Longitudinal metric properties of disability rating scales for Parkinson's disease

Bridging the gap between statistical significance and clinical relevance: A systematic review of minimum clinically important difference (MCID) thresholds of scales reported in movement disorders research

Background

Minimum clinically important difference (MCID) is the smallest change in an outcome measure that is considered clinically meaningful. Using validated MCID thresholds for outcomes powers trials adequately to detect meaningful treatment effects, aids in their interpretation and guides development of new outcome measures.

Objectives

To provide a comprehensive summary of MCID thresholds of various symptom severity scales reported in movement disorder.

Methods

We conducted systematic review of the literature and included studies of one or more movement disorders, and reporting MCID scales.

Results

2763 reports were screened. Final review included 32 studies. Risk of bias (RoB) assessment showed most studies were of good quality. Most commonly evaluated scale was Unified Parkinson's Disease Rating Scale (UPDRS) (11 out of 32). Four studies assessing MDS-UPDRS had assessed its different sub-parts, reporting a change of 2.64,3.05,3.25 and 0.9 points to detect clinically meaningful improvement and 2.45,2.51,4.63 and 0.8 points to detect clinically meaningful worsening, for the Part I, II, III and IV, respectively. For Parts II + III, I + II + III and I + II + III + IV, MCID thresholds reported for clinically meaningful improvement were 5.73, 4.9, 6.7 and 7.1 points respectively; while those for clinically meaningful worsening were 4.7, 4.2, 5.2 and 6.3 points, respectively. MCID thresholds reported for other scales included Abnormal Involuntary Movement Scale (AIMS), Toronto Western Spasmodic Torticollis Rating Scale (TWSRS), and Burke-Fahn-Marsden Dystonia Scale (BFMD).

Conclusion

This review summarizes all the MCID thresholds currently reported in Movement disorders research and provides a comprehensive resource for future trials, highlighting the need for standardized and validated MCID scales in movement disorder research.

Minimal Clinically Important Difference (MCID) in Patient-Reported Outcome Measures for Neurological Conditions: Review of Concept and Methods

The concept of the minimal clinically important difference (MCID) emerged from the recognition that statistical significance alone is not enough to determine the clinical relevance of treatment effects in clinical research. In many cases, statistically significant changes in outcomes may not be meaningful to patients or may not result in any tangible improvements in their health. This has led to a growing emphasis on the importance of measuring patient-reported outcome measures (PROMs) in clinical trials and other research studies, in order to capture the patient perspective on treatment effectiveness. MCID is defined as the smallest change in scores that is considered meaningful or important to patients. MCID is particularly important in fields such as neurology, where many of the outcomes of interest are subjective or based on patient-reported symptoms. This review discusses the challenges associated with interpreting outcomes of clinical trials based solely on statistical significance, highlighting the importance of considering clinical relevance and patient perception of change. There are two main approaches to estimating MCID: anchor-based and distribution-based. Anchor-based approaches compare change scores using an external anchor, while distribution-based approaches estimate MCID values based on statistical characteristics of scores within a sample. MCID is dynamic and context-specific, and there is no single 'gold standard' method for estimating it. A range of MCID thresholds should be defined using multiple methods for a disease under targeted intervention, rather than relying on a single absolute value. The use of MCID thresholds can be an important tool for researchers, neurophysicians and patients in evaluating the effectiveness of treatments and interventions, and in making informed decisions about care.

The dilemma between milestones of progression versus clinical scales in Parkinson's disease

There are significant challenges in accurately documenting the progression of Parkinson's disease (PD). The disease course is highly heterogeneous, there are no validated biomarkers, and we are reliant on repeated clinical measures to assess disease state over time. Yet, the ability to chart disease progression accurately is vital in both observational and interventional study designs, where reliable measures are critical to determine whether an outcome has been met. In this chapter, we first discuss the natural history of PD, including the spectrum of clinical presentation and expected developments through the course of the disease. We then explore in detail the current strategies for measuring disease progression, which can be broadly divided into: (i) the use of quantitative clinical scales; and (ii) determination of the onset time of key milestones. We discuss the strengths and limitations of these approaches for use in clinical trials, with a particular focus on disease modification trials. The selection of outcome measures for a particular study will depend on multiple factors, but trial duration is an important determinant. Milestones are reached over a course of years rather than months, and hence clinical scales with sensitivity to change are needed for short-term studies. However, milestones represent important markers of disease stage which are not confounded by symptomatic therapies and are of critical relevance to the patient. Prolonged but low intensity follow-up beyond a limited period of treatment with a putative disease-modifying agent may allow milestones to be incorporated into evaluation of efficacy in a practical and cost-effective way.

Gait Analysis with Wearables Is a Potential Progression Marker in Parkinson's Disease

Gait disturbance is a prototypical feature of Parkinson's disease (PD), and the quantification of gait using wearable sensors is promising. This study aimed to identify gait impairment in the early and progressive stages of PD according to the Hoehn and Yahr (H-Y) scale. A total of 138 PD patients and 56 healthy controls (HCs) were included in our research. We collected gait parameters using the JiBuEn gait-analysis system. For spatiotemporal gait parameters and kinematic gait parameters, we observed significant differences in stride length (SL), gait velocity, the variability of SL, heel strike angle, and the range of motion (ROM) of the ankle, knee, and hip joints between HCs and PD patients in H-Y Ⅰ-Ⅱ. The changes worsened with the progression of PD. The differences in the asymmetry index of the SL and ROM of the hip were found between HCs and patients in H-Y Ⅳ. Additionally, these gait parameters were significantly associated with Unified Parkinson's Disease Rating Scale and Parkinson's Disease Questionnaire-39. This study demonstrated that gait impairment occurs in the early stage of PD and deteriorates with the progression of the disease. The gait parameters mentioned above may help to detect PD earlier and assess the progression of PD.

