Individual
Differences
in Children’s
Response
to Pain: Role of Temperament
and Parental
Characteristics
Neil L. Schechter, MD*
t;
Bruce A. Bernstein, PhD*t;
ArneBeck, PhDf; Lisa Hart, MA*; and Lawrence Scherzer, MD
t §
From the *Depment of Pediatrics, Saint Francis Hospital and Medical Center, Hartford, Connecticut; tDepartment of Pediatrics, University of Connecticut School of Medicine, Farmington; Program Evaluation and Planning Department, Fort Logan Mental Health Center, Denver, Colorado; and §Department of Pediatrics, Kaiser Permanente Health Center, East Hartford, Connecticut
ABSTRACT. Sixty-five families were enlisted in a study exploring factors associated with distress behavior in 5-year-old children receiving diphtheria-thtanus-pertussis
immunizations. At a home visit 1 month before the immunization, the following measures were obtained: (1) the Behavioral Style Questionnaire, a measure of tern-perarnent; (2) parental self-reports of medically related attributes (eg, “good patient”); (3) parental attitudes to-ward pain in children and responsiveness to their child’s pain; and (4) parental prediction of distress at upcoming immunization. The child’s distress behavior during the immunization was evaluated using a modification of the Procedure Rating Scale-Revised and, after the procedure, the child’s assessment of his or her pain was elicited using the Oucher. Children’s mean Procedure Rating Scale-Revised score was 2.57 ofa possible 11. Thirty-one (48%) had low (1) and 7 (11%) had high distress scores (2 SD above the mean). Factors positively correlated with distressed behavior included more “difficult child” cluster characteristics, the individual temperamental dimension of adaptability, but few parental attitudes and attributes. Parents’ predictions of distress were the strongest come-lates. These findings document the variation that chil-dren demonstrate in response to pain and offer some insight into associated innate and environmental factors. These results imply that treatment strategies derived from parental knowledge and tailored to individual char-acteristics ofthe child may be most effective in alleviating pain-related distress in medical settings. Pediatrics
1991;87:171-177; Pain, immunization, temperament,
pa-rental attitude.
Little is known about how best to manage pain in children because little is known about how
chil-Received for publication Dec 7, 1989; accepted Feb 5, 1990. Presented, in part, at the annual meeting of the Ambulatory Pediatric Association, Washington, DC, May 1988.
Reprint requests to (N.L.S.) Dept of Pediatrics, Saint Francis Hospital and Medical Center, 114 Woodland St, Hartford, CT 06105.
PEDIATRICS (ISSN 0031 4005). Copyright © 1991 by the
American Academy of Pediatrics.
dren experience pain. This lack of knowledge may be responsible, at least in part, for the well-docu-mented undertreatment of childrens’ pain in most clinical settings.’3
An important aspect of children’s experience of pain that has received little attention is the individ-ual variation that children exhibit in response to painful stimuli. Some children may react vigorously
and with much emotion whereas others may not
react at all to a similar painful event. Although this phenomenon is frequently observed by most clini-cians, there has been limited formal effort to doc-ument these individual differences. In addition, the reasons for these differences have not been exam-med. Certainly both biologic and psychosocial hy-potheses can be offered to explain these differences, but the effect of personality style, individual tern-perament, and parental values and attitudes on the child’s response to pain has not been formally ex-amined. These questions have relevance in plan-ning interventions to help ameliorate pain in chil-dren.
To address this gap in our information, we de-signed a study that looked at two questions: (1) Are there individual differences in the way children respond to a uniform, painful stimulus? (2) If there are differences, what factors in the child and his or her family correlate with high-distress behavior?
We hypothesized that there would be differences in the way children respond to a uniform, painful
stimulus and in the amount of pain they reported.
We also believed that parents would be able to
predict their child’s distress pattern. With regard to correlates of high-distress behavior, we
an-noying stimuli and more negative mood than the average child. We also hypothesized that highly distressed children would be more likely to have parents who described themselves as fearful of med-ical situations and who had beliefs and attitudes that tended to overemphasize or denigrate pain expression in their children.
