functioning), and (3) an overall assessment of well-being (e.g. glo- bal health status). HR QOL scores are oft en summarized as broad- band scores for physical health and psychosocial health. Integral to the assessment of HRQOL is the domain of physical functioning. Physica l functioning refers to actual participation in physical activi- ties and ability to perfor m physical tasks, as well as the individual \200\231s perception of diffi culty or restrict ion in activity participation. Physical function should be a primary treatment outcome for youth with pain and represents a specifi c domain requiring detailed assessment. Th e Pediatric Initiative on Methods, Mea surement, and Pain Assessment in Clinical Trials (Ped-IMMPACT) recommended outcome measures for clinical trials investigating acute and chronic pain in children (McGrath et al., 2008 ) and identifi ed physical and role functioning as two of the eight core outcome domains. In this chapter, we review approaches for assessment of HRQOL as a mul- tidimensional const ruct that incorporates the domains of physical and role functioning, and we separately revi ew specifi c approaches to the assessment of physical functioning. We further describe meas ures of HRQOL and physical functioning in pediatric pain populations. Health-related quality of life and physical function in children with painful conditions Se veral examinations of HRQOL in children and adolescents with pain conditions (e.g. headache , sickle cell disease, mixed pain con- ditions) have found that they report signifi cantly poorer HRQOL in comparison to healthy children (Nodari et al., 2002 ; Palermo et al., 2002 ). Moreover, unexplained chronic pain in adolescents has been associated with poor quality of life for the adolescent and his or her family (Hunfeld et al., 2001 ). Predictors of poo r HRQOL within pain populations include the presence of sleep problems (Palermo and Kiska, 2005 ), fatigue (Berrin et al., 2007 ), pain-re- lated hospitalizations (Palermo et al., 20 02 ), low socioeconomic conditions (Palermo et al., 2008c ) and increasing child age. Littl e is known, however, about how HRQOL changes over time in youth with pain. Introduction It is well recognized that medical conditions and ill health may have signifi cant impact across diff erent areas of a child \200\231s life. Pain, particu- larly chronic pain, may impair school attendance, mobility, self-care, interpersonal interactions, life activities, and community activities (Palermo, 2000 ). Health-related quality of life (HRQO L) refers to an individual \200\231s perception of the impact of an illness, symptoms, and its consequent treatment on their physical, psychological, and social well-being, as well a s perception of overall well-being in relation to their health (Eiser et al. 2001 ). Measur ement of HRQOL incorpo- rates assessment of three levels: (1) components of specifi c domai ns of functioning (e.g. diffi culty walking up stairs), (2) individual domains of functioni ng (e.g. psychosocial, physical, school, and role SECTION 5 measurement of pain 418 Similarly, physical function has also been fairly extensively stud- ied in youth with vario us pain conditions primarily to identify how chronic pain can aff ect children \200\231s pa rticipation in developmentally appropriate physical and social activities. In one epidemiol ogical study of chronic pain in a community sample of youth (Roth-Isigkeit, et al., 2005 ), impairments most commonly reported were: sleep problems (53.6%), inability to pursue hobbi es (53.3%), eating prob- lems (51.1%), school absence (48.8%), and inability to meet friend s (46.7%). Huguet and Miro (2008) examined pain severity including impact from pain using v alidated measures in a population based sample. Th ey found that 36.8% of youth had some di sability, with 31.7% categorized as having a low level of disability and 5.1% having modera te to severe disability. Th ese studies highlight that pain and disability can vary conside rably among children with pain. interview to establish rapport, obtain a pain history, and to under- stand impact of pain o n aspects of the child \200\231s daily life. Interview probes about school, daily activitie s, sports participation, recrea- tional and peer activities, and self-care activities can u ncover areas of signifi cant limitation in physical function (see Table 41.1 ). See supplem entary online materials for additional interview probes in multiple domains of assessment. Functional goals are oft en developed with children and parents around specifi c areas of l imitation tailored to each child \200\231s needs. Re-assessment of these allows for monitor ing and tracking of patient outcomes. Th ere are limitations to the use of