Although quality of life is difficult to define clearly, a number of instruments and questionnaires have been developed and applied to patients who have amyotrophic lateral sclerosis (ALS). This article reviews the spectrum of quality-of-life questionnaires and instruments used for ALS and the data generated from them. It discusses positive and negative factors that can affect quality of life for the patient and caregiver and concludes with suggestions for ongoing management to enhance quality of life.
Amyotrophic lateral sclerosis (ALS) is characterized by relentless progression of weakness causing loss of physical independence for the patient and also for the caregiver and family. There is no effective therapy to slow progression, and ALS is uniformly fatal with median survival of 2 to 4 years after diagnosis. At the time of diagnosis and explanation of the nature of the disease, patients express concern for their quality of life. Their perceptions can influence decisions on drug treatment (riluzole) and interventions (noninvasive ventilation and gastric feeding tube). Thus, it is important that health care providers for patients who have ALS be knowledgeable about quality of life when addressing patients’ and families’ concerns and questions. It perhaps is surprising that, when measured formally, patients who have ALS usually rate their quality of life to be relatively good. Although this finding may be counterintuitive to the newly diagnosed patient, it is important to convey this finding to the patient and his or her family. To assist health care providers, this article reviews definitions of quality of life, how it is measured, data from numerous studies, and how quality of life can be influenced. Consideration is given to both the patient and the caregiver.
Defining quality of life
It is difficult to provide a concise definition of quality of life. Many factors and different vantage points should be considered. Obvious factors include the patient’s background (ethnic, cultural, past experiences), expectations, current support (family, friends), and spiritual beliefs (organized religion or beliefs). The World Health Organization states that quality of life “is a broad ranging concept affected in a complex way by the person’s physical health, psychologic state, level of independence, social relationships, personal beliefs and their relationship to salient features of their environment.” From a patient’s vantage point, especially when there is a serious illness such as ALS, physical health looms large and can influence the interpretation of quality of life and outlook for the future. The progression of weakness and loss of physical independence with no cure emphasizes the negative aspects of the illness, including fears about dying and concerns for the caregiver and family. There are, however, positive aspects for the patient and caregiver that may not be appreciated at time of diagnosis. It is important to consider all these factors when helping the patient view his or her quality of life and to review these factors as they change over time.
Measuring quality of life
Questionnaires or instruments addressing issues related to quality of life can be divided into three broad groups: those that cover general health status, those that focus on a specific factor or issue that may be influential in quality of life, and those that specifically address overall quality of life ( Box 1 ). Within these groups, questionnaires can be simple (a single question) or complex (multiple sections, each with many questions). This article focuses on questionnaires and instruments that specifically address quality of life with limited reference to the other two groups.
General health-related status
- •
Sickness Impact Profile (SIP)
- •
Short Form-36 (SF-36)
Specific for quality of life in general of for other diseases
- •
Single question
- •
McGill Quality of Life Questionnaire (MQOL)
- •
Schedule of the Evaluation of Individual Quality of Life-Direct Weigh (SEIQoL-DW)
Specific for quality of life in ALS
- •
Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40)
- •
ALS-Specific Quality Of Life (ALSSQOL)
a See text for full descriptions.
Instrument development
Formal methods are used to design, refine, and validate complex questionnaires.
Questionnaires or instruments are designed to address specific elements or areas that, from prior ground work, are thought to be factors affecting quality of life. Responses to the elements or areas result in subscores for the various sections in addition to a summation score that gives an overall measure of quality of life. Complex quality-of-life questionnaires are developed and validated by a rigorous multistep process. The areas or elements of interest frequently are identified from interviews with the groups of interest (patients and caregivers). Specific questions are formulated to address issues and concerns brought out from the interviews. An initial version of the questionnaire is tested in the designated group. The validity of the various elements or areas is assessed by having subjects simultaneously complete other focused questionnaires that previously have been established as good measures of the particular element or area. Comparisons then are made to determine how the new questions capture the specific information. To reduce the number of questions to a minimum while retaining full information, answers to each question are compared with each other to determine which questions are answered similarly and thus can be dropped. The final, shortened version then is retested to see if it retains overall sensitivity and specificity to the original version.
Quality-of-life questionnaires developed for one patient population (eg, patients who have cancer) can be used for another population (eg, patients who have ALS) but should be assessed formally for consistency and validity in the new patient population. When an existing questionnaire developed for one population is modified for another population, questions frequently are changed, added, or dropped to meet specific perceived needs of the new population. The modified questionnaire should be reassessed in the new population to ensure validity. When translating a questionnaire or instrument to another language, the document should be translated to the new language and then back to the original language and then validated for consistency.
Questionnaires related to general health status
Questionnaires related to general health status cover a broad spectrum of perceived contributors to health and can be used for a variety of medical conditions; comparisons can be made between conditions. Such a questionnaire includes sections that assess emotional and mental well-being and sections that assess functional activities. In ALS, muscle strength and the ability to perform activities of daily living inexorably decline. Thus, functional element subscores fall over time and may drive or influence the total score .
