The Development and Validation of the Impact of Multiple Sclerosis Scale and the Symptoms of Multiple Sclerosis Scale

Article Outline

• Abstract
• Methods
  • Design
  • Participants
  • Procedure
  • Measures
• Results
  • Demographics: Time 1
  • Construct Validity of the IMSS
  • Construct Validity of the SMSS
  • Discriminant Validity: Comparison of IMSS and SMSS Scores by Type of MS
  • Convergent Validity
  • Effect of Duration of MS on the Experience of Symptoms and Impact of MS
  • Time 2 Data: Temporal Stability of the Constructs of the IMSS and SMSS
  • Construct Stability: the IMSS and SMSS
  • Retest Stability
• Discussion
• Conclusions
• APPENDIX 1. The IMSS
• APPENDIX 2. Questions omitted from the IMSS after PCA
• APPENDIX 3. The SMSS
• References
• Copyright

Abstract 

McMillan L, Moore KA. The development and validation of the Impact of Multiple Sclerosis Scale and the Symptoms of Multiple Sclerosis Scale.

Objective

To develop and validate the Impact of Multiple Sclerosis Scale (IMSS) and the Symptoms of Multiple Sclerosis Scale (SMSS) using the Extended Disability Status Scale (EDSS) for construct validity.

Design

Panel design involving test-retest over 4 months.

Setting

A mailed survey.

Participants

Volunteers with a diagnosis of multiple sclerosis (MS) recruited from an MS support service in Australia: 193 people (mean age, 39y) and 150 people participated at time 1 and time 2, respectively.

Interventions

Not applicable.

Main Outcome Measures

Principal components analyses, the Cronbach α, and descriptive statistics for the 2 scales; correlations for construct validity with the EDSS and retest; and confirmatory factor analysis to test the stability of IMSS and SMSS components over time.

Results

The IMSS yielded 5 independent and reliable components; the SMSS yielded 3 components; both component structures were stable over time. These scales showed convergent validity with the EDSS.

Conclusions

The IMSS and SMSS are psychometrically sound scales suitable for clinical and research purposes to assess the symptoms and impact of MS.

Key Words:  Multiple sclerosis , Rehabilitation , Reliability and validity , Signs and symptoms

THE PAST 2 DECADES have seen advances in the diagnosis¹, ² and early treatment of multiple sclerosis (MS). Less attention has been paid to the assessment of the severity of MS symptoms or the trajectory and impact of MS on people’s level of well-being, both of which are variable and uncertain. The aim of this study was to develop and validate 2 measures: one quantifying the experience of a range of physical symptoms related to MS and the second assessing the impact on psychosocial factors that are associated with living with MS. These scales will enable clinicians and researchers to track the impact of MS across time and may be useful in assessing response to treatment.

At present, the most commonly used scale to measure the impact of MS is the Extended Disability Status Scale (EDSS) of Kurtzke.³ However, the EDSS is limited by its focus on mobility to the exclusion of other symptoms and by the requirement that it be completed by a trained clinician, usually a neurologist. It also seems that scores on the EDSS do not reflect a full range of mobility impairment, because several studies have found the distribution of scores on the EDSS to be bimodal,⁴, ⁵ although a unimodal or even a skewed distribution would be expected of scores representing the impact of a progressively degenerative disease on people’s mobility.

Perhaps more important, Coulthard-Morris⁶ reported that the EDSS lacks sensitivity to change. This lack of sensitivity is particularly evident when attempting to track the progressive impairments related to MS over relatively short time spans.⁷, ⁸, ⁹ Poor interrater reliability is another concern with respect to the EDSS. The lack of congruence between trained administrators can be as much as 1 standard deviation (SD), particularly in the lower score range.¹⁰ Furthermore, low scores on the EDSS suggest that the person is hardly affected by MS at all; however, because of the EDSS’s focus on mobility we suggest that such low scores will, at least in some instances, camouflage the presence of other symptoms and impairments in other life domains.