clinical inter- views to assess physical function, however, including that questions may be asked in diff e rent ways (i.e. lack of standardization), demand characteristics may infl uence responses, and there is a limited abil- ity to make comparisons across children. Empirical support is not yet available to recommend a standardized clinical interview for assessing physical fun ction in pediatric pain. Prior reviews of HRQOL and function measures Several recent reviews have provided summaries of measures that have been used to assess HRQOL and physical function in medical populatio ns experiencing chronic pain or chronic illness. Eccleston et al. ( 2006 ) identifi ed nine measures of the impact of pain on HRQOL and physical functioning in children with headache , arthri- tis, abdominal pain, and mixed pain conditions. Th ey concluded that for the majo rity of the measures, the psychometric evaluations were limited in scope, and had only been used in a few studies. HRQOL questionnaires HRQOL can be assessed on questionnaires that can be generic or conditi on-specifi c measures (Palermo et al., 2008b ). Generic measures are not intended for a spe cifi c population, and allow for comparisons across children with diff erent pain or medica l condi- tions. Condition-specifi c HRQOL measures, on the other hand, are developed for ex amination of specifi c impairments experienced by children with the same health conditions. Th is may increase sen- sitivity in capturing the nuances of living with specifi c conditi ons. However, condition-specifi c instruments do not allow for com- parative measurements a cross diff erent illness groups, or between children with and without pain. Palermo et al. ( 2008b ) reviewed 16 measures of HRQOL and func- tional impairment that hav e been used with pediatric populations including children with painful conditions. Th is re view classifi ed measures as being well established, approaching well established, or promi sing. Several well-established measures were found used in pain populations including the P ediatric Quality of Life Inventory (PedsQL; Varni et al., 1999 ), the Functional Disability Inventory (FDI; Walker and Greene, 1991 ), and the Child Activity Limitations Interview (C ALI; Palermo, et al., 2004 ). Specifi c measures are dis- cussed in more detail in later se ctions. Th is review called for further research, particularly regarding the validity of HR QOL and func- tional disability measures in response to interventions, and the clin- ical u tility of changes in these measures (Palermo et al., 2008b ). Two commonly used, well-established generic HRQOL meas- ures that have been applied to pain populations are the Child Health Questionnaire (CHQ) and PedsQL. Th e CHQ is a widely used instrument, initially developed for use in healthy children Table 41.1 Clinical interview questions to assess physical and role function Th ere is little information available concerning measurement of HRQOL, physical or role fu nctioning in children experiencing acute pain. Th is is in large part due to the way that m easures have been developed in the fi eld where the primary focus has been on the longer-te rm impact of illness on children. However, we recog- nize that HRQOL, physical, and role fu nction may be important endpoints in the treatment of children with acute pain as well. Domain Sample question Overall health status How would you describe your overall health? Daily living Describe a typical day. What is your routine? What activities do you do during the day? Self-care What do you do to take care of yourself and your body? Methods of evaluation of HRQOL and physical function Starting with the most commonly used m ethod of evaluation, a clin- ical interview can be used to evaluate physical function. Howe ver, the evidence base reviewed here pertains to the use of standard- ized measures of HRQO L and physical function using validated questionnaires and objective/observational measures of perform- ance. Examples of measurements within each of these methods are reviewed in th e following sections; however, this is not intended to serve as an exhaustive review of the literature. School participation How often do you attend school? When you go to school, how long do you stay? Do you have an y di \203 culties completing schoolwork? Community participation Do you participate in hobbies, like clubs or after-school activities, or church? Physical activities Do you participate in sports or other athletic activities? What activities are di \203 cul t for you to do because of your pain? What would you like to be able to do that you can \200\231t do now? Activities with peers How often do you spend time with friends? What do you do with friends? Clinical interview Th e