Measurement tools to assess activities of daily living in patients with Parkinson's disease: A systematic review

Introduction

Parkinson's disease (PD) is associated with a progressive inability to accomplish essential activities of daily living (ADL) resulting in a loss of autonomy and quality of life. Accurate measurement of ADL in PD is important to monitor disease progression and optimize care. Despite its relevance, it is still unclear which measurement instruments are the most suitable for evaluating ADL in people with PD.

Objective

To identify and critically appraise which measurement instruments have been used to assess ADL in PD.

Methods

A systematic review was conducted using the databases CENTRAL, MEDLINE, and PEDro from their inception to October 2021 to identify all observational and experimental studies conducted in PD or atypical parkinsonism that included an ADL assessment. Titles and abstracts were screened independently by two authors. The clinimetric properties of the measurement instruments were assessed, and the instruments were classified as "recommended," "suggested," or "listed."

Results

A total of 129 articles were included, with 37 measurement instruments used. The Unified Parkinson's Disease Rating Scale (UPDRS), the Schwab & England ADL scale (S&E scale), the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), the Barthel Index, the Lawton-Brody Instrumental Activities of Daily Living Scale, the Functional Independence Measure (FIM) and the Alzheimer's Disease Cooperative Study - ADL (ADCS-ADL) scale were the seven most frequently cited measurement instruments. Of these, only two included an assessment of basic and instrumental ADL.

Conclusion

MDS-UPDRS and the S&E scale were the only two scales that could be classified as recommended. For the MDS-UPDRS, either the full version or only Part II, which is focused on ADL, can be used. Future studies should explore the use of wearable devices to assess ADL remotely and more continuously.

Impact of Parkinson’s Disease on Functional Mobility at Different Stages

Introduction

Specific functional assessments to determine the progression of Parkinson’s Disease (PD) are important to slow down such progression and better plan rehabilitation. This study aimed to explore possible differences in the performance of different functional tasks included in a mobility test using sensors embedded in an Android device, in people at different PD stages.

Materials and Methods

Eighty-seven participants with PD agreed to participate in this cross-sectional study. They were assessed once using an inertial sensor and variables related to functional status were recorded (i.e., MLDisp, APDisp, DispA, Vrange, MLRange, PTurnSit, PStand, TTime, and RTime).

Results

There was significant impairment of the vertical range during gait between stages I and II. Further, when stages II and III were compared, the sit-to-stand power was significantly impaired, and the total time required to complete the test increased significantly (p < 0.05). Even more significant differences were obtained when stages I and III were compared, in particular, dysfunction in postural control, vertical range, sit to stand power and total time. Finally, there were no significant differences between stages in the medial-lateral displacements and reaction time (p > 0.05).

Conclusion

Functional mobility becomes more significantly impaired in the PD population as the PD stages progress. This implies impaired postural control, decreased ability to sit down or stand up from a chair, increased metabolic cost during walking, and overall slowing-down of motor function.

Plasma proteome profiling using tandem mass tag labeling technology reveals potential biomarkers for Parkinson's disease: a preliminary study

PURPOSE

Parkinson's disease (PD) is the second most frequently occurring progressive neurodegenerative disorder. Biomarkers are useful indicators for tracking disease progression, early diagnosis, and intervention of disease progression. We aimed to develop plasma biomarker panel which maybe aid to predict the onset and progression of PD.

EXPERIMENTAL DESIGN

Tandem mass tag (TMT) mass spectrometry was applied using an Orbitrap Lumos mass spectrometer to analyze plasma protein expression in patients diagnosed with PD and healthy controls.

RESULTS

In total, 555 proteins were quantified. Using a cut-off of p < 0.05 and a fold change of >1.2 for the variation in expression, 25 proteins were differentially expressed between the PD and control groups. Sixteen proteins were upregulated and nine were downregulated. Several proteins, including Chitinase-3-like protein 1 (CHI3L1) and thymosin beta-4 (TMSB4X) were implicated in PD pathogenesis.

CONCLUSIONS

The data from the TMT-based proteomic profiling of plasma samples in PD may help advance the understanding of the molecular mechanisms of PD and identify potential novel biomarkers of PD for further characterization.

The Efficacy of Tai Chi and Stretching Exercises Based on a Smartphone Application for Patients With Parkinson's Disease: A Protocol for a Randomized Controlled Trial

Introduction: Parkinson's disease (PD) is a common neurodegenerative disease that seriously impairs patients' quality of life, and increases the burden of patients and caregivers. Both drugs and exercise can alleviate its motor and non-motor symptoms, improving the quality of life for PD patients. Telehealth, an increasingly popular tool, makes rehabilitation accessible at home, overcoming the inconvenience of traffic and scheduling. Care-PD is a phone application designed for rehabilitation training, which provides Tai Chi and stretching exercises through tutorial videos as well as an online evaluation system. In this protocol, we will explore the efficacy of Tai Chi and stretching exercises as a PD rehabilitation therapy based on the smartphone application Care-PD.