METHODS
The painful stimulus investigated in this study was the preschool diphthenia-tetanus-pertussis im-munization. Families of all children who were scheduled to receive this immunization at a health maintenance organization were contacted and asked to participate in this study. Consenting fam-ilies were visited in their homes by a research assistant 2 to 4 weeks before the office visit at which the immunization was to be administered.
Home Visit
During the home visit parents completed the Behavioral Style Questionnaire,4 a standardized measure of child temperament, and a pain ques-tionnaire which explored two areas: (1) parental attributes and (2) parental beliefs. In the section on attributes, parents were asked to rate themselves and their child on a five-point scale regarding a variety of medically related attributes (eg, ability
to tolerate pain, fearfulness of doctors, concerns about getting sick). In the section on parental
be-liefs or attitudes, a number of parental beliefs were assessed about children’s ability to handle pain in general and about the parents’ role in comforting children in pain. Parents were asked to rate on a five-point scale their opinions of a variety of pain-related statements (eg, “at age 4 to 5 children can handle minor hurts without their parents becoming involved” and “you can spoil a child by providing too much comfort when he or she is hurt”). They were also asked to respond to a number of vignettes that involved children getting hurt or complaining of discomfort.
In addition to these questionnaires parents were asked to predict the amount of discomfort their child would experience from the upcoming immu-nization.
Information was also gathered directly from the child during this visit by means of a semistructured interview. These data will not be reported in this paper.
Office Visit
At the office visit the child was immunized by one of four nurses in a standardized manner with
the parents present in the room. The nurses had previously agreed on a specific protocol involving the location of the shot, the technique used, and
their verbalizations during the administration of the immunization. The child’s response to the im-munization was assessed by the research assistant
using a modification of the Procedure Rating Scale-Revised (PRS-R),5 a standardized observation scale developed for use with children undergoing painful
procedures. It was designed to assess the presence of a variety of behavioral responses such as resist-ance to the procedure, muscular rigidity, crying, screaming, and facial gestures. Although originally developed for evaluation of pain during lumbar punctures and bone marrow aspirations, it has
sub-sequently been used to evaluate pain in many other pediatric procedures and is believed to be a reliable and valid measure of overt distress. In addition, the research assistant gave an overall global assessment of the child’s discomfort on a 0 to 5 scale. Finally, the child was asked to rate his or her discomfort on the Oucher,#{176} a standardized child self-report pain assessment scale. The Oucher consists of six pho-tographs of children in varying phases of discomfort and the child is asked to select the face that sym-bolizes his or her level of discomfort. Each photo-graph is linked to a specific value on a accompa-nying 100-point scale.
Finally, the research assistant recorded the length of time the child took to calm after the injection.
Data Analysis
The primary measure of distress used in our analyses was the PRS-R score, which was consid-ered an interval-level measure. “Distressed” and “nondistressed” groups were also categorized by dichotomizing at 2 SD above the mean PRS-R score. Quantitative descriptions of temperament were derived from mothers’ and fathers’ responses on the Behavioral Style Questionnaire in a manner described by McDevitt and Carey.4 These include continuous level measures of nine “categories” or dimensions of temperament (eg, adaptability, mood; see Table 2) and groupings of children into
one of five “diagnostic clusters” according to scores on the temperament categories (Table 3). In our analysis, “slow to warm up” was included in the “low intermediate” category. Responses to
ques-tions concerning attributes, attitudes, vignettes, disciplinary style, and predictions of children’s re-sponses were treated as ordinal-level data.
Number of Children 20
15
10
5j
nnnnnnn
0 1 2 3 4 5 6 7 8 9 10 11
h4INIMA. EXTREME
RESPONSE
RRS
Score
RESPONSEFig 1. Behavioral response to injection. PRS, Procedure Rating Scale.
