Origins of operant treatment for chronic pain Although the focus of this book and, therefor e, this chapter is on methods for understanding and treating pain in infants, children, and youth, it will be helpful to consider the origins of the operant SECTION 7 psychosocial interventions 532 conceptualization of pain behavior in the adult clinical pain man- agement literature. Wilb ert Fordyce and colleagues conducted some of the earliest work applying operant behavioral concepts to understanding and treating patients \200\231 pain (Fordyce, 1976 ). He and his colleagues proposed that a signifi cant part of clinical pain is the patient \200\231s over t behavior that can be infl uenced by myriad social and environmental factors in addition t o being infl uenced by actual tissue damage or irritation (see Fordyce and colleagues \200 \231 work sum- marized in Sanders, 2003 ). the environment may come to sustain the pain behavior even aft er the condition that caused the pain has resolved. \200\230Environment \200\231 in this context refers primarily to t he social environment. Th at is, overt expressions or demonstrations of pain behavior may f requently be followed by attention and attempts by family members and/or medical personnel to provide comfort (Fordyce et al., 1968 ). Th e patient in this case had complained of low back pain for 18 years and had decreased ab ility to function in the physical activ- ities of daily living. She could maintain a maximu m of 20 min of continuous activity without reclining to rest. When a pain episode occurred, she ceased all activity, laid down, took pain medication, and cried until the pain subside d. At these times she received a lot of solicitous and ministering attention from her husba nd and son. She had undergone surgical interventions to remove a herni- ated disk (the sour ce of nerve root irritation) and a lumbosacral spine fusion to stabilize her spine. Aft er a careful medical evalu- ation revealed no evidence of remaining neurological disorder, the investigators reasoned that this patient \200\231s behavior was main- tained by contingent attention, medication, and rest. Th erefore, the fi rst intervention based on operant cond itioning theory was to remove the contingent relationships between pain complaints and medi cation administration. Instead of being provided on an \200\230as needed \200\231 basis in response to pain complaints, the medication was provided according to a standard medicatio n schedule and gradually faded in dosage until completely discontinued. At the same time, t he medical and rehabilitation staff were instructed to be as neutral and socially unrespons ive as possible to the patient \200\231s complaints of pain or discomfort. Instead, wheneve r the patient was engaged in an out of bed activity and not speaking of her pain the staff provided positive social attention including praise for any observed increase in physical a ctivity. In this way, pain behavior was placed on operant extinction and physical functioni ng was diff erentially positively reinforced. Using these modifi ed contin- gencies, a prog ram of occupational and physical therapy was developed that used rest and attention as the positive reinforcer for increasing participation in activities (e.g. weaving) and walk- ing . As a result, the patient showed a marked increase in her activ- ity level and her pain co mplaints nearly disappeared in a period of about 8 weeks. Th e operant conceptual framework for understanding chronic pain is that consequences that immediately follow pain behaviors may have a powerful infl uence on the probability of the pain behav- iours occurring again in the future. As a result of this behavior- consequence association, pain behaviors that originated because of body damage or tissue irritation may come under control of consequences and conditioning that occur in the patient \200\231s so cial environment. According to Fordyce, the two general processes that are responsible for this operant conditioning are positive rein- forcement and avoidance learning. Positive rei nforcement suggests that the occurrence of pain behaviors will increase in frequency if fol lowed by positive consequences. By defi nition, if a behavior increases in frequency aft er a specifi c consequence consistently follows it, then whatever the consequence was is hypo thesized to be a positive reinforcer. Positive reinforcers of pain behavior may include con tingent social attention in the form of attempts to com- fort and console, eff orts by othe rs to soothe the pain, and providing contingent pain medication (pro re nata, prn, or \200 \230take when needed \200\231 medication). Avoidance learning of pain behavior occurs when the frequency of a behavior increases aft er that behavior allowed the patient to escape or avoid aversive stimulation. In this process, pain behaviors such as limping, bracing, or