Methods and Analysis: A double-blind, parallel randomized controlled trial will be conducted in this study. The recruitment, intervention, and evaluation processes will be implemented through the Care-PD application. Persons with PD will fill out questionnaires on Activities of Daily Living (ADL), upload the latest case report, and sign the informed consent form in the application. Afterward, doctors and researchers will screen and enroll 180 participants who will be randomly (1:1:1) assigned to Tai Chi group, stretching exercises group, or control group. The subjects will participate in a 1-h exercise session three times per week for 12 weeks, ending with another 4 weeks of follow-up study. Each exercise session includes 10 min of warm-up, 45 min of exercise, and 5 min of cool-down. The primary outcomes are Motor Aspects of Experiences of Daily Living and the 39-item Parkinson's disease Questionnaire. The secondary outcomes include the 9-item Wearing-Off Questionnaire, the Freezing of Gait Questionnaire, the Caregiver Strain Index, Non-motor Experiences of Daily Living, ADL, and Morse Fall Scale. All assessments will be performed at baseline, week 12 and 16.

Discussion: Care-PD integrates subject recruitment, intervention, and evaluation, providing a new perspective on clinical rehabilitation for persons with PD. This study will evaluate the efficacy of Tai Chi and stretching exercises on patients' quality of life and disease progression based on a smartphone application. We aim to provide a new rehabilitation training platform for persons with PD.

Ethics and Dissemination: This study was approved by the Scientific Research Ethics Committee (102772020RT132) of Shanghai University of Sport. Data collection begins after the approval of the ethics committee. The participants must sign an informed consent form before enrollment. The results will be published in relevant journals, seminars, and be disseminated among rehabilitation practitioners and patients with PD.

Clinical Trial Registration: Chinese Clinical Trial Registry, identifier [ChiCTR2100042096]. Registered on January 13, 2021.

Psychosocial Difficulties (PSD) Experienced by People across Brain Disorders and the Implications for Occupational Therapy: A Cross-Sectional Study

Psychosocial difficulties are defined as impairments in mental and body functions, activity limitations and participation restrictions, experienced in common across brain disorders. This cross-sectional study compared the psychosocial difficulties among people with Parkinson's disease (n = 61), schizophrenia (n = 84) and stroke (n = 70). The extent of difficulties was found to be similar across the three disorders in most of the domains studied. Psychosocial difficulties were also found to be associated with sociodemographic and illness related factors. The results challenge the brain disorder-specific approach to psychosocial difficulties commonly carried out in neurological and psychiatric research. Implications to occupational therapy are presented.

Analysis of Gait for Disease Stage in Patients with Parkinson's Disease

Understanding the motor patterns underlying the movement of individuals with Parkinson's disease (PD) is fundamental to the effective targeting of non-pharmacological therapies. This study aimed to analyze the gait pattern in relation to the evolutionary stages I-II and III-IV according to the Hoehn and Yahr (H&Y) scale in individuals affected by PD. The study was conducted with the participation of 37 PD patients with a mean age of 70.09 ± 9.53 years, and of whom 48.64% were women. The inclusion criteria were (1) to be diagnosed with PD; (2) to be in an evolutionary stage of the disease between I and IV: and (3) to be able to walk independently and without any assistance. Kinematic and spatial-temporal parameters of the gait were analyzed. The results showed differences in speed of movement, cadence, stride length, support duration, swing duration, step width, walking cycle duration, and double support time between the stages analyzed. These results confirmed the differences in PD gait pattern between stages I-II and III-IV. Different behaviors of the same variable were recorded depending on whether the right or left side was affected by PD.

Relation of chair rising ability to activities of daily living and physical activity in Parkinson's disease

Background

Many persons living with Parkinson’s disease (PD) have difficulty rising from a chair. Impaired ability to perform the chair rise may be associated with low physical activity levels and reduced ability to perform activities of daily living (ADL).

Methods

Cross-sectional analysis was performed in 88 persons with PD to study the association of chair rising ability with ADL and physical activity.

Results

We found that the participants who pushed themselves up from the chair had more severe PD, higher motor impairment and more comorbidity than those who rose from a chair normally. The Unified Parkinson’s Disease Rating Scale ADL (UPDRS-ADL), Schwab and England Activities of Daily Living Scale (SE-ADL) and the Physical Activity Scale for the Elderly (PASE) scores for the participants who pushed themselves up to rise (17.20 ± 7.53; 76.67 ± 13.23; 46.18 ± 52.64, respectively) were significantly poorer than for those who rose normally (10.35 ± 3.79; 87.64 ± 8.30; 112.90 ± 61.40, respectively) (all p < .05). Additionally, PASE scores were significantly poorer for participants who pushed themselves up to rise compared to those who rose slowly (95.21 ± 60.27) (p < .01). Pushing up to rise from a chair was a significant predictor of UPDRS-ADL (β = .357; p < .001; R² = .403), SE-ADL (β = −.266; p = .009; R² = .257) and PASE (β = −.250; p = .016; R² = .162).

Conclusions

Ability to rise from a chair was associated with ADL limitation and physical activity in persons with PD. Poor ability to rise from a chair may prevent persons from living independently and engaging in physical activity.

