Response-contingent Stimulation Research Articles

A Behavioral Approach to Treatment and Assessment of People with Disorders of Consciousness: The Response-contingent Stimulation Strategy

Response-contingent stimulation is a behavioral strategy used to improve the situation of patients with disorders of consciousness. Such strategy involves the presentation of brief periods (e.g., 10 to 15 s) of stimulation considered preferred by the patients, contingent on (immediately after) the emission of specific patients' responses. The aim is to help the patients learn the link between their responding and the preferred stimulation and thus learn to use their responding to access the stimulation in a self-determined/independent manner. Achieving these goals is considered important for the patients' recovery process and thus the response-contingent stimulation strategy that promotes such an achievement can be considered a valuable treatment approach. The same strategy combined with the use of periods of non-contingent stimulation (i.e., stimulation delivered independent of responding) may also serve as an assessment supplement with patients with apparent unresponsive wakefulness. The patients' increase in responding during the response-contingent stimulation and decline in responding during the non-contingent stimulation could be taken as a sign of discrimination between conditions, and possibly a sign of awareness of the immediate environmental situation, compatible with a diagnosis of minimally conscious state. This paper analyzes a number of studies aimed at using the response-contingent stimulation as a treatment strategy and a number of studies aimed at combining response-contingent stimulation with non-contingent stimulation for treatment and assessment purposes. The results of the studies are discussed in terms of the effectiveness, accessibility and affordability of the strategy. The need for new research (i.e., replication studies) is also pointed out.

Behavioral intervention approaches for people with disorders of consciousness: a scoping review

Purpose This review was intended to provide an overall picture of work conducted during the last decade to assess the impact of behavioral intervention strategies on people with disorders of consciousness (i.e., comatose state, vegetative state/unresponsive wakefulness, or minimally conscious state). The intervention strategies considered were those not based on music or including music as a component of the intervention package. Methods Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) checklist, a scoping review was carried out to identify and provide a synthesis of eligible studies published in English during the 2010–2021 period. Three databases (i.e., PubMed, PsycINFO, and Web of Science) were employed for the literature search. Results Forty studies met the inclusion criteria. Those studies were grouped into three categories based on whether they assessed the effects of: (i) verbal stories/messages, (ii) multiple stimulation, and (iii) response-contingent stimulation. Then, a narrative synthesis of the studies of each of the three categories was provided to specify the types of patients involved, the intervention and assessment conditions implemented, and the outcome attained. Conclusions The evidence reported in most of the studies might be considered encouraging and convincing. Even so, it might be very difficult to view the evidence of the various studies cumulatively and make general/conclusive statements due to a number of differences in the intervention conditions applied. Implications for rehabilitation An informative picture of the studies using behavioral interventions with people with disorders of consciousness is essential to any professional working in the area. Such picture can be highly useful in providing a view of the intervention strategies used for those people, of the variations existing within and across strategies, and of the evidence available. An analysis of the strategies, their implementation and their effects may provide new insights for improving those strategies and eventually increasing their impact. The individuals charged with the implementation process (e.g., family members or nurses) may have a relevant influence on the overall impact of the strategy.

Verbal Contingencies in the Lidcombe Program: A Noninferiority Trial.

Purpose The Lidcombe Program is an efficacious and effective intervention for early stuttering. The treatment is based on parent verbal response contingent stimulation procedures, which are assumed to be responsible for treatment effect. The present trial tested this assumption. Method The design was a parallel, open plan, noninferiority randomized controlled trial. In the experimental arm, the five Lidcombe Program verbal contingencies were removed from parent instruction. The primary outcome was beyond-clinic percentage syllables stuttered at 18-month follow-up. Seventy-four children and their parents were randomized to one of the two treatment arms. Results Findings of noninferiority were inconclusive for the primary outcome of stuttering severity, based on a margin of 1.0 percentage syllables stuttered. Conclusions The inconclusive finding of noninferiority means it is possible that verbal contingencies make some contribution to the Lidcombe Program treatment effect. However, considering all primary and secondary outcomes, an overriding impression from the trial is a similarity of outcomes between the control and experimental arms. The clinical applications of the trial are discussed, along with further research that is needed.

Behavioral treatments for children and adults who stutter: a review.

