Multiple Sclerosis Impact Scale (MSIS-29): reliability and validity in hospital based samples

Background and aim: The psychometric properties of rating scales are sample dependent and need evaluations in different samples. The Multiple Sclerosis Impact Scale (MSIS-29), a new patient based rating scale for multiple sclerosis (MS) was predominantly developed from a community based sample derived from the MS Society. A number of important patient characteristics of this sample remain unknown. The aim of the study was to evaluate five psychometric properties of the MSIS-29 in three hospital based samples: people admitted for rehabilitation, people admitted for intravenous corticosteroid treatment for MS relapses, and people with primary progressive MS. METHODS: People with MS were recruited from the three clinical settings. They completed several health measures. MSIS-29 data were evaluated for data quality, scaling assumptions, acceptability, reliability and validity, and compared with those from a previously reported community based study. RESULTS: A total of 233 people (rehabilitation p=53; corticosteroids p=76; primary progressive p=104) completed questionnaires. In all samples, missing data were low (or=0.91). Correlations between the MSIS-29 and other scales were consistent with a priori hypotheses. Findings were consistent with those from the community samples. CONCLUSIONS: The psychometric properties of the MSIS-29 are consistent across three hospital based samples, and similar to those in the community samples. These findings further support its use as an outcome measure in different clinical settings.     

Evidence-based measurement in multiple sclerosis: the psychometric properties of the physical and psychological dimensions of three quality of life rating scales

The selection of measures of quality of life used in clinical trials of multiple sclerosis (MS) should be evidence-based. Head-to-head comparison of measures facilitates the selection of measures. The aim of the study was to compare the psychometric properties of the physical and psychological dimensions in three measures of quality of life to aid choice of the most appropriate scale for use in clinical trials of MS. One hundred and twenty-one people with MS (rehabilitation = 57; steroids = 64) completed a selection of health measures before and after treatment. The psychometric properties of three measures of physical function (MSIS-29 physical, SF-36 physical functioning, FAMS mobility) and three measures of psychological function (MSIS-29 psychological, SF-36 mental health, FAMS emotional well-being) were compared by examining data quality, scaling assumptions, acceptability, reliability, validity and responsiveness. Physical (0.63-0.71) and psychological (0.70-0.75) scales were substantially correlated indicating they measure related constructs. The MSIS-29 physical and psychological scales satisfied all criteria for internal consistency reliability (physical = 0.91; psychological = 0.89) and validity. The SF-36 physical scale had a notable floor effect (20%). The FAMS mobility scale had lower reliability (alpha = 0.78) compared to other measures. The MSIS-29 physical (effect size = 0.91) and psychological (effect size = 0.62) scales were the most responsive. In these three samples, the MSIS-29 had better measurement properties for combined physical and psychological health than the SF-36 and the FAMS.     

The multiple sclerosis impact scale (MSIS-29) is a reliable and sensitive measure

OBJECTIVE: The aim of this study was to assess the psychometric properties of the Multiple Sclerosis Impact Scale (MSIS-29) for patients in the community and in a hospital setting. METHODS: During an epidemiological study, 172 people with multiple sclerosis (MS) were examined and completed the MSIS-29, the London Handicap Scale, and Beck's Depression Inventory; disability was assessed by the Kurtzke Expanded Disability Status Score (EDSS) and the Multiple Sclerosis Functional Composite. At the hospital neurology clinic, 102 MS patients completed the MSIS-29 and EDSS assessments were performed; 41 of these patients had repeat evaluations six months later. The psychometric properties of the MSIS-29 were examined. RESULTS: In the 172 community and the 102 hospital patients the psychometric properties of the MSIS-29 were satisfactory, with high convergent and low divergent validity. It was significantly responsive to change in the contexts of self-reported change (p<0.034) and EDSS worsening (p<0.001). The MSIS-29 physical score did not change over time when the EDSS was stable, and increased significantly in proportion to EDSS deterioration (p = 0.014). CONCLUSIONS: The psychometric properties of the MSIS-29 are acceptable; it is a valuable outcome measure in intervention studies of patients with MS.     