Barthel Index and modified Rankin Scale: Psychometric properties during medication phases in idiopathic Parkinson disease

BACKGROUND

Independence in activities of daily living (ADL) is one of the most important aspects in planning treatment for people with Parkinson disease (PD). The Barthel Index (BI) and modified Rankin Scale (mRS) are commonly used in neurological diseases.

OBJECTIVE

This study was conducted to confirm the validity and reliability of the BI and mRS in PD during ON and OFF medication phases.

METHODS

We included 260 individuals with a diagnosis of idiopathic PD. The disability in ADL was measured by the BI, mRS, Parkinson's Disease Questionnaire-39 (PDQ-39), Unified Parkinson Disease Rating Scale-Activities of Daily Living (UPDRS-ADL), and Schwab and England ADL scale (SE). Test-retest, inter-rater reliability, and internal consistency were assessed by the intra-class correlation (ICC) and Cronbach α coefficients. Dimensionality was evaluated by factor analysis. Convergent validity was assessed by the SE, Berg Balance Scale (BBS), PDQ-39 and UPDRS-ADL.

RESULTS

For the 260 participants (187 [71.9%] males; mean [SD] age 60.3 [12.3] years), both the BI and mRS achieved an acceptable level of test-retest and inter-rater reliability (ICC=0.77 to 0.91) in ON and OFF medication phases. The Cronbach α for BI was 0.85 and 0.88, respectively. We found 1 and 2 factors for BI in ON and OFF phases, respectively. Investigation of convergent validity showed moderate to high correlation for the BI with the UPDRS-ADL, SE, PDQ-39 (ADL), BBS and mRS scores in ON and OFF phases (ρ=0.51-0.74) and mRS with SE, UPDRS-ADL, PDQ-39 (ADL) and BBS scores (ρ=0.48-0.82).

CONCLUSION

The BI and mRS showed acceptable validity and reliability to measure the degree of disability in patients with PD in daily activities in both ON and OFF medication phases.

The impact of levodopa therapy-induced complications on quality of life in Parkinson's disease patients in Singapore

The objective of this study was to investigate the impact of levodopa therapy-induced complications on the quality of life (QoL) of Parkinson's disease (PD) patients in Singapore over a 1-year follow-up period. 274 PD patients were prospectively recruited, of which 78 patients completed the follow-up. Patients were evaluated on: (1) motor symptoms, (2) non-motor symptoms, (3) levodopa therapy-induced complications and (4) QoL. Levodopa-induced complications including dyskinesia and OFF symptoms occurred in 13.5% and 55.9% of the study population, respectively. In patients who completed the 1-year follow-up, there was a trend suggestive of increasing dyskinesia duration, more disabling dyskinesia as well as longer, more sudden and unpredictable OFF periods. There was a significant decline in the overall QoL at follow-up, in particular, activities of daily living, emotional well-being, cognition and communication domains were the most affected. The multivariable analysis demonstrated that worsening of UPDRS IV total score over 1-year interval was associated with worsening in PDQ-Summary Index score (d = 0.671, p = 0.014). In conclusion, levodopa-induced complications had significant adverse impacts on QoL. This study substantiates the importance for clinicians to closely monitor and promptly manage levodopa therapy-induced complications that may arise in patients.

An 8-Week Low-Intensity Progressive Cycling Training Improves Motor Functions in Patients with Early-Stage Parkinson's Disease

BACKGROUND AND PURPOSE

The effects of high-intensity cycling as an adjuvant therapy for early-stage Parkinson's disease (PD) were highlighted recently. However, patients experience difficulties in maintaining these cycling training programs. The present study investigated the efficacy of cycling at a mild-to-moderate intensity in early-stage PD.

METHODS

Thirteen PD patients were enrolled for 16 serial cycling sessions over a 2-month period. Motor function was assessed using the Unified Parkinson's Disease Rating Scale part III (UPDRS III) and Timed Up and Go (TUG) test as primary outcomes. The Montreal Cognitive Assessment (MoCA), modified Hoehn and Yahr Stage (mHYS), total UPDRS, Falls Efficacy Scale, New Freezing of Gait Questionnaire, Schwab and England Activities of Daily Living, 39-item Parkinson's Disease Questionnaire, Patient Global Impression of Change, and gait performance were assessed as secondary outcomes.

RESULTS

The age and the age at onset were 59.67±7.24 and 53.23±10.26 years (mean±SD), respectively. The cycling cadence was 53.27±8.92 revolutions per minute. The UPDRS III score improved significantly after 8 training sessions (p=0.011) and 16 training sessions (T2) (p=0.001) in the off-state, and at T2 (p=0.004) in the on-state compared to pretraining (T0). The TUG duration was significantly shorter at T2 than at T0 (p<0.05). The findings of MoCA, total UPDRS, double limb support time, and mHYS (in both the off- and on-states) also improved significantly at T2.

CONCLUSIONS

Our pioneer study has demonstrated that a low-intensity progressive cycling exercise can improve motor function in PD, especially akinesia. The beneficial effects were similar to those of high-intensity rehabilitation programs.

Development and validation of prognostic survival models in newly diagnosed Parkinson's disease

OBJECTIVE

The objective of this study was to develop valid prognostic models to predict mortality, dependency, and "death or dependency" for use in newly diagnosed Parkinson's disease (PD).

