD refractory subgroup. In addition, it is not clear whether such deficits are secondary to the clinical symptoms or may constitute a primary deficit. The aim of this study was to explore the speed of processing hypothesis in treatment-refractory OCD patients, and to clarify to what extent slowness is related to psychopathological symptoms. Both clinical and neuropsychological examination was conducted to assess 39 OCD refractory patients candidates for neurosurgery and 39 healthy matched individuals. Principal component analysis revealed a three-component structure in the neuropsychological battery being used, including a speed of processing, working memory, and conflict monitoring components. Group comparisons revealed that OCD patients performed significantly worse than healthy individuals in speed measures, but no differences were found in executive tests not influenced by time. Correlation analyses revealed a lack of association between neuropsychological and clinical measures. The results suggest that treatment-refractory OCD patients exhibit a primary deficit in information processing speed independent of clinical symptoms.

A Videogame-Based Approach to Measuring Information Processing Speed in Multiple Sclerosis Patients

Objective: Slowing information processing speed (IPS) is a biomarker of neuronal damage in patients with multiple sclerosis (pwMS). A focus on IPS might be the ideal solution in the perspective of promptly detecting cognitive changes over time. We developed a tablet-based home-made videogame to test the sensitivity of this device in measuring subclinical IPS in pwMS. Materials and Methods: Forty-three pwMS without cognitive impairment and 20 healthy controls (HCs) were administered the videogame task with a tablet. Response times (RTs) and accuracy were recorded. Results: PwMS (mean RTs = 505.5 ± 73.9 ms) were significantly slower than HCs (mean RTs = 462.3 ± 40.3 ms, P = 0.014) on the videogame task. A moderate but significant correlation (r = -0.35, P = 0.03) between mean RTs and the Symbol Digit Modalities Test was observed. Conclusion: Our videogame showed good sensitivity in measuring IPS in apparently cognitive normal pwMS. Computerized testing might be useful in screening initial cognitive dysfunction that should be monitored as a marker of underlying disease progression. IRB approval Number is 2332CESC.

Computerized Simple Reaction Time and Balance in Nondemented Parkinson's Patients

BACKGROUND

Parkinson's disease (PD) patients are known to suffer from subtle cognitive and balance deficits from the early stages although they usually manifest in advanced stages. Postural instability (PI) has been correlated with slower information processing speed. Simple reaction time (SRT) tasks can be used to measure the speed of information processing. The main objective of this study was to examine the usefulness of SRT as a valid predictor of balance in PD, thus providing a simple and complementary assessment method.

METHODS

This cross-sectional study included 52 PD patients without dementia who were evaluated for balance using the pull test (PT) maneuver and Biodex® limits of stability (LOS). In addition, a reaction time task was used to measure processing speed. Correlation and linear regression analyses were performed.

RESULTS

The performance of SRT tasks was correlated with the evaluation of LOS% and PT, suggesting that the SRT may be a predictor of balance performance. Longer reaction time and poorer postural stability were also associated with disease duration but not with age.

CONCLUSIONS

Poor performance in a simple reaction task can predict altered PI and can complement staging and evaluation in PD patients.

The Symbol Digit Modalities Test (SDMT) is sensitive but non-specific in MS: Lexical access speed, memory, and information processing speed independently contribute to SDMT performance

BACKGROUND

The Symbol Digit Modalities Test (SDMT) is the most sensitive metric of neurocognitive function in multiple sclerosis (MS), and is consistently interpreted as a measure of information processing speed (IPS).

OBJECTIVE

To evaluate the cognitive psychometric profile captured by the SDMT to identify whether different cognitive processes independently underlie performance.

METHODS

Three samples of MS patients (total n=661; 185 research patients at MS center; 370 clinical patients at MS center; 106 persons with MS from the community) completed objective assessments of neuropsychological function across cognitive domains. Exploratory factor analysis (EFA) was used to derive latent cognitive factor scores, and operationalize cognitive domain composite scores, to understand the unique, shared and redundant contribution of different cognitive domains to SDMT performance using hierarchical multiple regression and commonality analysis.

RESULTS

Across three independent samples we provide converging strong evidence that the cognitive domains of Memory, IPS and Rapid Automatized Naming (lexical access speed) jointly and uniquely contribute to SDMT performance.

CONCLUSION

The SDMT measures multiple cognitive processes, which likely explains the high degree of sensitivity to cognitive change in MS. Researchers and clinicians should interpret the SDMT as a multifarious measure of general cognition rather than a specific test of IPS.

Associations of prenatal exposure to phthalates with measures of cognition in 7.5-month-old infants

BACKGROUND

Phthalates are endocrine disrupting chemicals that have been associated with adverse neurobehavior, but little is known about their influence on infant cognition.

METHODS

A visual recognition memory task was used to assess cognition in 244 7-8-month-old infants (121 females; 123 males) from a prospective cohort study. Phthalate metabolites were quantified in maternal urines pooled from across pregnancy. The task included familiarization trials (infant shown 2 identical faces) and test trials (infant shown the now familiar face paired with a novel one). Half of the infants saw one set of faces as familiar (set 1) and half saw the other set as familiar (set 2). During familiarization trials, average run duration (time looking at stimuli before looking away, measure of processing speed), and time to familiarization (time to reach 20 s looking at the stimuli, measure of attention) were assessed. During test trials, novelty preference (proportion of time looking at the novel face, measure of recognition memory) was assessed. Multivariable generalized linear models were used to assess associations of monoethyl phthalate (MEP), sum of di(2-ethylhexyl) phthalate metabolites (ΣDEHP), sum of di(isononyl) phthalate metabolites (ΣDINP), and sum of anti-androgenic phthalate metabolites (ΣAA) with each outcome.

RESULTS

Mothers were mostly white and college educated, and urine phthalate concentrations were similar to those in reproductive age women in the U.S.

POPULATION

All phthalate exposure biomarkers, except MEP, were associated with increases in average run duration. However, depending on the phthalate, associations were only in males or infants who saw the set 2 stimuli as familiar. Unexpectedly, ΣAA was associated with a shorter time to reach familiarization. Phthalate biomarkers also were associated with modest decrements in novelty preference, but these associations were nonsignificant.

CONCLUSION

Prenatal exposure to phthalates may be related to slower information processing and poorer recognition memory in infants.

