What Are the Minimal Detectable Changes in SDMT and Verbal Fluency Tests for Assessing Changes in Cognitive Performance in Persons with Multiple Sclerosis and Non-Multiple Sclerosis Controls?

Test-retest reliability, practice effects and estimates of change: A study on the Mindmore digital cognitive assessment tool

The present study aimed to establish test-retest reliability and investigate practice effects of the Mindmore cognitive assessment tool, a digital adaptation of traditional pencil and paper tests designed for self-administration. Additionally, normative change scores for the most frequently used tests were derived. A total of 149 healthy Swedish adults (aged 20-79) completed the test battery twice, 1 month apart. The battery assessed attention and processing speed, memory, language, visuospatial functions, and executive functions. Test-retest reliability, measured by ICC and Spearman coefficients, and practice effects were estimated for 22 main-scores and 33 sub-scores. Regression models were used to assess change in performance while controlling for demographics, computer equipment, testing location (online or in-laboratory) and baseline performance for 12 main-scores and nine sub-scores. Test-retest reliability was good for 11 main-scores (≥0.70), satisfactory for five (0.60-0.69), and minimal for six (<0.60) albeit three having satisfactory sub-scores. Practice effects were observed for tests with a major speed component, but not for reaction time, sustained attention, verbal memory and naming (alternate forms), nor visuospatial functions. Trackpad negatively influenced change for one test. Demographics and testing location did not significantly affect the change scores. Our study provides support for test-retest reliability and practice effects of the Mindmore cognitive assessment tool which were comparable to those of traditional tests. These findings, together with the normative change scores, can aid researchers and clinicians in interpreting test results and distinguishing between normal variations in performance and changes indicative of clinical impairment.

Assessment of phonemic verbal fluency in Portuguese patients with multiple sclerosis

BACKGROUND

Executive dysfunction occurs in 15% to 20% of multiple sclerosis (MS) patients and verbal fluency tests are frequently used to assess this deficit. The Word List Generation (WLG) is one of the most used measures in MS. This study aims to compare the performance of WLG of MS patients and healthy controls and to analyze the influence of clinical and demographic factors on the performance of MS patients.

METHODS

One hundred and nine MS patients and an age- and gender-matched group of 138 healthy controls were evaluated with WLG Portuguese version, as well as other tests from the Brief Repeatable Battery of Neuropsychological Tests (BRBN-T), subtests from WAIS, a phonemic fluency test (M, R, and P), and measures of psychological symptomatology and cognitive fatigue. The MS group (70.6% females) was mainly diagnosed with RRMS (89.2%).

RESULTS

The MS group performed significantly lower than healthy controls on the WLG. In the MS group, this performance was significantly correlated with the level of education. Significant differences were found between the two groups regarding cognitive fatigue, with MS patients reporting higher levels than healthy controls. However, this variable was not related to the performance on the WLG for MS patients.

CONCLUSIONS

This study suggests that MS is associated with large levels of cognitive decline on the phonemic verbal fluency tests. These results are consistent with other studies and highlight the importance of verbal fluency and cognitive speed measures in the neuropsychological assessment of MS. Deficits on this task seem to be highly related to the level of education of the patient rather than other demographic and clinical factors.

Smartphone-Based Assessment of Mobility and Manual Dexterity in Adult People with Spinal Muscular Atrophy

Background

More responsive, reliable, and clinically valid endpoints of disability are essential to reduce size, duration, and burden of clinical trials in adult persons with spinal muscular atrophy (aPwSMA).

Objective

The aim is to investigate the feasibility of smartphone-based assessments in aPwSMA and provide evidence on the reliability and construct validity of sensor-derived measures (SDMs) of mobility and manual dexterity collected remotely in aPwSMA.

Methods

Data were collected from 59 aPwSMA (23 walkers, 20 sitters and 16 non-sitters) and 30 age-matched healthy controls (HC). SDMs were extracted from five smartphone-based tests capturing mobility and manual dexterity, which were administered in-clinic and remotely in daily life for four weeks. Reliability (Intraclass Correlation Coefficients, ICC) and construct validity (ability to discriminate between HC and aPwSMA and correlations with Revised Upper Limb Module, RULM and Hammersmith Functional Scale - Expanded HFMSE) were quantified for all SDMs.

