Measurement properties of the Non-Communicating Adult Pain Checklist (NCAPC): A pain scale for adults with Intellectual and Developmental Disabilities, scored in a clinical setting
Introduction
Pain experience is generally hard to measure due to its subjectivity and multi-dimensional expressions (Abu-Saad, 2000), and pain measurement is extremely challenging in populations with communication difficulties, such as individuals with Intellectual and Developmental Disabilities (IDD) (Hadjistavropoulos, Von baeyer, & Craig, 2001).
Individuals with IDD are found to suffer from more painful medical conditions than the general population (Oberlander, O’Donnell, & Montgomery, 1999), and they are probably exposed to more painful situations than people without IDD (Bodfish et al., 2006, Stallard et al., 2001). Despite this fact, their pain experience has scarcely been investigated, particularly in adults, and appropriate assessment tools have been lacking. A substantial part of people with IDD do not have the ability to give valid pain reports (Collignon and Ginsiano, 2001, Defrin et al., 2006, Stallard et al., 2001). Therefore, in an effort to develop a suitable assessment tool for this population, we focused on an indirect method for assessing pain by observing their pain behaviors.
At the initiation of scale development, there were no existing pain scales specifically designed for adults with IDD, only for children (Hunt et al., 2004, Stallard et al., 2002) and adolescents (Collignon and Ginsiano, 2001, Giusiano et al., 1995). Among those scales, the Non-Communicating Children Pain Checklist—Revised (NCCPC-R) (Breau, Finley, McGrath, & Camfield, 2002) together with the well established Facial Action Coding System (FACS) were considered promising also for adults with IDD. The NCCPC-R had previously demonstrated good measurement properties and FACS had been found effective in evaluating pain behaviors in adults with mild–moderate levels of IDD (Lachapelle, Hadijistavropoulos, & Craig, 1999). These measures were therefore chosen for an initial study to explore and compare the measures’ sensitivity to pain during an influenza vaccination in adults with different levels of IDD. When all levels of IDD were taken into consideration the results indicated that the NCCPC-R was a more promising pain assessment tool than FACS in this population (Defrin et al., 2006).
We than explored the sensitivity to pain of each test item in NCCPC-R, and only items that were found sensitive to pain, were included in the final version (NCAPC). Internal consistency (α = 0.77) of NCAPC was sufficiently high, and sensitivity to pain of the whole scale was found highly satisfactory for the whole sample as well as for all subgroups of IDD, Standardized Response Mean (SRM) ranging 1.20–2.07 (Lotan, Ljunggren, et al., 2009). Reliability of the measure was addressed in another study, finding high intrarater reliability (ICC = 0.94) and interrater reliability (ICC = 0.91–0.92) in groups of caregivers, physical- and occupational therapists (Lotan, Moe-Nilssen, Ljunggren, & Strand, 2009).
All the above measurement properties were derived from test scores, obtained from observations of video-uptakes. In clinical work however, video-uptakes may not be feasible to use since they are time-consuming, necessitate special equipment, and prevent immediate response to pain behaviors. Therefore it remains to be seen whether scoring the NCAPC directly in a clinical situation may be feasible and provide valid scores.
Pain intensity, duration of pain as well as the setting in which the painful experience occurs, have been found to be influential factors in pain perception (Lollar, Smits, & Patterson, 1982). As we were looking for situations where pain could be measured without being inflicted by the researchers, we chose settings that were used in the past to evaluate pain in individuals with IDD such as an influenza injection (Lachapelle et al., 1999) and a dental clinic (Phan, Edwards, & Robinson, 2005) so as to have a previous points of reference. We assumed, in the present study, that dental treatment might be more painful than influenza injection. While the pain provoking procedure of the influenza injection was short, with minor tissue involvement, and performed in a familiar place (participants’ residential settings), the duration of the dental hygiene treatment was longer, the tissue involvement larger and it occurred in a medical setting (dental clinic). Our assumption is also supported by ratings of anxiety provoking procedures at the dental clinic: having an injection was rated by the participants at the 14th place, while “cutting or tearing in soft tissue”, typical of dental hygiene treatments, was rated at the 6th place (Oosterink, de Jongh, & Aartman, 2008). No articles discussing the attitudes of individuals with IDD to different parts of the dental intervention could be found.
The aim of the present investigation was to evaluate measurement properties and thus applicability of the NCAPC in a clinical setting. This was done by examining the ability of the scale to distinguish between pain and non-pain situations and different levels of pain (discriminate validity) and by examining sensitivity to pain in subgroups of adults with different levels of IDD.
We hypothesized that in a clinical setting:
During a given observed situation (painful or non-painful), individuals will present rather consistent behavior throughout the situation.
Individuals are more likely to exhibit pain behaviors when exposed to painful procedures than when they are not exposed to painful procedures.
Individuals are likely to exhibit less pain behavior when exposed to milder painful procedures than when they are exposed to more severe painful procedures.
Section snippets
Participants
The participants of the present study were derived from a total sample of 265 individuals with IDD living in different residential settings, representing the diversity of residential dwellers with IDD in Israel (Merrick & Kandel, 2003). Individuals were considered for inclusion in the present study if they were healthy adults residing at the Elwyn residential centers, Jerusalem, had previously been video-filmed while receiving their annual influenza vaccination, and received a routine dental
Results
The research sample consisted of 59 adults, mean age 40.7 ± 14.6 years, range 21–62, and diagnosed with different levels of IDD (Table 1). Of this group, 38 were mobile while the others were ambulatory by means of a wheelchair. Internal consistency of NCAPC by Cronbach's alpha was 0.72.
Discussion
In this study, we examined measurement properties of the NCAPC based on test scores derived directly from observation of pain behaviors of adults with different levels of IDD in a clinical setting. Fifty-nine participants were scored before and during a dental hygiene intervention, and the findings were compared with previous pain measurements based on video scores of the same individuals receiving an influenza injection. The validity of the NCAPC was demonstrated by its ability to discriminate
Conclusions
In the present study the ability of the NCAPC to distinguish between painful and non-painful situations and between different painful interventions and ability to capture pain at all levels of IDD was indicated, suggesting that it is a valid scale for assessing acute procedural pain behaviors of adults, at different ages and at different levels of IDD. It is of particular interest to note that in the present study the NCAPC was scored directly in a clinical situation, while prior data from
Conflict of interest
The authors’ hereby declare that there are no financial and non-financial conflicts of interest, and no direct or indirect financial benefits.
Acknowledgements
The authors would like to thank all the residents at Israel Elwyn for their participation in this project, as well as the management and staff of Israel Elwyn for supporting and aiding in the accomplishment of this project. The authors appreciate the support for this research received through a grant from the “Shalem” Foundation for the development of services for the challenged individual. Furthermore the authors thank Lyn Breau for supporting this project and allowing us to adjust the NCCPC-R
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