activ- ity avoidance become as sociated with decreased or no pain sensa- tion, and as a result these behaviors are negativ ely reinforced and are maintained or increase in frequency. In chronic pain patients this p rocess may become elaborated to the point that the anticipa- tion of suff ering becomes a c onditioned aversive stimulus. Th us, in the context of anticipated pain, if the patient dis plays protective pain behaviors and pain perception or its exacerbation does not occur, the n the same protective behaviors are more likely to be emitted in the future. During the 1970s and 1980s, a few similar case studies of chil- dren were published using t he same type of operant behavioral contingencies as those fi rst described by Fordyce and c olleagues ( 1968 ). For example, Sank and Biglan ( 1974 ) used operant pro- cedures within a controlled case study to treat a 10-year-old boy with severe stomach pains. Th e investig ators developed a token economy in which tokens were awarded to positively reinforce non-pa in behaviors while attention was withheld from the boy \200\231s pain complaints. Th is tre atment was reported to decrease the fre- quency of pain attacks, the magnitude of the boy \200\231s pain ratings, and to increase his school attendance. Furthermore, Fordyce noted that once such avoidance learning occurs, it requires little ong oing reinforcement to maintain it. In this context reinforcement refers to the avoidance of nociception. If a behavior occurs due to anticipation of pain and motivation to avoid both the aversive experience of the anticipation (anxiety, physiological arousal) and the nocic eptive stimulus, the patient will maintain the avoidance behavior even if the nociceptive s timula- tion is never again experienced. In this situation the goal of operant treatment is to prompt and reinforce normative physical activity and arrange the environment such that the patient attempts typical physical activity without the self-protective pain behaviors, and does not experience pain or experiences it at much lower intensity or magnitude. Miller and Kratochwill ( 1979 ) published another controlled case study in which time out w as used to treat a 10-year-old girl with complaints of severe stomach pain that were hypoth esized to be maintained by parental attention. Th e behavioral treatment in this case invol ved removing adult attention and social activities contin- gent on pain complaints. With th is intervention, pain complaints in the home decreased from two per day during baseline obs ervation to approximately one per week aft er treatment, and this improve- ment was maintai ned at 1-year follow-up. A similar decrease in Fordyce et al. ( 1968 ) fi rst applied operant conditioning meth- ods to modify environment al contingencies in order to change chronic pain in an adult patient. Th ese investigators hypothesized that responses by others to overt pain behavior accompanying the patient \200 \231s subjective pain experience may reinforce some aspects of the pain behavior. If this o ccurs for a protracted period of time, CHAPTER 51 operant treatment 533 pain complaints was reported to occur at school when the same treatment contingencies were introduced. to conditioning effects, strategies for treatment can be based on counterconditioning or be havior-change principles. Varni et al. ( 1980 ) also published an early case demonstration that the overt pain behavi or of a child being treated for severe burns could be impacted by modifying environmental c ontingen- cies. Th ese authors used a combination of multiple baseline and reversal single- subject experimental designs to document a reduc- tion in the verbal and motor pain behavio r of a 3-year-old child across hospital bedroom, clinic, and physical therapy settings. Beh avioral treatment consisted of rearranging reinforcement contingencies to minimize reinforc ement of pain behavior and maximize reinforcement of observed \200\230well \200\231 behavi ors; including wearing required splints and participating in exercises in physical therapy. 4. Multiple behavior change methods exist that can be focused on modifying pain behavior di rectly, rather than attempting to directly change subjective pain perception. Th is conceptualization does not suggest that nociception should not be changed directly, i f possible, through medication or other medical intervention, but is based on the assumptio n that in chronic pain cases traditional medical approaches have not been eff ective in eli minating the patient \200\231s pain. In their 1982 case study Fordyce and colleagues demons trated the eff ectiveness of behav- ioural intervention based on this avoidance \200\223co nditioning concep- tualization. In that case the 21-year-old male with a 15-year history of pain, dizziness, and abnormal gait was treated with behavioral intervention because of his inactivity and