Back Pain and Operant Conditioning
Elizabeth Wargo
Chronic low back pain is a pervasive and unabating issue in clinical practice. Not only does treatment for this condition drain clinical resources, it is also a constant burden for those who suffer from it (Rohling et al., 1995) . Often low back pain symptomology presents itself after an accident or injury and is usually accompanied by the presence of a tangible underlying organic pathology. However, once the condition has manifested itself for a duration of at least 6 months and is present almost constantly even though the underlying pathology has subsided, the condition is termed " chronic pain" (Fordyce et al., 1968). A patient with chronic low back pain will often be treated symptomatically with narcotics, analgesics, and topical treatments. Relief from these interventions is often brief, temporary, and at worst addictive. Other courses of therapy include physical therapy, therapeutic massage, and surgery. While success with these treatments often is more optimistic than with medications, these therapies can be financially draining and do not work for all patients. Often following prolonged treatments that offer no substantial relief from pain, patients are left frustrated, depressed and narcotic addicted (Fordyce et al., 1967; Smith 1980). Often medical providers re also left frustrated: their patients condition fails to improve and they must continue to prescribe narcotics to manage patients pain, and they have run out of treatment options.
One possible treatment option which has not been thoroughly investigated and implemented in most treatment programs is the behavioral application of the principles of operant conditioning to the pathogenesis and treatment of chronic low back pain. Application of operant principles to this dilemma suggests that certain consequences of chronic low back pain and pain behavior have positive reinforcing properties for the patients behavior Conditioning and Pain 2 (Fordyce, 1967; Catania, 1994 ). The positive consequences of the patients pain behavior create a teleological process (Premarck, 1965 ) that encourages pain behavior and increases its frequency (Catania, 1994; Premarck, 1965, Fordyce, 1967; Smith 1980). Thus, the reinforcement of the patients pain response may be largely responsible for the experience and presence of pain, rather than the underlying pathology. Behavioral applications of the principles of operant conditioning have been used in the treatment of addictions, weight control, and in children with behavioral and attentional disorders with enormous success ( Catania, 1994).
The basic tenant of operant conditioning is that the consequences of behavior will determine whether or not the behavior will be emitted again in the future. Behaviors that are followed by positive consequences or reinforcement will be increased in the future, while behaviors that are followed by negative consequences or punishment will be decreased in the future (Catania, 1994; Premarck: 1965, Skinner, 1960). The schedule in which the reinforcement or punishment occurs following behavior is critical. Consequences that followed every incidence of behavior ( Fixed Ratio FR) will increase the frequency of behavior rapidly. Should the consequences stop abruptly ( Extinction) the behavior will temporarily increase, but then subside quickly (Skinner, 1980; Catania, 1994). This is analogous to a pigeon who has received food pellets for pecking on a key in a skinner box. When the food pellets stop, the pigeon's responding increases, he will peck more frequently at the key, move around in the chamber and increase overall activity . Eventually after several attempts of emitted behavior with no reinforcement, extinction of the keypecking response will diminish( Catania, 1994). Consequences that follow behavior variably ( Variable/Interval ratio schedule) will produce behavior slowly and steadily and will Conditioning and Pain 3 be extremely resistant to the effects of extinction. Likewise, if the same pigeon in the Skinner box is receiving food pellets for key pecks, but those food pellets are distributed randomly, a stop in the food pellets will be less likely to cause a diminish in It should be noted that the term "reinforcement" refers to consequences that are reinforcing to the individual or subject. There is no such thing as a "general" reinforcer, or a reinforcer that has positive consequences for everyone( Fordyce, 1967; Catania, 1994; Skinner, 1980). This is clearly illustrated with the pigeon in the Skinner box. If the pigeon is food deprived, and pecking on a key is rewarded with food pellets , the key pecking response will likely to be emitted, because the receipt of food is reinforcing because most likely the pigeon is hungry. However, if the same pigeon is force fed and then placed in the skinner box where pecks on a key are followed by food delivery, it is unlikely that key pecking will be maintained in this pigeon, because food is no longer a reinforcer, if anything it is probably aversive( Catania; 1994; Premarck, 1965).
It is important to make this distinction in reinforcement when discussing the operant principles and the application of these principles to humans who suffer from back pain. Attention and medication may be reinforcing consequences for some individuals, but not for others. The operant conditioning model can easily be applied to the etiology and pathogeneses of chronic low back pain. Although pain originates organically and is transmitted through certain neuronal pathways and processes in the Central Nervous System ( Ackerman, 101), it can still occur and be experienced in the absence of organic pathology. ( fordyce, 1960) Pain signals are mainly activated by stimulation of the peripheral receptors in the central nervous system and may originate in any part of the body. pain usually signals some form of tissue Conditioning and Pain 4 damage and is usually acute or temporary. However when pain persists continuously or intermittently for greater than 6 months it is termed chronic pain. Despite the fact that pain signals originate from underlying pathology it can also be conceptualized in terms of operant conditioning and learning theory. Pain in itself may not be a pleasant experience or associated with positive consequences, however positive reinforcement does occur following pain behavior.