cornerstone of the clinical evaluation and assessment of the child in pain is the clinical interview. Th e clinician uses the Activities with family What activities do you do with your family (parents, siblings)? CHAPTER 41 measurement of health-related quality of life and physical function 419 (Landgraf et al., 1996 ). It incorporates 13 domains including psy- chosocial functioning, physical and role functioning, family cohe- sion, school and activity limitations, behavior , self-esteem, and the emotional and time impact on the parent. Broad band meas- ures of ph ysical health and psychosocial health can be derived. Th is instrument has been used for HR QOL assessment in children with chronic pain conditions such as juvenile idiopathic arthrit is and sickle cell disease (e.g. Panepinto et al., 2005 ; Selvaag et al., 2003 ). Notable s trengths of the CHQ are the broad generalizability across diff erent medical conditions (Br uijn et al., 2009 ; Krab et al., 2009 ), widespread international experience (Ruperto et al ., 2001 ), and feasibility via Internet administration (Raat et al., 2007 ). Primary disadv antages of the CHQ are the excessive length of the scale in comparison to other HRQOL measu res, the more limited range of child self-report (only available for age 10 and above), and that the parent and child versions are not parallel which prohibits direct comparison of p arent and child reports. 4.0 has been used for descriptive purposes in general pain popula- tions and in specifi c p ain conditions such as sickle cell disease and fi bromyalgia (Dale et al., 2011 ; Gold et a l., 2009 ; Varni et al., 2007a ). It has been used in several intervention studies for outc ome assess- ment (Hicks et al., 2006 ; Langley et al., 2011 ). Several disease-specifi c mo dules may be relevant for use with pain populations such as the Rheumatology Module (Varni et al., 2002 ) which includes subscales for pain and hurt, daily activities, treatment, wor ry, and communica- tion. One unique feature of the PedsQL is the applicability across a wid e age range; it has been validated for use from birth to 18 years old, with multiple versio ns for diff erent ages (Varni et al., 2011 ). Research on the validity of this measure has been conducted internationally (Amiri et al., 2010 ; Tsuji et al., 2011 ) and across severa l ethnic and racial groups (Limbers et al., 2009 ). Construct validity was demon- strated b y determining responsiveness following medical interven- tion over time (Varni et al., 1999 ). Several studies have found that the electronic (e-PedsQL) Internet mode of administrati on demon- strates equivalent properties to the paper and pencil mode of admin- istration (V arni et al., 2008a ; Young et al., 2009 ). Th e disadvantage of the PedsQL 4.0 is that the instrument provides a broad assessment of HRQOL and may not be responsive to changes in dis ease-specifi c symptoms. Additional details on psychometric evaluation of the generic measu res of HRQOL can be found in Table 41.2 . Another commonly used instrument is PedsQL (Varni et al., 1999 ). Initially developed to as sess HRQOL in children with cancer, it has undergone development and validation as both a c ore instru- ment and disease-specifi c modules within numerous pediatric medical population s. It assesses four core broad-band domains of physical, psychological, social and school f unctioning. Th e PedsQL Table 41.2 Psychometric characteristics of HRQOL and physical function measures Name of measure Number of items/ administration burden Validity Reliability Population developed Construct Criterion Content Temporal Test \200\223retest Internal consistency Sensitivity to change Interrater reliability stability Child Health Questionnaire (CHQ) Child: 87 Parent: 98, 50, and 28 (3 versions) x x x x Healthy and medical pediatric populations Pediatric Quality of Life Inventory (PedsQL) Child: 23 Parent: 23 Short form: 15 x x x x Pediatric medical populations Pain Experience Questionnaire (PEQ) Child: 15 Parent: 12 x x x Pediatric chronic pain Bath Adolescent Pain questionnaire (BAPQ) Child: 61 Parent: 61 x x x Pediatric chronic pain Functional Disability Inventory (FDI) Child: 15 Parent: 15 x x x x x x Pediatric chronic pain Child Activity Limitations Interview (CALI) Child: 21 Parent: 21 x x x x Pediatric chronic pain Timed walk task Up to 10 min to x x Healthy and medical pediatric populations administer Sit-to-stand task Approx. 