Perceptualand MotorSkills, 1991, 73,415-418. O Perceptual and Motor Skills 1991
AGE DIFFERENCES I N CHILDREN'S PAIN JANICE LANDER AND SUSAN FOWLER-KERRY
Universiq of Alberta Summo7y.-A cross-sectional study of venipuncture pain and anxiety was conducted with 180 consecutively referred children and their parents. Analysis indicated that younger children report more venipuncture pain than older children. Anxiety was related to both age and pain. As well, anxiety was lowest among children with no previous venipuncture experience and among those with the greatest experience.
It is generally recognized that there has been little research on children's pain. This has resulted in a lack of knowledge about their pain experience and in the propagation of myths. While age differences are expected, the nature of that relationship is unclear. Some research on age has been conducted with experimentally induced pain which can be characterized as safe, localized, ultra short, and mild in nature. It is not likely to mimic clinical pain and so results of laboratory studies on age and pain may not generalize to clinical settings . In one laboratory study, pain threshold to pressure pain was higher among younger than older children (3). This finding was generally supported by another investigation in which older children and adults were assessed for threshold to a pin-point heat stimulus (9). Thresholds were lower for older adults than younger adults and children. Children were grouped in that study with young adults for the purposes of analysis, which precluded a more detailed assessment of age and pain. Other research on developmental aspects of children's clinical pain has been conducted with observed distress as the outcome measure rather than children's perceptions about their own pain. Older children exhibit fewer distress behaviors than younger children (4, 5). However, these behavioral pain scales overrepresent behaviors typical of younger children, an important consideration when interpreting data which indicate significantly greater distress among younger than older children. Research has also been conducted on children's descriptions of and knowledge about pain. Ross and Ross (8) did not find developmental differences in knowledge about pain among those aged 5 to 12 years. By contrast, Gaffney and D u m e (2) found that children's definitions of pain have a pattern which corresponds to Piaget's developmental stages. Moreover, children's 'We are indebted to the staff and patients of the laboratory of a general hospital. This study was supported by a grant from the National Health Research Development Program, Health and yelfare Canada. Address correspondence to Janice Lander, Ph.D., 3-103 Clinical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
416
J. LANDER & S. FOWLER-KERRY
ability to control pain improves with age (1, 7). Many of these studies have involved healthy children who are imagining their responses to hypothetical situations. Obtaining descriptive data is an essential first step for improving our ability to manage children's pain. The purpose of the study reported in this paper was to assess whether the pain experienced by school-aged children and adolescents who were having venipuncture was associated with age. A cross-sectional descriptive design was employed. A convenience sample was obtained of consecutive referrals of children to the outpatient laboratory of a general hospital. As no attempt was made to select subjects proportionally on the basis of age, sex, disease, or any other criterion, the sample characteristics were typical of the pediatric laboratory population. All persons attending the laboratory were screened to see if they were in the specified age range. Those who were between 5 and 17 years were approached to ascertain whether a parent was present to provide consent. In total, 223 children were approached, and data from 180 were included in this study. The most common reasons for not participating were lack of time required for the study (48%), child not being accompanied by a parent (17%), and child refusing to participate (14%). There were 90 girls and 90 boys who completed the study. Their ages ranged from 5 yr., 0 mo. to 17 yr., 11 mo. (mean 11.8). Several instruments were administered. State anxiety was measured on the State-Trait Anxiety Inventory (10). Nine sketches of simple faces, ranging from happy to sad, form the affective pain scale (6). Scores range from .06 to .94. The visual analogue scale used in thls study was a vertical line of 100 mm. The anchors for this scale were "no pain" and "worst pain possible." This scale is the most often used one for the sensory dimension of pain. After instruction on use of the instruments and prior to venipuncture, the child rated expected pain (on the visual analogue scale) and state anxiety. Then venipuncture was performed. A11 blood was drawn by a laboratory technician from a vein in the right or left arm at the antecubital space. No child required more than one neede puncture. Immediately after the laboratory technician exited the room, the child was asked to rate pain intensity from the venipuncture by making a mark on the visual analogue scale. The child was also asked to choose the face on the affective scale which best indicated how he felt about the venipuncture. First-order correlations were computed among the study variables. Anal-
417
AGE DIFFERENCES IN CHILDREN'S PAIN
ysis indicated that many of the variables (including age, anxiety, and the three pain ratings) were interrelated. Therefore, a standard multiple regression analysis was conducted to assess which variables would predict pain intensity (sensory pain). The following variables predicted 51% of the variance in pain intensity: expected pain, state anxiety, pain affect, age, and gender. Of those variables, only age, expected pain, and pain affect made significant contributions to the prediction of pain intensity. State anxiety was significantly correlated with pain affect (Pearson r = .43, p 7-9 >9-11 >11-13 >13-15 > 15 ALISubjects
Expected Pain
AND
A ~ m BYn AGEGROUP
State Anxiety*
Pain Affect
Pain Intensity
M
SD
M
SD
M
JD
M
SD
45.2 32.8 34.4 27.7 26.3 24.4 30.3
41.6 35.1 29.4 24.1 26.2 22.6 29.3
58.1 56.8 53.8 52.6 47.3 47.0 51.8
12.7 18.5 11.6 12.3 15.4 15.4 15.1
.7 .5 .5 .4
.3 3 .3 .2 .2 .2 .3
52.4 27.2 25.6 21.3 21.9 17.5 25.1
38.8 32.9 26.0 20.6 20.9 21.3 27.3
.5 .4 .5
n 16 30 31 30 35 38 180
*Percentile score given.
