Behavioral methods in medical rehabilitation.

The process of assimilation of physical disability and of patient management strategies in medical rehabilitation are analyzed in behavioral terms. Four major problem areas are identified; (1) the aversive characteristics of forced entry from accidental injury or illness into permanent disability; (2) relinquishing pre-onset behavior no longer appropriate because of the disability; (3) acquisition of disability appropriate behaviors; and (4) maintenance of performance or generalization of treatment effects. Each of those problem areas is analyzed in behavior-consequence terms. Case examples are presented to illustrate both analysis of problems in behavioral terms and contingency management strategies for helping.

Gain of the ventilatory exercise stimulus: definition and meaning.

The ratio G = delta VE/delta VCO2 where delta VA is change in ventilation and delta VCO2 is change in CO2 production, is often used to quantitate the ventilatory response to exercise and is the overall system gain (G). However, the actual variable of interest often is the gain for the exercise stimulus (GEX). Exercise stimulus refers to a stimulus or group of stimuli other than the mean levels of arterial PO2 (PaCO2), PCO2 (PaCO2), and pH (pHa) that act to increase ventilation during exercise. GEX will be equal to G only if the response to exercise is precisely isocapnic, normoxic, and without metabolic acidosis. A mathematical model was used to examine the relationship between G and GEX when 1) the response to exercise is not strictly isocapnic and 2) when the resting PaCO2 is shifted away from its normal value. It was found that 1) when the exercise response was not strictly isocapnic, G was a poor estimate of GEX and 2) when resting PaCO2 was changed while GEX wa assumed to remain constant, G was a function of the resting PaCO2. However, this dependence of G on resting PaCO2 is a system property that was caused by the nonlinear properties of the gas exchange processes and was not a fundamental property of the controller. It is concluded that G may not always be a good estimate of GEX and may lead to incorrect conclusions concerning the nature of the exercise stimulus.

Respiratory drive during status epilepticus and its treatment: comparison of diazepam and lorazepam.

In order to examine the respiratory effects of tonic-clonic seizures and their treatment with i.v. diazepam or lorazepam, we utilized a spontaneously breathing piglet seizure model. A tracheostomy, arterial catheter, and epidural electrodes were inserted and pigs were maintained under ketamine anesthesia. After baseline recordings, seizures were induced with a pentylenetetrazol (PTZ) bolus and a 20 min infusion (5-6 mg/kg/min). After 10 min of PTZ infusion, randomly assigned animals received diazepam (D; N = 7; 0.5 mg/kg), lorazepam (L; N = 7; 0.2 mg/kg), or 0.9% saline (C; N = 7; controls) by rapid peripheral vein injection. Minute ventilation (Ve), Pa(CO2), and the pressure change in response to airway occlusion at end-expiration (P0.1) were measured at standard intervals. All groups had comparable increases in respiratory drive during untreated seizures. Changes in Ve and P0.1 were reduced to at or below baseline values in groups D and L, but not C, from 2 to 45 min after treatment (P < 0.05). No significant changes were observed in Pa(CO2) after either intervention. Following anticonvulsants, the cumulative duration of seizures was significantly reduced in L and D groups, compared to C (P < 0.05). We conclude that increases in respiratory drive occur during tonic-clonic seizures induced with PTZ. Amelioration of seizure activity with lorazepam or diazepam results in a reduction in respiratory drive, but not respiratory failure, in this tracheostomized model.

MMPI scale 3 as a predictor of back injury report: what does it tell us?

Items and selected subscales of Scale 3 (Hysteria) of the MMPI were examined to pinpoint personality or emotional factors predictive of back injury reports in an industrial setting. Data were derived from a previous prospective-design study of back pain in volunteer hourly wage employees of an aircraft manufacturing company. After physical examination and completion of questionnaires pertaining to demographic, psychosocial (including the MMPI), and workplace factors, workers were followed for an average of 3 years. Those who subsequently reported back injury were compared with those who did not. In that study three variables predicted report of back injury, one of which was Scale 3 of the MMPI. Individual items, Ornduff et al. subscales of Psychological Denial and Body Concern, and the five Harris-Lingoes (1955) subscales of Scale 3 were analyzed. Three Harris-Lingoes subscales showed significant relationships to the criterion. Hy-3: Lassitude/Malaise; Hy-1: Denial of Social Anxiety; and, marginally, Hy-2: Need for Affection, significantly contributed to prediction effectiveness. Results and implications for the understanding of factors predicting back injury reports and for the medical evaluation of pain and the concept of pain are discussed.

A model for evaluation of gas exchange: mouth to mouth ventilation of infants by emergency medical technicians.

We describe a model for evaluating techniques of infant ventilation during resuscitation. The utility of the model is illustrated by testing performance of emergency medical technicians in mouth to mouth ventilation of a model 4 kg infant. Ventilation was generally adequate with mean (+/- S.D.) frequency 22 +/- 9 breaths per minute and tidal volume 40 +/- 13 ml. Gas delivered to the model consisted of PICO2 7 +/- 6 mmHg and FIO2 0.20 +/- 0.007. Assuming normal metabolic rate and respiratory dead space, alveolar gas composition resulting from the simulated resuscitations would be PACO2 = 31 +/- 20 and PAO2 = 110 +/- 19 mmHg. Nine of ten rescuers would have achieved satisfactory PACO2 less than or equal to 50 and PAO2 greater than or equal to 100. However, the rescuers' exhaled oxygen concentration is not adequate to correct hypoxemia if associated with hypoventilation or a wide alveolar to arterial oxygen gradient.