Several commonly occurring symptoms of MS have been identified and include fatigue, visual disturbance, bladder and bowel dysfunction, sexual dysfunction, spasticity, and pain.¹¹, ¹², ¹³, ¹⁴, ¹⁵ In addition, people with MS also experience cognitive impairment and mood and relationship disturbances.¹⁶, ¹⁷ In fact, it is often difficult to say which of these factors are symptoms of MS and which are the impact of living with the disease.

Despite the identification of these symptoms and the many consequences of living with MS such as family problems¹¹ and reduced ability to maintain career and work,¹⁸, ¹⁹ there are no comprehensive measures of the symptoms and the impact of MS. Even the several scales that have been developed in the last decade or so are limited in their range of domains. Like the EDSS, scales such as the Multiple Sclerosis Functional Composite Scale of Fischer et al²⁰ are restricted to tests of mobility and dexterity, or like the Multiple Sclerosis Impact Scale of Hobart et al²¹ and the Health-Related Quality of Life Questionnaire for Multiple Sclerosis Patients of Pfennings et al,²² they are limited to 2 factors: the physical and psychologic impact of MS. Even the Multiple Sclerosis Quality of Life Scale (MSQOL)−54²³ and the Multiple Sclerosis Quality of Life Inventory²⁴ are extensions of the Medical Outcomes Study 36-Item Short-Form Health Survey developed by Ware and Sherbourne²⁵ for which Freeman et al²⁶ noted marked floor effects. Furthermore, Joy and Johnston¹¹ pointed out that health status measures such as the MSQOL-54 do not respond well across spectrums of impairments or within selected populations. At present, there is a paucity of psychometrically sound instruments designed specifically to assess the range of symptoms and factors on which MS has an impact.

Certainly, a patient’s clinical issues can be understood through a comprehensive medical diagnosis and the use of instruments such as magnetic resonance imaging, but for people living with MS it is their perceptions of or beliefs about their own health status that can be equally informative to health care practitioners and more influential on their well-being. Such information can be gathered effectively via reliable and valid standardized self-report questionnaires, and this study aims to present psychometric data on 2 such scales: the Impact of Multiple Sclerosis Scale (IMSS) and the Symptoms of Multiple Sclerosis Scale (SMSS). The EDSS, as the most widely used assessment, will be adapted for use in this study as a self-report indicator of validity for the new scales. The results of this study will provide theoretically relevant and psychometrically sound assessments that are sensitive to changes in symptomotology over types of MS and potentially over the course of MS. Knowledge of the impact of MS on the person and the ability to assess symptom progression are critical to providing effective monitoring and evaluating treatment and intervention strategies.

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Methods 

Design 

A test-retest design was used to explore the factor structure, construct validity, internal reliability, and temporal stability of the newly developed IMSS and SMSS.

Based on a review of the literature, clinical experience, and consultation with a focus group of people with MS, we developed 59 items to assess the impact of MS; these items related to mood, memory, mobility, relationships, and independence. We also developed 12 questions to quantify the symptoms of MS such as fatigue, numbness, visual impairment, and pain, which can be used in conjunction with the IMSS as an indicator of the overall impact of MS. These 2 instruments were developed in parallel, because it is often difficult to establish what constitutes symptoms and what constitutes the impact of disease. All questions were reviewed by 2 medical practitioners before administration.

Participants 

A random sample of 400 people with a confirmed diagnosis of MS was drawn electronically from the database of the Multiple Sclerosis Society of Australia (Victoria). Because the questionnaires were completed anonymously, the questionnaires and a plain language statement inviting participation and outlining the objectives and retest requirements of the study were mailed to the entire sample at times 1 and 2. To match participants’ data from time 1 with data from time 2, the response sheets included a self-generated 6-letter code, comprised of the first 3 letters of mother’s and of father’s given names.

At time 1, 193 people (156 women: mean age ± SD, 40.49±7.66y; 29 men: mean age, 38.97±9.80y; 8 subjects failed to specify sex) returned completed questionnaires, which represented a response rate of 48.25%. This sex imbalance might reflect, in part, epidemiologic data that show that 74% of all Australians with MS are women.²⁷ It might also reflect a tendency on the part of women to respond more to survey requests. There was no significant age difference between male and female respondents.

