Extending Normative Data of the Paced Auditory Serial Addition Test to Account for Preliminary Psychometric Properties among Elderly Individuals in Taiwan

OBJECTIVE

The Paced Auditory Serial Addition Test (PASAT) is widely used to assess cognitive performance in clinical settings. However, availability of normative data for Revised Version of PASAT (PASAT-R) is often constrained by sample size among elderly individuals. In this study, we sought to establish normative data for PASAT-R for elderly individuals in Taiwan.

METHODS

This study recruited 166 individuals aged over 65 years stratified in accordance with the general population in terms of demographic characteristics, including age, educational level, and sex. We assessed PASAT-R test results in terms of psychometric properties.

RESULTS

PASAT-R demonstrated good internal consistency and test-retest reliability. Performance on PASAT-R was correlated with performance on the criterion tests. Performance on PASAT-R was negatively correlated with age and positively correlated with educational level. This study provides normative data for PASAT-R for elderly Taiwanese individuals.

CONCLUSIONS

PASAT-R is applicable to neuropsychological assessment among elderly Taiwanese individuals.

Separating EEG correlates of stress: Cognitive effort, time pressure, and social-evaluative threat

The prefrontal cortex is a key player in stress response regulation. Electroencephalographic (EEG) responses, such as a decrease in frontal alpha and an increase in frontal beta power, have been proposed to reflect stress-related brain activity. However, the stress response is likely composed of different parts such as cognitive effort, time pressure, and social-evaluative threat, which have not been distinguished in previous studies. This distinction, however, is crucial if we aim to establish reliable tools for early detection of stress-related conditions and monitoring of stress responses throughout treatment. This randomized cross-over study (N = 38) aimed to disentangle EEG correlates of stress. With linear mixed models accounting for missing values in some conditions, we found a decrease in frontal alpha and increase in beta power when performing the Paced Auditory Serial Addition Test (PASAT; cognitive effort; n = 32) compared to resting state (n = 33). No change in EEG power was found when the PASAT was performed under time pressure (n = 29) or when adding social-evaluative threat (video camera; n = 29). These findings suggest that frontal EEG power can discriminate stress from resting state but not more fine-grained differences of the stress response.

Monitoring cognitive change in multiple sclerosis using a computerized cognitive battery

Background

Cognitive monitoring that can detect short-term change in multiple sclerosis is challenging. Computerized cognitive batteries such as the CogState Brief Battery can rapidly assess commonly affected cognitive domains.

Objectives

The purpose of this study was to establish the acceptability and sensitivity of the CogState Brief Battery in multiple sclerosis patients compared to controls. We compared the sensitivity of the CogState Brief Battery to that of the Paced Auditory Serial Addition Test over 12 months.

Methods

Demographics, Expanded Disability Status Scale scores, depression and anxiety scores were compared with CogState Brief Battery and Paced Auditory Serial Addition Test performances of 51 patients with relapsing-remitting multiple sclerosis, 19 with secondary progressive multiple sclerosis and 40 healthy controls. Longitudinal data in 37 relapsing-remitting multiple sclerosis patients were evaluated using linear mixed models.

Results

Both the CogState Brief Battery and the Paced Auditory Serial Addition Test discriminated between multiple sclerosis and healthy controls at baseline (p<0.001). CogState Brief Battery tasks were more acceptable and caused less anxiety than the Paced Auditory Serial Addition Test (p<0.001). In relapsing-remitting multiple sclerosis patients, reaction time slowed over 12 months (p<0.001) for the CogState Brief Battery Detection (mean change -34.23 ms) and Identification (-25.31 ms) tasks. Paced Auditory Serial Addition Test scores did not change over this time.

Conclusions

The CogState Brief Battery is highly acceptable and better able to detect cognitive change than the Paced Auditory Serial Addition Test. The CogState Brief Battery could potentially be used as a practical cognitive monitoring tool in the multiple sclerosis clinic setting.

Cognitive functioning following one-year natalizumab treatment: A non-randomized clinical trial

OBJECTIVES

Cognitive impairment is common in multiple sclerosis (MS) and can have serious impact on social and occupational functioning. Natalizumab reduces relapse rates, magnetic resonance imaging (MRI) lesions, and progression of disability. Previous studies on cognitive functioning have not based inclusion on cognitive performance criteria. The aim of the present study was to determine any potential natalizumab-related cognitive effects on MS patients performing below normal limits on neuropsychological testing.

MATERIALS AND METHODS

Patients starting natalizumab (n = 21) and a quasi-control group of stable MS patients (n = 13) on first line disease modifying treatment were included following neuropsychological assessment demonstrating subnormal cognitive performance. Assessment, using ten cognitive variables, was repeated after 12 months. Symptoms of fatigue, anxiety and depression were also examined. Raw scores on the cognitive tests were transformed into Z-scores based on published age-corrected normative data.

