Laryngomalacia in a 12-year-old child after laryngeal mask use.

OBJECTIVE: We present an unusual case of a 12-year-old child with state-dependent laryngomalacia presenting after anaesthesia with a laryngeal mask airway. METHOD: Current literature on state-dependent laryngomalacia and injury following laryngeal mask use is reviewed. RESULTS: A child who had previously suffered with laryngomalacia as an infant presented with disturbed breathing at night and during exercise. After anaesthesia using a laryngeal mask airway, these symptoms became more pronounced. Microlaryngoscopy revealed laryngomalacic type movement of the larynx. CONCLUSION: Our case seems to support a more complex, multifactorial aetiology for laryngomalacia, including both the neurological control of the larynx as well as its structure.

Drug-intake regulation and the interplay between economic costs and benefits: comment on Lynch and Carroll (2001).

W. J. Lynch and M. E. Carroll's (2001) review argues against aversive effects and for satiation and direct effects as the mechanisms responsible for the descending limb of the dose-response function. Analysis is provided that suggests they may prematurely dispose of the aversive-effects account. Further analysis of the evidence for satiation and direct effects supports the authors' contention that neither can be exclusively supported. A brief behavioral-economic analysis of drug-intake regulation and the descending limb of the dose-response function is presented.

Needle sharing in opioid-dependent outpatients: psychological processes underlying risk.

Needle sharing contributes to the spread of the human immunodeficiency virus and other health concerns and remains a persistent problem among injection drug users. We determined whether needle sharing may be related to the discounting of the value of delayed outcomes. Outpatients in treatment for heroin dependence indicated preference for immediate versus delayed hypothetical monetary and heroin outcomes in a titration procedure that determined indifference points at various delays. The degree to which the delayed outcomes lost value was estimated with a nonlinear decay model. Participants who agreed to share a needle in a scenario (N=15) discounted delayed money more steeply than did the nonsharing group (N=17). Both groups discounted delayed heroin more steeply than delayed money. Persistent needle sharing may be related to the relative inability of delayed outcomes to impact current behavior. Training to mitigate the effect of delay on outcome value may offer reductions in needle sharing and drug abuse.

Three predictions of the economic concept of unit price in a choice context.

Economic theory makes three predictions about consumption and response output in a choice situation: (a) When plotted on logarithmic coordinates, total consumption (i.e., summed across concurrent sources of reinforcement) should be a positively decelerating function, and total response output should be a bitonic function of unit price increases; (b) total consumption and response output should be determined by the value of the unit price ratio, independent of its cost and benefit components; and (c) when a reinforcer is available at the same unit price across all sources of reinforcement, consumption should be equal between these sources. These predictions were assessed in human cigarette smokers who earned cigarette puffs in a two-choice situation at a range of unit prices. In some sessions, smokers chose between different amounts of puffs, both available at identical unit prices. Individual subjects' data supported the first two predictions but failed to support the third. Instead, at low unit prices, the relatively larger reinforcer (and larger response requirement) was preferred, whereas at high unit prices, the smaller reinforcer (and smaller response requirement) was preferred. An expansion of unit price is proposed in which handling costs and the discounted value of reinforcers available according to ratio schedules are incorporated.

Comparing the reinforcing efficacy of nicotine containing and de-nicotinized cigarettes: a behavioral economic analysis.

RATIONALE: Smoking-related respiratory stimuli produced by de-nicotinized cigarettes may function as conditioned reinforcers, but behavioral data on such reinforcing effects are limited. OBJECTIVES: The present experiment compared the reinforcing efficacy of cigarettes that provided only smoking-related stimuli (de-nicotinized cigarettes) and cigarettes that provided both smoking-related stimuli and nicotine. METHODS: Eight human subjects responded on a progressive-ratio schedule in which the number of plunger pulls required for standardized cigarette puffs increased across sessions. In one phase, the breakpoints, number of puffs earned per session, peak response rates, ratio producing peak response rates, and the elasticity of demand for cigarette puffs were compared for nicotine-containing and de-nicotinized cigarettes when each cigarette type was the only one available. In another phase, subjects chose between the two cigarette types at some of the prices examined in the previous phase. RESULTS: Nicotine-containing and de-nicotinized cigarettes produced similar measures of reinforcing efficacy when each was presented alone, but there was a strong preference for nicotine-containing cigarettes when subjects were given a choice. CONCLUSIONS: These data support suggestions that smoking-produced sensory stimuli may function as conditioned reinforcers and that the relative reinforcing efficacy of cigarettes is determined by the combined effects of the nicotine/conditioned reinforcing complex provided by smoking.