After the second mailing—which, because of anonymity requirements, went to all 400 people in the original sample—89 of the 193 people from time 1 responded (46% of the original respondents). A further 61 people (51 women, 3 men; 7 participants did not report sex) completed the second-wave questionnaire (representing an additional 15.25% of the original sample of 400). Multivariate analysis of variance (MANOVA) showed that there were no significant differences on time 1 scores for the components of the IMSS and SMSS for those time 1 respondents who replied at time 2 and those who did not. No compelling explanation can be offered for why 61 people completed the questionnaire at time 2 but not at time 1.

Procedure 

This study was approved by the Ethics Committee of Deakin University and the Research Committee of the Multiple Sclerosis Society of Australia (Victoria). A plain language statement outlining the aims of the study, the questionnaire, and a postage-paid envelope were mailed to 400 randomly selected members of the Multiple Sclerosis Society with an invitation for them to participate in a study to validate a questionnaire to assess the impact of MS. The statistical package MS Care^a random generator was used to generate the sample from the 4030 registered members with MS.

Participants were advised that participation in the study would require them to complete a questionnaire on 2 occasions 4 months apart and return it to the researchers in the postage-paid envelope provided.

Measures 

Participants were requested to provide demographic data including age, sex, the age at which they first became aware of the symptoms of MS, year diagnosed with MS, and the type of MS identified. In addition, participants completed the 59 items of the IMSS and the 12 items of the SMSS developed for this study. Both sets of questions were answered on a 5-point Likert scale to indicate the frequency with which each item is experienced from 1 (never) to 5 (always).

Although it was not designed as a self-report measure, we asked participants to complete the EDSS³ to provide a form of concurrent validity data. The EDSS assesses 10 domains, which in the current study, were written in the first person (eg, I have difficulty in walking normally), and participants answered yes or no.

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Results 

The data were analyzed using SPSS/PC, version 12,^b and AMOS, version 5.^b Principal components analysis (PCA), a technique that aggregates large numbers of questions into sets of underlying constructs or components, and the Cronbach α, a technique to assess the theoretic consistency of the questions within each such construct, were used to explore the component structure and internal reliability of the IMSS and the SMSS using time 1 data. Pearson product-moment correlations were used to assess the convergent validity of these scales with the EDSS, and MANOVA was used to assess their divergent validity across types of MS.

A first-order confirmatory factor analysis (CFA) was used with the data obtained from all respondents at time 2 to confirm the validity of the components of the IMSS and the SMSS extracted by PCA at time 1. Pearson product-moment correlations were used to ascertain the stability of the components over time using only data from people who replied at both times 1 and 2.

Demographics: Time 1 

The average age ± SD at which participants first became aware of their MS symptoms was 29.38±8.90 years. The average number of years participants had been diagnosed with MS was 8.24±5.53 years. Sixty-two percent of respondents reported that they had relapsing-remitting MS; 14% had benign MS; 10.9% had secondary chronic progressive MS; 8.3% had primary chronic progressive MS; and 4.6% of respondents failed to answer this question.

Construct Validity of the IMSS 

A correlation matrix of the 59 items of the IMSS showed that only 1 item (My personal beliefs give me strength) failed to correlate at least .30 with any other item. Following Tabachnick and Fidell’s recommendation²⁸ that this item would be unlikely to contribute to any component, we removed it from further analysis.

We performed PCA on the remaining 58 items of the IMSS to extract the underlying constructs. After successive extractions and the removal of 36 items, a 5-component independent solution was accepted. These 5 components explained 67.86% of the variance in the respondents’ scores on the components, and these were labeled as follows: negative mood (5 items), memory impairment (5 items), independence (5 items), successful self-management (4 items), and family relationships (3 items). Each component showed good internal consistency (Cronbach α range, .76–.93).²⁹ The final component structure, showing the questions that load onto each component and their weight or contribution to that factor (range 0.4–1.0 being singularity), eigenvalues, percentage of variance explained, descriptive statistics, intercorrelations among the factors, and the Cronbach α, are presented in table 1 (APPENDIX 1, APPENDIX 2).