Paradoxical effect of cumulative stress exposure on information processing speed in Hispanics/Latinos with elevated heart rate variability

Chronic stress has a deleterious effect on prefrontal lobe functioning. Empirical evidence suggests elevated vagal tone, indexed by elevated heart rate variability (HRV), mitigates the effect of mental stress on frontal lobe function. Here, the mitigating effect of HRV on stress-related decrements in cognitive performance is assessed based on information processing speed (DSST), word fluency and verbal learning task performance. Artifact free electrocardiogram (ECG) data was analyzed from 1420 Hispanic/Latino adults from the Sociocultural Ancillary of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). A 12-lead ECG was used to collect short-term recordings of the root mean square of successive differences in all normal R-peak to R-peak intervals (RMSSD) and the change between adjacent beats and the standard deviation of those intervals (SDNN) as indices of total HRV. As predicted, an interaction emerged for HRV and stress on the task presumed to require the greatest prefrontal lobe involvement, i.e., the DSST. After accounting for sociodemographic factors, chronic stress was associated with better DSST performance amongst individuals at higher quartile of SDNN, but not RMSSD. The paradoxical effect for greater stress exposure on DSST performance may in part be explained by increased speed of information processing and decision making often reported in high-stress cohorts. The nature of this interaction highlights the importance of examining the relationship between stress and cognition across a spectrum of vagal tone.

Cognitive reserve relates to executive functioning in the old-old

Cognitive reserve (CR) is known to reduce or even protect against the negative effects of aging on cognitive functioning. Nonetheless, little is known about how CR influences the relationship between different cognitive abilities and age in the old–old. The goal of the present study was, therefore, to test the hypothesis whether, in the old–old, CR still modifies the relationship between age and cognitive functioning. Eighty-three adults (aged 71–94) without mild cognitive impairment or dementia residing in residential care facilities completed a detailed neuropsychological test battery. CR was estimated using a combination of educational attainment and an estimation of verbal intelligence. Moderation analyses revealed a significant effect for fluency and a trend for flexibility, showing that the negative relationship between age and cognitive performance is reduced as the level of CR increases. These results demonstrate that CR still influences the relationship between age and executive functions in adults of advanced age.

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.

Effect of cognitive rehabilitation on neuropsychological and semiecological testing and on daily cognitive functioning in multiple sclerosis: The REACTIV randomized controlled study

BACKGROUND

Specific cognitive rehabilitation (SCR) has been suggested for multiple sclerosis (MS). A randomized controlled trial (RCT) evaluating the therapeutic effects of SCR is necessary.

OBJECTIVE

To demonstrate the superiority of a SCR program (REACTIV) over nonspecific intervention (NSI) for neuropsychological (NP) assessment, virtual reality (VR) cognitive testing and daily cognitive functioning.

METHODS

A single-blind RCT compared SCR and NSI in patients with MS with cognitive complaint. Both programs included 50 individual sessions, 3 times a week for 17 weeks in a real-world setting. The primary end-point was NP assessment. Secondary end-points included semiecological VR tasks (Urban Daily Cog®) and daily cognitive functioning assessment. Maintenance of the effects at 8 months was studied.

RESULTS

Of the 35 patients, 18 completed the SCR, and 17 completed the NSI. Several NP and semiecological scores improved significantly more after SCR than after NSI. More NP scores improved significantly after SCR than after NSI. SCR improved daily cognitive functioning. Most improvements were maintained at 8 months.

CONCLUSION

SCR performed in a real-world setting is superior to NSI for improving performance in specific cognitive domains and information processing speed, and for improving cognitive functioning, as evaluated by ecological tools close to daily life and a daily cognitive functioning questionnaire.

Visual and motor confounds on the symbol digit modalities test

BACKGROUND

Slowed information processing speed is the most prevalent cognitive symptom in persons with multiple sclerosis (MS). The most commonly used instrument to measure information processing speed in MS is the Symbol Digit Modalities Test (SDMT). However, visual, oculomotor, and oralmotor deficits are frequently observed in persons with MS, and performance on the SDMT relies on these visual and motor functions, in addition to cognition.

METHODS

The current study examined the relationship between the SDMT and the King-Devick Test (KDT). The KDT encompasses similar oculomotor and oralmotor demands as the SDMT but requires a smaller attentional load. One hundred and thirty participants with MS completed the oral version of the SDMT and the KDT. Ordinary nonparametric bootstrapped regression models were performed with 1000 bootstrapped samples. Bootstrapped confidence intervals (CIs) were bias-corrected.

RESULTS

KDT performance explained 31% (bootstrapped CI: 18 - 43%) of the variance of SDMT performance (moderate correlation), much more than demographic and disease-related variables (0.7% and 10%, respectively).

CONCLUSIONS

Visual, oralmotor, and oculomotor functions contributed significantly to SDMT performance. Therefore, these sensory and motor functions must be taken into account when interpreting SDMT scores.

Characterization of performance on an automated visual recognition memory task in 7.5-month-old infants

Infant looking behaviors measured during visual assessment paradigms may be more reliable predictors of long-term cognitive outcomes than standard measures such as the Bayley Scales of Infant Development typically used in environmental epidemiology. Infrared eye tracking technology offers an innovative approach to automate collection and processing of looking behavior data, making it possible to efficiently assess large numbers of infants. The goals of this study were to characterize infant looking behavior measures including side preference, fixation duration, and novelty preference using eye tracking and an automated version of an established visual recognition memory paradigm that includes both human faces and geometric figures as stimuli. An ancillary goal was to assess the feasibility of obtaining a precise measure of looking to the eye region of faces from the eye-tracking data. In this study, 309 7.5-month-old infants from a prospective birth cohort were assessed using a visual recognition memory (VRM) paradigm. Infrared eye tracking was used to record looking time as infants were shown nine blocks of trials with a pair of identical faces or shapes followed by two trials in which the familiar stimulus was paired with a novel one. Infants were assessed in one of four conditions: in conditions A and B, stimulus set 1 were the familiar stimuli and set 2 were novel; in conditions C and D, set 2 were familiar and set 1 novel. The novel stimuli were presented on the right first in conditions A and C and on the left first in conditions B and D. We observed a significant right side preference, which has not been reported before (57% of looking time spent looking at right side stimulus, p-value < 0.0001). Infants showed a preference for the novel stimuli similar to that published in prior studies (57-60% of looking time spent looking at the novel stimulus, p-value < 0.0001), as well as average fixation durations similar to previous studies. Infants also showed a strong preference for the eyes versus the rest of the face (p-value < 0.0001). Novelty preference was significantly higher when set 2 stimuli were novel (p-value < 0.0001), suggesting a preference among infants for set 2 stimuli compared to set 1 stimuli. The pattern of novelty preference across trials was significantly different between infants who saw the novel stimuli on the left first and those who saw them on the right first (p-value < 0.0001) but the overall mean novelty preference was not significantly different between these groups. There were also significant differences in average fixation duration and eyes preference measures across stimuli (p-values < 0.05). These findings show that VRM assessment can be automated for use in large-scale epidemiological studies using infrared eye tracking with looking behavior measure results similar to those obtained with standard non-automated methods, and that side and stimulus preferences are important modifiers of looking behavior that are critical to consider in this type of assessment.

Is obesity associated with impaired reaction time in youth?

