The Life Changes in Epilepsy Scale: Development and Establishment of Content and Face Validity

Abstract

Purpose/Objectives

Epilepsy is the most common chronic neurological disease in the United States. Adults with epilepsy suffer downturns in quality of life. The development of self-management interventions aimed at improving the quality of life of adults with epilepsy is hindered by the lack of a sensitive, patient-centered outcome measure. The purpose of this study was to develop the Life Changes in Epilepsy Scale (LCES); a second purpose was to establish evidence of the content and face validity of the LCES.

Methods

The LCES was developed based on existing qualitative data and a theoretical framework derived from the literature; items were developed to measure perceived changes in the areas of social functioning, somatic health, and subjective well-being since epilepsy onset. Content validity indices were calculated based on evaluation of the scale by three experts in the field of epilepsy, while face validity was evaluated by five adults with epilepsy who were recruited from a Midwestern epilepsy clinic; qualitative data regarding the appropriateness of outcomes included in the LCES were also collected.

Results

The initial version of the LCES included 41 items. Following review of the LCES by experts in which both scale- and item-content validity indices of 1.0 were achieved, the number of items was reduced to 35. All 35 items were maintained following review of the LCES by adults with epilepsy. Qualitative comments from participants supported the inclusion of outcomes measured by the LCES.

Conclusions/Implications

Results of this study provide evidence of both content and face validity of the LCES. Further psychometric testing of the scale is ongoing. In addition to being used as an outcome measure in intervention studies, the psychometrically-tested LCES can serve as a valuable tool for advanced practice nurses caring for adults with epilepsy in inpatient, outpatient, and community settings. The LCES can allow for a brief assessment of ways in which patients’ lives have been affected by epilepsy, thus allowing nurses to develop targeted nursing interventions for these patients.

Epilepsy, often incurable, is the most common chronic neurological disease in the United States (U.S.), affecting more than 3 million Americans. In the U.S., 500 people are diagnosed with the condition each day. Seventy percent of new-onset epilepsy diagnoses occur in adults.¹ Given epilepsy’s chronic nature, those affected by it are often charged with managing the disease for the remainder of their lives. Prior research indicates that adults with epilepsy experience marked decrements in quality of life (QoL).^2,3

The development and testing of behavioral self-management interventions for adults with epilepsy is hindered by the lack of a sensitive, patient-centered outcome measure. There currently exist several epilepsy-specific QoL measures, many of them having demonstrated evidence of reliability and validity. However, these measures are not sensitive enough, as they do not measure perceived changes in QoL caused by epilepsy. That is, they are not capable of detecting life changes specifically caused by epilepsy and its associated self-management. Recent patient-centered outcomes research involving persons with adult-onset epilepsy has revealed that adult-onset epilepsy causes undesired life changes, including alterations in social functioning, somatic health, and well-being.^2,4,5 A tool that can be easily used in clinical practice to measure these life changes resulting from having epilepsy is needed to prioritize and guide the development of interventions for adults with epilepsy, and to provide a more comprehensive and sensitive assessment of outcomes for adults with epilepsy.

The purpose of this study was to develop an instrument, the Life Changes in Epilepsy Scale (LCES), designed to measure perceived life changes in adults’ lives since the onset of epilepsy. In addition, we sought to establish content and face validity of the LCES.

Development and testing of the LCES is consistent with priorities established by the Centers for Disease Control and Prevention Managing Epilepsy Well Network.⁶ Sensitive outcome measures are needed to test the effectiveness of new and innovative epilepsy self-management and symptom-relief interventions. Not only does the LCES have the potential to serve as a sensitive outcome measure for future clinical trials, but it might also serve as an assessment tool in practice to improve the lives of those living with epilepsy. In addition, the development of this instrument aligns with the health-related QoL initiative of Healthy People 2020, a specific goal of which is to promote the development of measures to evaluate the effects of chronic illness on QoL.⁷