The combination of visible or auditory signals sent by the patient such as limping, crying, grimacing, moaning and asking for medication is termed pain behavior (Fordyce, 1967). Often when pain behavior occurs, individuals in the vicinity of the patient such as family, friends, medical support staff will respond in a manner that reinforces the patients pain behavior. The ensuing attention, rest medication from family and friends becomes a reinforcing consequence to the patient pain behavior. These consequences become more reinforcing to the patient, thus pain behavior becomes more likely to occur (Premarck, 1965; Fordyce, 1967). Alternatively, the family members behavior and attention is likewise reinforced by gratitude signals by the patient. As discussed in the model of operant conditioning, when reinforcement occurs after each pain behavior response, the patients pain behavior will increase dramatically, but will be vulnerable to extinction when the positive consequences cease (Catania, 1994). Thus despite the evidence that pain itself is not pleasant, pain signals and behavior can continually be activated in the presence of reinforcing consequences. A teleological cycle is created in which the patient receives positive consequences for "being in pain", so pain is more likely to occur in frequency.
The treatment of chronic low back pain using operant conditioning principles involves Conditioning and Pain 5 removing the positive consequences that follow the pain behavior thus forcing the existing behavior into extinction. In a pain model posited by Fordyce (1967, 1985), pain behavior is a subset of total behavior and its existence follows the same principles that govern all behavior: behavior is governed by its consequences. If positive consequences followed pain behavior on a fixed ratio schedule, removing the reinforcement would theoretically result in a temporary increase in pain behavior followed by a rapid extinction. More likely though is that pain behavior has been reinforced on a variable or interval schedule, thus making the behavior more resistant to extinction, but would still be possible. In addition to removing the positive consequences from behavior, an attempt must be made to reinforce other more desirable behavior in the patient. Exercise that is well tolerated and efforts to become more productive can be more likely to occur in frequency if they are followed by positive consequences ( Fordyce, 1967, 1980; Catania, 1994) .Similarly, new desired behaviors such as returning to work and increased physical activity can be increased in frequency if immediately followed by positive reinforcement. As discussed previously, reinforcement is only effective if it is positively reinforcing for the patient involved. ( Catania, 1994; Skinner 1980) Positive attention from family and friends, food, money, and others may not be viewed as positive consequences for all individuals and may actually be aversive for some. If a particular consequence is not viewed positively by the patient it is not a "reinforcer". ( Catania, 1994) Empirical evidence supporting the operant conditioning model of pain behavior has been demonstrated in several studies. Fordyce , Fowler, Lehmann, and Delateur (1967) used positive reinforcement and punishment to strengthen or extinguish certain behaviors in Conditioning and Pain 6 inpatients with chronic low back pain.
Typical pain behavior such as grimacing, moaning, and limping were not acknowledged by family and medical staff and were ignored. Thus, attention was no longer a consequence of pain behavior. Medication, which had previously be given on an "as requested basis" was given 6 times a day at the same time, regardless of level of pain and independent of request. By giving pain medication independently of behavior it ceased to be a positive reinforcer of pain behavior but still allowed for palliative management of pain (Fordyce et al., 1967). Positive reinforcement in the form of praise and attention were given for "well"behavior such as increased physical activity and social interaction. (Fordyce et al., 1967) Analyses of the data from this study revealed that patients "pain behavior" decreased significantly as did their perceptions of pain. ( Fordyce et al., 1967) Reinforcement other than attention and medication may impact on pain behavior. In a meta- analyses conducted by Rohling, Binder, and Rohling, (1995)conducted an analyses of 136 studies which investigated the impact of financial compensation on duration and experience of chronic low back pain, results indicated that financial compensation such as disability or compensation payments for pain were associated with greater experience of pain as well as reduced treatment efficacy. ( Rohling et al., 1995) Researchers hypothesize that with these individuals financial compensation becomes a sufficient positive consequence of pain behavior that it increases the incidence of behavior as well as its duration. (Rohling et al., 1995) Most empirical studies are conducted on an inpatient population for practical reasons such as the control of extraneous variables which may alter treatment outcome and data and may influence the internal validity of the study. However a study is only externally valid if it Conditioning and Pain 7 can be replicated outside of the laboratory and if its applications can be used to solve a "real world" problem.