Table 1. Components of the IMSS, Component Weightings, Descriptive Statistics, and Correlations Among the Components

Components	Components
	1	2	3	4	5
Component 1: negative mood
I often feel desperate	.91
I often feel unworthy	.88
I often feel worthless	.88
I often feel miserable	.83
I often feel hopeless	.82
Component 2: memory impairment
I forget people’s name		.87
I cannot remember phone numbers		.83
I am aware that I forget things more than before		.81
I need to write down my activities for the day		.77
I sometimes miss appointments		.75
Component 3: independence
MS has made me more independent in many ways			.73
My friendships with others have strengthened			.72
I have become closer to my family/friends			.71
MS has made me value life more			.68
I am more motivated now that I have MS			.63
Component 4: successful self-management
Difficulties in getting around affect me (R)				.85
I am able to do my housework as usual				.82
MS has made me more dependent upon others (R)				.77
I am able to manage my life as usual.				.76
Component 5: family relationships
My relationship with my children has deteriorated (R)					.85
I am able to look after my children as usual					.81
My relationship with my spouse/partner has deteriorated (R)					.51
Eigenvalue	6.59	2.63	2.21	1.97	1.52
Percentage of variance explained	29.96	11.96	10.05	8.96	6.92
Cronbach α	.93	.87	.76	.84	.76
Mean	10.22	12.73	15.21	12.89	8.91
SD	4.65	5.03	4.28	4.38	4.88
Possible scoring range	5–25	5–25	5–25	4–20	3–15
Correlations among components
1. Negative mood	1
2. Memory impairment	.29	1
3. Independence	−.22	−.17	1
4. Successful self-management	−.34	−.26	−.21	1
5. Family relationships	−.02	−.14	−.12	.03	1

Construct Validity of the SMSS 

The 12 items of the SMSS were submitted to PCA. Although some statistical indicators suggested the presence of 1 component, an independent 3-component structure was accepted as the final solution, because these components are more informative than a single component. These components explained 57.63% of the variance in respondents’ scores and were labeled as follows: bodily dysfunction (4 items), cognitive and psychological impairment (4 items), and sensory-motor impairment (4 items). Each component had acceptable internal consistency (Cronbach α range, .66–.83).²⁹ The final component structure, showing the questions that load onto each component and their weight or contribution to that factor (range 0.4–1.0 being singularity), eigenvalues, percentage of variance explained, descriptive statistics, intercorrelations among the factors, and the Cronbach α, are presented in table 2 (appendix 3).

Table 2. Components of the SMSS, Component Weightings, Descriptive Statistics, and Correlations Among the Components

Components	Components
	1	2	3
Component 1: bodily dysfunction
Bladder difficulties	.90
Bowel difficulties	.80
Loss of balance	.64
Spasticity	.52
Component 2: cognitive and psychological impairment
Lack of concentration		.85
Fatigue		.76
Inability to communicate		.64
Visual impairment		.51
Component 3: sensory-motor impairment
Tremors			.69
Numbness			.67
Pain			.60
Paralysis			.58
Eigenvalue	4.41	1.42	1.08
Percentage of variance explained	36.75	11.85	9.03
Mean	10.95	11.25	9.84
SD	4.27	2.94	3.15
Cronbach α	.83	.68	.66
Correlations among components
1. Bodily dysfunction	1
2. Cognitive and psychological impairment	.27	1
3. Sensory-motor impairment	.36	.32	1

Discriminant Validity: Comparison of IMSS and SMSS Scores by Type of MS 

We performed a 1-way between-subjects MANOVA to investigate differences in scores on the components of the IMSS and the SMSS by respondents’ self-reported type of MS (ie, benign, relapsing/remitting, primary chronic progressive, or secondary chronic progressive). Because 9 people failed to indicate type of MS, only data from 184 people were analyzed. A significant global effect was found for type of MS on the components of the IMSS and SMSS. The univariate comparisons showed significant differences by type of MS across all dependent variables: successful self-management, negative mood, memory impairment, independence, bodily dysfunction, cognitive and psychological impairment, and sensory-motor impairment (table 3).