METHODS

The models were developed in the Parkinsonism Incidence in North-East Scotland study (UK, 198 patients) and validated in the ParkWest study (Norway, 192 patients), cohorts that attempted to identify and follow-up all new PD cases in the study area. Dependency was defined using the Schwab & England scale. We selected variables measured at time of diagnosis to include in the models. Internal validation and external validation were performed by calculating C-statistics (discrimination) and plotting observed versus predicted risk in quantiles of predicted risk (calibration).

RESULTS

Older age, male sex, increased severity of axial features, and Charlson comorbidity index were independent prognostic factors in the mortality model. Increasing age, higher smoking history, increased severity of axial features, and lower MMSE score were independent predictors in the models of dependency and "death or dependency." Each model had very good internal calibration and very good or good discrimination (internal and external C-statistics for the models were 0.73-0.75 and 0.68-0.78, respectively). Although each model clearly separated patients into groups according to risk, they tended to overestimate risk in ParkWest. The models were recalibrated to the baseline risk in the ParkWest study and then calibrated well in this cohort.

CONCLUSIONS

We have developed prognostic models for predicting medium-term risk of important clinical outcomes in newly diagnosed PD. These models have validity for use for stratification of randomization, confounder adjustment, and case-mix correction, but they are inadequate for individualized prognostication. © 2017. The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Predictors of functional dependency in Parkinson's disease

BACKGROUND

Functional dependency, the need for help in basic activities of daily living, is an important patient-oriented outcome. We aimed to describe the development of dependency in Parkinson's disease (PD) and identify independent prognostic factors for this outcome.

METHODS

We analyzed data from the Parkinsonism Incidence in North-East Scotland (PINE) study, a prospective, community-based incident cohort of PD with ongoing follow-up. We described the development of dependency defined by a Schwab & England score of < 80% and a Barthel Index of <19. We identified the baseline predictors of dependency using multivariable Cox regression.

RESULTS

In 198 patients with PD, the rate of development of dependency was 14 per 100 person years. Older age at diagnosis (hazard ratio for 10-year increase 2.23 [95% confidence interval 1.66-2.98]), greater smoking history (hazard ratio for 10-pack-year increase, 1.15 [1.04-1.26]), more severe axial impairment (hazard ratio for 5-point increase in sum of axial items from UPDRS scale, 1.78 [1.30-2.44]), and lower MMSE score (hazard ratio 0.88 [0.79-0.98]) were independently associated with a higher risk of dependency as defined by Schwab & England. Only older age (hazard ratio for 10-year increase 1.35 [1.04-1.76]) and severity of axial impairment (hazard ratio for 5-point increase 1.85 [1.31-2.62]) were associated with a higher risk of dependency as defined by the Barthel Index. Sex, deprivation, comorbidity, overall UPDRS motor score, and disease stage were not independently associated with dependency.

CONCLUSION

This is the first community-based study of dependency in PD. There was a high rate of dependency development. Older age, more smoking, more axial impairment, and poorer cognition were independent predictors. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Dynamics of change in self-reported disability among persons with Parkinson's disease after 2 years of follow-up

Symptoms of Parkinson's disease (PD) progress over time causing significant disability. Yet, change in disability over shorter time periods has not been entirely understood. The purpose of this study was to assess the Self-Assessment Disability Scale (SADS) in persons with Parkinson's disease (PD) after 2 years of follow-up and compare it with the score observed at baseline. Additionally, we aimed at evaluating association of motor and non-motor PD features at baseline with a higher disability after 2 years of follow-up. A total of 120 consecutive persons with PD, who denied falling in the past 6 months, were initially recruited. After 2 years of follow-up, 88 (73.3%) persons with PD were evaluated for SADS. The total disability (SADS) score did not change after follow-up (p = 0.529). We observed increase in difficulty at "Getting out of bed" (p = 0.006), "Getting up out of armchair" (p = 0.013), "Walking about house/flat" (p = 0.003), "Walking outside" (p = 0.010), and "Traveling by public transport" (p = 0.014). After adjusting for several potential confounding factors, falls in the past year (β = 8.32, 95% confidence interval (CI) 1.04-15.59) and higher Unified Parkinson's Disease Rating Scale part 3 at baseline (β = 0.26, 95%CI 0.01-0.51) remained associated with higher PD-related disability. This finding suggests that accumulation of overall PD-related disability tends to occur over a longer time span. Further studies are needed to gradually assess long-term evolution of disability in PD.

Dose-Response Analysis of the Effect of Carbidopa-Levodopa Extended-Release Capsules (IPX066) in Levodopa-Naive Patients With Parkinson Disease

Parkinson disease is an age-related disorder of the central nervous system principally due to loss of dopamine-producing cells in the midbrain. Levodopa, in combination with carbidopa, is widely regarded as an effective treatment for the symptoms of Parkinson disease. A dose-response relationship is established for carbidopa-levodopa extended-release capsules (IPX066) in levodopa-naive Parkinson disease patients using a disease progression model. Unified Parkinson Disease Rating Scale (UPDRS) part II plus part III scores from 171 North American patients treated with placebo or IPX066 for approximately 30 weeks from a double-blind, parallel-group, dose-ranging study were used to develop the pharmacodynamic model. The model comprised 3 components: a linear function describing disease progression, a component describing placebo (or nonlevodopa) effects, and a component to describe the effect of levodopa. Natural disease progression in early Parkinson disease as measured by UPDRS was 11.6 units/year and faster in patients with more severe disease (Hoehn-Yahr stage 3). Maximum placebo/nonlevodopa response was 23.0% of baseline UPDRS. Maximum levodopa effect from IPX066 was 76.7% of baseline UPDRS, and the ED50 was 450 mg levodopa. Equilibration half-life for the effect compartment was 62.8 days. Increasing age increased and being female decreased equilibration half-life. The quantitative model allowed description of the entire time course of response to clinical trial intervention.