Validity of Korean Versions of the Multiple Sclerosis Impact Scale and the Multiple Sclerosis International Quality of Life Questionnaire

Background and Purpose

Assessment of the health-related quality of life (HRQoL) is important in clinical evaluations of multiple sclerosis (MS) patients for quantifying the impact of illness and treatment on their daily lives. Although MS-specific HRQoL instruments have been used internationally, there are no data regarding HRQoL instruments specifically designed for patients with MS in Korea. The objective of this study was to determine the reliability and validity of the Korean Multiple Sclerosis Impact Scale (MSIS-29) and the Multiple Sclerosis International Quality of Life (MusiQoL) questionnaire.

Methods

Fifty-six patients with MS were recruited from June 2009 to February 2010 at the National Cancer Center in Korea. The original English versions of the MSIS-29 scale and the MusiQoL questionnaire were translated into Korean and evaluated for their acceptability, reliability, and validity.

Results

The patients wereaged 36.5±8.6 years (mean±SD; range, 20-56 years). Their score on the Expanded Disability Status Scale was 2.0±1.9 (mean; range, 0-7.5), and their disease duration was 5.2±4.7 years (mean±SD; range, 1-24 years). The Korean versions of the MSIS-29 and MusiQoL questionnaires showed satisfactory psychometric properties, including construct validity (item-internal consistencies of 0.59-0.95 and 0.59-0.92, respectively; item-discriminant validities of 95-100% and 93.8-100%), internal consistency (Cronbach''s alpha coefficients of 0.96-0.97 and 0.77-0.96), reliability (intraclass correlation coefficients of 0.78-0.90 and 0.50-0.93), unidimensionality (Loevinger scalability coefficients of 0.70-0.78 and 0.63-0.90), and acceptability. External validity testing indicated the presence of significant correlations between similar aspects of the two questionnaires.

Conclusions

The Korean translated versions of the MSIS-29 and MusiQoL questionnaires demonstrated reliability and validity for measuring HRQoL in Korean patients with MS.     

How responsive is the Multiple Sclerosis Impact Scale (MSIS-29)? A comparison with some other self report scales

OBJECTIVES: To compare the responsiveness of the Multiple Sclerosis Impact Scale (MSIS-29) with other self report scales in three multiple sclerosis (MS) samples using a range of methods. To estimate the impact on clinical trials of differing scale responsiveness. METHODS: We studied three discrete MS samples: consecutive admissions for rehabilitation; consecutive admissions for steroid treatment of relapses; and a cohort with primary progressive MS (PPMS). All patients completed four scales at two time points: MSIS-29; Short Form 36 (SF-36); Functional Assessment of MS (FAMS); and General Health Questionnaire (GHQ-12). We determined: (1) the responsiveness of each scale in each sample (effect sizes): (2) the relative responsiveness of competing scales within each sample (relative efficiency): (3) the differential responsiveness of competing scales across the three samples (relative precision); and (4) the implications for clinical trials (samples size estimates scales to produce the same effect size). RESULTS: We studied 245 people (64 rehabilitation; 77 steroids; 104 PPMS). The most responsive physical and psychological scales in both rehabilitation and steroids samples were the MSIS-29 physical scale and the GHQ-12. However, the relative ability of different scales to detect change in the two samples was variable. Differing responsiveness implied more than a twofold impact on sample size estimates. CONCLUSIONS: The MSIS-29 was the most responsive physical and second most responsive psychological scale. Scale responsiveness differs notably within and across samples, which affects sample size calculations. Results of clinical trials are scale dependent.     