severely impaired ability to walk. Treatment was introduced in two phases. First, improved walking was established by reintroducing walking between parallel bars and positively reinforcing patient participation and achieve- ment of increasing distances. In the second phase reinforcement was provided for walking at increasing speeds that were inco mpat- ible with the patient \200\231s initially abnormal gait. In addition, a thera- pist m et weekly with the patient and on three occasions with the patient \200\231s mother. Th ese sessions focused on altering the social con- sequences of \200\230sick \200\231 and \200 \230well \200\231 behavior displayed by the patient. Th e therapist practiced and taught th e mother to withdraw social support for the patient \200\231s inactivity and to provide enc ouragement and social support for his progress with walking. Aft er the provi- sion of this multimodal intervention, the patient became normally active, ambulated normally, and retur ned to productive activity. Aft er completing treatment he enrolled in and began attending col- lege, and at 21 months post-treatment was maintaining his treat- ment gains. To demons trate the eff ectiveness of this treatment, the authors employed a changing criterion singl e-subject experimental design. Using this design they showed that each time the criterion f or reinforcement was changed, the patient \200\231s behavior changed accordingly to meet th e criterion set (e.g. increased walking speed requirement). Th e role of aversive conditioning and escape-avoidance learning in the development and mai ntenance of chronic pain behavior As already discussed, early operant conceptualizations by Fordyce and colleagues focused primarily on operant extinction of positively reinforced pa in behavior (eliminating pain behavior-contingent positive reinforcement). However, these i nvestigators subsequently conceptualized some pain behavior in terms of escape-avoidance le arning. For example when pain behavior occurs in the context of physical exertion, the pati ent will discontinue the exertion and thereby escape the pain associated with the exertion. With experi- ence, the patient may learn not only to stop physical activity that produces pain or discomfort, but may also learn to avoid the situ- ations in which physical activity might be required. Th us, an adult may begin to avoid going to work, leaving the house or even getting out of bed. Children and adolescents may learn to avoid going to school, parti cipating in athletics, or even having social interactions with peers. Fordyce et al. ( 1982 ) published a description of the escape- avoidance conceptualization along with the case study of a 21-year- old-male with a 15-year history of hospitalizations for \200\230abnormal abdominal pain \200\231. Th is publication described a procedural in no- vation specifi cally designed to modify chronic pain behaviors that were hypothesized t o have been acquired through avoidance learning. In their article, Fordyce and colleagues p resented the basic premises underlying the behavior analysis and treatment of chronic pain, which are paraphrased in the following list (Fordyce et al., 1982 ): Application of operant conditioning principles to the management of children \200\231s pain behavior during burn wound care Following upon the conceptual and case study publications described earlier, Kelly et al. ( 1984 ) conducted a single-subject experimental study usin g a reversal design with two girls aged 4 and 6 years with severe burns who required daily hydrotherapy, wound debridement, and application of a topical antibiotic medi- cation. In t his study, the investigators noted that the child with burns encounters frequent pairings o f environmental stimuli (sights, sounds, and smells in the hospital) with pain (nociceptive stimulation from burn wound care). As a result the child likely learns that in the presenc e of these stimuli he or she experiences pain. Th e children in this study responded to the pain with cry- ing, thrashing, and other verbal and motor pain behaviors and these behavio rs resulted in intermittent escape from or delay of the painful procedures as well as incre ased attention from adults attempting to soothe the distressed child. 1. Pain behavior, de \201 ned as indicators of pain and suffering, may become chronic for reasons other than its original etiology. That is, chronic pain behaviors may have little o r no remaining link to nociception from the body site where the pain problem began. 2. A chronic pain problem may persist for reasons other than the originating etiology, and a parsimonious explanation with empirical support is that chronic pain may be understood in terms of learning and conditioning factors occurring in the interactions between the patie nt and the social environment. 