- Email: [email protected]
Health-related quality of life in child patients with temporomandibular disorder pain
European Journal of Pain 11 (2007) 557–563 www.EuropeanJournalPain.com
Health-related quality of life in child patients with temporomandibular disorder pain Elizabeth Jedel a
a,b,*
, Jane Carlsson a, Elisabet Stener-Victorin
a,b
Faculty of Health and Caring Sciences, Institute of Occupational and Physical Therapy, Box 455, Sahlgrenska Academy at Go¨teborg University, SE-40530 Go¨teborg, Sweden b Cardiovascular Institute, Wallenberg Laboratory, SU Sahlgrenska Academy at Go¨teborg University, SE-413 45 Go¨teborg, Sweden Received 26 October 2005; received in revised form 12 July 2006; accepted 17 July 2006 Available online 28 August 2006
Abstract Temporomandibular disorders (TMDs) occurs frequently in children and measuring health-related quality of life (HRQL) can complement efficacy measures, offering a complete picture of the impact of disease and treatment on overall well-being. Aim: To compare HRQL, pain threshold (PT) and range of motion (ROM) in child patients with temporomandibular disorder (TMD) pain and an age and gender matched control group. Methods: The study design was a controlled cross-sectional study. Forty-two children participated in the study. Twenty-one child patients referred to a dental pediatric clinic for specialist treatment because of TMD pain and an age and gender matched control group completed the Child health questionnaire-child form 87 (CHQ-CF87). PT was measured with Pain matcherÒ and ROM in terms of maximum unassisted mandibular opening was measured with a ruler. Results: The child patients with pain more than once a week had a pain duration ranging from 3 months to almost 6 years. The median for pain intensity measured with visual analogue scale (VAS) was 47 ranging from 5 to 80 and the median for behavioral rating scale (BRS) was 3 ranging from 1 to 4. Child patients with TMD pain more than once a week reported significantly lower scores in CHQ-CF87 when compared with a control group. The results for PT and ROM were non-significant. Conclusion: CHQ-CF87 could be used for measuring health and to evaluate the efficacy of treatment in child patients with TMD pain. Ó 2006 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Ltd. All rights reserved. Keywords: Pain threshold; Range of motion
1. Introduction Abbreviations: PT, pain threshold; ROM, range of motion; TMD, temporomandibular disorder; CHQ-CF87, Child health questionnairechild form 87; RDC, research diagnostic criteria; HRQL, health related quality of life; JCA, juvenile chronic arthritis; CTTH, chronic tension type headache; RPT, registered physical therapist; VAS, visual analogue scale; BRS, behavioral rating scale. * Corresponding author. Present address: Munkeba¨cksgatan 20, SE41653 Go¨teborg, Sweden. Tel.: +46 31 7075844. E-mail address: [email protected] (E. Jedel).
Temporomandibular disorders (TMDs) occurs frequently in children with a pain point prevalence of 7% (List et al., 1999). TMD is a term embracing clinical problems involving the masticatory system, the temporomandibular joint and associated structures. It is a number of analogue disorders having pain and dysfunction in the masticatory system in common (McNeill et al., 1990).
1090-3801/$32 Ó 2006 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ejpain.2006.07.007
558
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
Research diagnostic criteria for TMD (RDC/TMD) is a classification system developed in the United States by Dworkin and Le Resche (Dworkin and Le Resche, 1992). RDC/TMD divides the most common sub-types of TMD into three categories: (a) muscular disorders, (b) disc displacements and (c) arthralgia, arthritis and arthrosis, allowing multiple diagnoses (Dworkin and Le Resche, 1992). RDC/TMD includes clinical examination and a questionnaire, interpreted into Swedish (List and Dworkin, 1996) and tested for reliability in children (Wahlund et al., 1998). In children RDC/TMD selfreported questionnaire showing TMD pain more than once a week or more, and measure of range of motion (ROM) has a higher reliability than other variables of the examination (Wahlund et al., 1998). Across genders, it has been found that the majority of children who reported TMD pain once a week or more had a significantly higher perceived need for treatment than those who reported less frequent pain (List and Dworkin, 1996). TMD pathophysiology and etiology is not clearly understood but pain in the masticatory system is the cardinal symptom making patients with TMD seek care (Ohrbach and Dworkin, 1998). Acute pain is due to peripheral mechanisms. Microtrauma or ischemia is followed by substance release locally effecting the blood circulation causing pain by direct activation or by increased sensitivity in nociceptors (Svensson and Yaksh, 2002). Central sensitivity of nociceptors could be a mechanism which causes acute pain to become recurrent (Porreca et al., 2002). Recurrent pain lasting more than 3 months has been named chronic and could be divided into infrequent/frequent subtypes (Olesen et al., 2004). Pain threshold (PT) has been used to evaluate the perception of pain and the efficacy of treatment outcomes in adults (Kosek and Ordeberg, 2000a; Kosek and Ordeberg, 2000b). PT scores in the hand, measured with the pressure algometer, an instrument used almost exclusively in research, have not shown significant results when comparing children with TMD and a control group (Wahlund et al., 2005). There is a need to evaluate other instruments measuring PT in children with TMD. Pain matcherÒ (Lundeberg et al., 2001) has been designed for clinical use in pain measurement and is based on electrical stimulation applied to the skin. The aim is to activate receptors in the thumb and index finger. Pain matcherÒ is a safe instrument tested for reliability (Lundeberg et al., 2001). TMD pain in adults leads to consequences such as limitations in social function, emotional well-being and energy level resulting in decreased health related quality of life (HRQL) (Di Fabio, 1998). HRQL measures functional health and well-being and is the patient’s view of his or her condition (Erling, 1999). Measuring HRQL in children can complement efficacy
measures, offering a complete picture of the impact of disease and treatment on overall well-being (Rentz et al., 2005). The patient’s perspective is needed to understand the impact of a disorder on the HRQL (Table 1). HRQL is an important concept in regards to treatment outcomes but has not been used in studies evaluating TMD pain in children. The aims were to compare health-related quality of life, pain threshold and range of motion in child patients with temporomandibular disorder pain and a control group.