Categorical data were obtained about frequency of past venipuncture (none, 1-4, 5-10, 11 + ). Frequency of previous venipuncture was significantly related to age (F,,,,, = 3.57, p = .02). The older the child, the more the opportunity to experience illness and require venipuncture. State anxiety was significantly related to frequency of venipuncture after age was controlled by analysis of covariance (F,,,,, = 3.19, p = .02). It was lowest for those who had either more than 10 or no previous venipuncture.
DISCUSSION On average, reported venipuncture pain in children was mild. However, when considering age differences, pain was most severe and most distressing for 5 - to 7-yr.-old children. Their reported pain was twice as intense as that
418
J. LANDER & S. FOWLER-KERRY
of other children. Although it is possible that biological factors are responsible for the more intense pain experience of young children, another explanation seems more plausible. Research on children's conceptions of pain suggests that children who experienced the most intense pain had not reached a developmental stage at which they could see a purpose to the pain or could generate coping strategies (1, 7). This explanation could also account for the elevated state anxiety in young children. I t may be that anxiety increases the expectation of pain. I t is possible that our questions about pain and anxiety served to increase state anxiety and influence expectations about pain. Regardless, presence of substantial anxiety could be considered evidence of poor coping. Both anxiety and pain expectation may provide information about coping skills and styles. Further research is required. Besides being related to age, anxiety was related to previous experience with venipuncture. Anxiety was lowest when there had been no experience or multiple experience with venipuncture; and this was evaluated with effects of age controlled. Perhaps children require some direct experience with venipuncture to develop anxiety. Further, ability to cope may improve with repeated exposure to venipuncture. Additional research on the effects of multiple exposures to painful stimuli upon anxiety and pain is in order. REFERENCES 1. BROWN,J., O'KEEFFE, J., SANDERS,S., & BAKER,B. (1986) Developmental changes in children's cognition to stressful and painful situations. Journal of Pediah.ic Psychology,
11, 343-357. GAFFNEY, A., & DUNNE,E. (1986) Developmental aspects of children's d e f i ~ t i o n sof pain. Pain,. 26.. 105-117. 3. HASLAM, D. (1969) Age and the perception of pain. Psychonomic Science, 15, 86-87. 4. JAY,S., OZOLINS, M., ELLIOTT,C., & CALDWELL,S. (1983) Assessment of children's distress during painful medication procedures. Health Psychology, 2, 133-147. 5 . KATZ,E., KELLERMAN, J., & SIEGEL,S. (1980) Distress behavior in children with cancer 2.
undergoing medical procedures: developmental considerations. Journal of Consulting and Clinical Psychology, 48, 356-365. 6. MCGRATH, P, A , , DEVEBER,L., & HEARN, M. (1985) Multidimensional pain assessment in children. In H. Fields, R. Dubner, & F. Cervero (Eds.), Advances in pain research and herapy. New York: Raven. Pp. 387-402. 7. RIESSLAND, N . (1983) Cognitive maturity and the experience of fear and pain in hospital. Social Science and Medicine, 17, 1389-1395. 8. Ross, D., & Ross, S. (1984) Childhood pain: the school-aged child's viewpoint. Pain, 20,
179-191.
9. SCHLUDERMANN, E., & ZUBEX,J. (1962) Effect of age on pain sensitivity. Perceptual and Motor Skillr, 14, 295-301. 10. SPELBERGER,C. D., GORSUCH, R. L., LUSHENE, R. E., VAGG,P., & JACOBS, G. (1983) Manual for the State-Trait Anxiety Inventory. Palo Alto, CA: Consulting Psychologists Press.