The following case studies illustrate how a behavioral and operant conditioning approach may benefit the patient's condition. A.B. is a 48 year old caucasian male. He has been married to the same woman for 20 years ad they have two teenage daughters. Eight years ago he was involved in an on site accident at his place of employment and since that time has complained of virtually constant low back pain. A CT scan and MRI were both negative as well as physical and neurological assessments . A.B. also participated in physical therapy, but often cited that he was "in too much pain" to complete the exercises or do home follow up. For the past 7 years he has been on several narcotic prescription medication in increasing dosages including Demerol, Percodan, Valium, Flexeril, Morphine extentabs. A.B. states that the medications do relieve his pain , but only temporarily. Because of A.B.'s chronic pain, he has been unable to work and has been receiving disability payments in addition to a structured settlement from his employer. A.B. is happy that the state and his employer "came through for him, although he adds that it would not be "right " to receive the settlement and disability checks if he was not "truly in pain". A.B's wife does not hold a job outside of the home, so she is able to take care of him 24 hours per day, administering his medication, giving him therapeutic back massage, reading to him and keeping him company. Both daughters also have been instructed on how to respond when their father is in pain; they are to give him his medication and sit with him until he falls asleep. At this time, A.B. is reluctant to attempt physical therapy again, or to increase any of his physical activity on his own. A.B. wife states that while she wishes that her husband would get better, that she enjoys caring for him especially now that Conditioning and Pain 8 their daughters are growing up and" do not need her anymore". ( Interview/Medical notes[11])
In this case study, A.B. has suffered from low back pain that has lasted for almost eight years with relatively no relief. He has taken several addictive medications and attempted physical therapy with little success. Despite negative findings both neurologically and radiographically, A.B. is virtually bedridden, unable to work or care fully for himself. It is clear that A.B wife provides his behavior with positive reinforcement. When he is in pain she responds to him by caring for him, being supportive, administering his medications, and reading to him. Similarly, she has instructed her children to respond in the same manner to their fathers pain behavior. A.B.s wife's behavior is also positively reinforced by her husbands gratitude and by feeling "needed" by him. The disability payments and structured settlement may also serve as a positive reinforcer to A.B.'s pain behavior. Additionally, A.B. feels that in order to receive these payments that he must be in pain. Thus, A.B.s pain behavior are followed by the positive consequences of his wife's supportive actions and his financial compensation for the accident that he was involved in. Applying operant conditioning principles to the case of A.B. would involve removing the attention he recieves from his wife and daughters when he is in pain. In order to manage residual chronic back pain, A.B.'s total average daily medication dosage should be divided into 4-6 equal doses which are to be given at designated times regardless of pain. Furthermore, the wife and daughters should be instructed to provide attention and support only to desired behaviors such as increased mobility and productivity.
Reinforcing consequences are also evident in the case review of R.F., a 46 year old Conditioning and Pain 9 caucasian female with spinal stenosis at L4. R.F. was employed as a kindergarten school teacher until 3 years ago after she sustained multiple injuries in a motor vehicle accident. Treatment following the accident included physical therapy three times weekly and medication for pain management, which she only took occasionally. Despite the fact that much inflammation had healed, R.F still complains of significant and debilitating pain that has prevented her from working. She rarely leaves her house except to go to her doctor or physical therapy appointments. R.F. has no family and has lost contact with most of her friends. R.F. says that she occasionally misses her friends, but that she has become friendly with the nurses and doctors who take care of her and she often will talk to them about her personal problems.[ Interview/ Medical notes {12}] The medical staff at R.F.'s doctors office like her very much. R.F. often brings them candy and thank you cards. They applaud her hard work and persistence in physical therapy and her refusal to take pain relieving medications. They feel terrible that she is suffering and consider her to be "very brave" for tolerating so much pain without medication. Sometimes the nurses will "beg" R.F. to take medication because she is hunched over and in pain. Despite R.F.'s frequent doctor and physical therapy visits, she has made little progress in her pain management. R.F. states that she will keep trying, despite her severe pain and that she is very lucky to have such kind physicians and nurses taking care of her.
In this case study, although R.F. does not have any family or friends at home, she derives positive reinforcement for her pain behavior from her medical staff at her doctors office. R.F. makes frequent appointments because her condition never improves. Rather than become frustrated and medication addicted, she is the "perfect patient". She brings gifts to Conditioning and Pain 10 the office, refuses to take addicting medication and appears to work hard and be "brave". The staff at the doctors office always give R.F. a lot of attention, especially if she is in pain. They will beg her to take pain medications and when she refuses, they tell her how "brave" she is. R.F. has clearly become dependent on the support that she receives from the medical staff. She has lost contact with many of her friends, so she only has the nurses at the doctors office to talk to. Thus they provide her with basic social support and friendship. If R.F. were to get better, it would be more difficult for her to reinstate herself into her previous world and she would most likely lose the contact with her doctors office. R.F. might benefit from the operant conditioning principles as well. At this time her pain behavior is being positively reinforced for "failing" to get better. The medical staff and physical therpists may want to try to reward R.F. for feeling well and accomplishing physical therapy goals. Pain behavior can be conceptualized as a subset of general behavior which according to operant principles is governed by its consequences. If pain behavior is reliably followed by positive consequences, it is likely to increase in frequency. Alternatively, if the positive consequences of pain behavior cease suddenly, the behavior will extinguish ( Catania, 1994; Skinner 1980). It is not suggested that all chronic low back pain should be treated with operant conditioning principles without regard for other medical, social, and environmental factors. It is also not implied that patients that suffer from prolonged chronic pain are " faking" pain or that it is entirely psychosomatic. However, when chronic pain persists relentlessly despite other types of medical interventions, the operant conditioning model combined with other medical and therapeutic components, can be of significant benefit.