2. Methods 2.1. Design The study-design was a controlled cross-sectional study. 2.2. Patients Patients recruited for the study were child patients referred to a dental pediatric clinic in Go¨teborg, Sweden for specialist treatment because of TMD pain. The dental pediatric clinic is a specialist unit receiving referrals from the districts of south-western Sweden. Inclusion criteria were patients 10–18 years of age with TMD pain more than once a week and reported pain duration of at least 3 months. Exclusion criteria were patients with juvenile chronic arthiritis (JCA), Ehler Danlos syndrome, myocitis occificans, diabetes, chronic tension type headache (CTTH), migraine. The child patients and their parents were contacted by telephone and asked about pain frequency (more than once a week) and pain duration (more than 3 months). A letter explaining the objectives of the study offering participation, and the RDC/TMD selfreported questionnaire including two methods for the rating of pain, was sent to the child patients and their parents prior to their scheduled appointment. The visual analogue scale (VAS) consists of a 100 mm straight line on which the child patients marked their pain intensity. Children over 7 years are generally able to understand the use of VAS (Denecke and Hunseler, 2000). In addition behavioral rating scale (BRS) (Blanchard and Andrasik, 1982) was included to measure the effect of the pain on patients daily activities: 0 = no pain; 1 = pain, I am only aware of it if I pay attention to it; 2 = pain, but I can ignore it at times; 3 = pain, I can not ignore it but I can do my usual activities; 4 = pain, it is difficult to concentrate; 5 = pain, such that I can not do anything. BRS demands minimal instruction and are generally understood by children over 9 years (Blanchard and Andrasik, 1982).
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
559
Table 1 Summary of concepts in the Child health questionnaire-child form 87 (CHQ-CF87): interpretation of low and high scores Concepts
Number of items
Low score
High score Child performs all types of physical activities, including the most vigorous, without limitations due to health Child has no limitations in school work or activities with friends as a result of emotional problems Child has no limitations in school work or activities with friends as a result of behavior problems Child has no limitations in school work or activities with friends as a result of physical health Child has no pain or limitations due to pain
Physical functioning
9
Child is limited a lot in performing all physical activities, including self-care, due to health
Role emotional
3
Child is limited a lot in school work or activities with friends as a result of emotional problems
Role behavioral
3
Child is limited a lot in school work or activities with friends as a result of behavior problems
Role physical
3
Bodily pain
2
Child is limited a lot in school work or activities with friends as a result of physical health Child has extremely severe, frequent and limiting bodily pain Child very often exhibits aggressive, immature, delinquent behaviour Child has feelings of anxiety and depression all of the time Child is very dissatisfied with abilities, looks, family/peer relationships and life overall Child believes child’s health is poor and likely to get worse Child’s health is much worse now than 1 year ago The child’s health very often limits and interrupts family activities or is a source of family tension Family‘s ability to get along is rated ‘‘poor’’
Behaviora
17
Mental health
16
Self esteem
14
General healtha
12
Change in health Family activities
1 6
Family cohesiona
1
a
Child never exhibits aggressive, immature, delinquent behavior Child feels peaceful, happy and calm all of the time Child is very satisfied with abilities, looks, family/ peer relationships and life overall Child believes child’s health is excellent and will continue to be so Child’s health is much better now than 1 year ago The child’s health never limits or interrupts family activities nor is a source of family tension Family‘s ability to get along is rated ‘‘excellent’’
Includes a stand-alone global item that measures along a five level response continuum from ‘‘excellent’’ to ‘‘poor’’.
Of a total of 44 child patients referred to the dental pediatric clinic for specialist treatment because of TMD pain more than once a week for at least 3 months, 21 were included in the study. Sixteen child patients were diagnosed with JCA, 1 was diagnosed with Ehler Danlos syndrome, 1 was diagnosed with myocitis occificans and 2 were diagnosed with CTTH and did not fulfil the inclusion criteria. Three child patients declined participation. 2.3. Control group Recall patients from a dental clinic in Go¨teborg, Sweden with no reported TMD pain were recruited as a control group prior to their scheduled recall appointment. The dental clinic is a general practice for children living within the city-limits of Go¨teborg. Recall patients with any of the following diagnoses were excluded: JCA, Ehler Danlos syndrome, myocitis occificans, diabetes, CTTH, migraine, TMD. The matching procedure was carried out by asking an age and gender matched control group for participation. A letter explaining the objectives of the study offering participation and the RDC/TMD self-reported questionnaire was presented and signed prior to inclusion. Of a total of 33 recall patients scheduled for their recall appointment, 21 were individually matched by age and gender to the child patients with TMD, and included in the study. All recall patients fulfilled the inclusion criteria but 12 patients declined participation.
2.4. Measurements The child patients and the control group were examined by one of the authors, a registered physical therapist (RPT), with the following measurements: Health-related quality of life: was measured with Child health questionnaire-child form 87 (CHQ-CF87) (Landgraf et al., 1999). CHQ-CF87 is a generic instrument, developed in the United States (Landgraf et al., 1999), interpreted into Swedish (Andersson et al., 2001). CHQ-CF87 has a multidimensional profile design, covering physical and psychosocial domains suitable for children 10–18 years. The instrument contains 12 scales and includes a total of 87 items asking for the child’s HRQL, predominately during the preceding 4 weeks. The items within each scale are summed and linearly transformed into a scale of 0 (poor) to 100 (optimal) for each dimension (Table 1) (Landgraf et al., 1999). CHQ-CF87 has been found valid and reliable in the United States (Landgraf et al., 1999) and other countries including Sweden (Norrby et al., 2003). PT: was measured with Pain matcherÒ, Cefar medical AB, Lund, Sweden (Lundeberg et al., 2001). Pain matcherÒ consists of a unit giving constant current stimulation with a microprocessor that provides rectangular pulses with a frequency of 10 Hz and amplitude of 10 mA. It is programmed to give a constant current stimulation despite variable skin resistance (e.g., influenced by sweating and anxiety of the child) up to 13 kX. The intensifying of stimulation is
560
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
achieved by successively increasing the pulse width from 0 to a possible maximum of 450 ls in increments of 7.5 ls, up to a total of 60 steps. The electrical charge per second is extremely low and varies through the different steps from 1.5 to 45 lC. The reached value (0–60) is directly related to the pulse width and is displayed on a liquid crystal display screen (StenerVictorin et al., 2002). The child was instructed to hold an electrode box in a horizontal position between the thumb and the index finger of the left hand. The electrical stimulation unit was turned on by the examiner and controlled by the child during delivery of electrical pulses at a random velocity and with increasing intensity. When the child first felt a sensation of pain in the left hand, the child was told to release her/his fingers from the electrode box, stopping the electrical stimulation. The value obtained, from 0 to 60 was automatically saved. The procedure was repeated within 30 s. Pain matcherÒ has been tested for its reliability (Lundeberg et al., 2001). ROM in terms of maximum unassisted mandibular opening: was measured with a graded ruler in accordance with a method tested for reliability in children (List and Dworkin, 1996). The child was seated in an upright position leaning towards the headrest and instructed to close his/her mouth while the examiner marked the vertical overbite. The child was then instructed to perform maximum unassisted opening letting the examiner measure the distance between the incisors and the vertical overbite. 2.5. Ethics Written consent was obtained from the child patients’ and their parents. The study was approved by the Local ethics committee in Go¨teborg, Sweden. 2.6. Statistical analyses Group differences in CHQ-CF87, PT and ROM were tested using independent t-tests.