Review of Literature

There is ample evidence demonstrating that epilepsy is a life-altering condition. Adults with epilepsy are likely to experience unpleasant symptoms, are at high risk for psychiatric co-morbidities and other chronic conditions,⁸ and commonly experience unemployment and negative changes in social relationships and physical functioning.^2,9

Existing quality of life measures

Table 1 summarizes a critique of six QoL instruments that are epilepsy-specific or widely-used in the population: the Medical Outcomes SF-36 Health Survey (SF-36),¹⁰ Impact of Epilepsy Scale,¹¹ Quality of Life Index-Epilepsy (QoLIE),¹² Quality of Life in Epilepsy-31 (QoLIE-31),¹³ and the Patient Reported Outcomes Information System (PROMIS®) Impact of Illness Scales.¹⁴ The SF-36 is a general measure of health with evidence of reliability and validity, including in the epilepsy population. However, it is a global measure not sensitive to the context of epilepsy. Jacoby and colleagues¹⁵ administered the SF-36 to a sample of persons with epilepsy (N=3,520) to assess psychometrics in this population. Although demonstrating evidence of reliability and validity, the SF-36 had substantial ceiling effects in all subscales. These authors recommended the use of population-specific measures when assessing the health-related quality of life in those with epilepsy. Birbeck and colleagues¹⁶ administered the SF-36, as well as an epilepsy-specific measure of health-related QoL (QoLIE-31), to adults with epilepsy over time. The authors correlated scores from both tools with objective measures including number of seizures experienced, days of work missed, clinic visits, and complications. Scores from the epilepsy-specific measure had correlations with objective findings that were statistically significantly larger than were those from the SF-36, and epilepsy-specific measure scores were more sensitive to change in the objective measurements than were SF-36 scores.¹⁶ In addition to being too global for the epilepsy population, the SF-36 does not measure perceived changes in health.

Table 1.

Critique of Existing Instruments

Instrument	Epilepsy-Specific	Theory-Based	Measures Perceived Changes	Evidence of Reliability and Validity
SF-36 Health Survey		✓		✓
Impact of Epilepsy Scale	✓		✓
QoLIE	✓	✓		✓
QoLIE-31	✓	✓		✓
PROMIS Illness Impact Negative Scale		✓	✓	✓
PROMIS Illness Impact Positive Scale		✓	✓	✓

The Impact of Epilepsy Scale, though epilepsy-specific and sensitive to measuring perceived changes, lacks evidence of reliability, validity, and was theoretically-based. Both the QoLIE and QoLIE-31 are useful tools in assessing the health-related quality of life in adults with epilepsy; both have evidence of reliability and validity, a theoretical basis, and are epilepsy-specific.^12,13 However, neither measures perceived changes in health-related QoL, and thus do not remedy the gap in measurement tools for this population described earlier. The QoLIE scales render a cross-sectional view of the QoL of a person with epilepsy, making it impossible to determine how a person’s life has be changed by epilepsy. The Patient Reported Outcomes Measurement Information System (PROMIS)¹⁴ is a system of patient-reported measures for physical, mental, and social well-being. The PROMIS has demonstrated evidence of reliability and validity in a variety of chronic disease populations. This system includes two instruments that measure the impact of a chronic condition (illness impact negative or positive). This system has not, however, been used in a population of those with epilepsy, and the illness impact scales lack epilepsy-specific items. Epilepsy is a complex condition and is characterized by its unique effects on those who suffer from it. Thus, an epilepsy-specific measure is needed to adequately capture life changes due to having adult-onset epilepsy.

Conceptual framework

Our goal was to develop an epilepsy-specific, theory-based and patient-centered outcome measure sensitive to life changes caused by adult-onset epilepsy. The LCES was thus developed based on a review of the epilepsy and chronic disease self-management literature and portions of Lazarus and Folkman’s Theory of Stress, Coping, and Adaptation.¹⁷ Lazarus and Folkman identify three adaptational outcomes that are met to some degree as an outcome of coping: social functioning, somatic health, and subjective well-being.¹⁷ Based on qualitative research with adults with epilepsy, including that in which persons with epilepsy were asked to identify self-management outcomes of importance to them,^2,4 we posit that the adaptational outcomes included in Lazarus and Folkman’s¹⁷ theory are representative of patient-centered outcomes for adults with epilepsy.