BACKGROUND AND PURPOSE

Recent research demonstrates a significant relationship between weight status and impaired reaction time in young, adult, and elderly individuals. However, most such studies were performed on small samples, used only body mass index as the body obesity index, used simple reaction time, and oftentimes did not consider some potential confounders such as age, socioeconomic status, or physical activity in their studies. The present study explored the relationship between various reaction time tasks and various obesity indices in a sample of youth.

METHODS

Two hundred and thirty-four young males (19-24 years) underwent standard anthropometry, various information processing tasks (e.g., clinical reaction time, simple audio and visual reaction time, and choice reaction time), as well as an inhibitory control task (congruent and incongruent Simon reaction time).

RESULTS

Results revealed no significant relationship between any of the information processing tests and body mass index, nor for fat percentage, waist circumference, and waist-to-height ratio after adjustment for potential confounders. A weak positive association was observed only between congruent Simon reaction time (but not incongruent Simon reaction time) and waist circumference in participants (t value = 0.199; Std error = 0.0014; p = 0.047; Cohen's f² = 0.09).

CONCLUSION

Inhibitory control, but not information processing speed, was associated only with waist circumference in apparently healthy young men.

LEVEL OF EVIDENCE

Level I, experimental study.

Cognitive processing speed deficits in multiple sclerosis: Dissociating sensorial and motor processing changes from cognitive processing speed

BACKGROUND

The assessment of cognitive information processing speed (IPS) is complicated in MS, with altered performance on tests such as the Symbol Digit Modalities Test (SDMT) potentially representing changes not only within cognitive networks but in the initial sensorial transmission of information to cognitive networks, and/or efferent transmission of the motor response.

OBJECTIVE

We aimed to isolate and characterise cognitive IPS deficits in MS using ocular motor tasks; a prosaccade task (used to assess and control for sensorial and motor IPS) which was then used to adjust performance on the Simon task (cognitive IPS).

METHODS

All participants (22 MS patients with early disease, 22 healthy controls) completed the ocular motor tasks and the SDMT. The Simon task assessed cognitive IPS by manipulating the relationship between a stimulus location and its associated response direction. Two trial types were interleaved: (1) congruent, where stimulus location = response direction; or (2) incongruent, where stimulus location ≠ response direction. RESULTS MS patients did not perform differently to controls on the SDMT. For OM tasks, when sensorial and motor IPS was controlled, MS patients had significantly slower cognitive IPS (incongruent trials only) and poorer conflict resolution. SDMT performance did not correlate with slower cognitive IPS in MS patients, highlighting the limitation of using SDMT performance to interpret cognitive IPS changes in patients with MS.

CONCLUSION

Cognitive IPS deficits in MS patients are dissociable from changes in other processing stages, manifesting as impaired conflict resolution between automatic and non-automatic processes. Importantly, these results raise concerns about the SDMT as an accurate measure of cognitive IPS in MS.

Neurogenic orthostatic hypotension impairs information processing speed and attention

Neurogenic orthostatic hypotension (NOH) is characterized by a drop in systolic blood pressure (SBP) ≥20 mmHg or diastolic blood pressure (DBP) ≥10 mmHg within three minutes of upright posture. NOH is common in the elderly population. This group of individuals is at an increased risk for deficits in multiple cognitive domains such as information processing speed (IPS) and attention. The objective of the current study was to investigate the change in IPS and attention during head-up tilt (HUT) in patients with NOH compared to controls. Cognitive function was assessed in the supine and HUT positions using the symbol digit modalities test (SDMT) which assesses IPS and the Stroop Test which measures attention. 40 participants completed the study, 20 controls (age 64.50 ± 9.25) and 20 NOH patients (age 69.55 ± 7.43) with associated conditions of Parkinson's disease (n = 11), multiple systems atrophy (n = 3), early Lewy body dementia (n = 1) and idiopathic NOH (n = 5). NOH patients had no difference in IPS between supine (43.20 ± 15.26) and HUT (42.90 ± 14.33; p = .77). Controls had significantly faster IPS in the HUT position (69.90 ± 12.02) compared to supine (63.55 ± 9.96; p < .001). NOH patients had significantly slower IPS in both the supine and HUT position compared to controls (p < .001). Attention in the HUT position was significantly worse in NOH patients (-14.86 ± 8.96) compared to controls (-8.68 ± 7.13; p = .029). During HUT, NOH patients experienced a significant decrease in mean SBP by -64.11 ± 18.96 from baseline, whereas controls only had a mean decrease of -5.69 ± 7.65. It is evident that NOH patients have impaired IPS and attention compared to controls and likely plays an important role in the morbidity of these individuals.

Assessing cognitive performance in radiologically isolated syndrome

BACKGROUND

Radiologically isolated syndrome (RIS) is defined as the occurrence of incidental brain MRI lesions suggestive of multiple sclerosis (MS) in otherwise healthy subjects without any signs or symptoms that could indicate to the disease. We evaluated cognitive performance in a cohort of RIS patients.

METHODS

A retrospective analysis of prospectively collected data from a population-based registry documenting demographic, clinical and imaging data of MS patients followed at our institution. Cognitive performance of subjects diagnosed with RIS according to Okuda's criteria was evaluated. Cognitive assessment was performed using MindStreams Global Assessment Battery to evaluate memory, executive function, visual spatial perception, verbal function, attention, information processing speed and motor skills, and compared to that of age- and education-matched healthy population.

RESULTS

Thirty patients diagnosed with RIS, mean age at first MRI, 34.3 ± 1.9 years, and disease follow up ranging from 1 to 15 years, were included in the study. Eight patients (26.6%) converted to MS within 4.2 ± 1.4 years. Cognitive performance was relatively preserved with a mean global cognitive score of 98.4 ± 1.6 (median, 100), but all cognitive measurements were below the mean performance for age- and education-matched healthy population. Similar to MS patients, information processing speed was the most impaired cognitive function, mean 94.7 ± 2.04, median 94. Cognitive performance did not differ between RIS patients who converted to MS and those who remained with sustained RIS.

CONCLUSIONS

Cognitive performance in RIS subjects was below average for age- and education-matched norms. Information processing speed was the most impaired cognitive test. Cognitive performance of RIS subjects should be followed closely in order to identify any changes that may indicate conversion to MS.

Hemoglobin A1c and 10-year information processing speed in Japanese community dwellers

Background

Hyperglycemia is believed to be a risk factor for cognitive decline, but the longitudinal relationship between hyperglycemia and cognitive decline in the Japanese population is unclear. The present study aimed to clarify the association between blood glucose levels and information processing ability in middle-aged and older adults.

Methods

The subjects were 866 men and 815 women aged 40–79 years not taking medication for diabetes who participated in the first study wave (1997–2000) and then participated at least once in the subsequent six study waves (2000–2012) of the National Institute for Longevity Sciences—Longitudinal Study of Aging, Japan. Hemoglobin A1c (HbA1c) levels were categorized into four groups (< 5.6, 5.6 to < 6.0, 6.0 to < 6.5, ≥ 6.5%), and a mixed-effects model was used to evaluate the effects of the HbA1c level (four groups) on repeated measures of information processing speed. The models also included baseline age, body mass index, ethanol intake, smoking status, educational level, family income, and history of stroke, hypertension, heart disease, and dyslipidemia as covariates.