Measuring quality of life in multiple sclerosis: not as simple as it sounds

Data from a clinical study presented an opportunity to examine the psychometric properties of the Leeds Multiple Sclerosis Quality of Life scale (LMSQoL), which has undergone limited psychometric evaluation. LMSQoL and Multiple Sclerosis Quality of Life-54 (MSQoL-54) data were collected from 90 people with multiple sclerosis (MS) living in the community. Standard psychometric methods to examine data quality, scaling assumptions, scale to sample targeting, reliability, validity, and responsiveness were employed. The LMSQoL satisfied criteria for data quality (no missing data), scaling assumptions (item-total correlations: 0.24-0.56), reliability (Cronbach's alpha: 0.71), and demonstrated responsiveness (effect size: 0.34). Correlations between the LMSQoL and MSQoL-54 physical (range: -0.02 to -0.50) and emotional subscales (range: -0.38 to -0.65) were similar; the magnitude and pattern was not consistent with predictions based on the construct purported to be measured by the LMSQoL. The LMSQoL satisfied many psychometric criteria in this small study, however, it was difficult to interpret the validity data. From this, two fundamental measurement issues are highlighted. Firstly, current methods of examining rating scales provide only circumstantial evidence of validity; secondly, health-rating scales should be developed on the basis of clear conceptual definitions.     

Tried and tested: the psychometric properties of the multiple sclerosis impact scale (MSIS-29) in a population-based study

OBJECTIVE: To investigate the psychometric properties of the Multiple Sclerosis Impact Scale (MSIS-29) and to assess the relationship between the Kurtzke Expanded Disability Status Scale and the physical and psychological parts of this score. METHODS: A population-based study identified cases with definite multiple sclerosis (MS) in the north-east region of Ireland. They were examined and completed the MSIS-29. Cases were classified as mild (Expanded Disability Status Score (EDSS) 0-3.0), moderate (EDSS 3.5-5.5), or severe (6.0-9.5) MS. RESULTS: The 248 participants (82 male, 166 female) had a mean age of 49.1 years (SD 12.4). EDSS ranged from 0 to 9.5 (median 6.0). Data quality was excellent (0.02% missing data), physical and psychological scores spanned the entire range with low floor and ceiling effects. Internal consistency was high (Cronbach's alpha 0.97 - physical score, 0.93 - psychological score). The convergent validity of the physical impact score of the MSIS-29 with the Kurtzke EDSS was confirmed with a high Spearman's rank coefficient correlation of 0.63 (P = 0.01). Physical impact scores for mild, moderate, and severe disability as were statistically different at 25.9%, 48.0%, and 63.9%, respectively. Mean psychological score was non-significantly higher in the moderately disabled group at 47.4% compared with the severely disabled at 44.3% (P = 0.58). CONCLUSIONS: The MSIS-29 is an acceptable, reliable, and valid method of recording quality of life. A significant relationship between higher physical impact scores of the MSIS-29 and higher Kurtzke EDSS values suggests that is may be of use in clinical trials to monitor progression.     

Proxy ratings from multiple sources: disagreement on the impact of multiple sclerosis on daily life

Background and purpose:  The use of self-report measurements may be problematic in patients with limitations that interfere with reliable self-assessment like cognitive impairment, as may be the case in multiple sclerosis (MS). In these situations proxy respondents, such as close relatives or healthcare providers, may provide valuable information. To examine the accuracy and value of healthcare providers and close relatives to assess disease impact of MS.
Methods:  MS patients, close relatives and healthcare providers completed the Multiple Sclerosis Impact Scale (MSIS-29) before and after a rehabilitation program. Agreement between outcomes was assessed by calculating mean absolute and directional differences and intraclass correlation coefficients.
Results:  Comparison of ratings between patients and proxy respondents revealed low levels of agreement. Close relatives appeared to significantly overestimate the disease impact of MS whereas healthcare providers tended to underestimate the disease impact of MS.
Conclusion:  Caution is advised when incorporating close relatives and healthcare providers as proxy respondents in a rehabilitation setting. However, when close relatives are consulted, one should expect a certain level of overestimation of disease impact. When consulting healthcare providers, one should expect a certain level of underestimation of disease impact.     