TABLE 1. Response to Injection
PRS-R scores and by comparing mean distress scores according to diagnostic cluster groups using
analyses of variance and Tukey post hoc tests. Significance of differences in distress responses
between male and female children were evaluated
by comparing the mean PRS-R scores (two-tailed t
test) and the percent “distressed” of the two groups
(x2
test). Difference in mean time-to-calm between males and females was also assessed with a two-tailed t test. Rank order correlations were used to assess associations of distress with parents’ reports of their own and their child’s attributes, attitudes, disciplinary style, and predictions of response. Fa-thers’ and mothers’ attitudes toward pain in chil-dren were compared using Wilcoxon match-paired signed-ranks tests. Oucher score frequencies and correlations between Oucher and PRS-R scores were also obtained.RESULTS
Sample Characteristics
A total of 65 children (35 females and 30 males) were included in the study. Ages ranged from 52 to
66 months, with a mean of 60. Demographic data were collected and Behavioral Style Questionnaires were completed by mothers of all and fathers of 57 children (8 were members of single-parent fami-lies). Parents were generally well-educated (mean education for both parents was approximately 15 years) and occupational status was generally of managerial range (mean Duncan Socioeconomic Index7 = 56.0 ± 3.05 for fathers, 50.7 ± 2.89 for mothers). Approximately 85% of the families were white; the remainder were black and Hispanic.
Response to the Injection
Responses to the immunization, as measured by the PRS-R, ranged from 0 (no distress behaviors
observed) to 11 (all possible behaviors), but the response pattern was skewed toward the low end of the scale (mean = 2.6, median = 2) (Fig. 1, Table
1). Approximately one fourth of the children (17 of
65) exhibited no response, nearly half (31, 47.7%) scored 0 on 1, and 75% scored 3 or less. A total of 7 children (10.8%), who scored 8 or more (+2 SD) on the PRS-R, were categorized as “distressed.” Girls had a slightly higher mean PRS-R score and per-centage distressed compared with boys, but neither of these differences was statistically significant. We also analyzed the children’s reports of their pain by using the Oucher. The distribution of Oucher scores is reported in Fig. 2. Oucher scores were signifi-cantly correlated with pain behaviors (PRS-R score) (r = .46, P < .001). Although this was a
Subjects Mean PRS-R No. () Mean Time-to-Calm
(Range)* Distressedt (Range), mint
Boys 2.2 ± 0.5 (0-11) 2 (6.7)11 0.41J ± 0.17 (0-3)
Girls 2.9 ± 0.54 (0-11) 5 (14.3)11 1.40l ± 0.43 (0-8) Total 2.6 ± 0.37 (0-11) 7 (10.8) 0.88 ± 0.23 (0-8)
*n = 65; 35 girls, 30 boys. PRS-R, Procedure Rating
Scale-Revised.
t PRS-R score 8 (2 SD above the mean). n = 65; 35 girls, 30 boys.
:1:
n = 42; 20 girls, 22 boys.§Mean difference not significant (two-tailed t-test, P = .312).
IIPercent distressed not significantly different for males vs females (two-tailed Fisher’s exact, P .44).
#{182}P < .05 (two-tailed t-test).
strong association, there were some discrepancies between self-report and behavior. Specifically, 6 children who reported significant pain (60 or greater on the Oucher) displayed no or little pain behavior. Further analysis revealed no difference between this group and the other children with regard to sex, ethnicity, or any temperamental
di-mensions as rated by mothers or fathers.
“Time-to-calm” in minutes was recorded for 42 of the children (Table 1). The majority (57.1%) either had no distress or calmed within a minute, and all but 1 calmed within 3 minutes. The latter required 8 minutes. The mean time-to-calm for girls
15
10 #{149}1
0 20 60 80
MINIMAL
PAIN
Oucher
Score
Fig 2. Self-report of pain caused by injection.
100
EXTREME
PAl N
Number Children TABLE 2. Correlations* Between Temperament
Sub-.05. The mean time-to-calm for the “distressed” group was 3.8 minutes compared with 0.49 minutes for the “nondistressed” group (P < .001). This difference remained significant even when the child who cried for 8 minutes was removed.
