Validation of the Brazilian version of the patient-determined disease steps scale in persons with multiple sclerosis

Validation of the Patient-Determined Disease Steps in ambulatory older adults with multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is increasingly prevalent among older adults, and this results in the cumulative effects of aging and MS on mobility disability. The Patient-Determined Disease Steps (PDDS) is a patient-reported outcome measure of mobility disability in adults with MS, but its validity has not been established in older adults. This study validated the PDDS in older adults with MS by examining correlations with conceptually-relevant objective and subjective measures, including neuroimaging markers.

METHODS

The sample included older adults with MS (N = 87, mean age = 64.67 ± 4.24yrs, percent female = 65.5). Primary outcome measures for validation included the Timed 25-foot Walk (T25FW), Short Physical Performance Battery (SPPB), University of Alabama at Birmingham Life-Space-Assessment scale (UAB-LSA), Nine-Hole Peg Test (9HPT), oral Symbol-Digit Modalities Test (Oral SDMT), and Fatigue Severity Scale (FSS). Structural measures of brain integrity, evaluated via 3T MRI, included grey matter volumes (thalamus, caudate, putamen, globus pallidus, hippocampus), and total white matter lesion load (WMLL). Spearman correlations were used for analyses based on non-normality of the data.

RESULTS

Higher PDDS scores were significantly correlated with slower walking speed (T25FW time: ρ= 0.664, p < .001), worse lower extremity functioning (SPPB: ρ= -0.540, p < .001), poor fine motor dexterity (9HPT time) bilaterally (dominant hand: ρ= 0.367, p < .001; non-dominant hand: ρ= 0.263, p= .014), worse fatigue (FSS: ρ= 0.383, p < .001), and lower community mobility (UAB-LSA: ρ= -0.586, p < .001). Higher PDDS scores were also associated with lower grey matter volume in the caudate (ρ= -0.218, p= .042), putamen (ρ= -0.226, p= .036), and hippocampus (ρ= -0.213, p= .047). There were no significant correlations with WMLL, Oral SDMT, or socio-demographic covariates.

CONCLUSION

The PDDS is a valid self-report measure of MS-related disability in ambulatory older adults with MS.

Perceived physical and mental fatigability in older adults with and without multiple sclerosis

BACKGROUND

Fatigue stands out as a prevalent and debilitating symptom in both Multiple Sclerosis (MS) and the aging population. Traditional methods for measuring perceived fatigue may not adequately account for individual activity differences, leading to varied prevalence rates. Perceived fatigability anchors fatigue to specific activities with predetermined intensity and duration, thereby mitigating self-pacing bias. Despite its potential, perceived fatigability is poorly understood in older adults, particularly those with neurological conditions, including MS. This study thus aimed to (1) investigate whether, among older adults, MS was associated with worse perceived physical and mental fatigability; (2) evaluate whether, among older adults with MS (OAMS), greater patient-reported disease-related disability was associated with worse perceived physical and mental fatigability.

METHODS

Participants were 96 older adults with a physician-confirmed diagnosis of MS (mean age: 64.6 ± 4.2) and 110 healthy controls (mean age: 68.2 ± 7.2), all confirmed to be dementia-free through established case conference procedures. Physical and mental fatigability were measured using the Pittsburgh Fatigability Scale, a 10-item questionnaire (score range: 0 to 50) designed to assess fatigue levels that individuals expect to feel after engaging in a range of typical activities for older adults. MS disease-related disability was assessed with the Patient Determined Disease Steps scale, which ranges from 0 (normal) to 8 (bedridden), with scores ≥ 2 indicating worse MS-related disability after a median split. Separate linear regression models were performed to investigate associations between group status (MS vs. Control) as the predictor and perceived physical and mental fatigability scores as the outcome variables. Within the MS group, additional linear regression models were performed to explore the relationship between disease-related disability and fatigability levels. All models adjusted for age, sex, race, education, global health, general cognitive function, and depressive symptoms levels.