3. Results Characteristics of child patients with TMD pain and the control group were calculated from the RDC/TMD self-reported questionnaire (Table 2). All child patients were between 11 and 18 years, born in Sweden and the dominant gender was girls. The child patients with pain more than once a week, had a pain duration ranging from 3 months to almost 6 years. The median for pain intensity measured with VAS was 47 ranging from 5– 80 and the median for BRS was 3 ranging from 1 to 4. Child patients with TMD pain more than once a week reported significantly lower scores in 3 of 12 CHQ-CF87 concepts when compared with a control group (Table 3). The concepts with significant lower scores for the child patients with TMD pain more than once a week were physical functioning, role emotional and role behavioral p = 0.042, p = 0.013 and p = 0.000 respectively. The mean for PT and for ROM was not significantly lower in children with TMD compared to a control group (Table 4).
4. Discussion This study indicates that HRQL is decreased in child patients with TMD pain more than once a week. Low scores for physical functioning means the child is limited a lot in performing all physical activities, including selfcare, due to health. Low scores for role emotional means the child is limited a lot in school work or activities with friends as a result of emotional problems. Low scores for role behavioral means the child is limited a lot in school work or activities with friends as a result of behavior problems. There was a limited amount of referrals to the dental pediatric clinic during the time the study was conducted. Suggestions for methodological improvements would be to recruit referrals from several dental pediatric clinics as well as TMD units. Another reason for the child patients with TMD pain more than once a week and
Table 2 Characteristics of child patients with temporomandibular disorder (TMD) pain and a control group Characteristics
Child patients with temporomandibular disorder (TMD) pain Median (minimum–maximum) (n = 21)
Control group Median (minimum–maximum) (n = 21)
Age (years) Gender: girls (%) Gender: boys (%) Immigrant child TMD pain frequency (% more than once a week) TMD pain duration (months) TMD pain intensity (VASa) TMD pain intensity (BRSb)
16 (11–18) 71 29 0 100
16 (11–18) 71 29 0 0
16 (3–70) 47 (5–80) 3 (1–4)
0 0 0
a b
Visual analogue scale. Behavioral rating scale.
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
561
Table 3 Health-related quality of life (HRQL) (Child health questionnaire-child form 87, CHQ-CF87) in child patients with temporomandibular disorder (TMD) pain compared with a control group Concepts
Child patients with TMD pain Mean (standard deviation) (n = 21)
Control group Mean (standard deviation) (n = 21)
Significance level
Physical functioning Role emotional Role behavioral Role physical Bodily pain Behavior Mental health Self esteem General health Change in healthb Family activities Family cohesionb
98.4 83.8 88.8 91.9 52.8 85.5 7.2 78.6 69.8 3.4 81.5 71.4
100.0 91.9 100.0 91.9 74.8 77.4 73.2 73.2 75.1 3.6 81.5 60.7
0.042 0.013 0.000 NSa NSa NSa NSa NSa NSa NSa NSa NSa
(7.4) (20.3) (22.1) (14.8) (24.7) (14.4) (16.4) (15.9) (24.8) (1.1) (24.9) (26.5)
(0.0) (14.8) (0.0) (18.2) (18.6) (20.8) (16.4) (20.3) (20.9) (0.9) (24.9) (27.8)
Lower scores indicate a lower degree of perceived functional health and well-being. a Not significant. b Single-item scale.
Table 4 Pain threshold (PT) and range of motion (ROM) in child patients with temporomandibular disorder (TMD) pain compared with a control group
PT ROM (mm)
Child patients with TMD Mean (standard deviation) (n = 21)
Control group Mean (standard deviation) (n = 21)
Significance level
6.7 (2.5) 43.5 (10.9)
8.8 (3.4) 51.6 (11.4)
NSa NSa
Lower scores indicate a lower PT and lower ROM. a Not significant.
the control group to differ on the dependent measures is referral bias. The referred group would be expected to present themselves as more impaired. Indeed, some of the behavioral difficulties in this group could have contributed to their referral for TMD treatment. General pain occurred in the control group. Several musculoskeletal pain conditions are common in children and it has a potential impact on daily activities and quality of daily living (Larsson, 1991). Child patients with TMD pain presented a broad range of TMD pain duration and TMD pain intensity when measured with RDC/TMD which could be partly explained by the TMD diagnosis. RDC/TMD divides the most common sub-types of TMD into muscular disorders, disc displacements and arthralgia, arthritis and arthrosis, allowing multiple diagnoses (Dworkin and Le Resche, 1992). This study included single and multiple diagnoses according to RDC/TMD but children with JCA were excluded since HRQL in children with JCA is decreased (Norrby et al., 2003). In this study a parametric test was used in accordance with CHQ-CF87 scoring instructions recommending parametric test (Landgraf et al., 1999). Level of measurement could be an important element in deciding whether to use parametric or non-parametric tests. CHQ-CF87 was easy to administer with minimal training and took between 15–35 min to complete.
CHQ-CF87 was well understood by the child patients with TMD pain more than once a week and the control group. The Swedish interpretation of the phrase ‘‘act too young for your age’’ was ‘‘childish’’, which was corrected verbally by the examiner at the time CHQ-CF87 was completed confidentially. A shorter version of the instrument would improve the objective standards of use in a clinical setting and are in progress to be developed (Landgraf et al., 1999). CHQ-CF87 may be used across different populations and can measure a broad range of health domains. By using generic and disease-specific HRQL instruments complimentary information can be provided (Graue et al., 2003). Disease-specific instruments have not been tested in child patients with TMD pain. The authors suggest conducting studies to test the following disease-specific instruments developed for adults with TMD: The oral health impact profile (Slade and Spencer, 1994) and Leakes index of chewing ability (Leake, 1990). The oral health impact profile evaluates the social impact of oral disorders and Leakes index of chewing ability is scored from 0 to 5 based on self reported ability to chew the most ‘‘difficult’’ of 5 foods. Svensson et al. (Svensson et al., 2001) have reported significant differences in PT between adult patients with TMD and a control group, indicating a generalized hyperalgesic response to somato-sensory stimulation.