Results

The smartphone-based assessments proved feasible, with 92.1% average adherence in aPwSMA. The SDMs allowed to reliably assess both mobility and dexterity (ICC > 0.75 for 14/22 SDMs). Twenty-one out of 22 SDMs significantly discriminated between HC and aPwSMA. The highest correlations with the RULM were observed for SDMs from the manual dexterity tests in both non-sitters (Typing, ρ= 0.78) and sitters (Pinching, ρ= 0.75). In walkers, the highest correlation was between mobility tests and HFMSE (5 U-Turns, ρ= 0.79).

Conclusions

This exploratory study provides preliminary evidence for the usability of smartphone-based assessments of mobility and manual dexterity in aPwSMA when deployed remotely in participants' daily life. Reliability and construct validity of SDMs remotely collected in real-life was demonstrated, which is a pre-requisite for their use in longitudinal trials. Additionally, three novel smartphone-based performance outcome assessments were successfully established for aPwSMA. Upon further validation of responsiveness to interventions, this technology holds potential to increase the efficiency of clinical trials in aPwSMA.

Novel and Emerging Treatments to Target Pathophysiological Mechanisms in Various Phenotypes of Multiple Sclerosis

The objective is to comprehensively review novel pharmacotherapies used in multiple sclerosis (MS) and the possibilities they may carry for therapeutic improvement. Specifically, we discuss pathophysiological mechanisms worth targeting in MS, ranging from well known targets, such as autoinflammation and demyelination, to more novel and advanced targets, such as neuroaxonal damage and repair. To set the stage, a brief overview of clinical MS phenotypes is provided, followed by a comprehensive recapitulation of both clinical and paraclinical outcomes available to assess the effectiveness of treatments in achieving these targets. Finally, we discuss various promising novel and emerging treatments, including their respective hypothesized modes of action and currently available evidence from clinical trials. SIGNIFICANCE STATEMENT: This comprehensive review discusses pathophysiological mechanisms worth targeting in multiple sclerosis. Various promising novel and emerging treatments, including their respective hypothesized modes of action and currently available evidence from clinical trials, are reviewed.

Microstructural analysis of verbal fluency performance in relapsing-remitting multiple sclerosis based on the impact of disability level

Verbal fluency (VF) evaluates language and cognitive abilities. This study compared VF in Relapsing-Remitting Multiple Sclerosis (RRMS) and healthy controls (HC), examining variables including correct responses (CR), mean cluster size (MCS), switches (S), and fluency difference score (FDS). RRMS participants were subgrouped by Expanded Disability Status Scale (EDSS), to explore the relationship between MS severity and VF. Twenty-four RRMS participants and matched HCs underwent Mini-Mental State Exam and VF Test. Statistical analysis compared VF between RRMS subgroups based on severity levels, and in HC. RRMS significantly impacted the CR, and S (CRSF p = 0.01, SSF p = 0.002; CRPF=0.002, SPF p = 0.002), while there was no significant difference in FDS between RRMS groups (p = 0.9). No significant relationship was found between EDSS scores, and VF subtests (CRSF p = 0.061, MCSSF p = 0.46, SSF p = 0.051, CRPF p = 0.521, MCSPF p = 0.966, SPF p = 0.599). In RRMS, our results demonstrate impairments in all VF parameters except the MCSSF+PF, and FDS. This study suggests that intact MCSSF+PF may reflect preserved verbal memory and word recall, while significant switching differences may indicate impaired cognitive flexibility. Similar FDS to those of HC suggest that no performance discrepancy in subtests in RRMS. Intact MCS might be a distinctive pattern in the early clinical stage of MS.

A much needed metric: Defining reliable and statistically meaningful change of the oral version Symbol Digit Modalities Test (SDMT)

BACKGROUND

The Symbol Digit Modalities Test (SDMT) has been recommended for use in clinical trials and outcome studies to monitor cognitive change. However, defining what is a meaningful change has been elusive for several years.

OBJECTIVE

The present investigation aimed to develop methods for assessing individual-level statistically significant change on the SDMT - reliable change indices (RCIs) and standardized regression-based (SRB) equations.

METHODS

A total of 219 healthy individuals completed the oral version SDMT at baseline, 6-month and 1-year follow-up.

RESULTS

The SDMT demonstrated high reliability across all time points (r's = 0.83 to 0.86). Reliable change scores of 7, 8, and 10 points for the 6-month intervals represented statistically meaningful change at the 0.70, 0.80, and 0.90 confidence intervals, respectively. Over 1-year, a difference of 8, 10, and 12 was statistically meaningful at the 0.70, 0.80, and 0.90 confidence intervals, respectively. SRB equations are also provided taking into account additional factors found to be predictive of SDMT scores over time.