Figure 1 depicts the conceptual framework in which the LCES is housed; it is based on a combination of a review of literature, social cognitive theory,¹⁸ socioecological theory,¹⁹ our prior qualitative research, and the Theory of Stress, Coping, and Adaptation.¹⁷ As described earlier, persons with epilepsy experience symptoms (such as physical, emotional, and cognitive), which persons with epilepsy have reported cause life changes in the areas of social functioning, somatic health, and well-being^2,4. These changes are moderated by individual characteristics such as epilepsy severity, social support, demographics, and existing co-morbidities, and may be mediated by internal variables of self-efficacy as defined in social cognitive theory¹⁸, disease knowledge, and multi-level thinking. Multi-level thinking refers to a person’s ability to consider multiple levels of his or her environment when making decisions and changing behaviors, and is derived from the socioecological model. The interactions between all of the just-described variables occur within the context of epilepsy-self-management.

Figure 1.

Conceptual Framework

Methods

Development

Following a review of literature, and based on the conceptual framework, we developed original items for the LCES; each epilepsy-specific item was designed to measure life changes since onset of epilepsy in the domains of social functioning, somatic health, and well-being. All items were written at a fifth grade reading level.²⁰ The response format was adapted from that of the Bakas Caregiving Outcomes Scale (BCOS),²¹ with responses measured on a 7-point scale (Changed for the Worst= −3 to Changed for the Best=+3). This response scale was chosen because it most accurately reflects Lazarus’ definition of adaptational outcomes. Developed based on Lazarus’ definition of adaptational outcomes, the BCOS has been shown to have strong evidence of internal consistency reliability and content, construct, and criterion-related validity.²¹ Initially, 41 items were generated.

Content validity

The content validity of the 41-item LCES was evaluated via review by three content experts. One expert had an active program of epilepsy research, one was an expert clinician specializing in treatment of epilepsy, and one had active epilepsy-focused clinical and research programs. Experts were provided with an evaluation form, on which they were asked to assign each item to a domain (social functioning, somatic health, or well-being), and to rate its relevance to adults with epilepsy on a 1–5 scale, with 1 indicating not at all relevant, and 5 indicating extremely relevant. Experts were also asked to provide suggestions for changes in wording and given the option to recommend the removal of any item. Experts were also given an area in which to leave qualitative comments about the measure. Item- and scale-level content validity indices (CVIs) were calculated using Polit and Beck’s²² guidelines. Complete agreement by all experts (item- and scale-level CVIs) was desired given there were only three reviewers. Thus, we sought CVIs of 1.0 at both the item and scale level.²² On both the item- and scale levels, CVIs were calculated by adding reviewers’ ratings of each item, and then the entire scale, and dividing by the total number of reviewers.

Face validity

To provide evidence of face validity, following institutional review board approval, five persons with adult-onset epilepsy recruited from a Midwestern neuroscience center were asked to evaluate the LCES after it had been evaluated for content validity. In order to be eligible, participants had to be age 18 years or older, diagnosed with epilepsy at age 18 or older, be prescribed at least one anti-epileptic drug, speak and read English, and be cognitively intact as measured by the Six-Item Screener for cognitive impairment.²³ Participants were sent a copy of the LCES via email or postal mail, along with an evaluation form. On the evaluation form, participants were asked to rate the clarity and relevance of each item using a Likert scale. They were also asked to indicate whether they suggested the removal of any items. In a follow-up phone conversation with the principal investigator, participants discussed their ratings and provided qualitative feedback regarding the scale’s ability to measure perceived life changes since onset of epilepsy. In order to determine congruence between participants’ reported life changes and those being measured by the LCES, the researcher used a semi-structured interview guide to ask participants about ways in which their lives have changed since being diagnosed with epilepsy.