1 min to x x Healthy and medical pediatric populations administer SECTION 5 measurement of pain 420 Th ere are two newer multidimensional measures designed spe- cifi cally for children with p ain conditions: the Bath Adolescent Pain Questionnaire (BAPQ; (Eccleston et al., 2005 ) and the Pain Experience Questionnaire (Hermann et al., 2008 ). Although a HRQOL frame- work wa s not used to develop these instruments, they both cover a range of constructs important in HRQOL assessment and were designed specifi cally to assess pain-related interference and f unction- ing. Th e BAPQ was designed for adolescent and parent report and focuses on assess ment of psychosocial, activity limitations, social, and family functioning. Th e PEQ was ba sed on the Multidimensional Pain Inventory, commonly used in adults with chronic pain, and is a multidimensional pain measure designed for ages 7 and up. Both instruments require add itional psychometric evaluation. However, the strengths of both measures are that they were developed for chil- dren and adolescents with chronic pain and may capture unique limi- ta tions and impact experienced by this population. Condition-specifi c measures of functional impairment are also available. For example, two measures assessing function in arthritis are the Child Health Assessment Questionnaire (CHA Q; Stephens et al., 2007 ) and the Juvenile Arthritis Functional Assessment Report (JAFAR). Th e CHAQ is a valid and reliable measure used to guide clinical decisions for level of as sistance for functional impairment and to evaluate functional improve- ment aft er interven tion (Halbig et al., 2009 ). Th e JAFAR has demonstrated good construct validity, reliabili ty and responsive- ness (Howe et al., 1991 ), and has been widely used in juvenile idiopath ic arthritis. In the migraine population, the PedMIDAS (Hershey et al., 2004 ) is a brief m easure with promising initial validation, and includes items assessing school, physical, re crea- tion and peer participation. Objective and observational measures of physical function Certain constructs within the dom ain of physical function, includ- ing physical fi tness and activity, are traditionally mea sured with objective and performance-based tools. For example, physical fi tness may be mea sured using oxygen exchange for aerobic or anaerobic capacity, isokinetic machines or force dynamometers that measure torque and strength, and body mass index or skin- fold calipers for body composition. Objective measures of physical activity may include motion sensing de vices such as pedometers and accelerometers. Th ere are also HRQOL measures designed for specifi c pediatric pain populations. For child ren and adolescents with chronic head- aches or migraines, available instruments include Th e Quality of Life Headache in Youth (QLH-Y) and Th e Migraine Specifi c Quality of Life Qu estionnaire Version 2.1(MSQ). Th e QLH-Y assesses the domains of psychological and social f unctioning, functional status, physical status, and satisfaction with life and health (Lang eveld et al., 1996 ). Th e MSQ assesses impact of pain on physical, emo- tional, and social functioning (Martin et al., 2000 ). Both measures have been validated in relatively small samples. For children with arthritis, the Arthritis Impact Measurement Scales 2 (AIMS 2) an d Juvenile Arthritis Quality of Life Questionnaire (JAQQ) have been used as disease specifi c measures of physical and psychosocial function in children with juvenile idiopathic arth ritis (Duff y et al., 1997 ; Meenan et al., 1992 ). Observational performance-based measures of function provide information about an individua l \200\231s actual performance on tasks which are typically designed to mimic naturalistic tasks that would be encountered in daily life (e.g. lift ing, walking). In rehabilitation s ettings, performance-based measures of function are routinely used in evaluation and re-eva luation of patients with chronic pain. In adult pain research, a broad range of observation al measure- ment systems have been developed to assess physical functioning, such as the So renson back extension test (Harding et al., 1994 ), the sit-to-stand (the number of times a n individual can move from a seated to a standing position in a 1 min time period), and the timed walk (how long it takes an individual to walk a certain dis- tance such as 10 meter s, or how far a person walks in a certain time period such as 2 or 6 min). Th ese measures are administered using standardized conditions (oft en in a gym). Questionnaires for assessment of physical function Questionnaires designed to capture activ ity limitations, restriction, and functional impairment or disability related to pain fall under the domain of physical function. Th ey may provide a more comprehensive examination o f areas of impact or disability that may be overlooked by general measures of HRQOL. For th e child with a pain condition, measures of physical function may identify specifi c areas o f decreased activity performance secondary to pain that could serve