Asymmetric responsiveness of disability and health-related quality of life to improvement versus decline in Parkinson's disease

PURPOSE

Clinical trials in Parkinson's disease commonly employ outcome measures of disability and quality of life. Responsiveness of these outcomes measures to symptomatic decline versus improvement has not been studied. We wanted to study the responsiveness of Schwab & England Activities of Daily Living Scale (SE) and Short Form-12 (SF-12) to symptomatic decline versus improvement in Parkinson's disease over a 4-year period among a naturalistic cohort of patients.

METHODS

Parkinson's disease patients (N = 228, disease duration 6.1 years) were followed for 4 years with assessments of disease severity, Unified Parkinson's Disease Rating Scale (UPDRS), health-related quality of life (SF-12 physical/mental health), and disability (SE). The sample was subdivided into those who declined (N = 118) or improved (N = 102) on total-UPDRS. Responsiveness was assessed with Cohen's effect size and standardized response mean.

RESULTS

At baseline, patients who improved over 4 years had greater disease severity and worse quality of life than decliners (p < .05). Decliners had a 13.5-point worsening on total-UPDRS, 26.3-39.8; p < .001) associated with concomitant decline on the SF-12 (physical health 42.9-39.2, mental health 50.0-46.6; both p < .001) and the SE (85-74 %; p < .001). Improvers had a 13.0-point improvement on total-UPDRS (39.8-26.8; p < .001) associated with minimal change on the SF-12 (physical health 40.8-39.5, mental health 47.1-46.3) and SE (79-79 %). Based on effect size, the rank order of responsiveness of measures for decliners from high to low was SE (-0.78), Short Form-12 mental health (-0.45), and SF-12 physical health (-0.34). Rank order of responsiveness for improvers was Short Form-12 physical health (-0.11), SF-12 mental health (-0.10), and SE (-0.03).

CONCLUSIONS

Among decliners, measures of disability and quality of life were moderate to highly responsive to change in disease severity. Among improvers, both disability and quality of life were poorly responsive despite UPDRS improvement of comparable magnitude.

A functional scale for spinal and bulbar muscular atrophy: Cross-sectional and longitudinal study

We aimed to develop, validate, and evaluate a disease-specific outcome measure for SBMA: the Spinal and Bulbar Muscular Atrophy Functional Rating Scale (SBMAFRS). We examined the Japanese version (SBMAFRS-J) in 80 Japanese SBMA subjects to evaluate its validity and reliability. We then assessed this scale longitudinally in 41 additional SBMA subjects. The English version (SBMAFRS-E) was also tested in 15 US subjects. The total score of the SBMAFRS-J was distributed normally without an extreme ceiling or floor effect. For SBMAFRS-J, the high intra- and inter-rater agreement was confirmed (intra-class correlation coefficients [ICCs] 0.910 and 0.797, respectively), and internal consistency was satisfactory (Cronbach's alpha 0.700-0.822). In addition, SBMAFRS-J demonstrated concurrent, convergent, and discriminant validity, except for the respiratory subscale. The inter-rater reliability and internal consistency of SBMAFRS-E were also satisfactory. Longitudinally, SBMAFRS-J showed a higher sensitivity to disease progression than the existing clinical measures. In conclusion, we developed and validated a disease-specific functional rating scale for SBMA in both Japanese and English versions, although it needs to be re-assessed in interventional studies with a larger sample size including English speaking subjects.

[Advanced Parkinson's disease: clinical characteristics and treatment (part 1)]

INTRODUCTION

A large percentage of patients with Parkinson's disease (PD) develop motor fluctuations, dyskinesias, and severe non-motor symptoms within 3 to 5 years of starting dopaminergic therapy, and these motor complications are refractory to treatment. Several authors refer to this stage of the disease as advanced Parkinson's disease.

OBJECTIVE

To define the clinical manifestations of advanced PD and the risk factors for reaching this stage of the disease.

DEVELOPMENT

This consensus document has been prepared by using an exhaustive literature search and by discussion of the contents by an expert group on movement disorders of the Sociedad Española de Neurología (Spanish Neurology Society), coordinated by two of the authors (JK and MRL).

CONCLUSIONS

Severe motor fluctuations and dyskinesias, axial motor symptoms resistant to levodopa, and cognitive decline are the main signs in the clinical phenotype of advanced PD.

EQ-5D rated by proxy in institutionalized older adults with dementia: psychometric pros and cons

AIM

Measurement of health-related quality of life in people with dementia is a challenge, because of their special characteristics and the difficulties that this term entails itself. The present study aimed at assessing the psychometric properties of the EQ-5D rated by a familiar or a professional caregiver of institutionalized older adults with dementia.

METHODS

We analyzed the EQ-5D psychometric properties from 525 questionnaires rated by proxy, in a sample of institutionalized older adults with dementia.