Results

Mean (standard deviation) HbA1c and follow-up time in participants were 5.2 (0.5) % and 10.0 (3.6) years, respectively. A linear mixed model showed that the main effect of the four HbA1c groups on information processing ability was not significant in either men or women, but the interaction of HbA1c and time with information processing speed in the higher HbA1c level groups (≥ 6.5% group in men, 6.0 to < 6.5% and ≥ 6.5% groups in women) was significant compared to the lower HbA1c level (< 5.6%) group (P < 0.05). When the slope of information processing speed by HbA1c level at baseline was examined, the slope of information processing speed in the higher HbA1c level (≥ 6.5%) group was higher than in the lower HbA1c level (< 5.6%) group, both in men (− 0.31/year) and in women (− 0.30/year), as well as in women with an HbA1c level of 6.0 to < 6.5% (− 0.40/year).

Conclusions

Higher baseline HbA1c was associated with greater subsequent decline in information processing ability in Japanese community dwellers, even with the pre-clinical HbA1c level (6.0 to < 6.5%) in women. The results suggest that good glycemic control or prevention of hyperglycemia may contribute to maintaining information processing ability.

Electronic supplementary material

The online version of this article (10.1186/s12199-019-0778-8) contains supplementary material, which is available to authorized users.

Symbol Digit Modalities Test: A valid clinical trial endpoint for measuring cognition in multiple sclerosis

BACKGROUND

The need for more robust outcomes in multiple sclerosis (MS) clinical trials has been a main priority of the field for decades. Dissatisfaction with existing measures has led to several consensus meetings and initiatives over the past few decades in hopes of defining and gaining acceptance of measures that are valid, reliable, sensitive to change and progression, and most importantly, relevant to those living with MS. The Multiple Sclerosis Outcome Assessments Consortium (MSOAC) was formed for this purpose.

OBJECTIVE

The objective of this paper is to describe the results of the MSOAC plan to obtain qualification for a cognitive performance measure that meets these requirements.

METHODS

Using data from 14 MS disease-modifying registration trials, we completed a comprehensive examination of the psychometric qualities of the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT) with the goal of compiling evidence to support the utilization of one of these measures in future clinical trials.

RESULTS AND CONCLUSION

Consistent with the published literature, the SDMT proved superior to the PASAT. The SDMT should be considered the measure of choice for MS trials in assessing cognitive processing speed.

The subtleties of cognitive decline in multiple sclerosis: an exploratory study using hierarchichal cluster analysis of CANTAB results

Background

It is essential to investigate cognitive deficits in multiple sclerosis (MS) to develop evidence-based cognitive rehabilitation strategies. Here we refined cognitive decline assessment using the automated tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) and hierarchical cluster analysis.

Methods

We searched for groups of distinct cognitive profiles in 35 relapsing-remitting MS outpatients and 32 healthy controls. All individuals participated in an automated assessment (CANTAB) and in a pencil and paper general neuropsychological evaluation.

Results

Hierarchical cluster analysis of the CANTAB results revealed two distinct groups of patients based mainly on the Simple Reaction Time (RTI) and on the Mean Latency of Rapid Visual Processing (RVP). The general neuropsychological assessment did not show any statistically significant differences between the cluster groups. Compared to the healthy control group, all MS outpatients had lower scores for RTI, RVP, paired associate learning, and delayed matching to sample. We also analyzed the associations between CANTAB results and age, education, sex, pharmacological treatment, physical activity, employment status, and the Expanded Disability Status Scale (EDSS). Although limited by the small number of observations, our findings suggest a weak correlation between performance on the CANTAB and age, education, and EDSS scores.

Conclusions

We suggest that the use of selected large-scale automated visuospatial tests from the CANTAB in combination with multivariate statistical analyses may reveal subtle and earlier changes in information processing speed and cognition. This may expand our ability to define the limits between normal and impaired cognition in patients with Multiple Sclerosis.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1141-1) contains supplementary material, which is available to authorized users.

Task-switching abilities in pre-manifest Huntington's disease subjects

INTRODUCTION

Huntington's Disease (HD) cognitive dysfunction occurs before unequivocal motor signs become apparent. The predominant early cognitive abnormal domains may include deficits in psychomotor speed, negative emotion recognition and executive functioning. Our study is aimed to investigate the executive control of cognition in pre-manifest (pre) HD subjects, by means of a task-switching protocol.

METHODS

We recruited 30 pre-HD subjects and 18 age-, sex- and education-matched Healthy Controls (HC). Subjects were assigned to two experimental groups: 15 pre-HD1 with a Total Motor Score (TMS) ≤4 (far from onset) and 15 pre-HD2 with a 5 ≤ TMS≤9 (near to onset and Diagnostic Confidence Level (DCL) still<4). Two different tasks were performed in rapid and random succession, so that the task was either changed from one trial to the next one (switch trials) or repeated (repetition trials). Switch trials are usually slower than repetitions, causing a so-called Switch Cost (SC).

RESULTS

Pre-HD subjects had worse performance than HC in the switch and repetition trials, as indicated by increased SC and reaction times. In particular, pre-HD2 showed impaired switching abilities with reaction times slower than pre-HD1 and HC.

CONCLUSIONS

Our study highlighted a task-switching impairment since HD was still at a pre-manifest stage. Such abnormalities worsen when pre-HD subjects start to show subtle motor manifestations, still nonspecific and insufficient to define the clinical diagnosis of HD (DCL<4). Considering that such abilities have obvious implications for activities of daily living, early cognitive rehabilitation programs addressing such deficits might be useful in the premanifest stage of the disease.

Association between physical fitness and cognitive performance in 19-24 year old males

The present study aimed to explore the association between physical fitness (PF) and cognitive performance in a sample of 19-24 year old males. Two hundred and eleven young males (20.2±1.5 years) participated in the study. Cognitive functioning tasks including information processing speed and inhibitory control were measured in addition to PF and motor fitness components such as aerobic fitness, static strength, explosive strength, agility and speed. Regression analysis showed that after adjustment for potential confounders (e.g. age, socioeconomic status, adiposity and physical activity), aerobic fitness (represented by shorter time in the one-mile run) was positively associated with composite inhibitory control scores (standardized β=0.17; p=0.04) and negatively associated with ∆ Simon (standardized β= -0.21; p=0.04). Explosive strength was negatively associated with composite information processing scores (standardized β= -0.24; P=0.01), and composite inhibitory control scores (standardized β= -0.22; p=0.02). Speed of movement, agility and static strength were not associated with any of the cognitive tests. In conclusion, aerobic fitness and explosive strength but not speed, agility or static strength might be indicators of underlying cognitive functioning tasks in 19-24 year old males.