Although questionnaires related to health status are considered also to assess quality of life, quality of life encompasses a broader array of life’s experiences than those related to health status . Despite these limitations, health-related quality-of-life scales have been used in ALS as a measure of quality of life. Specific instruments include the Sickness Impact Profile (SIP) and especially the Short Form-36 (SF-36) . One concern is that these questionnaires can be long and tiring for patients who have ALS, especially the SIP, which consists of 136 questions . Shorter versions have been developed, such as a 19-question version of the SIP (SIP/ALS-19) , and a 12-question version of the SF-36 (SF-12) .
An offshoot of the functional subscales in these instruments is linkage to patient strength. There are strong correlations between loss of muscle strength measured quantitatively by the Tufts Quantitative Neurologic Examination (TQNE) and the SF-36 . The set of questions related to function from the SIP were selected and incorporated in the shorter SIP/ALS-19, which is offered as a proxy for quantitative strength testing .
Single-question instruments
The simplest assessment instrument is a single question asking patients to rate their own quality of life over a specific time frame, such as currently, during the past week, in the past month, since an event, and so forth. The answer can be marked on a visual analogue scale from 0 to 10 cm, and the mark can be measured in metric units. This scale gives a general or global indication of quality of life. Despite its simplicity, there is merit in letting patients reach their own conclusions in a single score. The scale, however, does not provide insight into factors that affect quality of life.
Open instruments
Open quality-of-life instruments impose no specific questions and allow the subject to decide what elements make up their quality of life . In addition to the single global question discussed earlier, a more informative instrument has been developed in the Schedule of the Evaluation of Individual Quality of Life (SEIQoL) and a shorter direct weight version (SEIQoL-DW) . The procedure has three steps. In the first, the subject is asked to list five areas that make up his or her quality of life at the current time. In the second, the subject is asked to rate the current status of each area using a visual analogue scale. In the third, the patient is asked to rank the relative importance of each area using a pie chart. The data available for analysis include the five areas, the patient’s evaluation of each area, the areas’ relative importance, and a combined index score. These instruments have been validated with patients who have ALS and with patients who have a number of other diseases . An advantage of open questionnaires is that the same questionnaire can be used to assess quality of life for the patient and for the caregiver, among patients who have different diseases, and in healthy individuals.
Questionnaires specific to amyotrophic lateral sclerosis
ALS-specific quality-of-life questionnaires have been developed from the ground up based on interviews with patients and caregivers and with formal verification and statistical analysis to yield a validated instrument. Such questionnaires are the 40-question Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) and a shorter version, the five-question ALSAQ-5 . The ALSAQ-40 includes five dimensions: physical mobility, activities of daily living/independence, eating and drinking, communication, and emotional functioning, leading to subscores and a total score. It was developed in the United Kingdom, and a Dutch-language translation has been verified .
Another approach is to modify for ALS an existing quality-of-life questionnaire originally validated for another disorder. The McGill Quality of Life Questionnaire originally was designed for patients who have cancer or HIV . It is attractive for ALS because it is not heavily weighted toward physical function and includes an existential element (perception of purpose, meaning in life, and capacity for personal growth). The existential element is thought to be as important for patients who have ALS, as it is for patients who have cancer. A modified version of the McGill questionnaire for patients who have ALS has been validated as the ALS-Specific Quality of Life (ALSSQOL) questionnaire . Changes for the ALS population include reformatting for ease of administration and incorporating nondominant physical function, psychologic support, and existential elements and a broad spiritual element. Included is an open question asking the patient to list things that had the greatest effect on his or her quality of life over the past seven days. In an effort to include issues pertinent to the patient, a section was added asking the patient to identify troublesome symptoms from a list of 10.
Measuring quality of life
Questionnaires or instruments addressing issues related to quality of life can be divided into three broad groups: those that cover general health status, those that focus on a specific factor or issue that may be influential in quality of life, and those that specifically address overall quality of life ( Box 1 ). Within these groups, questionnaires can be simple (a single question) or complex (multiple sections, each with many questions). This article focuses on questionnaires and instruments that specifically address quality of life with limited reference to the other two groups.
General health-related status
- •
Sickness Impact Profile (SIP)
- •
Short Form-36 (SF-36)
Specific for quality of life in general of for other diseases
- •
Single question
- •
McGill Quality of Life Questionnaire (MQOL)
- •
Schedule of the Evaluation of Individual Quality of Life-Direct Weigh (SEIQoL-DW)
Specific for quality of life in ALS
- •
Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40)
- •
ALS-Specific Quality Of Life (ALSSQOL)
a See text for full descriptions.
Instrument development
Formal methods are used to design, refine, and validate complex questionnaires.