RESULTS

The fully adjusted models yielded the following key findings: OAMS reported significantly higher levels of perceived physical fatigability (M = 25.11 ± 9.67) compared to controls (M = 17.95 ± 8.35) (p = 0.003). Similarly, the perceived mental fatigability in OAMS (M = 16.82 ± 11.79) was significantly greater than that in controls (M = 9.15 ± 7.12) (p = 0.003). Within the MS group, individuals with greater disease-related disability reported significantly greater levels of both physical (M = 30.13 ± 7.71 vs. 18.67 ± 8.00, p < 0.001) and mental fatigability (M = 20.31 ± 12.18 vs. 12.33 ± 9.69, p = 0.009) compared to those with lower MS-related disability. Of note, the significance of these findings persisted in models that adjusted for depressive symptoms.

CONCLUSION

Our study provides compelling evidence that OAMS exhibit significantly higher perceived physical and mental fatigability compared to healthy controls. Additionally, worse MS-related disability correlates with worse physical and mental fatigability. These results persist after adjusting for confounders including depressive symptoms. Our findings underscore the necessity of holistic management strategies that cater to both physical and psychological aspects of MS, laying a foundation for future studies to uncover the pathophysiological mechanisms of fatigability in older adults with and without MS.

The Patient-Determined Disease Steps scale is not interchangeable with the Expanded Disease Status Scale in mild to moderate multiple sclerosis

BACKGROUND AND PURPOSE

The validity, reliability, and longitudinal performance of the Patient-Determined Disease Steps (PDDS) scale is unknown in people with multiple sclerosis (MS) with mild to moderate disability. We aimed to examine the psychometric properties and longitudinal performance of the PDDS.

METHODS

We included relapsing-remitting MS patients with an Expanded Disability Status Scale (EDSS) score of less than 4. Validity and test-retest reliability was examined. Longitudinal data were analysed with mixed-effect modelling and Cohen's kappa for concordance in confirmed disability progression (CDP).

RESULTS

We recruited a total of 1093 participants, of whom 904 had complete baseline data. The baseline correlation between PDDS and EDSS was weak (ρ = 0.45, p < 0.001). PDDS had stronger correlations with patient-reported outcomes (PROs). Conversely, EDSS had stronger correlations with age, disease duration, Kurtzke's functional systems and processing speed test. PDDS test-retest reliability was good to excellent (concordance correlation coefficient = 0.73-0.89). Longitudinally, PDDS was associated with EDSS, age and depression. A higher EDSS score was associated with greater PDSS progression. The magnitude of these associations was small. There was no concordance in CDP as assessed by PDDS and EDSS.

CONCLUSION

The PDDS has greater correlation with other PROs but less correlation with other MS-related outcome measures compared to the EDSS. There was little correlation between PDDS and EDSS longitudinally. Our findings suggest that the PDDS scale is not interchangeable with the EDSS.

Age-related differences in the severity of sexual dysfunction symptoms and psychological distress in individuals with multiple sclerosis

BACKGROUND

Sexual dysfunction (SD) is a common symptom for many with multiple sclerosis (MS). However, SD research in general appears to often overlook young adults within their samples, which can be a major issue for better understanding and treatment for the MS population. Few studies have compared age-related differences in distress in response to physical disability. Research has also found that many people diagnosed with MS do not discuss any SD struggles with their providers. The present study hopes to see whether age-related differences exist in the reporting of the levels of primary, secondary, and tertiary SD, as defined by subscale scores of the Multiple Sclerosis Intimacy and Sexuality Questionnaire-19 (MSISQ-19), and amount of distress, as defined by the 12-Item Short Form Health Survey (SF-12)'s Mental Component Summary (MCS-12). Additionally, we hope to determine if there are any age-related or sex-related differences in help-seeking behaviors for SD.

METHODS

Study participants were recruited from the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry. Participants completed the MSISQ-19, SF-12, and Patient Determined Disease Steps (PDDS), provided demographic information, and responded if they received medical or psychological treatment for SD. Study participants were 5815 respondents (Mage = 51 years, SD = 9.63, 75 % female, 30 % having attained a high school diploma, 35 % scoring "advanced disability" on the PDDS). Young adult (19-39 years), middle adult (40-64 years), and mature adult (65-older) were compared on SD.