RESULTS

The mean EQ-5D index score was 0.11 ± 0.38, and 51.54 ± 21.47 for the visual analog scale. The intraclass correlation coefficient was 0.72. Regarding internal consistency, Cronbach's alpha was 0.64, and the item-total correlation ranged from 0.33 to 0.53. Exploratory factor analysis identified a functional and a subjective factor, accounting for 67.35% of the variance. Convergent validity of EQ-5D with Quality of Life Alzheimer's Disease by proxy and Quality of Life in Late-stage Dementia scales was satisfactory (r = 0.36-0.58). The EQ-5D showed appropriate discriminative validity among patients grouped into several categories. Multiple linear regression models, using EQ-index and visual analog scale as dependent variables, identified dependence level, proxy characteristics, leisure and comorbidity as determinants of quality of life.

CONCLUSIONS

Despite some limitations in the more subjective dimensions, the proxy-rated EQ-5D showed satisfactory psychometric properties in the present study, suggesting that it is a valid and alternative instrument to assess quality of life in institutionalized older people with dementia.

Determinants of health-related quality of life in people with Parkinson's disease: a path analysis

PURPOSE

To identify the demographic factors, impairments and activity limitations that contribute to health-related quality of life (HRQOL) in people with idiopathic Parkinson's disease (PD).

METHOD

Two hundred and ten individuals with idiopathic PD who participated in the baseline assessment of a randomized clinical trial were included. The Parkinson's Disease Questionnaire-39 summary index was used to quantify HRQOL. In order to provide greater clarity regarding the determinants of HRQOL, path analysis was used to explore the relationships between the various predictors in relation to the functioning and disability framework of the International Classification of Functioning model.

RESULTS

The two models of HRQOL that were examined in this study had a reasonable fit with the data. Activity limitations were found to be the strongest predictor of HRQOL. Limitations in performing self-care activities contributed the most to HRQOL in Model 1 (β = 0.38; p < 0.05), while limitations in functional mobility had the largest contribution in Model 2 (β = -0.31; p < 0.0005). Self-reported history of falls was also found to have a significant and direct relationship with HRQOL in both models (Model 1 β = -0.11; p < 0.05; Model 2 β = -0.21; p < 0.05).

CONCLUSIONS

Health-related quality of life in PD is associated with self-care limitations, mobility limitations, self-reported history of falls and disease duration. Understanding how these factors are inter-related may assist clinicians focus their assessments and develop strategies that aim to minimize the negative functional and social sequelae of this debilitating disease.

Progression of Parkinson's disease in the clinical phase: potential markers

Neuromodulatory or even neuroprotective therapy could soon be available for Parkinson's disease (PD), raising the question of how we should define and measure disease progression. Reported evidence suggests that several symptoms worsen with disease duration. Bradykinesia, rigidity, and activities of daily living deteriorate faster at the beginning of the disease, and this deterioration is paralleled by a decline in functional presynaptic dopaminergic activity, as shown by imaging techniques. Cognitive, speech, sleep, and gait difficulties might progress linearly in proportion to disease duration. Reduced variability in heart rate, orthostatic dysfunction, and visual hallucinations start to develop at mid-stage disease and are more common in late stages than earlier stages. In this Review, we summarise our current understanding of the progression of PD-associated symptoms and markers and conclude that an effective measurement of progression of PD must adapt to the different stages of the disease. In addition to routine clinical rating scales, new quantitative assessments of motor and non-motor symptoms, which should be more broadly available, reasonably priced, and easy-to-use, are needed.

Comparative responsiveness of Parkinson's disease scales to change over time

The objective of the study is to examine the comparative responsiveness of outcome measures to assess progression over time in Parkinson's disease (PD). One hundred twenty-eight patients participating in a clinic-based naturalistic study of PD were assessed with the Hoehn and Yahr, UPDRS, MMSE, PDQ-39, PDQL, EQ-5D, and BDI scales at baseline and at 1 year. In addition, 82 patients in a community-based study of patients with PD who had completed self-rated Schwab and England, PDQ-39, EQ-5D, and BDI scales at baseline, were sent the same questionnaires at 1 and 4 years. Responsiveness was assessed using t-tests, standardised effect size, and standardised response mean. In both samples, the Hr-QoL measures were less responsive to change over time than the impairment and disability scales (Hoehn and Yahr, UPDRS, Schwab and England scales). In addition, in the clinic-based sample, Hoehn and Yahr and UPDRS ADL scale ("on") were more responsive to progression over time than UPDRS motor part and ADL part ("off"). Hr-QoL measures are less responsive to change over time than measures of impairment and disability. Although this suggests that these measures are less accurate in detecting subtle changes, it may also indicate that the multifactorial subjective assessment of Hr-QoL adapts to changes over time. Global assessment of overall impairment and disability (which incorporates motor and nonmotor features of PD), however, appeared relatively responsive to change over time in patients in a naturalistic setting.

Validity of spiral analysis in early Parkinson's disease

Spiral analysis is an objective, easy to administer noninvasive test that has been proposed to measure motor dysfunction in Parkinson disease (PD). We compared overall Unified Parkinson Disease Rating Scale Part III scores to selected indices derived from spiral analysis in seventy-four patients with early PD (mean duration of disease 2.4 +/- 1.7 years, mean age 61.5 +/- 9.7 years). Of the spiral indices, degree of severity, first order zero crossing, second order smoothness, and mean speed were best correlated with total motor Unified Parkinson's Disease Rating Scale (UPDRS) score (all P < 0.01), and these indices showed a gradient across worsening tertiles of UPDRS (P < 0.05). Spiral indices also correlated with UPDRS ratings for the worst side and worst arm scores as well. The domains of bradykinesia, rigidity, and action tremor were correlated with first order crossing, second order smoothness, and mean speed, where as rest tremor was most highly correlated with degree of severity. This suggests that the spiral analysis may supplement motor assessment in PD, although further analysis of spiral metrics, a larger sample and longitudinal data should be evaluated.