Affect of APOE on information processing speed in non-demented elderly population: a preliminary structural MRI study

APOE is one of the strongest genetic factors associated with information processing speed (IPS). Herein, we explored the neural substrates underlying APOE-related IPS alteration by measuring lobar distribution of white matter hyperintensities (WMH), cortical grey matter volume (GMV) and thickness. Using the ADNI database, we evaluated 178 cognitively normal elderly individuals including 34 APOE ε2 carriers, 54 APOE ε4 carriers and 90 ε3 homozygotes. IPS was determined using Trail Making Tests (TMT). We quantified lobar distribution of WMH, cortical GM lobar volume, cortical thickness among three groups. Finally, we used Pearson's correlation and general linear models to examine structural MRI markers in relation to IPS. There were significant differences of IPS among groups, with ε4 carriers displaying the worst performance. Across groups, significant differences in frontal and parietal WMH load were observed (the highest in ε4 carriers); however, no significant differences in cortical GMV and thickness were found. Pearson's correlation analysis showed parietal WMH volume was significantly related with IPS, especially in ε4 carriers. Subsequently a general linear model demonstrated that parietal WMH volume, age and the interaction between parietal WMH volume and age, was significantly associated with IPS, even after adjusting total intracranial volume (TIV), gender and vascular risk factors. Disruption of WM structure, rather than atrophy of GM, plays a more critical role in APOE ε4 allele-specific IPS. Moreover, specific WMH loci are closely associated with IPS; increased parietal WMH volume, especially in ε4 carriers, was independently contributed to slower IPS.

Investigation of the CADM2 polymorphism rs17518584 in memory and executive functions measures in a cohort of young healthy individuals

The common polymorphism rs17518584, near the cell adhesion molecule 2 gene (CADM2), was previously identified as playing a role in information processing speed in a genome-wide association study of executive functions and processing speed performed in a cohort of non-demented older adults. In this study, we investigated this polymorphism in a younger population cohort (≤30 years old, median age 19 years), with no known memory or psychiatric disorders, for which we had phenotyped all participants for memory function (n = 514), and a subset of the participants for executive functions (n = 338), using a battery of tests measuring visuo-spatial memory, working memory, verbal memory, and frontal lobe functions (visual scanning, graphomotor speed, and cognitive flexibility). The polymorphism rs17518584 was genotyped by a restriction fragment length polymorphism assay and analysis indicated that the CADM2 polymorphism showed evidence of association with information processing speed as inferred from scores from the Stroop Word, Colour, and Colour-Word Tests (p = 0.005, p = 0.04, and p = 0.028, respectively, in a dominant inheritance model), as well as Trail Making Test Part A (p = 0.005 in an additive model). Significant associations of rs17518584 with scores from other tests of memory subtypes were not detected. The findings of this study provide further support for a role of CADM2 in aspects of cognitive function, in particular reading and information processing speed, and suggest that this role extends to younger individuals.

Reduced caudate volume and cognitive slowing in men at risk of fragile X-associated tremor ataxia syndrome

Fragile X-associated tremor ataxia syndrome is an inherited neurodegenerative disorder caused by premutation expansions (55-200 CGG repeats) of the FMR1 gene. There is accumulating evidence to suggest that early cognitive and brain imaging signs may be observed in some premutation carriers without motor signs of FXTAS, but few studies have examined the relationships between subcortical brain volumes and cognitive performance in this group. This study examined the relationships between caudate volume and select cognitive measures (executive function and information processing speed) in men at risk of developing FXTAS and controls with normal FMR1 alleles (<45 CGG repeats). The results showed that men with premutation alleles performed worse on measures of executive function and information processing speed, and had significantly reduced caudate volume, compared to controls. Smaller caudate volume in the premutation group was associated with slower processing speed. These findings provide preliminary evidence that early reductions in caudate volume may be associated with cognitive slowing in men with the premutation who do not present with cardinal motor signs of FXTAS. If confirmed in future studies with larger PM cohorts, these findings will have important implications for the identification of sensitive measures with potential utility for tracking cognitive decline.

Information processing speed in multiple sclerosis: Relevance of default mode network dynamics

Objective

To explore the added value of dynamic functional connectivity (dFC) of the default mode network (DMN) during resting-state (RS), during an information processing speed (IPS) task, and the within-subject difference between these conditions, on top of conventional brain measures in explaining IPS in people with multiple sclerosis (pwMS).

Methods

In 29 pwMS and 18 healthy controls, IPS was assessed with the Letter Digit Substitution Test and Stroop Card I and combined into an IPS-composite score. White matter (WM), grey matter (GM) and lesion volume were measured using 3 T MRI. WM integrity was assessed with diffusion tensor imaging. During RS and task-state fMRI (i.e. symbol digit modalities task, IPS), stationary functional connectivity (sFC; average connectivity over the entire time series) and dFC (variation in connectivity using a sliding window approach) of the DMN was calculated, as well as the difference between both conditions (i.e. task-state minus RS; ΔsFC-DMN and ΔdFC-DMN). Regression analysis was performed to determine the most important predictors for IPS.

Results

Compared to controls, pwMS performed worse on IPS-composite (p = 0.022), had lower GM volume (p < 0.05) and WM integrity (p < 0.001), but no alterations in sFC and dFC at the group level. In pwMS, 52% of variance in IPS-composite could be predicted by cortical volume (β = 0.49, p = 0.01) and ΔdFC-DMN (β = 0.52, p < 0.01). After adding dFC of the DMN to the model, the explained variance in IPS increased with 26% (p < 0.01).

Conclusion

On top of conventional brain measures, dFC from RS to task-state explains additional variance in IPS. This highlights the potential importance of the DMN to adapt upon cognitive demands to maintain intact IPS in pwMS.

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Problems with information processing speed occur often in multiple sclerosis (MS)

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Dynamics in brain communication can reflect information transfer within the brain

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With fMRI, dynamic communication can be measured, which increases upon task demands

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This increase in dynamics explains information processing speed in MS

Symbol Digit Modalities Test adaptation for Magnetic Resonance Imaging environment: A systematic review and meta-analysis

BACKGROUND

The Symbol Digit Modalities Test (SDMT) is widely used for cognitive evaluation of information processing speed (IPS), required in many cognitive operations. Despite being unspecific for different neurological disorders, it is sensitive to assess impaired performance related to stroke, Parkinson's disease, traumatic brain injury, and multiple sclerosis. However, in addition to evaluate the presence and severity of IPS impairment, it is of interest to determine the localization and integration of brain regions responsible for the functions assessed by the SDMT.

OBJECTIVE

To review the studies that adapted the SDMT to the magnetic resonance environment and obtain the brain areas associated with the performance of the task in healthy subjects with a meta-analysis.