CONCLUSION

Clinicians frequently denote a decline of 4 points on the SDMT as meaningful. Results in this large normative sample show that higher cut-points are needed to demonstrate statistically significant decline at the individual level. RCIs are provided for 6 month and one year assessment, which is typical in clinical practice and trials. SRB equations are also provided for use when applicable and may provide a more precise assessment of meaningful change.

Semantic fluency and processing speed are reduced in non-cognitively impaired participants with Parkinson's disease

Introduction: Parkinson's disease (PD) is associated with a range of cognitive deficits. Few studies have carefully examined the subtle impacts of PD on cognition among patients who do not meet formal criteria for MCI or dementia. The aim of the current study was thus to describe the impact of PD on cognition in those without cognitive impairment in a well-characterized cohort.Methods: Non-cognitively impaired participants (122 with PD, 122 age- and sex-matched healthy volunteers) underwent extensive cognitive testing. Linear regression analyses compared diagnostic group performance across cognitive measures. For cognitive tasks that were significantly different between groups, additional analyses examined group differences restricting the group inclusion to PD participants with mild motor symptoms or disease duration less than 10 years.Results: Processing speed and semantic verbal fluency were significantly lower in the PD group (B = -3.77, 95% CIs [-5.76 to -1.77], p < .001, and B = -2.02, 95% CIs [-3.12, -0.92], p < .001, respectively), even after excluding those with moderate to severe motor symptoms (B = -2.73, 95% CIs [-4.94 to -0.53], p = .015 and B = -2.11, 95% CIs [-3.32 to -0.91], p < .001, respectively) or longer disease duration (B = -3.89, 95% CIs [-6.14 to -1.63], p < .001 and B = -1.58, 95% CIs [-2.78 to -0.37], p = .010, respectively). Semantic verbal fluency remained significantly negatively associated with PD diagnosis after controlling for processing speed (B = -1.66, 95% CIs [-2.79 to -0.53], p = .004).Conclusions: Subtle decline in specific cognitive domains may be present among people diagnosed with PD but without evidence to support a formal cognitive diagnosis. These results suggest the importance of early awareness of the potential for diminishing aspects of cognition in PD even among those without mild cognitive impairment or dementia.

Validating the walking while talking test to measure motor, cognitive, and dual-task performance in ambulatory individuals with multiple sclerosis

INTRODUCTION

Multiple Sclerosis (MS) is associated with demyelination of the central nervous system that negatively impacts both motor and cognitive function, resulting in difficulty performing simultaneous motor and cognitive tasks, or dual-tasks. Declines in dual-tasking have been linked with falls in MS; thus, dual-task assessment with the Walking While Talking Test (WWTT) is commonly utilized in the clinical setting. However, the validity and minimal detectable change (MDC) of the WWTT has not been established for persons with MS. The primary objective of the study was to establish the WWTT as a valid measure of dual-task function by examining concurrent validity with other motor, cognitive and dual-task measures, and to establish the MDC for both the simple and complex conditions of the WWTT.

METHODS

In a single visit, 38 adults (34 female, mean (SD) age 49.8(±9.1), Patient Determined Disease Steps (PDDS) mean 3, range 1-6) completed the WWTT simple (walk while reciting the alphabet) and complex (walk while reciting every other letter of the alphabet) conditions as well as a battery of cognitive and motor tests. Spearman correlations were used to examine concurrent validity. The sample was divided into low and high disability groups to determine the impact of disability severity on relationships among WWTT and cognitive and motor function.

RESULTS

Excellent concurrent validity (r ≥ 0.79; p < 0.001) was observed for the WWTT simple and complex with both motor (Timed Up-and-Go, Timed 25-Foot Walk, forward and backward walking velocity, Six-Spot Step Test) and dual-task measures (Timed Up-and-Go Cognitive). The WWTT-simple demonstrated moderate concurrent validity with measures of processing speed (Symbol Digit Modalities Test, p = 0.041) and was related to all motor and dual-task measures across disability levels. The WWTT complex was only related to complex motor tasks in the low disability group. Within the low disability group, WWTT was associated with processing speed (p = 0.045) and working memory (California Verbal Learning Test, p = 0.012). The MDC values were established for WWTT simple (6.9 s) and complex (8 s) conditions.

DISCUSSION

The WWTT is a quick, easy-to-administer clinical measure that captures both motor and cognitive aspects of performance for persons with MS. Clinicians should consider adding the WWTT to the evaluation of persons with MS to examine dual-task performance.