Similar consumption and responding across single and multiple sources of drug.

Two experiments were conducted to assess whether total response output and total consumption would be similar when drugs are available from single and multiple sources of reinforcement, as predicted by behavioral economics. In Experiment 1, cigarette-deprived smokers were exposed to a concurrent-chains schedule in which equal fixed-ratio schedules served as the initial links, and different reinforcer magnitudes (i.e., number of cigarette puffs) were arranged across alternatives. After the session, obtained unit price was calculated and imposed in the next session when a different number of puffs was available according to a single fixed-ratio schedule. Thus, the unit price at which cigarette puffs could be earned was yoked within subjects across the single and concurrent-chains schedules. When plotted as a function of unit price, similar consumption and response rates were usually obtained across these schedules. Experiment 2 addressed a weakness of Experiment 1, namely, that responding was allocated exclusively to the larger reinforcer magnitude in concurrent-chains conditions, and therefore this schedule may have functioned as a single schedule. In Experiment 2, subjects were instructed to alternate responding between the two alternative schedules. Instructions produced approximately equal response allocation between the two alternatives. Again, similar consumption and response rates were observed across the single and instructed concurrent-chains schedules. These findings are discussed in the context of direct effects and behavioral economics perspectives of drug self-administration.

Abstinence and price effects on demand for cigarettes: a behavioral-economic analysis.

AIMS: To examine the separate and combined effects of cigarette pricing and cigarette abstinence on smoking. DESIGN: Within-subject design in which participants experienced all levels of price and abstinence conditions. SETTING: Laboratory conditions. PARTICIPANTS: Nine human cigarette smokers. INTERVENTION: Cigarette prices were manipulated across a 60-fold range (US$0.02-$1.20) in separate abstinent (5 + hours of non-smoking) and non-abstinent conditions. Participants earned money by pulling a response plunger (US$0.10 per 100 pulls) and could either keep the money or spend it on cigarette puffs. MEASUREMENTS: Total response output, cigarette consumption, price elasticity of demand and spending patterns. FINDINGS: Participants spent their earnings on cigarette puffs more quickly when abstinent than when they had smoked ad libitum before the session, and latency to spend money on puffs was a linear increasing function of price. Effects of abstinence on rates of smoking were a function of the price at which cigarette puffs could be purchased. At low prices participants smoked more puffs per session when abstinent, but this difference was negligible at high puff prices. Abstinence and non-abstinence effects were temporary, and tended to wane in the second 90 minutes of the sessions. During the first half of the sessions, demand for cigarettes was more inelastic during the abstinent condition than the non-abstinent condition, indicating relative insensitivity to price increases when abstinent. CONCLUSIONS: Behavioral-economic procedures and measures are sensitive to cigarette-abstinence manipulations and the laboratory methods employed here may prove beneficial in evaluating the probable effects of public-policy initiatives designed to reduce cigarette use.

Impulsivity and cigarette smoking: delay discounting in current, never, and ex-smokers.

RATIONALE: Impulsivity is implicated in drug dependence. Recent studies show problems with alcohol and opioid dependence are associated with rapid discounting of the value of delayed outcomes. Furthermore, discounting may be particularly steep for the drug of dependence. OBJECTIVES: We determined if these findings could be extended to the behavior of cigarette smokers. In particular, we compared the discounting of hypothetical monetary outcomes by current, never, and ex-smokers of cigarettes. We also examined discounting of delayed hypothetical cigarettes by current smokers. METHODS: Current cigarette smokers (n=23), never-smokers (n=22) and ex-smokers (n=21) indicated preference for immediate versus delayed money in a titration procedure that determined indifference points at various delays. The titration procedure was repeated with cigarettes for smokers. The degree to which the delayed outcomes were discounted was estimated with two non-linear decay models: an exponential model and a hyperbolic model. RESULTS: Current smokers discounted the value of delayed money more than did the comparison groups. Never- and ex-smokers did not differ in their discounting of money. For current smokers, delayed cigarettes lost subjective value more rapidly than delayed money. The hyperbolic equation provided better fits to the data than did the exponential equation for 74 out of 89 comparisons. CONCLUSIONS: Cigarette smoking, like other forms of drug dependence, is characterized by rapid loss of subjective value for delayed outcomes, particularly for the drug of dependence. Never- and ex-smokers could discount similarly because cigarette smoking is associated with a reversible increase in discounting or due to selection bias.