Accepted August 22, 1991.
AGE DIFFERENCES I N CHILDREN'S PAIN JANICE LANDER AND SUSAN FOWLER-KERRY
Universiq of Alberta Summo7y.-A cross-sectional study of venipuncture pain and anxiety was conducted with 180 consecutively referred children and their parents. Analysis indicated that younger children report more venipuncture pain than older children. Anxiety was related to both age and pain. As well, anxiety was lowest among children with no previous venipuncture experience and among those with the greatest experience.
It is generally recognized that there has been little research on children's pain. This has resulted in a lack of knowledge about their pain experience and in the propagation of myths. While age differences are expected, the nature of that relationship is unclear. Some research on age has been conducted with experimentally induced pain which can be characterized as safe, localized, ultra short, and mild in nature. It is not likely to mimic clinical pain and so results of laboratory studies on age and pain may not generalize to clinical settings . In one laboratory study, pain threshold to pressure pain was higher among younger than older children (3). This finding was generally supported by another investigation in which older children and adults were assessed for threshold to a pin-point heat stimulus (9). Thresholds were lower for older adults than younger adults and children. Children were grouped in that study with young adults for the purposes of analysis, which precluded a more detailed assessment of age and pain. Other research on developmental aspects of children's clinical pain has been conducted with observed distress as the outcome measure rather than children's perceptions about their own pain. Older children exhibit fewer distress behaviors than younger children (4, 5). However, these behavioral pain scales overrepresent behaviors typical of younger children, an important consideration when interpreting data which indicate significantly greater distress among younger than older children. Research has also been conducted on children's descriptions of and knowledge about pain. Ross and Ross (8) did not find developmental differences in knowledge about pain among those aged 5 to 12 years. By contrast, Gaffney and D u m e (2) found that children's definitions of pain have a pattern which corresponds to Piaget's developmental stages. Moreover, children's 'We are indebted to the staff and patients of the laboratory of a general hospital. This study was supported by a grant from the National Health Research Development Program, Health and yelfare Canada. Address correspondence to Janice Lander, Ph.D., 3-103 Clinical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G3.
416
J. LANDER & S. FOWLER-KERRY
ability to control pain improves with age (1, 7). Many of these studies have involved healthy children who are imagining their responses to hypothetical situations. Obtaining descriptive data is an essential first step for improving our ability to manage children's pain. The purpose of the study reported in this paper was to assess whether the pain experienced by school-aged children and adolescents who were having venipuncture was associated with age. A cross-sectional descriptive design was employed. A convenience sample was obtained of consecutive referrals of children to the outpatient laboratory of a general hospital. As no attempt was made to select subjects proportionally on the basis of age, sex, disease, or any other criterion, the sample characteristics were typical of the pediatric laboratory population. All persons attending the laboratory were screened to see if they were in the specified age range. Those who were between 5 and 17 years were approached to ascertain whether a parent was present to provide consent. In total, 223 children were approached, and data from 180 were included in this study. The most common reasons for not participating were lack of time required for the study (48%), child not being accompanied by a parent (17%), and child refusing to participate (14%). There were 90 girls and 90 boys who completed the study. Their ages ranged from 5 yr., 0 mo. to 17 yr., 11 mo. (mean 11.8). Several instruments were administered. State anxiety was measured on the State-Trait Anxiety Inventory (10). Nine sketches of simple faces, ranging from happy to sad, form the affective pain scale (6). Scores range from .06 to .94. The visual analogue scale used in thls study was a vertical line of 100 mm. The anchors for this scale were "no pain" and "worst pain possible." This scale is the most often used one for the sensory dimension of pain. After instruction on use of the instruments and prior to venipuncture, the child rated expected pain (on the visual analogue scale) and state anxiety. Then venipuncture was performed. A11 blood was drawn by a laboratory technician from a vein in the right or left arm at the antecubital space. No child required more than one neede puncture. Immediately after the laboratory technician exited the room, the child was asked to rate pain intensity from the venipuncture by making a mark on the visual analogue scale. The child was also asked to choose the face on the affective scale which best indicated how he felt about the venipuncture. First-order correlations were computed among the study variables. Anal-
417
AGE DIFFERENCES IN CHILDREN'S PAIN
ysis indicated that many of the variables (including age, anxiety, and the three pain ratings) were interrelated. Therefore, a standard multiple regression analysis was conducted to assess which variables would predict pain intensity (sensory pain). The following variables predicted 51% of the variance in pain intensity: expected pain, state anxiety, pain affect, age, and gender. Of those variables, only age, expected pain, and pain affect made significant contributions to the prediction of pain intensity. State anxiety was significantly correlated with pain affect (Pearson r = .43, p 7-9 >9-11 >11-13 >13-15 > 15 ALISubjects
Expected Pain
AND
A ~ m BYn AGEGROUP
State Anxiety*
Pain Affect
Pain Intensity
M
SD
M
SD
M
JD
M
SD
45.2 32.8 34.4 27.7 26.3 24.4 30.3
41.6 35.1 29.4 24.1 26.2 22.6 29.3
58.1 56.8 53.8 52.6 47.3 47.0 51.8
12.7 18.5 11.6 12.3 15.4 15.4 15.1
.7 .5 .5 .4
.3 3 .3 .2 .2 .2 .3
52.4 27.2 25.6 21.3 21.9 17.5 25.1
38.8 32.9 26.0 20.6 20.9 21.3 27.3
.5 .4 .5
n 16 30 31 30 35 38 180
*Percentile score given.