3. Given that pain behaviors may not be linked directly to nocic- eption in individuals wit h chronic pain, but instead may be due SECTION 7 psychosocial interventions 534 Th erefore, the authors employed an operant conceptualiza- tion that assumed burn treatment -related pain behavior is both positively and negatively reinforced over time. Th ey design ed their behavioral intervention with this conceptualization in mind. Th ey used a multicom ponent behavioral treatment approach to reduc- ing pain behavior during these painful proce dures. Th e interven- tion included cartoon viewing as a form of distraction during the pro cedures and implementation of a star feedback chart. Th e star feedback chart was used as a n incentive for the children to use the TV cartoon viewing for distraction and for crying l ess than they had during the same procedure on the previous day. Direct obser- vations were conducted and the occurrence of target behaviors was recorded during each 30-sec interval of the procedures. Th e target behaviors included the child \200\231s verbal and motor pain behav- iours and parent or physical therapist interactions with the child. Following each treatment session the parent, physical therapist, and child also completed behavior rating scales of the child \200\231s fear, cooperation, and pain using a 9-point scale. Th e star chart included a colorful graph showing the percentage of intervals during which the child displayed verbal or motor pain behavior during each medical treatment session. into anxiety-provoking, aversive stimuli, and nearly simultaneously operant delay, avoidanc e, and escape behaviors are both intention- ally and unintentionally reinforced by medical and family caregiv- ers. Th ese authors also emphasize how the loss of ability to predict a nd control the environment with respect to aversive stimulation interferes with the ability of children undergoing burn wound care to cope in the hospital environment and likely prom otes learned helplessness (Th urber et al., 2000 ). Following this conceptualiza- tion, Th urber and colleagues ( 2000 ) point out how behaviors of burn patients that are oft en labe led as \200\230manipulative \200\231 are, in fact, quite logical from the patient \200\231 s perspective of trying to learn what will result in reinforcing outcomes or events in the context of burn wound care. Indeed, despite best pharmacological practices com- plete elimi nation of pain and distress may be impossible, and escape behavior shaped through avoidance conditioning is expected and developmentally typical. Th e authors hypothesize that in the con- text of burn wound care, pauses and completion of painful proce- dures are the most s alient reinforcers. Based on this theoretical framework, a number of intervention strategies have been develope d and applied. First, one way to reduce the occurrence of repeated undesirable pain behavio rs, such as whining, complaining and constantly requesting pain medication, is to give the analgesic medication on a fi xed, time-based schedule rather than giving it on an \200\230 as needed \200\231 basis in response to increased pain behavior. Another strategy based on operant condition- ing theory that has been recommended is to place excessive pain behavior s \200\230on extinction \200\231 by withholding all unnecessary social attention (consolin g, coaxing, apologizing, etc.) while, alternatively, positively reinforcing cooperation and coping behaviors such as participating in safe and distracting activities. Additional trea tment strategies are based on the rationale of increasing the child \200\231s ability to pr edict and control at least some important aspects of his or her environment. Th is can be a ccomplished by providing the child with a limited quantity of \200\230passes \200\231 or \200\230break cards \200\231 that the child can use to request a brief break from the painf ul wound care. A case example on the application of this technique to another kind of wound care will be presented at the end of the present chapter. An alternative strategy is to al low the child to take planned or scheduled breaks that are established and explained to the child in advance. Making the temporary termination of painful stimulation contingent on th e passing of a preset time interval (using a timer visible to the child) or contingent on t he child presenting a break card helps to reduce the development of escape behavior in the context of burn wound care (Martin-Herz et al., 2000 ). Th is intervention that combined distraction and positive rein- forcement of decreased pain behavior resulted in an approxi- mately 40% reduction in the children \200\231s pain behav ior. In addition, both children indicated enjoying the TV cartoons (approximately 4 on a 5- point scale, with 5 = \200\230I enjoyed the TV very much \200\231). Based on the study des ign and data it was not possible for the authors to determine the relative