Results

Content validity

After experts’ initial review of the LCES, the scale CVI was 0.94, and six items had item-level CVIs of 0.67 or lower; all experts recommended removal of these six items. Removal was suggested due to lack of relevance and/or redundancy with other items. Removal of these six items rendered item- and scale-level CVIs of 1.0, resulting in a 35-item scale with evidence of content validity. Slight changes were made to the directions on the LCES, which were recommended by all reviewers.

Face validity

Three women and two men reviewed the LCES. Their average age was 41.2 years, with a range of 34–61 years. Mean age at diagnosis was 32.6 years, with a range of 21–51 years. Mean length of time since diagnosis was 8.6 years, with a range of 1–17 years. Participants’ ratings for all items ranged from 4.8–5. Qualitative comments provided by each participant were transcribed and analyzed via content analysis. All comments were supportive of all items being maintained in the scale, while no comments suggested the need for additional items. As one participant stated, “I feel like all the items…capture what has happened to me since I was diagnosed and areas where I think my life is different. It captures my changes at work, home, with my husband and parents…everyone. I can’t think of anything else I would add.” More specifically, comments supported participants having experienced life changes in the areas of social functioning, somatic health, and well-being. Comments illustrative of all items in each of the three domains were made by participants. Table 2 provides examples of some of these comments. Based on feedback from the five participants, all 35 items were maintained, and wording of some items was changed slightly to enhance clarity. Of note is that the number of items on the LCES will be significantly reduced following future psychometric testing and item analysis.

Table 2.

Domains of Life Changes and Supporting Qualitative Comments

Domain	Definition (Lazarus & Folkman, 1984)	Sample Items (participants indicate perceived change since epilepsy diagnosis)	Participant Responses
Social Functioning	The way(s) in which a person fulfills various roles and satisfaction with relationships; also refers to the skill set needed to maintain roles and relationships.	My relationship with my friends	“My social life is pretty much turned upside down…I find it real hard to maintain my friendships and also manage this.”
Somatic Health	A person’s physiological status, including symptoms.	How often I have unpleasant physical symptoms	“I’m having to deal with a lot of feeling tired…fatigued and it’s keeping me from the stuff I wanna be doing.”
Well-Being	How a person feels about him or herself and his or her life conditions.	My happiness in general	“I’m just not the same person anymore…it’s been real hard to figure out if I can be happy again…at least not until I get used to this.”

Discussion

The LCES is a patient-centered outcome measure designed to assess adults’ perceived life changes due to having epilepsy (See Table 3 for sample items). Evaluation of the LCES by content experts and persons with adult onset epilepsy led to evidence of the content and face validity of a 35-item version of the tool. Qualitative comments provided by adults with epilepsy who reviewed the LCES were supportive of the experience of life changes in the domains of social functioning, somatic health, and well-being following adult-onset epilepsy; this finding is congruent with findings from multiple studies involving adults with epilepsy in which participants reported decrements in quality of life in the three domains included in the LCES.^2,4

Table 3.

Sample items and instructions from the LCES

Based on current results, the LCES is a potentially useful patient-centered outcome measure for adults with epilepsy. Before the tool can be implemented, however, establishment of the psychometrical soundness of the LCES must occur. We are currently testing the psychometric properties of the LCES with a sample of 175 adults with epilepsy. Once evidence of reliability and validity of the LCES have been obtained, the tool will be used as an outcome measure in a pilot self-management intervention.

Limitations

Current findings are limited by a small convenience sample. Thus, results may not be generalizable beyond the participants in this sample. As discussed earlier, psychometric testing of the LCES with a large and more diverse sample is ongoing.

Conclusion

In addition to being used as an outcome measure in intervention studies, the psychometrically-tested LCES can serve as a valuable tool for advanced practice nurses caring for adults with epilepsy in inpatient, outpatient, and community settings. The LCES can allow for a brief and simple assessment of ways in which patients’ lives have been affected by epilepsy, thus allowing nurses to develop targeted nursing interventions for these patients.