Validation of patient determined disease steps (PDDS) scale scores in persons with multiple sclerosis

BMC Neurology (Impact Factor: 2.49). 04/2013; 13(1):37. DOI: 10.1186/1471-2377-13-37
Source: PubMed

ABSTRACT Background
The Patient Determined Disease Steps (PDDS) is a promising patient-reported outcome (PRO) of disability in multiple sclerosis (MS). To date, there is limited evidence regarding the validity of PDDS scores, despite its sound conceptual development and broad inclusion in MS research. This study examined the validity of the PDDS based on (1) the association with Expanded Disability Status Scale (EDSS) scores and (2) the pattern of associations between PDDS and EDSS scores with Functional System (FS) scores as well as ambulatory and other outcomes.

96 persons with MS provided demographic/clinical information, completed the PDDS and other PROs including the Multiple Sclerosis Walking Scale-12 (MSWS-12), and underwent a neurological examination for generating FS and EDSS scores. Participants completed assessments of cognition, ambulation including the 6-minute walk (6 MW), and wore an accelerometer during waking hours over seven days.

There was a strong correlation between EDSS and PDDS scores (ρ = .783). PDDS and EDSS scores were strongly correlated with Pyramidal (ρ = .578 &ρ = .647, respectively) and Cerebellar (ρ = .501 &ρ = .528, respectively) FS scores as well as 6 MW distance (ρ = .704 &ρ = .805, respectively), MSWS-12 scores (ρ = .801 &ρ = .729, respectively), and accelerometer steps/day (ρ = -.740 &ρ = -.717, respectively).

This study provides novel evidence supporting the PDDS as valid PRO of disability in MS.


Available from: Yvonne C Learmonth, Jun 16, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective To evaluate the degree of severity and disability progression in Japanese patients with multiple sclerosis (MS) using descriptive study methods.Methods Postal questionnaires were sent to patients through three Japanese MS patients' associations. Survey participants were asked to evaluate their disability and MS severity based on two scales: the Patient Determined Disease Steps (PDDS) and the Short Form-8 Health Survey.ResultsA total of 789 MS patients were surveyed. Approximately 45% of patients had gait disability (PDDS score of 3) or higher. Patients with a higher age of MS onset had rapid progression of disease. The mean duration from first symptom of MS to treatment initiation was 4.5 years. The time to treatment initiation was longer for the younger onset group, ≤29 years-of-age, than that of the older onset group, ≥40 years-of-age (6.2 years vs 2.2 years, respectively). The PDDS showed two-stage disability progression: while progression time to a PDDS score of 2 varied, progression time from a PDDS score of 2 to a score of 4 was similar across the participants.Conclusions Based on the patient-reported disability progression of MS, we showed that the possibility of severity and MS disease progression between Japanese and Western countries might be similar. The PDDS could be a useful alternative to assess MS disability.
    05/2015; DOI:10.1111/cen3.12216
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Behavioral interventions have significantly increased physical activity in people with multiple sclerosis (MS). Nevertheless, there has been interindividual variability in the pattern and magnitude of change. This study documented the efficacy and variability of a behavioral intervention for changing physical activity and examined the possibility that efficacy varied by the characteristics of individuals with MS. Eighty-two people with MS were randomly assigned to one of two conditions: behavioral intervention (n = 41) or waitlist control (n = 41). We collected information before the study on MS type, disability status, weight status based on body-mass index, and current medications. Furthermore, all participants completed the Godin Leisure Time Exercise Questionnaire and the abbreviated International Physical Activity Questionnaire and wore an accelerometer for 1 week to measure minutes of moderate-to-vigorous physical activity before and after the 6-month intervention period. Analysis of covariance (ANCOVA) indicated that participants in the behavioral intervention had significantly higher levels of physical activity than control participants after the 6-month period (P < .001). There was substantial interindividual variability in the magnitude of change, and ANCOVA indicated that MS type (relapsing vs. progressive) (P < .01), disability status (mild vs. moderate) (P < .01), and weight status (normal weight vs. overweight/obese) (P < .05) moderated the efficacy of the behavioral intervention. The behavioral intervention was associated with improvements in physical activity, particularly for those with mild disability, relapsing-remitting MS, or normal weight status.
    09/2014; 17(2):140903145137009. DOI:10.7224/1537-2073.2014-016
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have previously proposed a conceptual model of physical inactivity, physiological deconditioning, and walking impairment in persons with multiple sclerosis (MS) that suggests engaging in physical activity and improving physiological conditioning may lead to improvements in walking performance. This cross-sectional study examined the nature of associations among physical activity, aerobic capacity, and walking performance in persons with MS and healthy controls. The sample included 31 persons with MS and 31 controls matched by age, sex, height, and weight. Participants completed the 6-minute walk (6MW), wore an ActiGraph model GT3X accelerometer for 7 days as an objective measure of physical activity (expressed as time spent in moderate-to-vigorous physical activity [MVPA]), and completed an incremental exercise test on a cycle ergometer as a measure of aerobic capacity (VO2peak). Hierarchical linear regression analyses indicated that MVPA and VO2peak partially explained group differences in 6MW performance (R = 0.782), although group remained a significant predictor of 6MW performance (β = 0.304; P < 0.001). Path analysis indicated that group had both statistically significant direct and indirect effects on 6MW performance, and the indirect effect operated through pathways involving MVPA and VO2peak. These results provide direct preliminary evidence that physiological deconditioning, perhaps occurring as a result of physical inactivity, may explain variability in walking impairment in persons with MS. These findings support the design and implementation of targeted interventions for improving walking impairment in this population.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1,
    Journal of neurologic physical therapy: JNPT 03/2015; 39(2). DOI:10.1097/NPT.0000000000000087 · 2.89 Impact Factor