Response and Temperament
Pearson correlations between distress response (PRS-R) and temperament dimensions (subscales) dcfived from the Behavioral Style Questionnaires are provided in Table 2. Both mothers’ and fathers’ ratings of their child’s “adaptability” (the ease or
difficulty with which reactions to stimuli can be modified) were significantly correlated with level of distress (r = .43, P < .001 and r = .22, P < .05, respectively). Mothers’ ratings of their child’s “rhythmicity” (the regularity of physiologic func-tions such as hunger, sleep, and elimination) were also significantly correlated with distress (r = .21, P < .044), but fathers’ “rhythmicity” scores were not. No other significant correlations between tern-perament subscales and response to the shot were found.
Comparisons of PRS-R scores according to con-ventional temperament groupings also suggested
some meaningful relationships between tempera-ment characteristics and distress response patterns (Table 3). Although temperament categories de-nived from mothers’ and fathers’ Behavioral Style Questionnaire ratings were not always in
agree-scales and Distress
Subscale Mothers’ Fathers’
Ratings Ratings
(n=65) (n=57)
r J) r P
Activity .20 .054 .20 .067
Rhythmicity .21 .044 .18 .085
Approach .07 .284 .12 .184
Adaptability .43 .001 .22 .050
Intensity .06 .311 .01 .485
Mood .18 .073 .20 .067
Persistence .04 .372 .07 .297
Distractibility .10 .216 .17 .104
Threshold .08 .271 .11 .209
* Pearson’s r.
ment, univariate analyses of variance indicated sig-nificant differences in mean distress responses by group for both mothers’ and fathers’ ratings. The children categorized as “difficult” based on moth-ens’ Behavioral Style Questionnaire ratings had a
mean PRS-R score that was two to three times the means of the children in the other groups (6.5 vs
1.3 to 2.8). In the fathers’ ratings, the “high inter-mediate” group PRS-R mean score was two to three times those of the other groups. Post hoc analyses (Tukey procedure) identified the significant differ-ences as follows: (1) mothers’ ratings: “difficult” significantly greater than “easy” or “low interme-diate”; (2) fathers’ ratings: “high intermediate” sig-nificantly greater than “easy.”
Parents’ Attributes and Attitudes and Child’s
Distress
Few significant correlations were found between parents’ assessments of their own (medically re-lated) attributes and their child’s distress response (Table 4). The two exceptions were (1) fathers who said they were more afraid of shots than other people had children with significantly stronger re-sponses to the shot and (2) the children of mothers who thought they themselves were better patients than other people were stronger responders.
TABLE 3. Temperament Groups and Distress Response
Temperament Group
Mothers’ Ratings (n= 65)
Fathers’ Ratings (n = 57)
No. (%) Mean No. No. (%) Mean No.
PRS-R Distressed* PRS-R Distressed*
(%) (%)
Easy 16 (25) 1.3 0 (0) 13 (23) 1.5 0 (0)
Low intermediate 29 (45) 2.8 4 (14) 30 (53) 2.6 3 (10)
High intermediate 16 (25) 2.3 1 (6) 8 (14) 5.Ot 3 (38)
Difficult 4 (6) 6.5t 2 (50) 6 (10) 2.2 0 (0)
* Procedure Rating Scale-Revised (PRS-R) score 8 (2 SD above the mean).
t Difficult group significantly higher mean PRS-R scores than easy and intermediate
groups (Tukey procedure, P < .05).
:1:
High intermediate group significantly higher mean PRS-R scores than easy group (Tukey procedure, P < .05).TABLE 4. Correlations* Between Parents’
Self-as-cribed Attributes and Child’s Distress
Attribute Mo
r ther
P
Fat
r her
P
Tolerates pain .14 .450 -.13 .165
Goodpatient .33 .004 .01 .484
Scared of shots .05 .342 .22 .044
Afraidofdoctors .12 .184 .13 .160
Worried about getting sick .16 .112 .05 .342
* Spearman’s p.
TABLE 5. Parental Attitudes Toward Children’s Pain*
Mother Father
Children can handle hurts without 3.0 2.9 parents
Comforting encourages more crying 3.3 2.Gt
Children exaggerate pain 3.1 2.8
Children should be taught to handle 2.5 2.5 pain by themselves
Too much comfort spoils the child 3.8 2.9 Enduring pain builds character 3.7 3.3 Boys handle pain better than girls 4.1 3.2
* Values are mean ratings. 1= strongly agree, 5 = strongly disagree.
tP< .05.