Table 3. Simple Effects and Bonferroni Comparisons for the IMSS, SMSS, and EDSS by Type of MS

Scale	Benign (n=27)	Relapsing/Remitting (n=120)	Primary Chronic Progressive (n=16)	Secondary Chronic Progressive (n=21)	P
IMSS
Negative mood	7.30±3.04	10.43±4.76a	11.86±4.24a	11.52±4.85a	.002
Memory impairment	10.22±4.40a	12.73±4.96a,b	15.94±5.22b	13.67±4.44a,b	.002
Independence	16.04±4.30a	15.70±4.02a	12.12±4.42b	13.48±4.58a,b	.002
Successful self-management	17.15±2.58	13.56±3.63	8.56±3.74a	8.72±3.23a	.001
Family relationships	11.15±4.49a	9.30±4.83a,b	7.88±3.96a,b	6.92±4.73b	.014
SMSS
Bodily dysfunction	7.43±3.53	10.39±3.58	14.44±4.27a	15.48±3.57a	.001
Cognitive and psychological	8.56±2.61	11.30±2.57a	13.81±2.90b	12.00±2.65a,b	.001
Sensory-motor	7.71±3.02	9.85±2.57a	11.94±4.30a	10.43±3.97a	.001

NOTE. Values are mean ± SD. Those means sharing a common subscript do not differ at P<.05.

To determine differences among the 4 groups on each variable, we performed pairwise post hoc comparisons using the Bonferroni adjustment for multiple comparisons.²⁸ Results for all possible pair comparisons of group means are presented in table 3. Mean differences are significant at the .05 level.

The respondents who reported themselves as suffering from benign MS tended to report less frequency of symptoms and a lower impact of MS overall than the other groups, whereas those with primary chronic progressive MS and secondary chronic progressive MS tended to be the most affected. Not all variable scores for these groups differed significantly from those of people with other types of MS. However, people with benign MS reported less negative mood, lower levels of memory impairment, more independence, and better family relationships, and they reported being better able to self-manage their MS than people with primary chronic progressive MS and secondary chronic progressive MS. In general, the scores of people with relapsing/remitting MS fell between those of people with benign or primary chronic progressive MS.

The 4 groups showed a similar pattern of differences on the symptoms of MS. People in the benign group rated themselves as less symptomatic than those in the primary chronic progressive and the secondary chronic progressive groups and also less than people with relapsing/remitting MS. Again, the participants with relapsing/remitting MS scored between the benign MS group and the chronic progressive groups.

Convergent Validity 

The components of the SMSS showed a moderate level of convergent validity with the EDSS (r≥.46). These intercorrelations can be interpreted as providing evidence that the SMSS is a valid indicator of the symptoms of MS (table 4) although more diverse than a focus on mobility alone. The components of the IMSS also correlated with the EDSS (r≥−.21), providing some support for the convergent validity of these components while also suggesting their greater diversity. It is particularly noteworthy that successful self-management of MS correlated (r=−.84) with the EDSS.

Table 4. Intercorrelations of IMSS Factors, SMSS, and EDSS at Time 1

The symptoms of MS also correlated with the impact of MS components: in particular, successful self-management correlated negatively with bodily dysfunction (r=−.74), cognitive and psychological impairment (r=−.48), and sensory-motor impairment (r=−.48). Negative mood was strongly related to cognitive and psychological impairment (r=.42) and sensory-motor impairment (r=.31). The fact that respondents’ scores on the IMSS and SMSS differed in part across types of MS (see table 3) is also indicative of their convergent (and divergent) validity.

Effect of Duration of MS on the Experience of Symptoms and Impact of MS 

We correlated time since diagnosis with the IMSS and SMSS and, as might be expected, found that a longer time since diagnosis correlated significantly with reports of greater bodily dysfunction (r=.37) and sensory-motor impairment (r=.18); conversely, the longer the interval since diagnosis the more negatively people reported themselves as being successful at managing their MS (r=−.21).

Time 2 Data: Temporal Stability of the Constructs of the IMSS and SMSS 

The second wave of data for the IMSS and the SMSS, collected 4 months later, was submitted to CFA with AMOS using data from all respondents at this time (n=150).