contribution of the distraction and rein- forcement components of the intervention, but they speculated tha t the star chart positive reinforcement was critical because they had collected preliminary pilot data with three other children receiv- ing the TV distraction only, and these childr en showed only slight reductions in pain behaviors. Two caveats about this study should be noted. First, the most painful of these burn procedu res are conducted under sedation, but prolonged periods of sedation and sleep are avoided b ecause the child with burns needs to maintain high levels of caloric and fl uid intake to p revent dehydration and ensure adequate nutrition for healing. Th erefore, the child can ben efi t from being able to tolerate these treatments with reduced or no sedation as healing p rogresses. Th e second caveat stated by the authors is that the goal of this behavioral tre atment is not to completely suppress the child \200\231s pain behavior, but to distract the child to decrease pain perception dur- ing treatment and to teach the child to control the ir pain behavior to some degree (Kelly et al., 1984 ). Recent research on the use of behavior analysis in clinical den- tistry supports the benefi cial eff ects of providing breaks from uncomfortable dental procedures according to a fi x ed time sched- ule. O \200\231Callaghan et al. ( 2006 ) demonstrated that when fi ve childr en (4 \200\2237 years of age) were undergoing tooth preparation and restoration procedures, providing them with intermittent, 10 sec breaks regard- less of their level of disruptive behavior resulted in clinically signifi - cant reductions in disruptive behavior. Consequen tly, the need for physical restraint during treatment was reduced to near zero. From this pioneering work of Kelly et al. ( 1984 ) until the present day, principles of con ditioning and learning have been applied to the management of children \200\231s pain and d istress during burn wound care. A pair of informative review and discussion articles has be en published that present a theoretical framework and associated treat- ment applications f or burn wound care in children (Martin-Herz et al., 2000 ; Th urber et al., 2000 ). Th ree psychological principles are presented to help explain the association between burn care, p ain and anxiety. Th e principles include: classical conditioning, operant conditioning, and control coping. Using these principles, the authors describe the developmentally normal em ergence of avoidance behaviors that disrupt required wound care for burns. Using case examp les, the authors present their conceptualization of how classical conditioning converts neu tral environmental stimuli Pain behaviors as a class of operant responses Pain behaviors can vary considerably in term s of modality of expression (vocal, verbal, motor), frequency, intensity, and CHAPTER 51 operant treatment 535 duration. Yet, as Kalsher et al. ( 1985 ) pointed out, a variety of pain behaviors may have a similar eff ect on the patient \200\231s environment (e.g. attention from others, medica tion administration, avoidance of eff ortful physical demands). Given their common eff ect on the environment, these pain behaviors may be conceptualized as an operant response class . Kalsher and colleagues ( 1985 ) argued that examination of pain behaviors as a response c lass may identify behaviors that are most responsive to modifi cation and might facilitate effi cient treatment. Th e treatment effi ciency may result from the phenomenon known as re sponse covariation in which a change in the probability of one response in a response class results in corresponding changes in the probability of other members of the same response class. If screaming, crying and facial contortions are all members of the same response cla ss, then an intervention that decreases the occurrence of screaming might also result in de creased crying and grimacing. the patient \200\231s biological status for evidence of illness, tissue damage, or irritati on (Kalsher et al., 1985 ). Systematic reviews of empirical support for the operant conditioning model of pain behavior ; the interactional mixed model of learning and associated intervention strategies As can b e seen from the case studies and single-subject design experiments discussed earlier, the l iterature supporting the oper- ant behavioral conceptualization and treatment of chronic pa in in children and adults, and of medical procedure-related pain in children, grew steadily during the 1970s and 1980s. Fordyce et al. ( 1985 ) published a comprehensive review artic le on the use of oper- ant conditioning with adult chronic pain patients. Th ese authors re viewed ten studies that supported the effi cacy of behavioral interventions to systematical ly change the behavior of patients and sustain these changes over follow-up intervals of up to several years. Based