562
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
In this study PT measured with Pain matcherÒ in child patients with TMD pain more than once a week was not significantly lower than the control group. The implication of no difference in PT between child patients with TMD pain and a control group is that the TMD pain is not due to greater sensitivity to pain in child patients with TMD. This finding supports the proposition that the symptoms could be due to physical dysfunction in the masticatory system, the temporomandibular joint and/or associated structures rather than in some psychological disposition or trait of the child. The pain mechanisms in child patients with TMD need to be evaluated further. Okeson and O’Donell (Okeson and O’Donell, 1989) consider ROM to be an important measure of function. If the individual opening capacity at health is unknown, an opening of 40 mm is an accepted minimum limit from the age of 6–7 years (Okeson and O’Donell, 1989). This study indicates that ROM in terms of maximum unassisted mandibular opening in child patients with TMD pain more than once a week is not significantly lower than a control group. Based on these findings a ruler should not be used as a main outcome measure for physical function in child patients with TMD. Since the study was conducted with ethnically and geographically homogeneous samples of small size, it should not automatically be generalized to other settings. However, the results of this study indicate lower scores in HRQL in child patients with TMD pain compared with a control group. CHQ-CF87 could be used for measuring health and to evaluate the efficacy of treatment in child patients with TMD pain.
Acknowledgements The study was supported by Grants from the First mayflower campaign for child health, the Swedish national association for registered physical therapist and the Eva and Oscar Ahren foundation.
References Andersson GB, Ruperto N, Berg S, Hagelberg S, Jonsson NO, Magnusson B, et al. The Swedish version of the Childhood health assessment questionnaire (CHAQ) and the Child health questionnaire (CHQ). Clin Exp Rheumatol 2001;19(Suppl. 23): 146–50. Blanchard EB, Andrasik F. Psychological assessment and treatment of headache: Recent development and emergency issues. J Consult Clin Psychol 1982;50:859–79. Denecke H, Hunseler C. Assessment and measurement of pain. Schmerz 2000;14:302–8. Di Fabio RP. Physical therapy for patients with TMD: a descriptive study of treatment, disability, and health status. J Orofac Pain 1998;12:124–35.
Dworkin SF, Le Resche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examination and specifications, critique. J Craniomandib Disord 1992;6:301–55. Erling A. Methodological considerations in the assessment of healthrelated quality of life in children. Acta Paediatr Suppl 1999;88(428):106–7. Graue M, Wentzel-Larsen T, Hanestad BR, Ba˚tsvik B, Sovik O. Measuring self-reported, health-related, quality of life in adolescents with type 1 diabetes using both generic and disease-specific instruments. Acta Paediatr 2003;92:1190–6. Kosek E, Ordeberg G. Abnormalities of somatosensory perception in patients with painful osteoarthritis normalize following successful treatment. Eur J Pain 2000;4:229–38. Kosek E, Ordeberg G. Lack of pressure pain modulation by heterotopic noxious conditioning stimulation in patients with painful osteoarthritis before, but not following, surgical pain relief. Pain 2000;88:69–78. Landgraf JM, Abetz L, Ware JE. Child Health Questionnaire (CHQ) a User’s Manual. second ed. Boston: HealthAct; 1999. Larsson BS. Somatic complaints and their relationship to depressive symptoms in Swedish adolescents. J Child Psychol Psychiatry 1991;32:821–32. Leake JL. An index of chewing ability. J Public Health Dent 1990;50:262–7. List T, Dworkin SF. Comparing TMD diagnoses and clinical findings at Swedish and US TMD centers using research diagnostic criteria for temporomandibular disorders. J Orofac Pain 1996;10:240–53. List T, Wahlund K, Wenneberg B, Dworkin SF. TMD in children and adolescents: prevalence of pain, gender differences, and perceived treatment need. J Orofac Pain 1999;13:9–20. Lundeberg T, Lund I, Dahlin L, Borg E, Gustavsson C, Sandin L, et al. Reliability and responsiveness of three different pain assessments. J Rehabil Med 2001;33:279–83. McNeill C, Mohl ND, Rugh J, Tanatan TT. Temporomandibular disorders: diagnosis, management, education and research. J Am Dent Assoc 1990;120:252–63. Norrby U, Nordholm L, Fasth A. Reliability and validity of the Swedish version of Child health questionnaire. Scand J Rheumatol 2003;32:101–7. Ohrbach R, Dworkin SF. Five-year outcomes in TMD: relationship of changes in pain to changes in physical and psychological variables. Pain 1998;74:315–26. Okeson JP, O’Donell JP. Standards for temporomandibular evaluation in the pediatric patient. Pediatr Dent 1989;11: 329–30. Olesen J, Bousser MG, Diener HC, Dodick D, First M, Goadsby PJ, et al. The International Classification of Headache Disorders 2nd Edition. Cephalalgia 2004;24(Suppl 1):23–43. Porreca F, Ossipov MH, Gebbhart GF. Chronic pain and medullary descending facilitation. Trends Neurosci 2002;25:319–25. Rentz AM, Matza LS, Secnik K, Swensen A, Revicki DA. Psychometric validation of the child health questionnaire (CHQ) in a sample of children and adolescents with attention-deficit/hyperactivity disorder. Qual Life Res 2005;14(Apr): 719–34. Slade GD, Spencer AJ. Development and evaluation of the oral health impact profile. Community Dent Health 1994;11:3–11. Stener-Victorin E, Kowalski J, Lundeberg T. A new, highly reliable instrument for the assessment of pre- and postoperative gynecological pain. Anesth Analg 2002;95:151–7. Svensson P, List T, Hector G. Analysis of stimulus-evoked pain in patients with myofacial temporomandibular pain disorders. Pain 2001;92:399–409. Svensson CI, Yaksh TL. The spinal phospholipase-cyclooxygenaseprostanoid cascade in nociceptive processing. Ann Rev Pharmacol Toxicol 2002;42:553–83.
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563 Wahlund K, List T, Dworkin SF. Temporomandibular disorders in children and adolescents: reliability of a questionnaire, clinical examination and diagnosis. J Orofac Pain 1998;12: 42–51.
563
Wahlund K, List T, Ohrbach R. The relationship between somatic and emotional stimuli: a comparison between adolescents with temporomandibular disorders (TMD) and a control group. Eur J Pain 2005;9:219–27.