Categorical data were obtained about frequency of past venipuncture (none, 1-4, 5-10, 11 + ). Frequency of previous venipuncture was significantly related to age (F,,,,, = 3.57, p = .02). The older the child, the more the opportunity to experience illness and require venipuncture. State anxiety was significantly related to frequency of venipuncture after age was controlled by analysis of covariance (F,,,,, = 3.19, p = .02). It was lowest for those who had either more than 10 or no previous venipuncture.
DISCUSSION On average, reported venipuncture pain in children was mild. However, when considering age differences, pain was most severe and most distressing for 5 - to 7-yr.-old children. Their reported pain was twice as intense as that
418
J. LANDER & S. FOWLER-KERRY
of other children. Although it is possible that biological factors are responsible for the more intense pain experience of young children, another explanation seems more plausible. Research on children's conceptions of pain suggests that children who experienced the most intense pain had not reached a developmental stage at which they could see a purpose to the pain or could generate coping strategies (1, 7). This explanation could also account for the elevated state anxiety in young children. I t may be that anxiety increases the expectation of pain. I t is possible that our questions about pain and anxiety served to increase state anxiety and influence expectations about pain. Regardless, presence of substantial anxiety could be considered evidence of poor coping. Both anxiety and pain expectation may provide information about coping skills and styles. Further research is required. Besides being related to age, anxiety was related to previous experience with venipuncture. Anxiety was lowest when there had been no experience or multiple experience with venipuncture; and this was evaluated with effects of age controlled. Perhaps children require some direct experience with venipuncture to develop anxiety. Further, ability to cope may improve with repeated exposure to venipuncture. Additional research on the effects of multiple exposures to painful stimuli upon anxiety and pain is in order. REFERENCES 1. BROWN,J., O'KEEFFE, J., SANDERS,S., & BAKER,B. (1986) Developmental changes in children's cognition to stressful and painful situations. Journal of Pediah.ic Psychology,
11, 343-357. GAFFNEY, A., & DUNNE,E. (1986) Developmental aspects of children's d e f i ~ t i o n sof pain. Pain,. 26.. 105-117. 3. HASLAM, D. (1969) Age and the perception of pain. Psychonomic Science, 15, 86-87. 4. JAY,S., OZOLINS, M., ELLIOTT,C., & CALDWELL,S. (1983) Assessment of children's distress during painful medication procedures. Health Psychology, 2, 133-147. 5 . KATZ,E., KELLERMAN, J., & SIEGEL,S. (1980) Distress behavior in children with cancer 2.
undergoing medical procedures: developmental considerations. Journal of Consulting and Clinical Psychology, 48, 356-365. 6. MCGRATH, P, A , , DEVEBER,L., & HEARN, M. (1985) Multidimensional pain assessment in children. In H. Fields, R. Dubner, & F. Cervero (Eds.), Advances in pain research and herapy. New York: Raven. Pp. 387-402. 7. RIESSLAND, N . (1983) Cognitive maturity and the experience of fear and pain in hospital. Social Science and Medicine, 17, 1389-1395. 8. Ross, D., & Ross, S. (1984) Childhood pain: the school-aged child's viewpoint. Pain, 20,
179-191.
9. SCHLUDERMANN, E., & ZUBEX,J. (1962) Effect of age on pain sensitivity. Perceptual and Motor Skillr, 14, 295-301. 10. SPELBERGER,C. D., GORSUCH, R. L., LUSHENE, R. E., VAGG,P., & JACOBS, G. (1983) Manual for the State-Trait Anxiety Inventory. Palo Alto, CA: Consulting Psychologists Press.
Accepted August 22, 1991.