as the goal of interven tion. Two generic and fi ve condition-specifi c instruments of physical function are discus sed in the following paragraphs. Observational and performance measures have been used sur- prisingly little in pediatric pa in populations. In juvenile arthritis, standardized measures of fi tness such as grip stren gth have been shown to correlate with self-report measures of physical function (Wessel et al., 1999 ). Standardized back muscle endurance measures have also been used with youth who have chronic musculoskeletal pain (O \200\231Sullivan et al., 2011 ). Only one study of wh ich we are aware has utilized performance measures to assess intervention outcome. In this study, improvements were found in adolescents with chronic pain on sit-to-stand and timed w alk measures following an inten- sive interdisciplinary physical therapy and psychological treatment day hospital program (Eccleston et al., 2003 ). Observational measures have the a dvantage of reduced subjectivity compared to self-report. Disadvantages of these measures i nclude some burden in terms of additional time needed to administer the tasks, as well as n ecessitating training research or clinical staff . At this time, how- ever, the most signif i cant limitation is the lack of available data on any particular performance-based measure of physical function in children with painful conditions. Measures of functional impairment that assess subjective per- ception of diffi culty perfor ming activities include the Functional Disability Inventory (FDI) and the Child Activity Li mitations Interview (CALI). Both were developed for children and adoles- cents with chronic pain. Th e FDI (Walker and Greene, 1991 ) was initially developed for adolescents with abd ominal pain; it has since been used in children with other chronic pain conditions (headach es, musculoskeletal pain; Claar et al., 2006 ), as a descrip- tive measure (Kashikar-Zuck e t al., 2011 ), and as a treatment out- come measure (Kashikar-Zuck et al., 2005 ). Th e CAL I (Palermo et al., 2004 ; Palermo et al., 2008a ) was developed to assess activity limitati ons associated with chronic pain in broader populations, and to allow for both retrospectiv e assessment and daily prospec- tive assessment in a diary format. It has been factor analy zed and has been shown to be responsive to change in treatment outcome research (Palermo et al., 2009 ). Details of the psychometric evalu- ation of these measures can be found in Ta ble 41.2 . CHAPTER 41 measurement of health-related quality of life and physical function 421 Physical activity, a specifi c domain of overall physical function, can be measured via sel f-report, proxy-report, or via activity moni- tors that capture physical activity in daily life such as pedometers or actigraphic monitoring devices. Th is domain of physical functio n is relevant for acute and chronic pain conditions, as pain is oft en characterized by lim itations in movement and withdrawal from physical activities (Sullivan et al., 2008 ). Addi tionally, low levels of physical activity have been associated with the development of pain in adolescents (Skoff er et al., 2008 ). pain management or treatment. Th ere has been too little empirical work performed to date t o recommend specifi c objective measures of functional assessment in youth with pain. Outcomes measurement Enhancing children \200\231s functioning is oft en the primary treatme nt goal for youth with chronic pain. Re-assessment of HRQOL and function is important for u nderstanding the impact of treatments, both on individuals and on groups. To date, the majo rity of studies have used HRQOL and function to describe pediatric medical and pain populat ions, however, there have been limited studies using these tools as outcome measurements af t er intervention. Th ere are a few pediatric studies that utilized HRQOL as an outcome mea s- ure aft er pharmacologic intervention for rheumatologic conditions (Ruperto et al., 2010 ). With respect to psychological intervention, similarly, few randomized controlled trials of psychological treat- ments have measured change in children \200\231s physical or role func- tioning from pre- to post-treatment (Palermo et al., 2010 ). While psychological inte rventions are largely found to be eff ective in reducing pain intensity, a signifi cant gap remains in our knowledge of the eff ects of psychological interventions on physical and ro le functioning, especially in randomized controlled trials. Several self- and proxy-report measurement systems, including diary and recall reports, hav e been developed for assessment of physical activity in healthy adolescents (see review by Sirard et al., 2001 ). Examples of available measures include