A prospective study of work perceptions and psychosocial factors affecting the report of back injury.

A longitudinal, prospective study was conducted on 3,020 aircraft employees to identify risk factors for reporting acute back pain at work. The premorbid data included individual physical, psychosocial, and workplace factors. During slightly more than 4 years of follow-up, 279 subjects reported back problems. Other than a history of current or recent back problems, the factors found to be most predictive of subsequent reports in a multivariate model were work perceptions and certain psychosocial responses identified on the Minnesota Multiphasic Personality Inventory (MMPI). Subjects who stated that they "hardly ever" enjoyed their job tasks were 2.5 times more likely to report a back injury (P = 0.0001) than subjects who "almost always" enjoyed their job tasks. The quintile of subjects scoring highest on Scale-3 (Hy) of the MMPI were 2.0 times more likely to report a back injury (P = 0.0001) than subjects with the lowest scores. The multivariate model, including job task enjoyment, MMPI Scale-3, and history of back treatment, revealed that subjects in the highest risk group had 3.3 times the number of reports in the lowest risk group. These findings emphasize the importance of adopting a broader approach to the multifaceted problem of back complaints in industry and help explain why past prevention efforts focusing on purely physical factors have been unsuccessful.

A process for physical therapist student selection. The Q-technique.

The use of the Q-technique as a student selection procedure is described. The results of a one-year experience, the students who were selected and the attitudes of the faculty to the process are presented and discussed.

The effect of graded activity on patients with subacute low back pain: a randomized prospective clinical study with an operant-conditioning behavioral approach.

The aim of this study was to determine whether graded activity restored occupational function in industrial blue-collar workers who were sick-listed for 8 weeks because of subacute, nonspecific, mechanical low back pain (LBP). Patients with LBP, who had been examined by an orthopedic surgeon and a social worker, were randomly assigned to either an activity group (n = 51) or a control group (n = 52). Patients with defined orthopedic, medical, or psychiatric diagnoses were excluded before randomization. The graded activity program consisted of four parts: (1) measurements of functional capacity; (2) a work-place visit; (3) back school education; and (4) an individual, submaximal, gradually increased exercise program, with an operant-conditioning behavioral approach, based on the results of the tests and the demands of the patient's work. Records of the amount of sick leave taken over a 3-year period (ie, the 1-year periods before, during, and after intervention) were obtained from each patient's Social Insurance Office. The patients in the activity group returned to work significantly earlier than did the patients in the control group. The median number of physical therapist appointments before return to work was 5, and the average number of appointments was 10.7 (SD = 12.3). The average duration of sick leave attributable to LBP during the second follow-up year was 12.1 weeks (SD = 18.4) in the activity group and 19.6 weeks (SD = 20.7) in the control group. Four patients in the control group and 1 patient in the activity group received permanent disability pensions. The graded activity program made the patients occupationally functional again, as measured by return to work and significantly reduced long-term sick leave.

Behavioral factors in pain.

Pain is reconceptualized in learning-based behavioral terms. Methods to assess behavioral elements of pain and to discuss nonmedical influences on pain with patients as well as behaviorally based tactics for early and long-term management and reactivation are discussed in this article.

A behavioural perspective on chronic pain.

This review outlines a behavioural view of chronic pain, in which pain behaviours are considered as operants. This view is supported by experiments in which pain behaviour is shown to be under the influence of environmental factors. The number of exercises performed by pain patients working to tolerance tend to be in multiples of five, rather than following a chance distribution. The exercise deficit seen in pain patients under conditions where exercises are counted does not occur when feedback is removed, and under these circumstances pain patients do not differ from normals. Other studies show that tolerance can be increased by verbal reinforcement, and that pain ratings are influenced by the presence or absence of a patient's spouse. Implications of these findings for the maintenance or reduction of chronic pain are discussed.

The quota system in burn rehabilitation.

This article describes the quota system as a treatment for the helplessness behaviors and depressive symptoms that develop in some patients with burn injuries. With an A-B single-case design, the quota system was implemented for a patient who had sustained a particularly severe burn injury. A series of baseline behaviors were measured for 3 days, and then 80% of the patient's average performance on each of the targeted behaviors was computed and used as the initial quota value. The behavioral quotas were increased systematically and gradually by approximately 5% to 10% every day. The results suggest that the quota system may have been effective in decreasing an overall trend toward passivity, in increasing 3 of 4 targeted rehabilitation behaviors, and in reducing depressive symptoms in a patient with a particularly devastating injury.

On pain, illness and disability.

The biomedical perspective on management of pain, illness, and disability is analyzed and discussed. Pain and pain behavior are delineated. The distinction between acute and chronic pain, and the potential impact of social and environmental factors on pain behavior are reviewed. Distinctions between pain and suffering and between specific and non-specific pain are drawn and implications for the diagnostic process are considered. The importance of viewing clinical pain in biopsychosocial terms is emphasized and implications of that conceptual shift are reviewed. Attending to the social/environmental context in which patients function leads to an analysis of the social contract between individual and society. Implications of the concept of 'effort-related' on clinician as well as patient is considered. Clinician potential for stifling patient effort is reviewed. Finally implications of a biopsychosocial perspective on facilitation of return to work is considered.