Discounting of delayed rewards in opioid-dependent outpatients: exponential or hyperbolic discounting functions?

Recent theories of substance abuse have used value discounting of delayed rewards to partly explain the decision to take drugs. Normative-economic theory holds that an exponential function describes the effects of delay on discounting, whereas the matching law posits a hyperbolic discounting function. The ability of these functions to describe 18 human heroin-dependent individuals' monetary- and heroin-reward delay-discounting functions was assessed. In the 1st condition, participants chose between immediate and delayed hypothetical monetary rewards. Delayed rewards were $1,000, and the immediate reward amount was adjusted until choices reflected indifference. In the 2nd condition, participants chose between immediate and delayed heroin (the delayed amount was that which each participant reported he or she could purchase with $1,000). The hyperbolic function produced significantly higher R2 values and significantly lower sums of squared error values. Consistent with previous findings, delayed heroin rewards were discounted at a significantly higher rate than were delayed monetary rewards.

A comparison of measures of relative reinforcing efficacy and behavioral economics: cigarettes and money in smokers.

In this experiment, we compared behavioral economic measures and measures of the relative reinforcing efficacy of cigarettes and money between-participants. The experiment proceeded in two phases. In the first phase, money and cigarettes were available on separate progressive ratio (PR) schedules when they were solely available. The response requirement for the PR schedule increased across sessions, rather than within a session. In the second phase, money and cigarettes were made concurrently available at some of the response requirements employed during the PR schedule. Measures of (1) PR breakpoint, (2) peak response rate, (3) preference, (4) elasticity and (5) Pmax (the price at which the greatest amount of responding occurs) were compared within participant. Across the PR- and concurrent-schedule conditions, the three measures of reinforcing efficacy (breakpoint, response rate and preference) yielded an inconsistent assessment of the relative reinforcing efficacy of money and cigarettes. The reinforcer that resulted in greater peak response rates varied across subjects, while PR breakpoint was higher for cigarettes in all participants. Further, in concurrent schedules, preferences for cigarettes or money reversed across the response requirements. Behavioral economic analyses suggest that Pmax and elasticity are related to PR breakpoint, and that preference can be predicted from a comparison of the demand curves under single-schedule conditions. Implications for the concept of reinforcing efficacy are discussed.

Making sense of sensitivity in the human operant literature.

Human operant behavior is often said to be controlled by different variables or governed by different processes than nonhuman operant behavior. Support for this claim within the operant literature comes from data suggesting that human behavior is often insensitive to schedules of reinforcement to which nonhuman behavior has been sensitive. The data that evoke the use of the terms sensitivity and insensitivity, however, result from both between-species and within-subject comparisons. We argue that because sensitivity is synonymous with experimental control, conclusions about sensitivity are best demonstrated through within-subject comparisons. Further, we argue that even when sensitivity is assessed using within-subject comparisons of performance on different schedules of reinforcement, procedural differences between studies of different species may affect schedule performance in important ways. We extend this argument to age differences as well. We conclude that differences across populations are an occasion for more precise experimental analyses and that it is premature to conclude that human behavior is controlled by different processes than nonhuman behavior.

Modeling the effects of combined behavioral and pharmacological treatment on cigarette smoking: behavioral-economic analyses.

Effects of different response requirements, response-independent cigarette puffs, and an alternative nondrug reinforcer on cigarette smoking were assessed in 2 experiments. The response requirement to obtain 2 puffs on a cigarette was manipulated while various numbers of response-independent puffs were provided (0, 6, or 12 in Experiment 1; 0 or 12 in Experiment 2). In Experiment 2, effects of response-dependent money ($0.25) on smoking were assessed within subjects. Response-dependent puff consumption decreased as price increased and as the number of response-independent puffs increased. Concurrently available money also decreased response-dependent smoking. The largest decrease in smoking occurred when puffs were at the highest price and when response-independent puffs and response-dependent money were both concurrently available. Findings suggest that combined pharmacological and behavioral interventions produce the greatest reductions in smoking.

Impulsive and self-control choices in opioid-dependent patients and non-drug-using control participants: drug and monetary rewards.