Health-related quality of life in child patients with temporomandibular disorder pain Elizabeth Jedel a
a,b,*
, Jane Carlsson a, Elisabet Stener-Victorin
a,b
Faculty of Health and Caring Sciences, Institute of Occupational and Physical Therapy, Box 455, Sahlgrenska Academy at Go¨teborg University, SE-40530 Go¨teborg, Sweden b Cardiovascular Institute, Wallenberg Laboratory, SU Sahlgrenska Academy at Go¨teborg University, SE-413 45 Go¨teborg, Sweden Received 26 October 2005; received in revised form 12 July 2006; accepted 17 July 2006 Available online 28 August 2006
Abstract Temporomandibular disorders (TMDs) occurs frequently in children and measuring health-related quality of life (HRQL) can complement efficacy measures, offering a complete picture of the impact of disease and treatment on overall well-being. Aim: To compare HRQL, pain threshold (PT) and range of motion (ROM) in child patients with temporomandibular disorder (TMD) pain and an age and gender matched control group. Methods: The study design was a controlled cross-sectional study. Forty-two children participated in the study. Twenty-one child patients referred to a dental pediatric clinic for specialist treatment because of TMD pain and an age and gender matched control group completed the Child health questionnaire-child form 87 (CHQ-CF87). PT was measured with Pain matcherÒ and ROM in terms of maximum unassisted mandibular opening was measured with a ruler. Results: The child patients with pain more than once a week had a pain duration ranging from 3 months to almost 6 years. The median for pain intensity measured with visual analogue scale (VAS) was 47 ranging from 5 to 80 and the median for behavioral rating scale (BRS) was 3 ranging from 1 to 4. Child patients with TMD pain more than once a week reported significantly lower scores in CHQ-CF87 when compared with a control group. The results for PT and ROM were non-significant. Conclusion: CHQ-CF87 could be used for measuring health and to evaluate the efficacy of treatment in child patients with TMD pain. Ó 2006 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Ltd. All rights reserved. Keywords: Pain threshold; Range of motion
1. Introduction Abbreviations: PT, pain threshold; ROM, range of motion; TMD, temporomandibular disorder; CHQ-CF87, Child health questionnairechild form 87; RDC, research diagnostic criteria; HRQL, health related quality of life; JCA, juvenile chronic arthritis; CTTH, chronic tension type headache; RPT, registered physical therapist; VAS, visual analogue scale; BRS, behavioral rating scale. * Corresponding author. Present address: Munkeba¨cksgatan 20, SE41653 Go¨teborg, Sweden. Tel.: +46 31 7075844. E-mail address: [email protected] (E. Jedel).
Temporomandibular disorders (TMDs) occurs frequently in children with a pain point prevalence of 7% (List et al., 1999). TMD is a term embracing clinical problems involving the masticatory system, the temporomandibular joint and associated structures. It is a number of analogue disorders having pain and dysfunction in the masticatory system in common (McNeill et al., 1990).
1090-3801/$32 Ó 2006 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ejpain.2006.07.007
558
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
Research diagnostic criteria for TMD (RDC/TMD) is a classification system developed in the United States by Dworkin and Le Resche (Dworkin and Le Resche, 1992). RDC/TMD divides the most common sub-types of TMD into three categories: (a) muscular disorders, (b) disc displacements and (c) arthralgia, arthritis and arthrosis, allowing multiple diagnoses (Dworkin and Le Resche, 1992). RDC/TMD includes clinical examination and a questionnaire, interpreted into Swedish (List and Dworkin, 1996) and tested for reliability in children (Wahlund et al., 1998). In children RDC/TMD selfreported questionnaire showing TMD pain more than once a week or more, and measure of range of motion (ROM) has a higher reliability than other variables of the examination (Wahlund et al., 1998). Across genders, it has been found that the majority of children who reported TMD pain once a week or more had a significantly higher perceived need for treatment than those who reported less frequent pain (List and Dworkin, 1996). TMD pathophysiology and etiology is not clearly understood but pain in the masticatory system is the cardinal symptom making patients with TMD seek care (Ohrbach and Dworkin, 1998). Acute pain is due to peripheral mechanisms. Microtrauma or ischemia is followed by substance release locally effecting the blood circulation causing pain by direct activation or by increased sensitivity in nociceptors (Svensson and Yaksh, 2002). Central sensitivity of nociceptors could be a mechanism which causes acute pain to become recurrent (Porreca et al., 2002). Recurrent pain lasting more than 3 months has been named chronic and could be divided into infrequent/frequent subtypes (Olesen et al., 2004). Pain threshold (PT) has been used to evaluate the perception of pain and the efficacy of treatment outcomes in adults (Kosek and Ordeberg, 2000a; Kosek and Ordeberg, 2000b). PT scores in the hand, measured with the pressure algometer, an instrument used almost exclusively in research, have not shown significant results when comparing children with TMD and a control group (Wahlund et al., 2005). There is a need to evaluate other instruments measuring PT in children with TMD. Pain matcherÒ (Lundeberg et al., 2001) has been designed for clinical use in pain measurement and is based on electrical stimulation applied to the skin. The aim is to activate receptors in the thumb and index finger. Pain matcherÒ is a safe instrument tested for reliability (Lundeberg et al., 2001). TMD pain in adults leads to consequences such as limitations in social function, emotional well-being and energy level resulting in decreased health related quality of life (HRQL) (Di Fabio, 1998). HRQL measures functional health and well-being and is the patient’s view of his or her condition (Erling, 1999). Measuring HRQL in children can complement efficacy
measures, offering a complete picture of the impact of disease and treatment on overall well-being (Rentz et al., 2005). The patient’s perspective is needed to understand the impact of a disorder on the HRQL (Table 1). HRQL is an important concept in regards to treatment outcomes but has not been used in studies evaluating TMD pain in children. The aims were to compare health-related quality of life, pain threshold and range of motion in child patients with temporomandibular disorder pain and a control group.