the International Physical Ac tivity Questionnaire (IPAQ), which shows adequate reliability and has been validated with o bjective measures of energy expenditure in adolescents (Arvidsson et al., 2005 ). Brief phy sical activity screening measures are also available for use with adoles- cents (e.g. Proch aska et al., 2001 ). Th ese measures typically prompt the adolescent to recall a specifi c time period (e.g. the last 7 days) and estimate the amount of time spent in various levels of activity (e.g. vigorous enough to sweat). Despite the availability of self-report measures of physical activity, there are few publis hed studies examining these measures in youth with acute or chronic pain. Among youth with musculoskeletal pain, diary reports of physical activity demonstrate less time spent in phy s- ical activity compared to healthy controls (Kashikar-Zuck et al., 2010 ; Tarakci et al., 2011 ). Similarly, youth with nonspecifi c musculoskel- etal pain reported lower levels of activity using the Youth Activity Questionnaire (Ainsworth et al., 1993 ), compared to hea lthy youth matched for age and sex (O \200\231Sullivan et al., 2011 ). While there are lim- itations to self-report of physical activity in children and adolescents, particularly amo ng those with chronic pain (Kashikar-Zuck et al., 2010 ), additional research in this area would provide more informa- tion about the impact of pain on physical activity and to under stand- ing of how these measures perform in pain populations. Given the broad range of assessment measures and approaches available, clinicians must make choices to prioritize what informa- tion about HRQOL and functioning will be useful to col lect when evaluating an individual child with chronic pain and his or her fam- ily. Intervi ew and questionnaire reports of HRQOL and physical function should ideally be obtained from self-report if the child is cognitively and physically able to provide it. Parent or careg iver proxy reports can provide additional information on parent per- ception of the HRQOL a nd functioning of the child. As there is imperfect agreement between self and proxy report (Varni et al., 2007b ), proxy report should be used to supplement assessment of the child, not to replace information provided by self-report. Parent report has some unique correlate s; for example, parental percep- tion of HRQOL (rather than child perception) and function has been shown to be associated with children \200\231s healthcare utilization (Campo et al ., 2002 ; Janicke et al., 2001 ). Activity monitoring or actigraphy typically uses wrist- or hip- mounted accelerometers to t rack an individual \200\231s movements in daily life activities, which may be converted to caloric expenditure. Th ese measures of physical activity provide proxy data on actual move - ment patterns and have been used in a few studies of adolescents with chronic pain. Two s tudies have compared adolescents with mixed chronic pain problems (headaches, abdominal pai n, and musculoskeletal pain) to matched healthy controls on actigraphic measures of daytime activity, and found lower activity levels and more time spent in sedentary activity among youth with chronic pain (Long et al., 2008 ; Wilson et al., 2012 ). In one study of ado- le scents with juvenile primary fi bromyalgia syndrome, between- subject variability in physic al activity levels were high; among these untreated youth, higher activity was associated w ith signifi cantly lower levels of self-reported pain intensity, depressive symptoms, and f unctional disability (Kashikar-Zuck et al., 2010 ). Overall, acti- graphic measures have be en moderately correlated with self-reports of physical functioning among youth with chronic pain. Th ere are various monitoring devices and computer programs that have been developed for research purposes and can be used to assess physical activity (see review of activity monitoring in children and adoles- cents by Bjornson et al. ( 2004 )). To our knowledge, no published studies have examined physical activity in children experiencing acute or postop erative pain, or in association with acute or chronic Th ere are several new developments in measurement of physi- cal function. Most notably, co nsiderable work has been invested in the Patient Reported Outcomes Measurement Information System (PROMIS) funded by the National Institutes of Health. At present, preliminary valida tion has been conducted on a new measure of pain interference in children (Varni et al., 20 10 ) that can be admin- istered via self-report or computerized adaptive testing. Pain and function are areas identifi ed by PROMIS where ongoing work will continue to advance assess ment of health related outcomes in the pediatric pain