:l:P<.001.
Parents’ Predictions
Rank order correlations revealed significant as-sociations between parents’ predictions and their children’s responses (Table 6). Fathers were better predictors than mothers. Fathers’ and mothers’
pre-dictions were also significantly correlated with each other (p = .52, P < .001).
Parental assessments of temperament appeared to be important factors underlying these predic-tions. Mothers’ predictions of distress were signif-icantly correlated with six of nine temperament
dimensions: activity, rhythm, adaptability,
inten-sity, mood, and threshold (rank order correlations, P < .04). Two of these, intensity and mood, as
assessed by fathers, were significantly correlated
TABLE 6. Correlations and Distress Responses o
Between Parents’ Predictions f Children*
Distress Score
Mother’s Prediction
Mother’s prediction
Father’s prediction
.26 (.019)
.46 (.001)
.52 (.001) * Rank order correlations. P values in parentheses.
with fathers’ predictions (P < .04). Predictions of distress were also significantly associated with a number of parental assessments of their child’s
attributes, including tolerance of pain, not being a good patient, and fear of shots, as perceived by both parents; fear of doctors, as perceived by the mother; and worries about being sick, as perceived by the father (P < .04).
DISCUSSION
This study attempted to examine the relationship of a number of factors with distress behavior in children’s responses to injections. Our goal was to document the differences that children displayed and to sort out innate and environmental contni-butions to the child’s response style with the hope that such information would allow us better under-standing of pain in children and ways to ameliorate it.
We were surprised by the limited responses most children exhibited during their preschool diphthe-nia-tetanus-pertussis immunization. The majority
of children handled the immunization with minimal
distress. In fact, 26% displayed no visible response, and 48% displayed only minimal responses such as saying “ouch” or displaying mild muscular rigidity (ie, PRS-R score < 2). Seven children did appear
to form a separate subgroup of high-distress ne-spondens. We could find no other documentation of the frequency of specific response styles in
in their study of the response of infants (2 to 24 months) to immunization, did note that there was some individual variation among infants but pos-sibly because their study emphasized develop-mental trends, the full extent of these differences was not reported.
In addition to documenting children’s differing behavioral responses to injection, we also elicited their perception of the pain they were experiencing. Although there was a strong correlation between their behavior and their pain report, some children reported more pain than their behaviors would sug-gest. Our data provide no clues about how these
children are different from those whose rating of their pain matched their behavior. The methodo-logic and clinical implications of this discrepancy require further study.
We also identified subtle sex differences in neac-tivity to the immunization. Specifically, girls re-quined more time to calm after the immunization than did boys. This finding is in keeping with the results of most of the other studies’#{176} that have examined sex differences in children’s responses to painful stimuli. With one exception’#{176} in which no differences were identified, the other studies all found minor sex differences that were less than might have been predicted from the adult litera-tune.’ ‘ The relative biologic, social, and psychologic
contributions to these response patterns remain unclear and the limited extent of these differences suggests that their clinical usefulness may be
mm-imal.
There has been much debate on the construct of temperament and what it repnesents.’2’5 This de-bate is beyond the scope of this paper. For our purposes, however, we are assuming that tempera-ment represents the innate personality cone of the child, described by Thomas et al’6 as “the how of behavior,” which is relatively stable and predisposes the child to a particular behavioral style. We as-sume temperament to have biologic and genetic roots. We had predicted that children with more difficult temperaments, ie, poorly adaptable, in-tense, negative in mood, shy, and biologically irreg-ular, would be more reactive to immunizations. In fact, as a cluster (eg, the “difficult child”), these dimensions were mildly predictive of increased dis-tress. No “easy” children were in the highly dis-tressed group. One temperamental dimension (adaptability) was strongly negatively correlated with high-distress behavior. Carey has suggested
that adaptability, which he defines as “the ease on difficulty with which reactions to situations can be modified in a desired way,”2 is a temperamental cornerstone (W. B. Carey, phone conversation, 1989). Poor adaptability may therefore overshadow
other temperamental traits with respect to re-sponses to pain.