Measuring health-related quality of life in patients with progressive supranuclear palsy

The development of psychometrically sound health-related quality of life (Hr-QoL) instruments has made it possible to assess subjectively experienced Hr-QoL quantitatively, and to incorporate Hr-QoL as a measure in medical research and clinical trials. Hr-QoL in patients with progressive supranuclear palsy (PSP) has been measured using generic (not disease-specific) instruments, or Parkinson's disease-specific scales. We give an overview of the development of a disease-specific Hr-QoL instrument for patients with PSP. Based on interviews with 27 patients with PSP a preliminary Hr-QoL instrument was developed and administered to over 300 people with PSP in the UK and US. Following psychometric analysis a rating scale with a physical and a mental subscale emerged. In this patient sample, both subscales satisfied criteria for scaling assumptions, acceptability, reliability and validity (correlations with other measures consistent with a priori hypotheses). The psychometric properties of this questionnaire are undergoing further evaluation.     

Impact of depression and disability on quality of life in Iranian patients with multiple sclerosis

Multiple sclerosis (MS) can influence all aspects of a patient's health. This study determines the main factors affecting quality of life (QoL) in Iranian MS patients. QoL (Multiple Sclerosis Impact Scale; MSIS-29), disability (Expanded Disability Status Scale; EDSS) and depression (Beck Depression Inventory; BDI) were assessed in 106 MS patients. EDSS, clinical course and MS duration significantly correlated with physical MSIS-29. Depression highly correlated with both physical and psychological MSIS-29. Regression analyses showed that depression and EDSS predicted physical health. Psychological health was predicted by depression. These findings highlight that depression and physical disability strongly influence QoL in Iranian MS patients.     

Validation of selected aspects of psychometry of the Polish version of the Multiple Sclerosis Impact Scale 29 (MSIS-29)

BACKGROUND AND PURPOSE: Because of the small number of self-reported measures of disease impact on the quality of patients' life used in Poland and specific for multiple sclerosis (MS), the aim of the study was to validate selected aspects of psychometry of the Polish adaptation of the Multiple Sclerosis Impact Scale 29, MSIS-29. MATERIAL AND METHODS: MSIS-29 was first published by Hobart and Thompson in 2001, and consists of 29 questions, the first 20 of which address the physical impact component and 9 assess the psychological impact. The higher the score, the worse is the impact of the disease on quality of patient's life. Validation analysis consisted of translation of the original English version into Polish according to all necessary translation principles and of assessment of convergent validity and internal reliability of the Polish version of MSIS-29. 104 randomly selected patients with definite MS (according to McDonald criteria) were examined: 77 women and 27 men; mean age was 36.9+/-9.4 years, and the mean disease duration was 9.05+/-6.68 years. The disability of the patients was assessed according to the Expanded Disability Status Scale (EDSS). Apart from the examined measure (MSIS-29) subjects were also asked to complete the Functional Assessment of Multiple Sclerosis (FAMS), Beck's Depression Inventory (BDI-II) and the Fatigue Severity Scale (FSS). RESULTS: MSIS-29 correlated with EDSS, FAMS, BDI-II and FSS. Internal consistency of MSIS-29 was satisfactory. CONCLUSIONS: Psychometric-statistical analysis showed that the Polish version of MSIS-29 is a valuable measure to examine the impact of disease on patients' life. The studies should be continued taking into account other aspects of psychometry.     

Multiple Sclerosis Impact Scale (MSIS-29): relation to established measures of impairment and disability