Construct Stability: the IMSS and SMSS 

CFA is a statistical technique used to test the replicability of component structure in different samples. In this study, we used time 2 data from the 89 participants who responded on both occasions and data from the 61 respondents who responded only at time 2 (n=150). The questions from both scales were loaded onto their respective components (Fig 1, Fig 2), the components were allowed to covary (see double-headed arrows), and the analyses computed. The fit statistics indicated that the 5-component structure of the IMSS and the 3-component structure of the SMSS were stable across time. The value on each single-headed arrow represents the items’ β weight or contribution to the variance in the construct (eg, I often feel desperate weighs .80 on negative mood), and the numbers on the double-headed arrows represent the correlation between 2 constructs (eg, negative mood and memory impairment correlation, .31). The fit statistics also indicate that these underlying components are potentially stable in further samples. This last is especially encouraging, because the data used for this analysis were not completely independent of time 1 data because 89 of the 150 people whose data were used for this analysis participated at both time 1 and time 2.

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• Fig 1. 

  Confirmatory model of the 22-item IMSS.

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• Fig 2. 

  Confirmatory model of the 12-item SMSS.

Retest Stability 

Pearson product-moment correlations (table 5) were used to assess retest reliability using only the data from participants who had responded at both time 1 and time 2 (n=89). As can be seen by the figures on the leading diagonal, all components were reliable over the 4-month retest period (r≥.70).

Table 5. Four-Month Test-Retest Correlations for IMSS and SMSS

Scale	Negative Mood	Memory Impairment	Independence	Successful Self-Management	Family Relationships	Bodily Dysfunction	Cognitive and Psychological	Sensory-Motor
IMSS
Negative mood	.80†
Memory impairment	.29†	.85†
Independence	−.01	−.07	.71†
Successful self-management	−.25⁎	−.42†	.19	.84†
Family relationships	−.27⁎	−.21	.12	.34†	.70†
SMSS
Bodily dysfunction	.23⁎	.32†	−.21⁎	−.74†	−.13	.90†
Cognitive and psychological	.36†	.54†	−.11	−.54†	−.14	.44†	.80†
Sensory-motor	.40†	.34†	−.16	−.55†	−.17	.60†	.38†	.78†

NOTE. Values in italics represent test-retest correlations.

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Discussion 

The aim of this study was to develop and validate measures of the SMSS and the IMSS. Exploratory factor analysis showed 5 components in the IMSS: negative mood, memory impairment, independence, successful self-management, and family relationships and showed 3 components in the SMSS: bodily dysfunction, cognitive and psychological impairment, and sensory-motor impairment.

These factors, in conjunction with the mean scores for each factor (see Table 1, Table 2), show that MS has an impact on people’s mood and their perception of themselves—for instance, I feel desperate, hopeless, unworthy. Clinicians need to monitor such feelings, because at elevated levels these feelings can be indicative of clinical depression and perhaps, suicidal ideation. Memory impairment, especially for people’s names and phone numbers, is also a factor to consider, however; items such as I need to write down my activities for the day may be more indicative of the impact of MS rather than the former items, which can affect the population more generally unless, of course, they occur most of the time.

The independence, successful self-management, and family relationship components each reflect an aspect of one’s being in the world—that is, the levels of engagement with both metaphysical and social domains. A reduced ability to deal with or engage in these domains may have negative implications for how people with MS manage and on their long-term ability to look after themselves.

Both scales show excellent factor structure in terms of variance explained in respondents’ scores and the internal reliability of those scores. Although the CFA on the second-wave data collected 4 months later were subject to some bias associated with 60% (89/150) of the sample from time 1 being retested, nevertheless, the fit statistics confirmed the underlying components for both scales. Test-retest correlations, using only data from people tested at both times 1 and 2, indicated high levels of temporal stability of scores on the components over time.

Evidence of the discriminate validity of the scales is provided by the sensitivity of both the SMSS and the IMSS to discriminate among people with different types of MS, especially benign MS from primary and secondary chronic progressive MS, and those with relapsing/remitting MS tended to score between the benign and chronic groups. Future work with larger samples, across confirmed types of MS, and with people tracked over time is required to confirm the discriminant utility of the scales and their potential sensitivity to detect changes over time. These changes might be the negative impact of living with MS or benefits associated with treatment.