on these studies, they concluded that operant behav- ioural techni ques typically applied in the context of interdiscipli- nary pain programs have clinically signifi cant eff ects on overt pain behaviors such as activity level, medication usage for pain, and verbal expression and self-ratings of pain. Based on this conceptualization, Kalsher et al. ( 1985 ) studied behavioral covariation in a patient exhibiting a variety of pain behaviors. Th ese investigators studied the eff ects of reinforcement and contingent removal of reinforcement on one pain behavior (screaming) and also measured the eff ects of these interventions on other pain behaviors that were not targeted directly for treat- ment. Th e participant in this study was a 24-year-old male w ith borderline intelligence and a medical diagnosis of dystonia mus- culorum deformans, a g enetic neuromuscular disorder that is char- acterized by strong, sustained twisting and wri thing motions of the somatic muscles, adduction of the thigh, and continuous torsion spasms with associated severe, chronic muscular pain. A variety of pharmacological treatments had resulted in little improvement and the patient was at risk of residential placement outsid e of the family home because of the severity of his screaming. In this study, screaming and fi ve other pain behaviors including self-reports of pain were measured while varying beha vioral contingencies for screaming. Pain behaviors that were measured in addition to scream ing included facial contortions, muscle contractions, help- seeking, and sharp expulsion of breath. Th e experimental condi- tions involved non-contingent reinforcement compared to t he removal of reinforcement contingent on screaming. Unfortunately, because of the interdisciplinary context in which the interventions were app lied, it was not possible to conclude that operant conditioning-based behavioral interventi ons were solely responsible for the observed changes. Th erefore, continued research was en couraged and needed to determine the specifi c eff ects of the operant techniques on immedi ate and long-term pain behavior changes. Shortly thereaft er, Linton ( 1986 b) published a follow-up review that included fi ve additional, somewhat more methodo- logically sound stu dies, resulting in similar conclusions that oper- ant based interventions were eff ective a t increasing activity level, reducing medication usage, and to a lesser degree improving su b- jective pain reports. Since the pioneering work of Fordyce and colleagues, the oper- ant conditioning conceptuali zation and strategies based on it have played a predominant role in understanding and treat ing adult chronic pain patients (Sanders, 1985 , 2003 ). Sanders ( 2003 ) dis- cussed, at l ength, the behavioral conceptualization of pain and the research supporting this model. In this conceptualization clinical pain is defi ned as \200\230an interacting cluster of indi vidualized overt, cov- ert and neurophysiological responses capable of being produced by re levant tissue damage or irritation, but also produced and main- tained by other antecedent and consequent stimulus conditions \200\231. Sanders \200\231 operant conditioning model is based on six decades of behavioral science, which has produced extensive empirical evi- de nce that essentially all voluntary and most emotional behaviors are infl uenced by their en vironmental context and consequences. When applied to pain, the operant conditioning model emphasizes the equality of overt gross motor components of pain behavior with the cognitive /subjective and neurophysiological components. Furthermore, evidence indicates that these t hree types of pain responses do not always co-vary consistently (are not reliably posi- tiv ely correlated). As hypothesized, the pain behaviors did co-vary during behav- ioural and drug conditions ev en though the intervention only directly targeted screaming. Th e untargeted pain behaviors co- varied most during observations that followed rather than pre- ceded pain drug adminis tration. Furthermore, in contrast to the behavioral observation measures, physiological mea sures (elec- tromyography) did not diff er across conditions. Overall, the results of this study demonstrated that pain behavior such as screaming can be brought under operant contro l via manipulation of envi- ronmental contingencies. Furthermore, because the other pain be haviors co-varied with screaming, together they appeared to form a response class that shar ed a similar reinforcement history. While this response covariation can be benefi cial to t he effi ciency of behavioral intervention for pain behavior, the authors caution that behav ior therapy for pain should be conducted in a manner that will assure the maintenance of at least one appropriate but non-disruptive method of pain expression to allow for successful medical management. Th