OBJECTIVE: To validate the newly developed Multiple Sclerosis Impact Scale (MSIS-29) in a large, well characterized, independent group of MS patients by investigating the relation between the MSIS-29 and the Guy's Neurological Disability Scale (GNDS), the Expanded Disability Status Scale (EDSS) and the MS Functional Composite (MSFC). METHODS: Two hundred MS patients were recruited at our outpatient department. At the same visit GNDS, EDSS, MSFC and MSIS-29 were assessed. Data obtained from GNDS, EDSS and MSFC assessment were compared to both physical and psychological impact scores of the MSIS-29. In addition the contribution of GNDS subcategories, EDSS functional systems and MSFC components to the physical and psychological impact scores of the MSIS-29 was studied. RESULTS: Median scores were 37.5 for the physical and 22.2 for the psychological impact score of the MSIS-29, 13.0 for GNDS and 4.0 for EDSS. Mean MSFC was 0.07. The physical impact score showed good correlations with both GNDS (0.79) and EDSS (0.68) and a moderate correlation with the MSFC (-0.53). The psychological impact score showed weak correlations with EDSS (0.22) and MSFC (-0.30) and a moderately strong correlation with the GNDS (0.58). In 50 (25%) patients, scores on physical and psychological impact scales diverted, i.e., a relative high score on one scale combined with a relative low score on the other scale. This was related to the clinical disease course. CONCLUSION: Our study supports the use of the MSIS-29 as a measure for the assessment of physical impact of MS on normal daily life. In addition, our data provides a deeper understanding of the factors that determine both physical and psychological disease impact. Discrepancies between the latter two aspects deserve further attention.     

Psychometric characteristics of PIMS--compared to PDQ-39 and PDQL--to evaluate quality of life in Parkinson's disease patients: validation in Spanish (Ecuadorian style)

OBJECTIVE: Analyze PIMS (Parkinson's impact scale) properties following the recommendations of the Scientific Advisory Committee of the Medical Outcomes Trust. METHODS: An analytical cross-sectional study to evaluate the psychometric qualities and scale assumptions of PIMS: quality of data, acceptability, reliability, validity, internal consistency, and construct validity. RESULTS: The sample included 131 patients with Parkinson's disease (PD), of which 39 (29.7%) were women. Psychometric qualities and scale assumptions, all of them are suitable. CONCLUSIONS: We therefore believe that PIMS is a useful and recommendable specific tool for measuring quality of life in PD patients.     

The longitudinal relationship between the patient-reported Multiple Sclerosis Impact Scale and the clinician-assessed Multiple Sclerosis Functional Composite

BACKGROUND: To examine the longitudinal relationship between the patient-rated Multiple Sclerosis Impact Scale (MSIS-29) and the doctor-reported Multiple Sclerosis Functional Composite (MSFC). METHODS: Two-hundred and four MS patients at baseline and 150 patients one to three years later had MSFC and MSIS-29 assessments. Cross-sectional correlations between these measures and correlations of change in scores were examined. Minimally important change (MIC) in the MSFC was defined at either 0.5 or 0.32 SD from baseline. Effect sizes (ES) were calculated. RESULTS: Validity: The MSIS-29 physical correlated moderately with the total MSFC score and the 25-foot timed walk and 9-hole peg test. Correlations of the MSIS-29 physical with the PASAT, and the MSFC with the MSIS-29 psychological were weak. Responsiveness: When MIC in the MSFC was defined as 0.5, mean MSIS-29 physical change was 11.26 (ES = 0.53). At MSFC change of 0.32, mean MSIS-29 physical change was 10.4 (ES = 0.52). Change in MSFC scores correlated weakly with change in the MSIS-29 scores. Stability: In patients with stable MSFC scores, the mean MSIS-29 physical scores improved minimally over time with negligible ES. CONCLUSIONS: Although the MSIS-29 physical demonstrates moderate cross-sectional correlation with the MSFC, the weak correlations of change scores between the two instruments indicate that they measure different aspects of the effects of multiple sclerosis morbidity.     