METHODOLOGY

A systematic review was performed using ten studies published between 1990 and 2017, and selected from four databases. All studies included participants of both genders and age between 18 and 50 years, used Functional Magnetic Resonance Imaging (fMRI) and SDMT adaptation and reported brain regions associated with the task. Six of them also reported the region coordinates in a standard space, so they were included in a meta-analysis. Activation Likelihood Estimation algorithm, with significance for p < 0.05 corrected for multiple comparisons, was used to identify areas that are robustly related to the performance of the SDMT.

RESULTS

The areas predominantly reported in the studies of our meta-analysis were regions of the frontoparietal attentional network and occipital cortex, as well as cuneus, precuneus, and cerebellum. Individually all regions that survived the statistical threshold are consistent with what is expected after reviewing prospective studies.

CONCLUSIONS

The present study allowed the identification of brain areas activated during the performance of the SDMT in healthy subjects, and therefore it will help understanding the differences in brain activation by this task in clinical populations. Moreover, it may guide future studies of therapeutic strategies and interventions in those populations.

An examination of sex differences in neurocognition and social cognition in first-episode psychosis

Due to the dearth and conflicting findings of previous research, it is unclear whether males and females with first-episode psychosis (FEP) differ in their neurocognitive and social cognitive abilities. The aims of the current study were to investigate whether: (i) there are sex differences in neurocognition and social cognition among young people with FEP; and (ii) they resemble those observed in age-matched healthy controls. The current study involved secondary analysis of data from a previous study in which a large neurocognitive and social cognitive battery was administered to 146 individuals with FEP and 46 healthy controls aged 15-25 years. Seven two-way between-groups multivariate analysis of variances revealed that FEP participants were impaired relative to controls on all cognitive domains. Only one main effect of sex was found with males, regardless of group, outperforming females on verbal comprehension. A significant interaction effect was found for information processing speed with FEP females outperforming FEP males on the Symbol Digit Modalities Test; however, post-hoc analysis of the mean difference was not significant. Despite few sex differences, the current study highlights that cognitive impairment is a key feature of FEP that should be a treatment target in early intervention.

Do we still need IQ-scores? Misleading interpretations of neurocognitive outcome in pediatric patients with medulloblastoma: a retrospective study

Over the past decades, many studies used global outcome measures like the IQ when reporting cognitive outcome of pediatric brain tumor patients, assuming that intelligence is a singular and homogeneous construct. In contrast, especially in clinical neuropsychology, the assessment and interpretation of distinct neurocognitive domains emerged as standard. By definition, the full scale IQ (FIQ) is a score attempting to measure intelligence. It is established by calculating the average performance of a number of subtests. Therefore, FIQ depends on the subtests that are used and the influence neurocognitive functions have on these performances. Consequently, the present study investigated the impact of neuropsychological domains on the singular "g-factor" concept and analysed the consequences for interpretation of clinical outcome. The sample consisted of 37 pediatric patients with medulloblastoma, assessed 0-3 years after diagnosis with the Wechsler Intelligence Scales. Information processing speed and visuomotor function were measured by the Trailmaking Test, Form A. Our findings indicate that FIQ was considerably impacted by processing speed and visuomotor coordination, which leaded to an underestimation of the general cognitive performance of many patients. One year after diagnosis, when patients showed the largest norm-deviation, this effect seemed to be at its peak. As already recommended in international guidelines, a comprehensive neuropsychological test battery is necessary to fully understand cognitive outcome. If IQ-tests are used, a detailed subtest analysis with respect to the impact of processing speed seems essential. Otherwise patients may be at risk for wrong decision making, especially in educational guidance.

Information processing speed mediates the relationship between white matter and general intelligence in schizophrenia

Several authors have proposed that schizophrenia is the result of impaired connectivity between specific brain regions rather than differences in local brain activity. White matter abnormalities have been suggested as the anatomical substrate for this dysconnectivity hypothesis. Information processing speed may act as a key cognitive resource facilitating higher order cognition by allowing multiple cognitive processes to be simultaneously available. However, there is a lack of established associations between these variables in schizophrenia. We hypothesised that the relationship between white matter and general intelligence would be mediated by processing speed. White matter water diffusion parameters were studied using Tract-based Spatial Statistics and computed within 46 regions-of-interest (ROI). Principal component analysis was conducted on these white matter ROI for fractional anisotropy (FA) and mean diffusivity, and on neurocognitive subtests to extract general factors of white mater structure (gFA, gMD), general intelligence (g) and processing speed (gspeed). There was a positive correlation between g and gFA (r= 0.67, p =0.001) that was partially and significantly mediated by gspeed (56.22% CI: 0.10-0.62). These findings suggest a plausible model of structure-function relations in schizophrenia, whereby white matter structure may provide a neuroanatomical substrate for general intelligence, which is partly supported by speed of information processing.

Slowing of information processing speed without motor slowing in multiple sclerosis observed during two crossing-off tasks

INTRODUCTION

Slowing of information processing speed (IPS) is often considered one of the primary deficits seen in multiple sclerosis (MS). IPS is usually measured by tasks that involve many cognitive functions. The aim of this study was to determine whether similar IPS slowing can also be observed during two simple, timed, psychomotor crossing-off tasks.

METHOD

The Crossing-Off Test (COT), a simple psychomotor task, was performed under two conditions (COT1 corresponded to writing habits, COT2 used horizontal sweeping) in 25 relapsing-remitting MS patients (EDSS 0-1) and 25 healthy controls.

RESULTS

The MS group compared with the control group was impaired on COT1 (P=0.0043) and not on COT2 (P=0.4), and the COT1 performance of MS patients with EDSS 1 was more impaired than those of patients with EDSS 0 (P=0.008).

DISCUSSION/CONCLUSION

These results indicate that only some of the IPS cognitive subcomponents linked with COT1 tasks are initially involved in the slowing of IPS during MS, suggesting that different mechanisms are involved in each tested version of the COT.

Development of a Tablet-based symbol digit modalities test for reliably assessing information processing speed in patients with stroke

PURPOSE

To develop a Tablet-based Symbol Digit Modalities Test (T-SDMT) and to examine the test-retest reliability and concurrent validity of the T-SDMT in patients with stroke.

METHODS

The study had two phases. In the first phase, six experts, nine college students and five outpatients participated in the development and testing of the T-SDMT. In the second phase, 52 outpatients were evaluated twice (2 weeks apart) with the T-SDMT and SDMT to examine the test-retest reliability and concurrent validity of the T-SDMT.

RESULTS

The T-SDMT was developed via expert input and college student/patient feedback. Regarding test-retest reliability, the practise effects of the T-SDMT and SDMT were both trivial (d=0.12) but significant (p≦0.015). The improvement in the T-SDMT (4.7%) was smaller than that in the SDMT (5.6%). The minimal detectable changes (MDC%) of the T-SDMT and SDMT were 6.7 (22.8%) and 10.3 (32.8%), respectively. The T-SDMT and SDMT were highly correlated with each other at the two time points (Pearson's r=0.90-0.91).