The correlation of the components of the SMSS and IMSS with each other and with the EDSS, a measure of limited mobility among people with MS, provides some support for the convergent validity of these new scales. However, it must be noted that we used the EDSS as a self-report measure in the current study, and its validity as a self-report measure is unsupported.

It is important also to acknowledge that the time 1 response rate of 48.25%, although better than that typically achieved by mailing samples (some 20%–30%³⁰), might be a biased representation of those approached to participate in the study. Such a possibility pertains to all survey research.

Although we do not have any data at present that could be used to ascertain the sensitivity of the scales to treatment, based on the shown psychometric properties—particularly with respect to their sensitivity to discriminate across types of MS and their high levels of temporal stability—we suggest that the SMSS and IMSS have the potential to detect changes in the severity of MS over time.

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Conclusions 

In this article, we presented the development of 2 scales to assess the IMSS and SMSS. The scales have shown good psychometric properties, are stable across time, and discriminate among people with different types of MS. Although further research is required to confirm the research and clinical utility of these instruments, such as detecting treatment effects at both the individual and group level, we suggest that these scales have the potential to make an important contribution to the evaluation of the severity and impact of MS.

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APPENDIX 1. The IMSS 

The following words relate to the experience of MS for some people. Please rate your experience of these items 1 (Never) to 5 (Always).

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APPENDIX 2. Questions omitted from the IMSS after PCA 

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APPENDIX 3. The SMSS 

Please rate the extent to which you EXPERIENCE the following symptoms 1 (Never) to 5 (Always).