Questionnaires or instruments are designed to address specific elements or areas that, from prior ground work, are thought to be factors affecting quality of life. Responses to the elements or areas result in subscores for the various sections in addition to a summation score that gives an overall measure of quality of life. Complex quality-of-life questionnaires are developed and validated by a rigorous multistep process. The areas or elements of interest frequently are identified from interviews with the groups of interest (patients and caregivers). Specific questions are formulated to address issues and concerns brought out from the interviews. An initial version of the questionnaire is tested in the designated group. The validity of the various elements or areas is assessed by having subjects simultaneously complete other focused questionnaires that previously have been established as good measures of the particular element or area. Comparisons then are made to determine how the new questions capture the specific information. To reduce the number of questions to a minimum while retaining full information, answers to each question are compared with each other to determine which questions are answered similarly and thus can be dropped. The final, shortened version then is retested to see if it retains overall sensitivity and specificity to the original version.
Quality-of-life questionnaires developed for one patient population (eg, patients who have cancer) can be used for another population (eg, patients who have ALS) but should be assessed formally for consistency and validity in the new patient population. When an existing questionnaire developed for one population is modified for another population, questions frequently are changed, added, or dropped to meet specific perceived needs of the new population. The modified questionnaire should be reassessed in the new population to ensure validity. When translating a questionnaire or instrument to another language, the document should be translated to the new language and then back to the original language and then validated for consistency.
Questionnaires related to general health status
Questionnaires related to general health status cover a broad spectrum of perceived contributors to health and can be used for a variety of medical conditions; comparisons can be made between conditions. Such a questionnaire includes sections that assess emotional and mental well-being and sections that assess functional activities. In ALS, muscle strength and the ability to perform activities of daily living inexorably decline. Thus, functional element subscores fall over time and may drive or influence the total score .
Although questionnaires related to health status are considered also to assess quality of life, quality of life encompasses a broader array of life’s experiences than those related to health status . Despite these limitations, health-related quality-of-life scales have been used in ALS as a measure of quality of life. Specific instruments include the Sickness Impact Profile (SIP) and especially the Short Form-36 (SF-36) . One concern is that these questionnaires can be long and tiring for patients who have ALS, especially the SIP, which consists of 136 questions . Shorter versions have been developed, such as a 19-question version of the SIP (SIP/ALS-19) , and a 12-question version of the SF-36 (SF-12) .
An offshoot of the functional subscales in these instruments is linkage to patient strength. There are strong correlations between loss of muscle strength measured quantitatively by the Tufts Quantitative Neurologic Examination (TQNE) and the SF-36 . The set of questions related to function from the SIP were selected and incorporated in the shorter SIP/ALS-19, which is offered as a proxy for quantitative strength testing .
Single-question instruments
The simplest assessment instrument is a single question asking patients to rate their own quality of life over a specific time frame, such as currently, during the past week, in the past month, since an event, and so forth. The answer can be marked on a visual analogue scale from 0 to 10 cm, and the mark can be measured in metric units. This scale gives a general or global indication of quality of life. Despite its simplicity, there is merit in letting patients reach their own conclusions in a single score. The scale, however, does not provide insight into factors that affect quality of life.
Open instruments
Open quality-of-life instruments impose no specific questions and allow the subject to decide what elements make up their quality of life . In addition to the single global question discussed earlier, a more informative instrument has been developed in the Schedule of the Evaluation of Individual Quality of Life (SEIQoL) and a shorter direct weight version (SEIQoL-DW) . The procedure has three steps. In the first, the subject is asked to list five areas that make up his or her quality of life at the current time. In the second, the subject is asked to rate the current status of each area using a visual analogue scale. In the third, the patient is asked to rank the relative importance of each area using a pie chart. The data available for analysis include the five areas, the patient’s evaluation of each area, the areas’ relative importance, and a combined index score. These instruments have been validated with patients who have ALS and with patients who have a number of other diseases . An advantage of open questionnaires is that the same questionnaire can be used to assess quality of life for the patient and for the caregiver, among patients who have different diseases, and in healthy individuals.
Questionnaires specific to amyotrophic lateral sclerosis
ALS-specific quality-of-life questionnaires have been developed from the ground up based on interviews with patients and caregivers and with formal verification and statistical analysis to yield a validated instrument. Such questionnaires are the 40-question Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) and a shorter version, the five-question ALSAQ-5 . The ALSAQ-40 includes five dimensions: physical mobility, activities of daily living/independence, eating and drinking, communication, and emotional functioning, leading to subscores and a total score. It was developed in the United Kingdom, and a Dutch-language translation has been verified .
Another approach is to modify for ALS an existing quality-of-life questionnaire originally validated for another disorder. The McGill Quality of Life Questionnaire originally was designed for patients who have cancer or HIV . It is attractive for ALS because it is not heavily weighted toward physical function and includes an existential element (perception of purpose, meaning in life, and capacity for personal growth). The existential element is thought to be as important for patients who have ALS, as it is for patients who have cancer. A modified version of the McGill questionnaire for patients who have ALS has been validated as the ALS-Specific Quality of Life (ALSSQOL) questionnaire . Changes for the ALS population include reformatting for ease of administration and incorporating nondominant physical function, psychologic support, and existential elements and a broad spiritual element. Included is an open question asking the patient to list things that had the greatest effect on his or her quality of life over the past seven days. In an effort to include issues pertinent to the patient, a section was added asking the patient to identify troublesome symptoms from a list of 10.
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