RESULTS

Linear mixed effects modeling revealed that the MSISQ-19 subscale scores were significantly predicted by secondary SD (t = 2.48, p < .13). Young adult participants had the lowest primary SD (M = 13.87, 95 % CI [13.13, 14.61]) when compared to mature adult (M = 14.12, 95 % CI [13.27, 14.97]) and middle adult participants (M = 14.44, 95 % CI [14.21, 14.66]), though none were statistically significant. Mature adults had the lowest secondary SD (M = 16.50, 95 % CI [15.65, 17.35]), a statistically significant difference from the middle adults (M = 18.20, 95 % CI [17.97, 18.42]) and young adults (M = 18.91, 95 % CI [18.17, 19.65]). Mature adults had the lowest tertiary symptoms (M = 10.12, 95 % CI [9.27, 10.96]), followed by young adults (M = 12.23, 95 % CI [11.48, 12.97]), and middle adults (M = 11.65, 95 % CI [11.43, 11.88]), though none were statistically significant. Hierarchical multiple regressions found that age had the most significant impact on SD. When SF-12 MCS-12 was added, linear mixed effects did not reveal any statistically significant results between the age groups and SD levels. In contrast, hierarchical multiple regressions found that SF-12 MCS-12 scores had the most significant impact on SD. There were significant age-related and sex-related differences in help-seeking behaviors in those who sought psychological counseling as opposed to medical treatment for SD.

CONCLUSION

Our study has highlighted the importance of clinicians assessing for SD and psychological distress within their patients and to consider potential differences in symptom presentations of age groups to better address their unique needs.

A Systematic Review of the Validity and Reliability of the Patient-Determined Disease Steps Scale

BACKGROUND

The Patient-Determined Disease Steps (PDDS) scale is a patient-reported measure of disability used by at least 3 North American multiple sclerosis (MS) registries. We conducted a systematic review of the psychometric properties of the PDDS scale as part of a harmonization effort related to disability measures used in MS registries.

METHODS

We searched the EMBASE, Ovid Medline, Scopus, Cochrane Database of Systematic Reviews, CENTRAL, CINAHL Plus, and ClinicalTrials.gov databases from database inception through July 28, 2020. Two reviewers independently screened abstracts and full-text reports for study inclusion and data extraction and assessed study quality and risk of bias. We included studies that assessed the validity or reliability of the PDDS scale. We conducted a meta-analysis to quantitatively summarize the findings.

RESULTS

From the 2476 abstracts screened, 234 articles underwent full-text review, of which 5 met the inclusion criteria. These studies assessed criterion validity, construct validity, and test-retest reliability. In all studies, criterion validity was assessed by correlating the PDDS scale score with the Expanded Disability Status Scale score (pooled r = 0.73; 95% CI, 0.66-0.79). Test-retest reliability was high (pooled intraclass correlation coefficient = 0.96; 95% CI, 0.92-0.99).

CONCLUSIONS

In this systematic review, the PDDS scale demonstrated criterion and construct validity for assessing disability in individuals with MS who have mild to moderate disabilities. This review also supports the test-retest reliability of the PDDS scale, although further studies with larger samples are needed.

Is BDNF related to spatial-temporal gait parameters in people with multiple sclerosis? An observational study

BACKGROUND

It has been suggested that the protein Brain-derived Neurotrophic Factor (BDNF) plays a neuroprotective role in people with multiple sclerosis (pwMS). Also, BDNF seems to play a role in cognition performance. In the same line, gait in pwMS requires a higher cognitive resource, mainly during complex walking. Thus, maybe BDNF could be related to gait in pwMS.

OBJECTIVE

To investigate the relationship between BDNF and gait spatial-temporal parameters during unobstructed and obstructed conditions and the Timed Up and Go (TUG) in pwMS and healthy controls (HC).

METHODS

The study included 20 pwMS (11F/9M, 33.1±7.5 years, Expanded Disability Status Scale- EDSS 2.2±1.2) and 18 HC (13F/5M, 35.5±5.9 years). Both groups performed 20 gait attempts in two conditions: unobstructed walking (10 trials) and avoiding an obstacle. The obstacle was 15 cm in height and made of foam material. The BDNF serum concentration was collected with participants in fasting and completed before the clinical, gait, and mobility assessments. Clinical variables included the Symbol Digit Modality Test (SDMT), the Fatigue Severity Scale (FSS), and the International Physical Activity Questionnaire (IPAQ- short version). Associations between BDNF and spatial-temporal gait parameters, clinical variables, and TUG were determined by Pearson/Spearman correlations with Bonferroni's correction being applied (p<0.0013). Gait was compared by a two-way, repeated-measures ANOVA (group and condition) to characterize our cohort.