Psychometric attributes of the Hospital Anxiety and Depression Scale in Parkinson's disease

The Hospital Anxiety and Depression Scale (HADS) has been used in Parkinson's disease (PD) but information about its psychometric properties in this context is limited. The aim of this study is to assess the psychometric properties of the HADS in PD. In an observational, cross‐sectional analysis, HADS data quality, acceptability, scaling assumptions, internal consistency, construct validity, and precision were explored. From a sample of 387 PD patients, 22% and 14% scored ≥11 points (definite case) on the HADS anxiety and depression subscales, respectively. Cronbach's alpha was 0.81 and 0.83 for these subscales. Factor analysis revealed two factors (49.8% of the variance) representing anxiety and depression. The HADS closely correlated with health‐related quality of life (HRQL) measures and displayed satisfactory discriminative validity for patients grouped by severity level, disease duration, HRQL status, and treatment. The SEM was 1.84 for HADS‐Anxiety and 1.72 for HADS‐Depression. The HADS is an acceptable, consistent, valid, precise, and potentially responsive scale for use in PD. © 2009 Movement Disorder Society     

Talking the talk on walking the walk

Background The Multiple Sclerosis Walking Scale (MSWS-12) was developed to measure the impact of multiple sclerosis on walking. Many other disabling neurological conditions affect patients’ ability to walk, and a generic measure of walking could provide valuable insights into patients’ perceptions in clinical trials and epidemiological studies as well as routine clinical practice. Objective To evaluate the clinical usefulness and psychometric properties of the Walking Impact Scale (Walk-12), a modified version of the MSWS-12, in patients with neurological conditions. Design A prospective, observational study of 120 consecutive patients admitted for rehabilitation. The Walk-12 was used to measure the impact of neurological disability on walking. Traditional psychometric methods (data quality, scaling assumptions, targeting, reliability, validity and responsiveness) were used to assess the Walk-12. Transition questions were used on discharge to measure perception of change. Outcome was also measured using the timed walk test (TWT), Barthel Index (BI) and Functional Independence Measure (FIM). Results For the total group, missing data were few, scaling assumptions were satisfied, and internal consistency was 0.94. Correlations between the Walk-12 and TWT, BI and FIM motor score were moderate (r = −0.58, −0.26, −0.31). Responsiveness of the Walk-12 was high (effect size = 1.12). Relationships between effect size and patients’ and physiotherapists’ opinion of change in walking demonstrated good concordance. Preliminary subgroup analyses indicate satisfactory psychometric properties across different neurological conditions; however, sample numbers in these analyses are small. Conclusions In this sample of neurologically disabled patients the Walk-12 was clinically useful and satisfied standard psychometric criteria. This provides preliminary evidence that it may be suitable as a generic measure of walking ability. Received in revised form: 9 February 2006     

Measuring disability in multiple sclerosis: is the Community Dependency Index an improvement on the Barthel Index?

The Community Dependency Index (CDI) was developed due to concerns that the Barthel Index (BI) was limited as a measure of physical function in community settings. However, no studies have compared the two rating scales within multiple sclerosis (MS). The aim of this study was to determine whether, in a community-based sample of people with MS, the CDI is a better measure than the BI. BI and CDI data were collected from 90 people with MS. Four measurement properties were compared: scaling assumptions (item mean scores, corrected item-total correlations), acceptability (score distributions, floor/ceiling effects), reliability (Cronbach's alpha) and validity (concurrent, discriminant, group differences, relative validity). Both scales satisfied recommended criteria for scaling assumptions (indicating it was legitimate to report a summed score) and internal consistency reliability (alpha > 0.85). The scales were highly correlated (r = 0.96), indicating they measured the same construct. Both scales demonstrated good group differences validity, but the BI was marginally superior. Notable ceiling effects (BI > CDI) were demonstrated for both scales, particularly in those less disabled. This study sample had relatively minor levels of disability, with over 70% still being independently mobile. In this sample of people with MS, the measurement properties of the BI and CDI examined were very similar, suggesting the CDI does not appear to have achieved its goal of better measurement.     