at is, even though pain behaviors can be manipulated by modifying e nvironmental contingencies, the goal is not to make the patient completely stoic. Having a consistent, reli- able measure of pain behavior is necessary to be able to monitor Sander \200\231s model of pain is based on a larger Interactional Mixed Model of Learning t hat includes operant and respondent SECTION 7 psychosocial interventions 536 conditioning and observational learning eff ects. Fordyce et al. ( 1982 ) and Sanders ( 198 5 , 2003 ) argue that most gross motor and many cognitive/subjective responses can be chara cterized as escape-avoidance behaviors. For example crying, grimacing, avoiding activity an d lying down all may allow the individual to remove, escape, or avoid unpleasant stimulatio n such as painful tissue damage or irritation, or anxiety from anticipation of this aversiv e stimulation. Th is, as introduced earlier, is consistent with a negative reinforcement pa radigm, in which the termination of an unpleasant or non-preferred stimulus results in an i ncreased prob- ability of the behavior that brought about its termination. Sanders ( 2003 ) elaborates that behaviors strengthened or maintained by negative reinforcement have been s hown to be extremely resistant to change without direct intervention to modify their occurr ence. Th is is especially true for avoidance behavior because the behav- iour functions to avoid the aversive consequence. Without direct intervention there is no opportunity for the individual to ever experience the avoided stimulus conditions in the absence of the aversi ve stimulus (pain perception), and to associate it with other positive consequences. Th us, with behavior maintained by avoid- ance learning there is no spontaneous remedial learning mecha- nism for establishing new responses unless specifi c alterations are made in the co ntrolling stimulus conditions associated with the avoidance response. Sanders ( 2003 ) cite s multiple, well-controlled studies demonstrating that pain responses across response categ o- ries (cognitive/subjective, gross motor, neurophysiologic) can be infl uenced signifi ca ntly by antecedent and consequent stimulus condition changes in both analog and clinical en vironments. damage or irritation. Interventions that may reduce pain percep- tion include medication, n erve blocks, cognitive-behavioral cop- ing strategies (distraction, hypnosis, controlled de ep breathing, progressive muscle relaxation, visual imagery), acceptance and commitment int erventions, and other physical interventions (heat, cold, massage, acupuncture, electroderm al stimulation). In situa- tions in which environmental and psychosocial stressors are the antecedent events that set the occasion for pain behaviors, and these behaviors are positiv ely reinforced by special social atten- tion or ministering behavior from others, and/or ar e negatively reinforced by physical, social, educational or work activity avoid- ance, thes e maintaining variables must be addressed or pain treat- ment will not be eff ective. Following the logic and model just presented, Flor et al. ( 2002 ) conducted a study of the role of operant conditioning in the devel- opment and maintenance of chronic pain. Th e st udy compared 30 adult patients with chronic back pain to 30 healthy matched con- trol parti cipants on their verbal and neurophysiological respond- ing to an operant conditioning para digm. Th e results showed that both groups \200\231 verbal reports were able to be conditio ned, but the patients with chronic low back pain showed diff erent cortical and electromyog raphic responses. Specifi cally, the patients with chronic pain were more easily aff ected by operant conditioning factors at both the verbal and neurophysiological level. Flor and c olleagues hypothesized that individuals with greater susceptibility to condi- tioning eff e cts may be more likely to develop chronic pain condi- tions. In support of this hypothesis, there is recent evidence that aft er experiencing painful stimulation in an experiment, ch ronic pain patients evidenced decreased diff use noxious inhibitory con- trol (DNIC) in the brain when exposed to subsequent painful stimulation, while healthy control participants ( Meeus et al., 2008 ) and individuals with major depressive disorder did not show this dimin ution of DNIC (Normand et al., 2011 ). Sander \200\231s ( 1985 , 2003 ) conceptual model distinguishes between acute and chronic p ain states. In acute pain, neurophysiological and gross motor pain responses are dominant a nd the most prevalent controlling consequent stimuli are those associated with the reduc- t ion of pain perception arising directly from tissue damage or irri- tation. When pain becom es chronic, pain responses may become more predominantly cognitive and subjective (anticipa tion, fear and avoidance of pain sensation). In chronic