RESULTS

Between-group analyses on difference Z-scores (baseline - follow-up) yielded significant results on Paced Auditory Serial Addition Test-2 (PASAT-2) (P = .008), with the natalizumab group showing larger improvement than quasi control patients. On PASAT-2, 28,5% from the natalizumab group demonstrated >1 SD improvement, indicative of clinically meaningful change, compared with none in the quasi control group. Patients receiving natalizumab showed within-group improvements on six of the ten cognitive variables. There were no group differences in symptoms of fatigue, anxiety or depression.

CONCLUSIONS

The results demonstrate improvement in information processing speed following 12-months of natalizumab treatment. The results are interpreted as reflection of anti-inflammatory properties of natalizumab rather than retest- or long-term restorative effects.

The paced auditory serial addition test for working memory assessment: Psychometric properties

Background: The paced auditory serial addition test (PASAT) was primarily developed to assess the effects of traumatic brain injury on cognitive functioning. Working memory (WM) is one of the most important aspects of cognitive function, and WM impairment is one of the clinically remarkable signs of aphasia. To develop the Persian version of PASAT, an initial version was used in individuals with aphasia (IWA).

Methods: In this study, 25 individuals with aphasia (29-60 years) and 85 controls (18-60 years) were included. PASAT was presented in the form of recorded 61 single-digit numbers (1 to 9). The participants repeatedly added the 2 recent digits. The psychometric properties of PASAT including convergent validity (using the digit memory span tasks), divergent validity (using results in the control group and IWA group), and face validity were investigated. Test-retest reliability was considered as well.

Results: The relationship between the PASAT and digit memory span tests was moderate to strong in the control group (forward digit memory span test: r= 0.52, p< 0.0001; backward digit memory span test: r = 0.48, p< 0.0001). A strong relationship was found in IWA (forward digit memory span test: r= 0.72, p< 0.0001; backward digit memory span test: r= 0.53, p= 0.006). Also, strong testretest reliability (intraclass correlation= 0.95, p< 0.0001) was observed.

Conclusion: According to our results, the PASAT is a valid and reliable test to assess working memory, particularly in IWA. It could be used as a feasible tool for clinical and research applications.

Cognitive functions over the course of 1 year in multiple sclerosis patients treated with disease modifying therapies

OBJECTIVES

Disease-modifying therapies (DMTs) are applied to delay or prevent disease progression in multiple sclerosis (MS). While this has mostly been proven for physical symptoms, available studies regarding long-term effects of DMTs on cognitive functions are rare and sometimes inconsistent due to methodological shortcomings. Particularly in the case of fingolimod, comprehensive data on cognitive functions are not yet available. Therefore, we set out to reliably assess cognitive functions in patients with relapsing-remitting MS (RRMS) treated with DMTs over 1 year.

METHODS

Cognitive functions were assessed with eight tests at three timepoints: baseline, 6-month follow up and 12-month follow up. First, we investigated whether the stability of cognitive functions (i.e. not falling below the 5% cut-off in more than one test) over 1 year in RRMS patients (n = 41) corresponds to the stability in healthy individuals (n = 40) of a previous study. Second, we compared the percentage of declined and improved patients in the different tests. Third, we compared patients treated with fingolimod (n = 22) with patients treated with natalizumab (n = 11) with regard to cognitive stability. Fourth, based on the patient data, the Reliable Change Index was applied to compute cut-offs for reliable cognitive change.

RESULTS

Approximately 75% of RRMS patients treated with DMTs remained stable over the course of 1 year. The Paced Auditory Serial Addition Test (PASAT) and the Spatial Recall Test (SPART), produced improvements in 12.5% and 30.6%, respectively, probably due to practice effects. Patients treated with fingolimod did not differ from patients treated with natalizumab with regard to cognitive stability.

CONCLUSIONS

Cognitive functions remain relatively stable under DMT treatment over 1 year, irrespective of the type of medication. Furthermore, the tests PASAT and SPART should be interpreted cautiously in studies examining performance changes over time. The provided RCI norms may help clinicians to determine whether a difference in two measurements observed in a RRMS patient is reliable.

Including a subject-paced trial may make the PASAT more acceptable for MS patients

The Paced Auditory Serial Addition Test (PASAT) is regularly used in the evaluation of cognition in multiple sclerosis (MS). However, the test may impose frustration, distress, and anxiety in patients, which may result in refusal to participate by many patients.

OBJECTIVES

In this study, a subject- and experimenter-paced PASAT was compared and analyzed, with regard to independent measures of cognitive functions, as well as disability, fatigue, depression, and anxiety.

METHODS

A population-based sample of patients with MS (n = 34; mean age 47.2 ± 8.6) was examined with the PASAT, including a subject-paced condition, in addition to the standard experimenter-paced conditions using three levels of interstimuli intervals (ISI: 3.0, 2.5, and 2.0 s). A comprehensive set of neuropsychological tests, measures of disease severity, fatigue, anxiety, and depression were studied as potentially associated factors.