Dementia and functional decline in patients with Parkinson's disease

Functional decline in Parkinson's disease (PD), characterized by reduced ability to carry out activities of daily living, usually results from typical motor impairment and may be aggravated by concomitant cognitive impairment.

Objective

To compare the functional decline in Parkinson's disease between patients with dementia and cognitively preserved patients.

Methods

From an original sample composed of 50 patients with a clinical diagnosis of idiopathic PD seen in a consecutive series, 33 non-depressed patients were selected comprising 13 with dementia and 20 cognitively preserved individuals. All patients enrolled in this study were drawn from a public outpatient clinic, specialized in movement disorders. The clinical stage of PD was determined by the Hoehn & Yahr scale, and the functional capacity was verified using the Unified Parkinson's Disease Rating Scale UPDRS ADL (subscale II: activities of daily living) and the Schwab & England scale. The two last scales measure the functional degree of independence in activities of daily living. The neuropsychological assessment was performed using The Cambridge Examination for Mental Disorders of the Elderly - CAMCOG, Cognitive Section and the Stroop Color Word Test.

Results

As expected, in comparison with cognitively preserved patients, the group with dementia presented significantly lower scores throughout the neuropsychological evaluation. The patients with dementia were found to have a longer period of disease, a more advanced clinical staging according to the Hoehn & Yahr, and greater functional decline according both to the UPDRS ADL and Schwab & England, with statistically significant difference between the groups.

Conclusion

Patients with dementia were at a more advanced clinical stage of Parkinson's disease and evidenced greater functional decline in comparison with patients without dementia.

Test-retest reliability and minimal detectable change on balance and ambulation tests, the 36-item short-form health survey, and the unified Parkinson disease rating scale in people with parkinsonism

BACKGROUND AND PURPOSE

Distinguishing between a clinically significant change and change due to measurement error can be difficult. The purpose of this study was to determine test-retest reliability and minimal detectable change for the Berg Balance Scale (BBS), forward and backward functional reach, the Romberg Test and the Sharpened Romberg Test (SRT) with eyes open and closed, the Activities-specific Balance Confidence (ABC) Scale, the Six-Minute Walk Test (6MWT), comfortable and fast gait speed, the Timed "Up & Go" Test (TUG), the Medical

OUTCOMES

Study 36-Item Short-Form Health Survey (SF-36), and the Unified Parkinson Disease Rating Scale (UPDRS) in people with parkinsonism.

SUBJECTS

Thirty-seven community-dwelling adults with parkinsonism (mean age=71 years) participated. The Hoehn and Yahr Scale median score of 2 was on the lower end of the scale; however, the scores ranged from 1 to 4.

METHODS

Subjects were tested twice by the same raters, with 1 week between tests. Test-retest reliability was calculated using intraclass correlation coefficients (ICCs). Minimal detectable change was calculated using a 95% confidence interval (MDC(95)).

RESULTS

The ICCs for test-retest reliability were above .90 for the BBS, ABC Scale, SRT with eyes closed, 6MWT, and comfortable and fast gait speeds. The MDC(95) values for those functional tests were: BBS=5/56, ABC Scale=13%, SRT with eyes closed=19 seconds, 6MWT=82 m, comfortable gait speed=0.18 m/s, and fast gait speed=0.25 m/s. The ICCs for test-retest reliability of SF-36 scores were above .80, with the exception of the social functioning subscale. The MDC(95) values for the SF-36 ranged between 19% and 45%. The MDC(95) values for the UPDRS Activities of Daily Living section, Motor Examination section, and total scores were 4/52, 11/108, and 13/176, respectively.

DISCUSSION AND CONCLUSION

Minimal detectable change values are useful to therapists in rehabilitation and wellness programs in determining whether change during or after intervention is clinically significant. High test-retest reliability of scores for the BBS, ABC Scale, SRT with eyes closed, 6MWT, and gait speed make them trustworthy functional assessments in people with parkinsonism. The SF-36 and UPDRS provide quality-of-life and disease severity rating values in the ongoing assessment of people with parkinsonism.

Dopamine replacement therapy does not restore the ability of Parkinsonian patients to make rapid adjustments in motor strategies according to changing sensorimotor contexts

The ability of dopamine replacement to restore rapid motor adjustments in Parkinson's disease (PD) was investigated. Medicated and non-medicated patients performed finger-to-nose movements while simultaneously bending the trunk forward, without vision. Trunk motion was blocked unexpectedly, necessitating rapid adjustments in arm trajectories. Patients exhibited irregular hand paths, plateaus in hand velocity, and prolonged movement times, which were significantly greater in perturbed trials. Medication improved kinematics but perturbation-induced disturbances persisted and did not approximate the levels of non-perturbed trials nor those of controls. Dopaminergic replenishment in PD may therefore have limited restorative benefits for rapid context-specific motor control.