CONCLUSIONS

The T-SDMT demonstrated good concurrent validity with the SDMT. Because the T-SDMT had a smaller practise effect and less random measurement error (superior test-retest reliability), it is recommended over the SDMT for assessing information processing speed in patients with stroke. Implications for Rehabilitation The Symbol Digit Modalities Test (SDMT), a common measure of information processing speed, showed a substantial practise effect and considerable random measurement error in patients with stroke. The Tablet-based SDMT (T-SDMT) has been developed to reduce the practise effect and random measurement error of the SDMT in patients with stroke. The T-SDMT had smaller practise effect and random measurement error than the SDMT, which can provide more reliable assessments of information processing speed.

Brain white matter structure and information processing speed in healthy older age

Cognitive decline, especially the slowing of information processing speed, is associated with normal ageing. This decline may be due to brain cortico-cortical disconnection caused by age-related white matter deterioration. We present results from a large, narrow age range cohort of generally healthy, community-dwelling subjects in their seventies who also had their cognitive ability tested in youth (age 11 years). We investigate associations between older age brain white matter structure, several measures of information processing speed and childhood cognitive ability in 581 subjects. Analysis of diffusion tensor MRI data using Tract-based Spatial Statistics (TBSS) showed that all measures of information processing speed, as well as a general speed factor composed from these tests (g_speed), were significantly associated with fractional anisotropy (FA) across the white matter skeleton rather than in specific tracts. Cognitive ability measured at age 11 years was not associated with older age white matter FA, except for the g_speed-independent components of several individual processing speed tests. These results indicate that quicker and more efficient information processing requires global connectivity in older age, and that associations between white matter FA and information processing speed (both individual test scores and g_speed), unlike some other aspects of later life brain structure, are generally not accounted for by cognitive ability measured in youth.

Information processing speed and attention in multiple sclerosis: Reconsidering the Attention Network Test (ANT)

OBJECTIVE

The Attention Network Test (ANT) assesses attention in terms of discrepancies between response times to items that differ in the burden they place on some facet of attention. However, simple arithmetic difference scores commonly used to capture these discrepancies fail to provide adequate control for information processing speed, leading to distorted findings when patient and control groups differ markedly in the speed with which they process and respond to stimulus information. This study examined attention networks in patients with multiple sclerosis (MS) using simple difference scores, proportional scores, and residualized scores that control for processing speed through statistical regression.

METHOD

Patients with relapsing-remitting (N = 20) or secondary progressive (N = 20) MS and healthy controls (N = 40) of similar age, education, and gender completed the ANT.

RESULTS

Substantial differences between patients and controls were found on all measures of processing speed. Patients exhibited difficulties in the executive control network, but only when difference scores were considered. When deficits in information processing speed were adequately controlled using proportional or residualized score, deficits in the alerting network emerged. The effect sizes for these deficits were notably smaller than those for overall information processing speed and were also limited to patients with secondary progressive MS.

CONCLUSIONS

Deficits in processing speed are more prominent in MS than those involving attention, and when the former are properly accounted for, differences in the latter are confined to the alerting network.

Effects of information processing speed on learning, memory, and executive functioning in people living with HIV/AIDS

INTRODUCTION

It is unclear whether or to what degree literacy, aging, and other neurologic abnormalities relate to cognitive deficits among people living with HIV/AIDS in the combined antiretroviral therapy (CART) era. The primary aim of this study was to simultaneously examine the association of age, HIV-associated motor abnormalities, major depressive disorder, and reading level with information processing speed, learning, memory, and executive functions, and to determine whether processing speed mediated any of the relationships between cognitive and noncognitive variables.

METHOD

Participants were 186 racially and ethnically diverse men and women living with HIV/AIDS who underwent comprehensive neurological, neuropsychological, and medical evaluations. Structural equation modeling was utilized to assess the extent to which information processing speed mediated the relationship between age, motor abnormalities, major depressive disorder, and reading level with other cognitive abilities.

RESULTS

Age, motor dysfunction, reading level, and current major depressive disorder were all significantly associated with information processing speed. Information processing speed fully mediated the effects of age on learning, memory, and executive functioning and partially mediated the effect of major depressive disorder on learning and memory. The effect of motor dysfunction on learning and memory was fully mediated by processing speed.

CONCLUSIONS

These findings provide support for information processing speed as a primary deficit, which may account, at least in part, for many of the other cognitive abnormalities recognized in complex HIV/AIDS populations. The association of age and information processing speed may account for HIV/aging synergies in the generation of CART-era cognitive abnormalities.

Short-term, low-dose varenicline administration enhances information processing speed in methamphetamine-dependent users

Long-term, high-dose methamphetamine (METH) use is associated with decrements in neurocognition and, given the association between impaired neurocognition and poorer treatment outcomes in individuals dependent on alcohol and drugs, it is considered to be a neglected area of critical concern. The objective of this study was to determine whether varenicline, a partial agonist at α4β2- and a full agonist at α7-nicotinic acetylcholine receptors, enhances attention/information processing speed, episodic memory, and working memory in non-treatment seeking METH-dependent participants. Twenty-six participants were randomly assigned to receive oral placebo or oral varenicline (titrated up to 1 mg) over 5 days during three separate inpatient phases, and 17 completed each inpatient phase. Participants were predominately male (71%) and Caucasian (71%). Varenicline significantly improved reaction time on the n-back for visual stimuli (F(1,47)=5.369, p=0.025, η2=0.103), and a trend was observed for improvement in reaction time for auditory stimuli (F(1,47)=3.141, p=0.083, η2=0.063). For those study participants whose reaction time was in the lower half of the distribution at baseline, the effect was even more pronounced for auditory (F(1,22)=5.287, p=0.031, η2=0.194) and visual (F(1,22)=11.981, p=0.002, η2=0.353) stimuli relative to placebo. In contrast, varenicline did not modulate mean or maximum span of working memory or performance on tests of episodic memory or attention (p's>0.05). Given the potential importance of this finding, it should be replicated in a larger sample over a longer treatment period with a higher dose of varenicline (2 mg).

TRIAL REGISTRATION

clinicalTrials.gov Identifier NCT01571167.

Stability of intraindividual variability as a marker of neurologic dysfunction in relapsing remitting multiple sclerosis

BACKGROUND

Impairments in information processing speed are common in multiple sclerosis (MS), with affected individuals demonstrating slower responses and more intraindividual variability (IIV) in their performance on timed tasks. Evidence suggesting that IIV provides novel information about cognitive deficits in MS is accumulating; however, little is known about the stability of IIV across multiple assessments. In this study, we investigated IIV in response speed in persons with MS across 6 monthly sessions using the Attention Network Test-Interaction (ANT-I).