Delay discounting was investigated in opioid-dependent and non-drug-using control participants. The latter participants were matched to the former on age, gender, education, and IQ. Participants in both groups chose between hypothetical monetary rewards available either immediately or after a delay. Delayed rewards were $1,000, and the immediate-reward amount was adjusted until choices reflected indifference. This procedure was repeated at each of 7 delays (1 week to 25 years). Opioid-dependent participants were given a second series of choices between immediate and delayed heroin, using the same procedures (i.e., the amount of delayed heroin was that which could be purchased with $1,000). Opioid-dependent participants discounted delayed monetary rewards significantly more than did non-drug-using participants. Furthermore opioid-dependent participants discounted delayed heroin significantly more than delayed money.

Units of interaction, evolution, and replication: organic and behavioral parallels.

Organic and behavioral evolution both involve variation, selection, and replication with retention; but the individuals involved in these processes differ in the two kinds of evolution. In this paper, biological units of evolution, selection, and retention are compared with analogous units at the behavioral level. In organic evolution, natural selection operates on variations among organisms within a species, with the result of preserving in future generations of organisms those heritable characteristics that contributed to the organism's survival and reproduction. Species evolve as characteristics of the population change as a result of past selection. Continuity in a lineage in the biosphere is maintained by replication of genes with retention of organismic characteristics across successive generations of organisms. In behavioral evolution, reinforcement operates on variations among responses within an operant, with the result of preserving in future responses those characteristics that resulted in reinforcement. Continuity in a behavioral lineage, within the repertoire of a given organism, appears to involve retention and replication, but the unit of retention and replication is unknown. We suggest that the locus of retention and replication is the nervous system of the behaving organism.

Early complications of packing after nasal surgery with three different materials.

OBJECTIVE: To investigate and compare the early complications of nasal packing with three different packing materials after surgical trimming of nasal turbinates. DESIGN: From a group of patients admitted to two Ear, Nose and Throat Departments for surgical trimming of inferior turbinates, those who consented were included in this study. Randomised patient packs were used and randomisation was carried out by a third party not directly involved in the study. Patients' nostrils were packed with calcium sodium alginate (Kaltostat), glove finger packs or trousered paraffin gauze. SETTING: Two District General Hospitals (DGH) in the United Kingdom (UK) during the period from February 1989 to June 1990. SUBJECTS: 92 patients between the age of 16 years and 60 years who consented out of a population who were admitted to two DGHs for surgical trimming of inferior turbinates. MAIN OUTCOME MEASURES: The state of the nostrils in each patient was assessed by the authors (authors 1 and 3 in Hospital 1 and author 2 in Hospital 2) at the time of discharge and at a postoperative outpatient visit at 3 weeks after discharge. RESULTS: 5% of nostrils packed with calcium sodium alginate (Kaltostat), 27% of nostrils packed with glove finger packs and 20% of nostrils packed with paraffin trouser packs were found to have clots on discharge from the hospital. At the post-discharge followup, when each complication was considered separately, there were more complications in the group who had their nostrils packed for 48 hours (14.2%) than in those who had packs in for 24 hours (7.3%). Significantly less complications were seen at 3 weeks with paraffin gauze packs (6.6%) than in the other two packing material (13.9%). CONCLUSIONS: Our findings suggest that, of the pack types studied 1) nostrils packed with calcium sodium alginate (Kaltostat) leave less clots in the nostrils 2) leaving packing in for 48 hours produces significantly more complications in the early post-operative period especially with calcium sodium alginate.

Exchange delays and impulsive choice in adult humans.

Choice responding by adult humans in a discrete-trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point-delay conditions, subjects chose between an "impulsive" alternative that provided a small amount of points immediately and a "self-control" alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self-control alternative. In exchange-delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self-control preference observed for all subjects in the 1-day exchange-delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delays on the order of weeks.

Bilateral laryngoceles.

The authors present an unusual case of upper airway obstruction due to the presence of bilateral communicating laryngoceles. The use of aspiration techniques on the larger of the laryngoceles resulted in a significant improvement in upper airway function. This improvement avoided the need for a tracheostomy or intubation under potentially hazardous circumstances and allowed the eventual surgery to take place in more controlled conditions.

A randomized study to compare calcium sodium alginate fibre with two commonly used materials for packing after nasal surgery.

A prospective randomized study was undertaken to compare the qualities of calcium sodium alginate (Kaltostat), trousered paraffin gauze, and glove finger packs as nasal packing material following the operation of partial inferior turbinectomy. All three types of packing material were found to be similarly effective in preventing bleeding whilst the packs were in situ. Calcium sodium alginate (Kaltostat) was associated with significantly less bleeding on pack removal than the other two packing materials. Further, irrespective of the material used, leaving the packs in situ for 48 hours produced significantly less bleeding than when they were removed after 24 hours.