2. Methods 2.1. Design The study-design was a controlled cross-sectional study. 2.2. Patients Patients recruited for the study were child patients referred to a dental pediatric clinic in Go¨teborg, Sweden for specialist treatment because of TMD pain. The dental pediatric clinic is a specialist unit receiving referrals from the districts of south-western Sweden. Inclusion criteria were patients 10–18 years of age with TMD pain more than once a week and reported pain duration of at least 3 months. Exclusion criteria were patients with juvenile chronic arthiritis (JCA), Ehler Danlos syndrome, myocitis occificans, diabetes, chronic tension type headache (CTTH), migraine. The child patients and their parents were contacted by telephone and asked about pain frequency (more than once a week) and pain duration (more than 3 months). A letter explaining the objectives of the study offering participation, and the RDC/TMD selfreported questionnaire including two methods for the rating of pain, was sent to the child patients and their parents prior to their scheduled appointment. The visual analogue scale (VAS) consists of a 100 mm straight line on which the child patients marked their pain intensity. Children over 7 years are generally able to understand the use of VAS (Denecke and Hunseler, 2000). In addition behavioral rating scale (BRS) (Blanchard and Andrasik, 1982) was included to measure the effect of the pain on patients daily activities: 0 = no pain; 1 = pain, I am only aware of it if I pay attention to it; 2 = pain, but I can ignore it at times; 3 = pain, I can not ignore it but I can do my usual activities; 4 = pain, it is difficult to concentrate; 5 = pain, such that I can not do anything. BRS demands minimal instruction and are generally understood by children over 9 years (Blanchard and Andrasik, 1982).
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
559
Table 1 Summary of concepts in the Child health questionnaire-child form 87 (CHQ-CF87): interpretation of low and high scores Concepts
Number of items
Low score
High score Child performs all types of physical activities, including the most vigorous, without limitations due to health Child has no limitations in school work or activities with friends as a result of emotional problems Child has no limitations in school work or activities with friends as a result of behavior problems Child has no limitations in school work or activities with friends as a result of physical health Child has no pain or limitations due to pain
Physical functioning
9
Child is limited a lot in performing all physical activities, including self-care, due to health
Role emotional
3
Child is limited a lot in school work or activities with friends as a result of emotional problems
Role behavioral
3
Child is limited a lot in school work or activities with friends as a result of behavior problems
Role physical
3
Bodily pain
2
Child is limited a lot in school work or activities with friends as a result of physical health Child has extremely severe, frequent and limiting bodily pain Child very often exhibits aggressive, immature, delinquent behaviour Child has feelings of anxiety and depression all of the time Child is very dissatisfied with abilities, looks, family/peer relationships and life overall Child believes child’s health is poor and likely to get worse Child’s health is much worse now than 1 year ago The child’s health very often limits and interrupts family activities or is a source of family tension Family‘s ability to get along is rated ‘‘poor’’
Behaviora
17
Mental health
16
Self esteem
14
General healtha
12
Change in health Family activities
1 6
Family cohesiona
1
a
Child never exhibits aggressive, immature, delinquent behavior Child feels peaceful, happy and calm all of the time Child is very satisfied with abilities, looks, family/ peer relationships and life overall Child believes child’s health is excellent and will continue to be so Child’s health is much better now than 1 year ago The child’s health never limits or interrupts family activities nor is a source of family tension Family‘s ability to get along is rated ‘‘excellent’’
Includes a stand-alone global item that measures along a five level response continuum from ‘‘excellent’’ to ‘‘poor’’.
Of a total of 44 child patients referred to the dental pediatric clinic for specialist treatment because of TMD pain more than once a week for at least 3 months, 21 were included in the study. Sixteen child patients were diagnosed with JCA, 1 was diagnosed with Ehler Danlos syndrome, 1 was diagnosed with myocitis occificans and 2 were diagnosed with CTTH and did not fulfil the inclusion criteria. Three child patients declined participation. 2.3. Control group Recall patients from a dental clinic in Go¨teborg, Sweden with no reported TMD pain were recruited as a control group prior to their scheduled recall appointment. The dental clinic is a general practice for children living within the city-limits of Go¨teborg. Recall patients with any of the following diagnoses were excluded: JCA, Ehler Danlos syndrome, myocitis occificans, diabetes, CTTH, migraine, TMD. The matching procedure was carried out by asking an age and gender matched control group for participation. A letter explaining the objectives of the study offering participation and the RDC/TMD self-reported questionnaire was presented and signed prior to inclusion. Of a total of 33 recall patients scheduled for their recall appointment, 21 were individually matched by age and gender to the child patients with TMD, and included in the study. All recall patients fulfilled the inclusion criteria but 12 patients declined participation.
2.4. Measurements The child patients and the control group were examined by one of the authors, a registered physical therapist (RPT), with the following measurements: Health-related quality of life: was measured with Child health questionnaire-child form 87 (CHQ-CF87) (Landgraf et al., 1999). CHQ-CF87 is a generic instrument, developed in the United States (Landgraf et al., 1999), interpreted into Swedish (Andersson et al., 2001). CHQ-CF87 has a multidimensional profile design, covering physical and psychosocial domains suitable for children 10–18 years. The instrument contains 12 scales and includes a total of 87 items asking for the child’s HRQL, predominately during the preceding 4 weeks. The items within each scale are summed and linearly transformed into a scale of 0 (poor) to 100 (optimal) for each dimension (Table 1) (Landgraf et al., 1999). CHQ-CF87 has been found valid and reliable in the United States (Landgraf et al., 1999) and other countries including Sweden (Norrby et al., 2003). PT: was measured with Pain matcherÒ, Cefar medical AB, Lund, Sweden (Lundeberg et al., 2001). Pain matcherÒ consists of a unit giving constant current stimulation with a microprocessor that provides rectangular pulses with a frequency of 10 Hz and amplitude of 10 mA. It is programmed to give a constant current stimulation despite variable skin resistance (e.g., influenced by sweating and anxiety of the child) up to 13 kX. The intensifying of stimulation is
560
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
achieved by successively increasing the pulse width from 0 to a possible maximum of 450 ls in increments of 7.5 ls, up to a total of 60 steps. The electrical charge per second is extremely low and varies through the different steps from 1.5 to 45 lC. The reached value (0–60) is directly related to the pulse width and is displayed on a liquid crystal display screen (StenerVictorin et al., 2002). The child was instructed to hold an electrode box in a horizontal position between the thumb and the index finger of the left hand. The electrical stimulation unit was turned on by the examiner and controlled by the child during delivery of electrical pulses at a random velocity and with increasing intensity. When the child first felt a sensation of pain in the left hand, the child was told to release her/his fingers from the electrode box, stopping the electrical stimulation. The value obtained, from 0 to 60 was automatically saved. The procedure was repeated within 30 s. Pain matcherÒ has been tested for its reliability (Lundeberg et al., 2001). ROM in terms of maximum unassisted mandibular opening: was measured with a graded ruler in accordance with a method tested for reliability in children (List and Dworkin, 1996). The child was seated in an upright position leaning towards the headrest and instructed to close his/her mouth while the examiner marked the vertical overbite. The child was then instructed to perform maximum unassisted opening letting the examiner measure the distance between the incisors and the vertical overbite. 2.5. Ethics Written consent was obtained from the child patients’ and their parents. The study was approved by the Local ethics committee in Go¨teborg, Sweden. 2.6. Statistical analyses Group differences in CHQ-CF87, PT and ROM were tested using independent t-tests.