RESULTS

Subject- and experimenter-paced PASAT performance correlated significantly and the subject-paced administration correlated even higher with measures of information processing speed, executive function, attention, and working memory than standard experimenter-paced administration of PASAT.

DISCUSSION

The associations between PASAT performance and measures of fatigue, anxiety, and depression were not significant.

CONCLUSION

The results indicate that the altered PASAT procedure measures the same cognitive functions in MS as the standard procedure. At the same time, the altered procedure may make the PASAT more user-friendly for patients with MS.

Performance on Paced Auditory Serial Addition Test and cerebral blood flow in multiple sclerosis

BACKGROUND

To assess the relationship between performance on the Paced Auditory Serial Addition Test (PASAT) and both cerebral blood flow (CBF) and axonal metabolic integrity in normal appearing white matter (NAWM) of the centrum semiovale in patients with multiple sclerosis (MS).

METHODS

Normal appearing white matter of the centrum semiovale was investigated with magnetic resonance (MR) imaging in 28 non-depressed individuals (18 patients with MS and 10 healthy controls). CBF was assessed with pseudo-continuous arterial spin labeling. N-acetylacetate/creatine (NAA/Cr) ratios (a metabolic axonal marker) were measured using (1) H-MR spectroscopy. CBF was also measured in frontoparietal cortices and cerebellar hemispheres.

RESULTS

In subjects with MS, we found a positive correlation between performance on the PASAT and CBF to the left centrum semiovale (P = 0.008), but not with the NAA/Cr ratio. There were no correlations between PASAT scores and CBF to the right centrum semiovale, frontoparietal cortices, and cerebellar hemispheres. There was no correlation between PASAT scores and NAA/Cr ratios.

CONCLUSIONS

Our preliminary results suggest that performance on the PASAT in subjects with MS correlates with CBF to the left centrum semiovale, which contains left frontoparietal white matter association tracts involved in information processing speed and working memory.

Multitasking in multiple sclerosis: can it inform vocational functioning?

OBJECTIVE

To examine associations between multitasking ability defined by performance on a complex task integrating multiple cognitive domains and vocational functioning in multiple sclerosis (MS).

DESIGN

Survey data collection.

SETTING

Laboratory with referrals from an outpatient clinic.

PARTICIPANTS

Community-dwelling individuals with MS (N=30) referred between October 2011 and June 2012.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The modified Six Elements Test (SET) to measure multitasking ability, Fatigue Severity Scale to measure fatigue, several neuropsychological measures of executive functioning, and vocational status.

RESULTS

Among the sample, 60% of individuals have reduced their work hours because of MS symptoms (cutback employment group) and 40% had maintained their work hours. Among both groups, SET performance was significantly associated with performance on several measures of neuropsychological functioning. Individuals in the cutback employment group demonstrated significantly worse overall performance on the SET (P=.041). Logistic regression was used to evaluate associations between SET performance and vocational status, while accounting for neuropsychological performance and fatigue. The overall model was significant (χ(2)3=8.65, P=.032), with fatigue [Exp(B)=.83, P=.01] and multitasking ability [Exp(B)=.60, P=.043] retained as significant predictors.

CONCLUSIONS

Multitasking ability may play an important role in performance at work for individuals with MS. Given that multitasking was associated with vocational functioning, future efforts should assess the usefulness of incorporating multitasking ability into rehabilitation planning.

Cognitive processing speed is related to fall frequency in older adults with multiple sclerosis

OBJECTIVE

To examine mobility, balance, fall risk, and cognition in older adults with multiple sclerosis (MS) as a function of fall frequency.

DESIGN

Retrospective, cross-sectional design.

SETTING

University research laboratory.

PARTICIPANTS

Community-dwelling persons with MS (N=27) aged between 50 and 75 years were divided into 2 groups-single-time (n=11) and recurrent (n=16; >2 falls/12 mo) fallers-on the basis of fall history.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Mobility was assessed using a variety of measures including Multiple Sclerosis Walking Scale-12, walking speed (Timed 25-Foot Walk test), endurance (6-Minute Walk test), and functional mobility (Timed Up and Go test). Balance was assessed with the Berg Balance Scale, posturography, and self-reported balance confidence. Fall risk was assessed with the Physiological Profile Assessment. Cognitive processing speed was quantified with the Symbol Digit Modalities Test and the Paced Auditory Serial Addition Test.

RESULTS

Recurrent fallers had slower cognitive processing speed than single-time fallers (P ≤.01). There was no difference in mobility, balance, or fall risk between recurrent and single-time fallers (P>.05).

CONCLUSIONS

Results indicated that cognitive processing speed is associated with fall frequency and may have implications for fall prevention strategies targeting recurrent fallers with MS.