RESULTS

Reduced BDNF was observed for pwMS (41.66±4.45 ng/ml) in comparison with HC (61.67±7.07, p<0.001). However, although some correlations presented a moderate correlation between BDNF with gait variables, the correlations didn't reach a significant p-value after Bonferroni's correction. Lastly, pwMS presented shorter step length and slower step velocity for both gait conditions, with more evidence for obstacle conditions. Only pwMS changed gait behavior from unobstructed walking to obstacle avoidance conditions (i.e., reduced step length and velocity and increased step duration).

CONCLUSION

BDNF is not related to either clinical (i.e., EDSS, SDMT, FSS, or IPAQ) or gait parameters in pwMS and HC, even in a condition involving higher cognitive demand. These results may suggest that BDNF does not play a role in these parameters' performance.

Implications of lower extremity muscle power and force for walking and fatigability in multiple sclerosis - An exploratory pilot-study

BACKGROUND

Limitations in physical function are common in Multiple Sclerosis (MS), yet it is neither clear how muscle power implicates physical function and walking-fatigability. This pilot-study aims to investigate (1) deficits in muscle power/force alongside walking in persons with MS; (2) associations between muscle power/force and physical functions and (3) the impact of prolonged walking in muscle power/force.

METHODS

30 relapse-remitting persons with MS and 28 healthy controls performed chair rise and plantar flexion on a force platform before and after 12-minutes of intermittent walking to measure lower extremity muscle power/force. GaitRite measured walking speed. The percentage change in distance walked was also calculated. Persons with MS were classified into subgroups according to walking-fatigability and mobility disability status (Patient Determined Disease Steps).

FINDINGS

Higher deficits in muscle power compared to force were observed in persons with MS vs. healthy controls particularly in persons with MS having higher disability. Muscle power and force were associated with walking capacity, mobility disability and subjective fatigue, but not with percentage change in distance walked. Persons with MS slowed down over the course of the 12-min intermittent walking, whereas decrements in walking speed and muscle power/force (derived from chair rise) were observed in persons with MS presenting walking-fatigability only.

INTERPRETATION

Muscle power and force are impaired in persons with MS and appear to be critical for physical function in MS. This exploratory pilot study further suggests that muscle power/force from chair rise could contributes to walking-fatigability which therefore offer future treatment targets.

Effects of hippotherapy on postural balance, functional mobility, self-perceived fatigue, and quality of life in people with relapsing-remitting multiple sclerosis: Secondary results of an exploratory clinical trial

BACKGROUND

Multiple sclerosis (MS) results in worsening of postural balance, functional mobility, and self-perceived fatigue as influences of quality of life.

OBJECTIVE

To examine the effects of hippotherapy on postural balance, functional mobility, self-perceived fatigue, and quality of life in people with MS.

METHODS

Participants were assigned into a hippotherapy intervention group (n= 17) or a control group (n= 16). The intervention included 16 sessions of 30-minutes of hippotherapy conducted twice a week whereas the control group was maintained their therapeutic routine. Postural balance was evaluated as CoP speed (cm/s) and CoP 95% elliptical area (cm²) using a force platform under 4 experimental conditions: stable surface/ eyes open, stable surface/ eyes closed, foam surface/ eyes open, and foam surface/ eyes closed. Functional mobility was evaluated by the Timed Up and Go (TUG) test. The Fatigue Severity Scale (FSS) and Modified Fatigue Impact Scale (MFIS) measured perceived fatigue, and the Functional Assessment of Multiple Sclerosis (FAMS) measured quality of life. The data were examined using mixed model ANOVA with Bonferroni post hoc.

RESULTS

CoP speed and CoP 95% elliptical area (p < .05) significantly decreased across all testing conditions for the intervention group compared with control. The TUG improved over time in the intervention group (p = .001) as did the FSS (p < .001). In addition, there was also an improvement for the score and all the MFIS domains (p < .005) for the intervention group compared with control and for FAMS improved over time in the intervention group (p < .05).

CONCLUSION

Hippotherapy improved postural balance, functional mobility, fatigue, and quality of life in people with relapsing-remitting MS. This suggests that hippotherapy may be a useful approach for complimentary treatment among people with MS.