Pregnancy in multiple sclerosis: clinical and self-report scales

Relapse rate is decreased during pregnancy in multiple sclerosis (MS). Risk for postpartum relapse is increased in the first 3 months after delivery. We aimed to study clinical course of MS around pregnancy, using clinical as well as self-report scales, including data on quality of life (QoL), and to identify clinical factors predisposing for postpartum relapse. We performed a prospective, longitudinal study among 35 MS patients and 20 controls. In patients we assessed expanded disability status scale (EDSS), the Guy’s neurological disability scale (GNDS) and the multiple sclerosis impact scale 29 (MSIS-29). In patients and controls we assessed the MOS 36 item short form health survey questionnaire (SF36), consisting of eight domains. The previously described surge in relapses after delivery was also obvious in this study (p = 0.005). At group level EDSS and MSIS-29 did not show overt fluctuations over time. The GNDS, however, improved during the third trimester, compared to the first trimester (p = 0.003). A concomitant improvement in the SF36 domains vitality (p < 0.001) and general health (p = 0.001) was found in patients. At the final visit, at least 9 months after delivery, no worsening of EDSS, GNDS, MSIS-29 or SF36 was observed compared with the (for MS, beneficial) third trimester. Duration of disease, relapses in the year preceding pregnancy or relapses during pregnancy were not associated with postpartum relapse. QoL is improved during pregnancy. Although relapse rate was increased directly after delivery, in the mid long term after delivery no adverse effects of pregnancy on MS were found.     

International cooperative ataxia rating scale (ICARS): Appropriate for studies of Friedreich's ataxia?

Clinicians require scientifically rigorous, clinically meaningful rating scales to evaluate the health impact of disease and treatment that cannot be measured using conventional laboratory instruments. This study evaluated the psychometric properties of the International Cooperative Ataxia Rating Scale (ICARS), a commonly used clinician-rated measure, in Friedreich's ataxia (FRDA). People with confirmed FRDA were assessed by using the ICARS. Two assumptions of its measurement model were tested: the legitimacy of reporting ICARS scores in FRDA, and the acceptability, reliability, and validity of total and subscale scores. Seventy-seven people with FRDA were assessed. The ICARS total score effectively satisfied all psychometric criteria tested. The posture and gait disturbances subscale also performed well. The other three subscales did not pass standard criteria for tests of scaling assumptions, reliability, and validity. This small study recommends only the use of the ICARS total score as a measure of FRDA. However, the extent to which this score quantifies the true extent of FRDA remains uncertain as our validity testing was limited, partly by the lack of appropriate validating measures. Further validity testing, and examination of responsiveness, is required before the ICARS can be recommended as an outcome measure for treatment trials of FDRA.     

Quality of life in multiple sclerosis: should clinicians trust proxy ratings?

PURPOSE: Measures of quality of life (QoL) are increasingly used to monitor psychological and social well being of clients with chronic illnesses. They are particularly useful in cases where an illness results in multiple disabilities. Where clients have difficulty completing the measure, others who know them may act as proxies. It is important, therefore to assess the accuracy of proxy scores. This study compared the QoL scores given by people with multiple sclerosis (PWMS) with proxy scores given by close relatives. METHOD: The Functional Assessment of Multiple Sclerosis (FAMS) quality of life instrument (Cella et al.) was used. Forty PWMS completed the measure in face-to-face interviews with a speech and language therapist. Close relatives were asked to independently complete the measure on behalf of these clients. RESULTS: The overall correlation between client and proxy scores was 0.62, which Sneeuw et al. suggest indicates good agreement. As in previous studies with other groups of clients, proxies underestimated the scores of PWMS. Despite these findings, the results showed substantial disagreements for individual clients and their proxies and a relationship was found which suggests that proxies underestimate the scores of clients with better QoL and overestimate those with poorer QoL scores. CONCLUSION: The level of agreement found between client and proxy scores and the tendency for proxies to underestimate clients' scores are consistent with research with other client groups. The overestimation by proxies of clients who rate their QoL as poor needs further investigation. If confirmed it may complicate the estimation of client scores from those of proxies. We conclude that while proxy scores may be useful as a means of estimating the QoL of groups of clients in research studies they should be used cautiously in the prediction of the QoL of individual clients at the clinical level.