3. Results Characteristics of child patients with TMD pain and the control group were calculated from the RDC/TMD self-reported questionnaire (Table 2). All child patients were between 11 and 18 years, born in Sweden and the dominant gender was girls. The child patients with pain more than once a week, had a pain duration ranging from 3 months to almost 6 years. The median for pain intensity measured with VAS was 47 ranging from 5– 80 and the median for BRS was 3 ranging from 1 to 4. Child patients with TMD pain more than once a week reported significantly lower scores in 3 of 12 CHQ-CF87 concepts when compared with a control group (Table 3). The concepts with significant lower scores for the child patients with TMD pain more than once a week were physical functioning, role emotional and role behavioral p = 0.042, p = 0.013 and p = 0.000 respectively. The mean for PT and for ROM was not significantly lower in children with TMD compared to a control group (Table 4).
4. Discussion This study indicates that HRQL is decreased in child patients with TMD pain more than once a week. Low scores for physical functioning means the child is limited a lot in performing all physical activities, including selfcare, due to health. Low scores for role emotional means the child is limited a lot in school work or activities with friends as a result of emotional problems. Low scores for role behavioral means the child is limited a lot in school work or activities with friends as a result of behavior problems. There was a limited amount of referrals to the dental pediatric clinic during the time the study was conducted. Suggestions for methodological improvements would be to recruit referrals from several dental pediatric clinics as well as TMD units. Another reason for the child patients with TMD pain more than once a week and
Table 2 Characteristics of child patients with temporomandibular disorder (TMD) pain and a control group Characteristics
Child patients with temporomandibular disorder (TMD) pain Median (minimum–maximum) (n = 21)
Control group Median (minimum–maximum) (n = 21)
Age (years) Gender: girls (%) Gender: boys (%) Immigrant child TMD pain frequency (% more than once a week) TMD pain duration (months) TMD pain intensity (VASa) TMD pain intensity (BRSb)
16 (11–18) 71 29 0 100
16 (11–18) 71 29 0 0
16 (3–70) 47 (5–80) 3 (1–4)
0 0 0
a b
Visual analogue scale. Behavioral rating scale.
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
561
Table 3 Health-related quality of life (HRQL) (Child health questionnaire-child form 87, CHQ-CF87) in child patients with temporomandibular disorder (TMD) pain compared with a control group Concepts
Child patients with TMD pain Mean (standard deviation) (n = 21)
Control group Mean (standard deviation) (n = 21)
Significance level
Physical functioning Role emotional Role behavioral Role physical Bodily pain Behavior Mental health Self esteem General health Change in healthb Family activities Family cohesionb
98.4 83.8 88.8 91.9 52.8 85.5 7.2 78.6 69.8 3.4 81.5 71.4
100.0 91.9 100.0 91.9 74.8 77.4 73.2 73.2 75.1 3.6 81.5 60.7
0.042 0.013 0.000 NSa NSa NSa NSa NSa NSa NSa NSa NSa
(7.4) (20.3) (22.1) (14.8) (24.7) (14.4) (16.4) (15.9) (24.8) (1.1) (24.9) (26.5)
(0.0) (14.8) (0.0) (18.2) (18.6) (20.8) (16.4) (20.3) (20.9) (0.9) (24.9) (27.8)
Lower scores indicate a lower degree of perceived functional health and well-being. a Not significant. b Single-item scale.
Table 4 Pain threshold (PT) and range of motion (ROM) in child patients with temporomandibular disorder (TMD) pain compared with a control group
PT ROM (mm)
Child patients with TMD Mean (standard deviation) (n = 21)
Control group Mean (standard deviation) (n = 21)
Significance level
6.7 (2.5) 43.5 (10.9)
8.8 (3.4) 51.6 (11.4)
NSa NSa
Lower scores indicate a lower PT and lower ROM. a Not significant.
the control group to differ on the dependent measures is referral bias. The referred group would be expected to present themselves as more impaired. Indeed, some of the behavioral difficulties in this group could have contributed to their referral for TMD treatment. General pain occurred in the control group. Several musculoskeletal pain conditions are common in children and it has a potential impact on daily activities and quality of daily living (Larsson, 1991). Child patients with TMD pain presented a broad range of TMD pain duration and TMD pain intensity when measured with RDC/TMD which could be partly explained by the TMD diagnosis. RDC/TMD divides the most common sub-types of TMD into muscular disorders, disc displacements and arthralgia, arthritis and arthrosis, allowing multiple diagnoses (Dworkin and Le Resche, 1992). This study included single and multiple diagnoses according to RDC/TMD but children with JCA were excluded since HRQL in children with JCA is decreased (Norrby et al., 2003). In this study a parametric test was used in accordance with CHQ-CF87 scoring instructions recommending parametric test (Landgraf et al., 1999). Level of measurement could be an important element in deciding whether to use parametric or non-parametric tests. CHQ-CF87 was easy to administer with minimal training and took between 15–35 min to complete.
CHQ-CF87 was well understood by the child patients with TMD pain more than once a week and the control group. The Swedish interpretation of the phrase ‘‘act too young for your age’’ was ‘‘childish’’, which was corrected verbally by the examiner at the time CHQ-CF87 was completed confidentially. A shorter version of the instrument would improve the objective standards of use in a clinical setting and are in progress to be developed (Landgraf et al., 1999). CHQ-CF87 may be used across different populations and can measure a broad range of health domains. By using generic and disease-specific HRQL instruments complimentary information can be provided (Graue et al., 2003). Disease-specific instruments have not been tested in child patients with TMD pain. The authors suggest conducting studies to test the following disease-specific instruments developed for adults with TMD: The oral health impact profile (Slade and Spencer, 1994) and Leakes index of chewing ability (Leake, 1990). The oral health impact profile evaluates the social impact of oral disorders and Leakes index of chewing ability is scored from 0 to 5 based on self reported ability to chew the most ‘‘difficult’’ of 5 foods. Svensson et al. (Svensson et al., 2001) have reported significant differences in PT between adult patients with TMD and a control group, indicating a generalized hyperalgesic response to somato-sensory stimulation.