population. Best available evidence to guide current use of assessment tools A wide variety of methods have been used to measure HRQOL, physical function, physical activity, and physical fi tnes s. Clear guidelines are not presently available for measurement of physi- cal function doma ins in the pediatric pain population. Further research on psychometric properties of measur es and comparative analysis of measurement methods is needed in this area to establish SECTION 5 measurement of pain 422 Table 41.3 Recommendations for assessment of HRQOL and physical function in children and ad olescents with painful conditions Assessment Name of measure (acronym) Reference Primary scale content HRQOL \200\223generic measures Child Health Questionnaire (CHQ) Landgraf et al. (1996) Physical functioning, role functioning: emotional/behavioral, role functioning: physical, b odily pain, general behavior, mental health, self-esteem, general health perceptions, paren tal impact: emotional, parental impact: time, family activities, family cohesion, change in health Multidimensional pain- speci \201 c measures Pediatric Quality of Life Inventory 4.0 (PedsQL4.0) Varni et al. (1999) Physical, psychological, social, and school functioning Pain Experience Questionnaire (PEQ) Hermann et al. (2008) Pain severity, pain related interference, a \200 ective distress, perceived social support Bath Adolescent Pain Questionnaire (BAPQ) Eccleston et al. (2005) Physical functioning, social functioning, depression, general anxiety, pain-speci \201 c a nxiety, family functioning, and developmental functioning Functional Impairment Functional Disability Inventory (FDI) Walker and Greene (1991) Physical and psychosocial limitations due to pain Child Activity Limitations Interview (CALI) Palermo et al. (2004) Activity restrictions in daily, personal, recreational, physical, and social activities due to pain these guidelines. We have made recommendations to guide the use of instruments for measurem ent of HRQOL and physical function in pediatric pain populations in Table 41.3 . We have ch osen not to recommend measures within specifi c pain conditions given the small available e vidence base within any one condition. In addition, due to the limited available data on ob jective and performance- based measures in children with pain, it is premature to recom- me nd their routine use. levels of impairment. Moreover, the relationship between subjec- tive measures (questionnai res) and objective performance meas- ures requires specifi c consideration. In summary, HRQOL and physical functioning instruments may allow for objective assessment o f the global functioning of the child, enable standardized comparison within and across pai nful medical populations, and provide longitudinal monitoring of out- comes over time and i n response to intervention. Applications of HRQOL measurement reviewed by Varni et al. ( 20 05 ) suggest that standardized measures may improve communication between the health care p rovider and the child and family as well as improve child and parent satisfaction by active ly eliciting information about the child \200\231s functioning. Th us, in order to optimize the use of these measures, further research into the potential benefi ts are needed in ped iatric pain populations. Conclusion Collectively, information obtained from the clinical interview, ques- tionnaires , and observational measures allow for global evaluation of HRQOL and physical function in the child with pain. Due to the availability of numerous measures, the choice of instrument (s) needs to be guided by measurement quality of the instruments and the goals set by and t he clinician and/or the researcher. In examina- tion of the wide range of available instrum ents, we have identifi ed several research priorities: Case example \227\206 Validation of HRQOL and physical function measures for use in children with pain conditions requires further attention. At this time it is not clear whether currently avail able measures are appropriate in the context of acute pain or whether adaptations to existi ng measures or the development of new measures will be needed. Kristy is a 16-year-old female who began experiencing low back pain about 2 years ago. Prio r to pain onset, she participated in soft ball and volleyball at her school, but has now gi ven up these sports activities due to pain. Kristy has missed an increasing number of schoo l days in the past year, which she attributes to worsening pain from sitting for long perio ds. Her parents report that she is more sedentary than she used to be, spending much time l ying down at home. Th ey also note that she oft en refuses to do household chores that invo lve lift ing. Kristy has begun to avoid interactions