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References 

1. Poser CM , Paty DW , Scheinberg L , et al.   New diagnostic criteria for multiple sclerosis (guidelines for research protocols) . Ann Neurol . 1983;13:227–231
   • View In Article
   • MEDLINE
   • CrossRef
2. McDonald WI , Compston A , Edan G , et al.   Recommended diagnostic criteria for multiple sclerosis (guidelines from the international panel on the diagnosis of multiple sclerosis) . Special report. Ann Neurol . 2001;50:121–127
   • View In Article
3. Kurtzke JF . Rating neurological impairment in multiple sclerosis (an expanded disability status scale EDSS) . J Neurol . 1983;33:1444–1452
   • View In Article
4. Willoughby EW , Paty DW . Scales for rating impairment in multiple sclerosis (a critique) . Neurology . 1988;38:1793–1798
   • View In Article
   • MEDLINE
   • CrossRef
5. Whitaker JN , McFarland HF , Rudge P , Reingold SC . Outcomes assessment in multiple sclerosis clinical trials (a critical analysis) . Mult Scler . 1995;1:37–47
   • View In Article
   • MEDLINE
6. Coulthard-Morris ML . Clinical rehabilitation outcome measures . In:  Burks JS ,  Johnson JP editor. Multiple sclerosis (diagnosis, medical management and rehabilitation) . New York: Demos; 2000;p. 221–290
   • View In Article
7. Koziol JA , Frutos A , Sipe JC , Romine JS , Beutler E . A comparison of two neurologic scoring instruments for multiple sclerosis . J Neurol . 1996;243:209–213
   • View In Article
   • MEDLINE
   • CrossRef
8. Rudick R , Antel J , Confavreux C , et al.   Clinical outcomes assessment in multiple sclerosis . Ann Neurol . 1996;40:469–479
   • View In Article
   • MEDLINE
   • CrossRef
9. Sharrack B , Hughes RA . Clinical scales for MS . Neurol Sci . 1996;135:1–9
   • View In Article
10. Weinshenker BG , Issa M , Baskerville J . Long-term and short-term outcome of multiple sclerosis . Arch Neurol . 1996;53:353–358
    • View In Article
    • MEDLINE
11. In:  Joy JE ,  Johnston RB editor. Multiple sclerosis (current status and strategies for the future) . Washington (DC): Natl Acad Pr; 2000;
    • View In Article
12. La Rocca NG . Cognitive and emotional disorders . In:  Burks JS ,  Johnson KP editor. Multiple sclerosis (diagnosis, medical management and rehabilitation) . New York: Demos; 2000;p. 405–423
    • View In Article
13. Paty DW , Ebers GC . Clinical features . In:  Paty DW ,  Ebers GC editor. Multiple sclerosis (contemporary neurology series) . Philadelphia: FA Davis; 1998;p. 135–182
    • View In Article
14. Paty DW , Noseworthy JH , Ebers GC . Diagnosis of multiple sclerosis . In:  Paty DW ,  Ebers GC editor. Multiple sclerosis (contemporary neurology series) . Philadelphia: FA Davis; 1998;p. 48–134
    • View In Article
15. Polman CH , Thompson AJ , Murray TJ , McDonald WI . In: Multiple sclerosis (the guide to treatment and management) . 5th ed.. New York: Demos; 2001;
    • View In Article
16. Blazer DG , Kessler RC , McGonagle KA , Swartz MS . The prevalence and distribution of major depression in a national community sample. The National Comorbidity Survey . Annu J Psychiatry . 1994;151:979–986
    • View In Article
17. McCabe MP , McDonald E , Deeks AA , Vowels LM , Cobain MJ . The impact of multiple sclerosis on sexuality and relationships . J Sex Res . 1996;3:241–248
    • View In Article
18. Eklund VA , McDonald ML . Descriptions of persons with multiple sclerosis, with an emphasis on what is needed for psychologists . Professional Psychol Res Pract . 1991;22:277–284
    • View In Article
19. Murray TJ . The psychological aspects of multiple sclerosis . Neurol Clin . 1995;13:197–223
    • View In Article
    • MEDLINE
20. Fischer JS , Rudick RA , Cutter GR , Reingold SC  National MS Society Clinical Outcomes Assessment Task Force . The Multiple Sclerosis Functional Composite Measure (MSFC) (an integrated approach to MS clinical outcome assessment) . Mult Scler . 1999;5:244–250
    • View In Article
    • MEDLINE
    • CrossRef
21. Hobart J , Lamping D , Fitzpatrick R , Riazi A , Thompson A . The Multiple Sclerosis Impact Scale (MSIS-29) . Brain . 2001;124:962–973
    • View In Article
    • MEDLINE
    • CrossRef
22. Pfennings LE , Van der Ploeg HM , Cohen L , et al.   A health-related quality of life questionnaire for multiple sclerosis patients . Acta Neurol Scand . 1999;100:148–155
    • View In Article
    • MEDLINE
    • CrossRef
23. Vickrey BG , Hays RD , Harooni R , Myers LW , Ellison GW . A health-related quality of life measure for multiple sclerosis . Qual Life Res . 1995;4:187–206
    • View In Article
    • MEDLINE
    • CrossRef
24. Ritvo PG , Fischer JS , Miller DM , Andrews H , Paty DW , LaRocca NG . Multiple Sclerosis Quality of Life Inventory (MSQLI) (a user’s manual) . New York: National Multiple Sclerosis Society; 1997;
    • View In Article
25. Ware JE , Sherbourne CD . The MOS 36-Item Short-Form Health Survey (SF-36). I. Conceptual framework and item selection . Med Care . 1992;30:473–483
    • View In Article
    • MEDLINE
    • CrossRef
26. Freeman JA , Hobart JC , Langdon DW , Thompson AJ . Improving measurement scales (is adding items the answer?) . [abstract] Ann Neurol . 1999;46:507
    • View In Article
27. Access Economics . Actively positively (strategic implications of the economic costs of multiple sclerosis in Australia) . Canberra: Access Economics; 2005;
    • View In Article
28. Tabachnick BG , Fidell LS . In: Using multivariate statistics . 4th ed.. New York: Allyn & Bacon; 2001;
    • View In Article
29. Hair JF , Anderson RE , Tatham RL , Black WC . In: Multivariate data analysis . 4th ed.. Upper Saddle River: Prentice Hall; 1998;
    • View In Article
30. Moser C , Kalton G . In: Survey methods in social investigation . 2nd ed.. Aldershot: Gower; 1979;
    • View In Article

• a MS Society of Victoria Ltd, 54 Railway Rd, Blackburn, Victoria 3130, Australia.
• b SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL 60606.