While this study was in progress, two papers were
published examining aspects of the relationship of temperament and pain responsiveness in children. Wallace’#{176}examined the relationship of postopera-tive analgesic administration and temperament in 3- to 7-year-old children. She found that the van-able of intensity correlated with increased medica-tion administration, ie, the more intense the child, the more medication he on she was administered.
Whether those children had more pain on were
merely more persuasive in their requests for anal-gesia is unclear. Young and Fu,17 as pant of a study examining the efficacy of needle play in reducing
distress during blood drawing, also evaluated the influence of temperament on the young child’s
ne-sponse to pain. They found that the temperamental variable of nhythmicity helped minimally to explain the child’s self-report of discomfort shortly after the procedure and the temperamental variable of approach correlated with an objective rating of the child’s response to pain immediately after the pro-cedune. Although all of these studies identified dif-ferent temperamental variables as key, and al-though there were clean methodologic differences among them, as a group they suggest that there is a relationship between aspects of the child’s innate personality and his or her response to painful situ-ations. It may well be that different dimensions of temperament are associated with different aspects of the pain experience (eg, immediate response vs longer-term coping). These findings imply the need for more consideration of individual differences in the decisions about the preparation and manage-ment of children in medical settings and require more research to sort out their subtleties.
We also explored possible associations of chil-dren’s high-distress behavior with a number of pa-rental self-ascribed medically related chanactenis-tics, such as descriptions of themselves as being afraid of shots and fearful of medical situations. These parental attributes were weakly associated with children’s behavior at the injection. Although it may seem intuitive that the child’s style of
re-sponse to a painful stimulus, as well as how to cope with ongoing pain, may be substantially influenced by parental attitudes, the exact nature of that in-fluence is still unknown and requires further re-search.
Despite an attempt to elicit attitudes that might
school absenteeism, feelings about the nature of pain and its purposes, parental response to clinical vignettes about situations in which their child was experiencing pain) correlated with high-distress be-havion in the child. It is possible that we did not
elicit this information in an appropriate manner or that the role of parental attitudes on the child’s response to pain at age 5 is not as strong as in olden
children.
Of the variables measured in this study, parents’ predictions of the degree of distress the child would exhibit had the strongest correlations with actual distress. Inasmuch as most children had not re-ceived an injection for almost 3 years, parents were basing their prediction on a core response style of the child that they had extrapolated from the child’s responses to other related situations. From our data, we would hypothesize that some combination of temperamental and other personality character-istics of the child underlie parental intuitions. Al-though it would appear obvious that parents know
their child’s needs best, this fact is often not con-sidered in medical settings.
We believe that this study may be viewed as a general model for conceptualizing about pain neac-tions in children and as such has significant impli-cations for clinical practice. Many children do not demonstrate overt responses to discomfort even though they may be experiencing pain. In fact, approximately 10% of the children in our study reported significant pain but did not display the behaviors that we assume to be associated with that degree of pain. Therefore, a high index of suspicion may be necessary to determine whether a child is in pain. Parents, who were excellent predictors of their child’s reactions, should be considered as val-uable resources by health cane providers in devel-oping a plan for pain management in the child who will be experiencing discomfort. Significantly, the children who experienced more distress did not necessarily come from families that denigrated on magnified pain responses. Accordingly, parents should not be assumed to be overly solicitous or unempathetic if their child is displaying high-dis-tress behavior in response to medical procedures. Finally, the wide variability in children’s response styles and the individual differences that those styles represent suggest to us that the preparation ofchildren undergoing painful procedures may need to be examined. The uniform presentation of infon-mation to all children and their families may
re-quire individualization based on temperamental and other personality characteristics of the child and the family.
ACKNOWLEDGMENTS
This study was partially supported by a grant from the University of Connecticut Health Center Research
Ad-visory Committee.
We thank the staff of the Kaiser Health Center, East Hartford, for their enthusiastic participation in this study; Drs Paul Dworkin and Mark Greenstein for their critical reviews of this manuscript; Dr David Olson for technical support; and Carol Webb for secretarial assist-ance.
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