with her friends because they oft en c hoose activities that involve walking long distances. Currently, Kristy reports that she ca n go on walks on days when her pain is less intense, but only walks for 20 to 30 min once o r twice a week. She also experiences increased pain when walking up and down stairs, and wh en her pain is severe she will sleep on the couch at night to avoid walking upstairs to her bedroom. Her night-time sleep has been disrupted for the past several months and she is of t en fatigued during the day. \227\206 To extend the clinical utility of measures, additional work is required to establ ish the clinical meaning of changes in scores for individuals. Th e development of cut-poin ts to indicate clinical severity of the limitation in HRQOL or physical function may be use ful for certain measures. For an example, see Kashikar-Zuck et al. ( 2011 ) concerning clin ical utility of the FDI. \227\206 Th ere is limited information on any objective or performance- based measure of p hysical function or activity in children with pain. Additional work is needed with performa nce-based tasks (e.g. timed walk), activity devices (e.g. actigraphy), and with physical fi tness measures (e.g. grip strength) to develop norma- tive data in pediatric pain populati ons and understand relative CHAPTER 41 measurement of health-related quality of life and physical function 423 Eccleston , C. , Jordan , A. , McCracken , L. M. , Sleed , M. , Connell , H. , and Clinch , J. ( 2005 ). Th e Bath Adolescent Pain Questionnaire (BAPQ): development and preliminary p sychometric evaluation of an instrument to assess the impact of chronic pain on adolescents . Pain , 118 , 263 \200\223270. Assessment that includes a combination of interview ques- tions, standardized measures of H RQOL and physical function in conjunction with performance measures may provide clini- call y relevant information. Th e clinical interview could be used to assess in detail Kristy \200\231s participation in physical and role activi- ties (e.g. doing family chores at home , attending school, doing things with friends). Specifi c interview probes could be used wi th Kristy and her parent(s) to understand Kristy \200\231s expectations for activity and ro le participation and what her individual values are around functional activities. A measure of overall HRQOL, such as the PedsQL 4.0, would provide information about perception of ov erall health impact, while a measure of pain-related activity limitations or disability suc h as the FDI or the CALI-21 would provide information about pain impact on functioning that may identify specifi c intervention targets or goals. Because Kristy reports trouble walki ng, and a timed 10- meter walk would estab- lish a baseline performance that could be used throughout treat- ment to assess progress. Additional measures of performance and fi tness might be chosen by a physical or occupational therapist. Eccleston , C. , Jordan , A. L. , and Crombez , G. ( 2006 ). Th e impact of chronic pain on adolescents: a review of previously used measures . J Pediatr Psychol , 31 , 684 \200\223 697. Eccleston , C. , Malleson , P. N. , Clinch , J. , Connell , H. , and Sourbut , C. ( 2003 ). Chronic pain in adolescents: evaluation of a program of interdisciplinary cognitive behavi or therapy . Arch Dis Child , 88 , 881 \200\223885. Eiser , C. and Morse , R. ( 2001 ). Th e measurement of quality of life in children: past and future perspectives . J Dev Behav Pediatr , 22 , 248 \200\223256. Gold , J. I. , Mahrer , N. E. , Yee , J. , and Palermo , T. M. ( 2009 ). Pain, fatigue, and health-related quality of life in children and adolescents with chronic pain . Clin J Pain , 25 , 407 \200\223412. Halbig , M. and Horneff , G. ( 2009 ). Improvement of functional ability in children with j uvenile idiopathic arthritis by treatment with etanercept . Rheumatol Int , 30 , 229 \200 \223238. Harding , V. R. , Williams , A. C. , Richardson , P. H. , Nicholas , M. K. , Jackson , J. L . , Richardson , I. H. , et al . ( 1994 ). Th e development of a battery of measures for as sessing physical functioning of chronic pain patients . Pain , 58 , 367 \200\223375. Th ese measures can provide valuable information to assess Kristy on an individual basis, a nd to also compare the level of impairment secondary to pain in comparison to other adoles- cents with pain conditions. Furthermore, the measures can also allow the clinician to trac k Kristy \200\231s progress over time to objec- tively monitor her level of functioning and assess for changes in impairment if treatment is undertaken. Hermann , C. , Hohmeister , J. , Zohsel , K. , Tuttas , M. L. , and Flor , H. ( 2008 ). 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