562
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563
In this study PT measured with Pain matcherÒ in child patients with TMD pain more than once a week was not significantly lower than the control group. The implication of no difference in PT between child patients with TMD pain and a control group is that the TMD pain is not due to greater sensitivity to pain in child patients with TMD. This finding supports the proposition that the symptoms could be due to physical dysfunction in the masticatory system, the temporomandibular joint and/or associated structures rather than in some psychological disposition or trait of the child. The pain mechanisms in child patients with TMD need to be evaluated further. Okeson and O’Donell (Okeson and O’Donell, 1989) consider ROM to be an important measure of function. If the individual opening capacity at health is unknown, an opening of 40 mm is an accepted minimum limit from the age of 6–7 years (Okeson and O’Donell, 1989). This study indicates that ROM in terms of maximum unassisted mandibular opening in child patients with TMD pain more than once a week is not significantly lower than a control group. Based on these findings a ruler should not be used as a main outcome measure for physical function in child patients with TMD. Since the study was conducted with ethnically and geographically homogeneous samples of small size, it should not automatically be generalized to other settings. However, the results of this study indicate lower scores in HRQL in child patients with TMD pain compared with a control group. CHQ-CF87 could be used for measuring health and to evaluate the efficacy of treatment in child patients with TMD pain.
Acknowledgements The study was supported by Grants from the First mayflower campaign for child health, the Swedish national association for registered physical therapist and the Eva and Oscar Ahren foundation.
References Andersson GB, Ruperto N, Berg S, Hagelberg S, Jonsson NO, Magnusson B, et al. The Swedish version of the Childhood health assessment questionnaire (CHAQ) and the Child health questionnaire (CHQ). Clin Exp Rheumatol 2001;19(Suppl. 23): 146–50. Blanchard EB, Andrasik F. Psychological assessment and treatment of headache: Recent development and emergency issues. J Consult Clin Psychol 1982;50:859–79. Denecke H, Hunseler C. Assessment and measurement of pain. Schmerz 2000;14:302–8. Di Fabio RP. Physical therapy for patients with TMD: a descriptive study of treatment, disability, and health status. J Orofac Pain 1998;12:124–35.
Dworkin SF, Le Resche L. Research diagnostic criteria for temporomandibular disorders: review, criteria, examination and specifications, critique. J Craniomandib Disord 1992;6:301–55. Erling A. Methodological considerations in the assessment of healthrelated quality of life in children. Acta Paediatr Suppl 1999;88(428):106–7. Graue M, Wentzel-Larsen T, Hanestad BR, Ba˚tsvik B, Sovik O. Measuring self-reported, health-related, quality of life in adolescents with type 1 diabetes using both generic and disease-specific instruments. Acta Paediatr 2003;92:1190–6. Kosek E, Ordeberg G. Abnormalities of somatosensory perception in patients with painful osteoarthritis normalize following successful treatment. Eur J Pain 2000;4:229–38. Kosek E, Ordeberg G. Lack of pressure pain modulation by heterotopic noxious conditioning stimulation in patients with painful osteoarthritis before, but not following, surgical pain relief. Pain 2000;88:69–78. Landgraf JM, Abetz L, Ware JE. Child Health Questionnaire (CHQ) a User’s Manual. second ed. Boston: HealthAct; 1999. Larsson BS. Somatic complaints and their relationship to depressive symptoms in Swedish adolescents. J Child Psychol Psychiatry 1991;32:821–32. Leake JL. An index of chewing ability. J Public Health Dent 1990;50:262–7. List T, Dworkin SF. Comparing TMD diagnoses and clinical findings at Swedish and US TMD centers using research diagnostic criteria for temporomandibular disorders. J Orofac Pain 1996;10:240–53. List T, Wahlund K, Wenneberg B, Dworkin SF. TMD in children and adolescents: prevalence of pain, gender differences, and perceived treatment need. J Orofac Pain 1999;13:9–20. Lundeberg T, Lund I, Dahlin L, Borg E, Gustavsson C, Sandin L, et al. Reliability and responsiveness of three different pain assessments. J Rehabil Med 2001;33:279–83. McNeill C, Mohl ND, Rugh J, Tanatan TT. Temporomandibular disorders: diagnosis, management, education and research. J Am Dent Assoc 1990;120:252–63. Norrby U, Nordholm L, Fasth A. Reliability and validity of the Swedish version of Child health questionnaire. Scand J Rheumatol 2003;32:101–7. Ohrbach R, Dworkin SF. Five-year outcomes in TMD: relationship of changes in pain to changes in physical and psychological variables. Pain 1998;74:315–26. Okeson JP, O’Donell JP. Standards for temporomandibular evaluation in the pediatric patient. Pediatr Dent 1989;11: 329–30. Olesen J, Bousser MG, Diener HC, Dodick D, First M, Goadsby PJ, et al. The International Classification of Headache Disorders 2nd Edition. Cephalalgia 2004;24(Suppl 1):23–43. Porreca F, Ossipov MH, Gebbhart GF. Chronic pain and medullary descending facilitation. Trends Neurosci 2002;25:319–25. Rentz AM, Matza LS, Secnik K, Swensen A, Revicki DA. Psychometric validation of the child health questionnaire (CHQ) in a sample of children and adolescents with attention-deficit/hyperactivity disorder. Qual Life Res 2005;14(Apr): 719–34. Slade GD, Spencer AJ. Development and evaluation of the oral health impact profile. Community Dent Health 1994;11:3–11. Stener-Victorin E, Kowalski J, Lundeberg T. A new, highly reliable instrument for the assessment of pre- and postoperative gynecological pain. Anesth Analg 2002;95:151–7. Svensson P, List T, Hector G. Analysis of stimulus-evoked pain in patients with myofacial temporomandibular pain disorders. Pain 2001;92:399–409. Svensson CI, Yaksh TL. The spinal phospholipase-cyclooxygenaseprostanoid cascade in nociceptive processing. Ann Rev Pharmacol Toxicol 2002;42:553–83.
E. Jedel et al. / European Journal of Pain 11 (2007) 557–563 Wahlund K, List T, Dworkin SF. Temporomandibular disorders in children and adolescents: reliability of a questionnaire, clinical examination and diagnosis. J Orofac Pain 1998;12: 42–51.
563
Wahlund K, List T, Ohrbach R. The relationship between somatic and emotional stimuli: a comparison between adolescents with temporomandibular disorders (TMD) and a control group. Eur J Pain 2005;9:219–27.