METHOD

Individuals with relatively mild relapsing remitting MS and healthy controls completed the ANT-I at 6 monthly intervals. Clinical assessments (Sessions 1 and 6) and conventional magnetic resonance imaging (MRI) studies (Sessions 1-6) were examined for individuals with MS.

RESULTS

The MS group's clinical and neuroimaging measures were stable during the 6-month period. Individuals with MS were slower and more variable in reaction time performance on the ANT-I than were controls. Differences in IIV between groups were maintained across the 6 sessions, with IIV demonstrating less susceptibility to across-session practice effects than mean latency scores.

CONCLUSIONS

IIV provides a stable measure of cognitive performance in mildly affected persons with MS who are clinically and radiologically stable. Further studies exploring its utility as a clinical outcome are warranted.

Evaluation of Visual Information Processing Speed in Depressed People

BACKGROUND

Depression disorders are associated with serious dysfunction and depressive symptoms. Cognitive slowing is a clear symptom observed in all depressed people. PVSAT is a measure of cognitive function that specifically assesses visual information processing speed and flexibility, as well as calculation ability. The aim of the present study was to determine whether the Paced Visual Serial Addition Test (PVSAT) might constitute a useful procedure for assessing cognitive functions in depressive disorder.

METHOD

Twenty - eight depressed patients, together with fourteen healthy control (HC) subjects participated in the study. All participants performed the PVSAT and a set of clinical tasks assessing information processing speed, working memory and executive functions.

RESULTS

Compared with the HCs, the depressed patients were significantly impaired in their performance of the PVSAT. Significant impairment (compared with controls) was also evidenced by only one of the clinical tasks - the symbol coding task, which assesses information processing speed.

CONCLUSION

Our results demonstrate the high sensitivity of the PVSAT to cognitive impairment. However, correlation analyses showed that the main factor explaining the depressed patients PVSAT impairment was cognitive slowing.

Intra-individual variability in information processing speed reflects white matter microstructure in multiple sclerosis

Slowed information processing speed is commonly reported in persons with multiple sclerosis (MS), and is typically investigated using clinical neuropsychological tests, which provide sensitive indices of mean-level information processing speed. However, recent studies have demonstrated that within-person variability or intra-individual variability (IIV) in information processing speed may be a more sensitive indicator of neurologic status than mean-level performance on clinical tests. We evaluated the neural basis of increased IIV in mildly affected relapsing–remitting MS patients by characterizing the relation between IIV (controlling for mean-level performance) and white matter integrity using diffusion tensor imaging (DTI). Twenty women with relapsing–remitting MS and 20 matched control participants completed the Computerized Test of Information Processing (CTIP), from which both mean response time and IIV were calculated. Other clinical measures of information processing speed were also collected. Relations between IIV on the CTIP and DTI metrics of white matter microstructure were evaluated using tract-based spatial statistics. We observed slower and more variable responses on the CTIP in MS patients relative to controls. Significant relations between white matter microstructure and IIV were observed for MS patients. Increased IIV was associated with reduced integrity in more white matter tracts than was slowed information processing speed as measured by either mean CTIP response time or other neuropsychological test scores. Thus, despite the common use of mean-level performance as an index of cognitive dysfunction in MS, IIV may be more sensitive to the overall burden of white matter disease at the microstructural level. Furthermore, our study highlights the potential value of considering within-person fluctuations, in addition to mean-level performance, for uncovering brain–behavior relationships in neurologic disorders with widespread white matter pathology.

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Intra-individual variability (IIV) predicts neurologic status in multiple sclerosis (MS).

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Diffusion tensor imaging (DTI) was used to study the neural correlates of IIV in MS.

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IIV was significantly related to DTI metrics in many white matter regions.

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Compared to mean response speed, IIV may be more sensitive to disease burden in MS.

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Evaluating IIV may be important for characterizing brain–behavior relationships.

General fluid-type intelligence is related to indices of white matter structure in middle-aged and old adults

General fluid-type intelligence (gF) reflects abstract reasoning and problem solving abilities, and is an important predictor for lifetime trajectories of cognition, and physical and mental health. Structural and functional neuroimaging studies have demonstrated the role of parieto-frontal gray matter, but the white matter (WM) underpinnings of gF and the contribution of individual gF components to gF-WM relationship still need to be explored. The aim of this study was to characterize, in a sample of 100 healthy middle-aged and old subjects (mean=63.8 years), the relationship between gF and indices of WM structure obtained from diffusion tensor magnetic resonance imaging (DT-MRI) (fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD)). gF was estimated by principal component analysis including measures of episodic memory, reasoning, and processing speed. Tract-based spatial statistics and permutation-based inference statistics were used to test the association between gF and WM indices, while controlling for the effect of age and sex. We hypothesized a positive relationship between gF and WM structure. Based on previous studies, we further hypothesized that this relationship was heavily influenced by the processing speed component of gF. We found a robust relationship between gF and DT-MRI measures of FA, RD and MD in all major WM tracts. Higher gF score was related to higher degree of WM integrity, in middle-aged as well as old individuals. Thus, the distributed relationship between gF and indices of WM microstructure is consistent with the notion that gF reflects efficient signaling between cortical areas. Furthermore, analysis of relationships between WM measures and gF components revealed an association with information processing speed and reasoning ability, but not with episodic memory. Thus, although all subcomponents loaded high on gF factor, the speed-related components were most strongly associated with DT-MRI-derived measures. These results suggest that DT-MRI can be used to parse gF.

Cognitive change and neuroimaging following immunoablative therapy and hematopoietic stem cell transplantation in multiple sclerosis: A pilot study

BACKGROUND

Individuals with MS undergoing immunoablative therapy and hematopoietic stem cell transplantation (HSCT) show substantial decrease in brain volume over 2.4 months, presumably from chemotoxic effects, although other mechanisms have also been postulated.

OBJECTIVE

We examined whether volume loss was accompanied by a concomitant decrease in cognition. White and gray matter volumes, and the effect of stem cell dosage were considered.

METHODS

Seven individuals with rapidly progressing MS and poor prognosis underwent high dose immunosuppression and autologous HSCT. Neuropsychological testing and MRI scans were performed at baseline, 2 and 24 months post-procedure.

RESULTS

Cognitive impairment was noted at all times in most participants. Median decline of 1.39% in total brain volume was noted 2 months post-HSCT. By 24 months a further decline of 1.65% was noted. At 2 months significant decline was observed for areas of executive functioning. At 24 months almost no significant declines were noted. No significant correlations were found between cognitive decline and change in imaging variables or stem cell dosage.

CONCLUSIONS

Cognition changed in the early period following treatment but with little apparent relationship to volume changes. With temporal distance from the HSCT procedure, cognition returned to baseline levels. With the caution of a very small sample, preliminary results suggest that immunoablation and HSCT may have no lasting deleterious effects on cognition.