pain conditions, the most prevalent consequent stimuli maintaining pain behaviors involve escape or avoidance of anticipated p ain. Indeed, the patient now may be avoiding aversive environmental stressors associated wi th pain (e.g. physical contact or exertion, social interactions) or confused with subjectiv e pain perception (e.g. symptoms of anxiety, depression perceived as pain). In chronic pain states, this avoidance of physical activity and social interaction is maintained even aft er the original tissue damage or irritation is greatly diminished or no longer present. In addition, positive consequences such as social attention may play a greater role in chronic pain. Positive reinforcement of wellness behavior and the combination of operant and cognitive-be havioral interventions for clinical pain It is important to note that operant interventions for pain also include modifi cation of antecedent and consequent stimuli in order to stren gthen wellness-oriented behaviors that are alternatives to, or incompatible with, maladapti ve pain behavior. Examples of positive alternative behaviors include participation in thera py, use of pain coping strategies (distraction, muscle relaxation, positive self-statements ), increased physical and social activity, reduced use of narcotic pain medications, and re turn to role functioning (i.e. school or work). Given that the antecedent and consequent stimuli that maintain pain behavior may have shift ed when pain has become chronic, it is necessary to consider, and when possible, to modify these main- taining variables. As indicated by Sanders ( 2003 ), the eff ectiveness of any pain intervention is a function of the extent to which it sig- nifi cantly alters the prim ary antecedent and consequent stimuli initiating and maintaining the pain responses. For ex ample, if a patient is actually experiencing tissue damage or irritation (an antecedent con dition) then interventions that do not change the perception of this stimulus will not be e ff ective. Rather, escape- avoidance motivated pain behavior (e.g. avoiding physical activ- ity) will be maintained to the extent that the behavior reduces or eliminates perception o f pain resulting directly from the tissue In his excellent review article on operant therapy with patients with chronic pain, Sanders ( 2003 ) discussed the evidence base supporting the eff ectiveness of these operant interv entions, and emphasized that although operant conditioning can play a major role in modifyi ng pain behavior, it is not considered a complete or comprehensive treatment for clinical p ain. Th at is, medical, physi- cal and cognitive-behavioral interventions also should be us ed, when appropriate, in addition to operant behavioral treatment strategies. In clinical p ractice, operant procedures are rarely, if ever, used in isolation, and research evidence s upports the benefi ts of CHAPTER 51 operant treatment 537 combining these strategies with cognitive-behavioral techniques such as distraction, relaxa tion training and cognitive coping skills training. Th e evidence indicates that the additi on of cognitive- behavioral techniques to operant conditioning may signifi cantly enhance t he treatment eff ects accomplished with operant condi- tioning alone (Compas et al., 1998 ; Keefe et al., 1992 ; Lindstrom et al., 1992 ; Moraley et al., 1999 ; Sanders, 2003 ; Van T ulder et al., 2000 ). Based on his literature review and similar previous reviews by others , Sanders ( 2003 ) concluded that there is strong and sub- stantial evidence for the eff ec tiveness of operant conditioning inter- ventions demonstrated primarily with adult patients with low back pain. Th e evidence supports that operant conditioning alone or in combinati on with other treatment (e.g. cognitive-behavioral) strategies can produce signifi cant and sustained improvements in general activity level, work behavior, use of pain medication, a nd to a lesser degree subjective pain intensity ratings of patients with chronic pain when applied in either inpatient or outpatient settings. Th e evidence base is strong for adults with low back pain, but there are fewer methodologically rigorous data on the effi cacy of operant conditioning-based interventions on other pain conditions such as complex regional pain syndrome (CRPS), fi bromyalgia, and head- ache. Th e research evidence on operant con ditioning intervention eff ects with children, adolescents, and geriatric populations with diagnoses other than low back pain (either acute or chronic) were found to be less well dev eloped when Sanders conducted his 2003 review. this theory are studies indicating a signifi cant relationship between a family history of chronic pain and the occurrence of RAP. Th is relationship may be due to greater emphasis o n bodily sensations throughout the family or modeling of illness behavior by family members .