This paper provides a brief overview of stuttering followed by a synopsis of current approaches to treat stuttering in children and adults. Treatment is discussed in terms of multifactorial, operant, speech restructuring, and anxiolytic approaches. Multifactorial and operant treatments are designed for young children who stutter. Both of these approaches involve parent training and differ primarily in their focus on reducing demands on the child (multifactorial) or in their use of response contingent stimulation (operant conditioning). Speech restructuring and anxiolytic approaches are used with adults who stutter. Speech restructuring approaches focus on the mechanics of speech production, and anxiolytic treatments tend to focus on the symptoms and social and vocational challenges of stuttering. The evidence base for these different approaches is outlined. Response contingent therapy (for children) and speech restructuring therapy (for adults) have the most robust empirical evidence base. Multifactorial treatments for children and stuttering management approaches for adults are popular but are based on theoretical models of stuttering; the evidence base is not robust and tends to be inferred from work in areas such as cognitive behavior therapy and desensitization. Comprehensive, or holistic, approaches to treating stuttering are also discussed. Comprehensive approaches for treating stuttering in adults address both improved speech fluency and stuttering management.

Central nociceptive sensitization vs. spinal cord training: opposing forms of plasticity that dictate function after complete spinal cord injury

The spinal cord demonstrates several forms of plasticity that resemble brain-dependent learning and memory. Among the most studied form of spinal plasticity is spinal memory for noxious (nociceptive) stimulation. Numerous papers have described central pain as a spinally-stored memory that enhances future responses to cutaneous stimulation. This phenomenon, known as central sensitization, has broad relevance to a range of pathological conditions. Work from the spinal cord injury (SCI) field indicates that the lumbar spinal cord demonstrates several other forms of plasticity, including formal learning and memory. After complete thoracic SCI, the lumbar spinal cord can be trained by delivering stimulation to the hindleg when the leg is extended. In the presence of this response-contingent stimulation the spinal cord rapidly learns to hold the leg in a flexed position, a centrally mediated effect that meets the formal criteria for instrumental (response-outcome) learning. Instrumental flexion training produces a central change in spinal plasticity that enables future spinal learning on both the ipsilateral and contralateral leg. However, if stimulation is given in a response-independent manner, the spinal cord develops central maladaptive plasticity that undermines future spinal learning on both legs. The present paper tests for interactions between spinal cord training and central nociceptive sensitization after complete spinal cord transection. We found that spinal training alters future central sensitization by intradermal formalin (24 h post-training). Conversely intradermal formalin impaired future spinal learning (24 h post-injection). Because formalin-induced central sensitization has been shown to involve NMDA receptor activation, we tested whether pre-treatment with NMDA would also affect spinal learning in manner similar to formalin. We found intrathecal NMDA impaired learning in a dose-dependent fashion, and that this effect endures for at least 24 h. These data provide strong evidence for an opposing relationship between nociceptive plasticity and use-dependent learning in the spinal cord. The present work has clinical implications given recent findings that adaptive spinal training improves recovery in humans with SCI. Nociception below the SCI may undermine this rehabilitation potential.

Relative efficiency of response-contingent and response--Independent stimulation on child learning and concomitant behavior.

Observations of teachers' use of noncontingent stimulation to elicit behavior from young children with multiple disabilities and profound developmental delays led us to evaluate the relative efficiency of response-contingent and response-independent stimulation to affect child behavior change. Data from three children (2 females, 1 male) with multiple disabilities and delays were analyzed to determine how many child contingency, visual attention, and social affective behavior would be produced per 100 learning opportunities under contrasting stimulus conditions (contingent vs. noncontingent). Results showed for all three child behaviors, response-contingent stimulation was overwhelmingly more efficient in affecting behavior change compared to response-independent stimulation. Implications for intervention are described. Keywords: Response-contingent stimulation, response-independent stimulation, child operant learning, concomitant child behavior, efficiency ********** More than 25 years ago, we initiated a line of research and practice investigating the value of response-contingent learning opportunities with young children with multiple disabilities and profound developmental delays (e.g., Dunst, 1981; Dunst, Cushing, & Vance, 1985; Dunst & Didoha, 1976; Laub & Dunst, 1974). This work was begun in response to experience showing that traditional early intervention and therapy was not effective in promoting the learning and development of these children. Observations of many practitioners over many years have found that the interventions they used with young children with profound developmental delays more often than not involved response-independent or noncontingent stimulation to elicit or evoke child behavior. In most cases, the more disabled and delayed the children, the greater the likelihood that practitioners would spend large amounts of time using noncontingent stimulation to attempt to affect changes in child behavior. The influences of response-contingent and response-independent stimulation on child learning and behavior has been the focus of investigation for many years (e.g., Dunst, 1984; O'Brien, 1992; Utley, Duncan, Strain, & Scanlon, 1983; Vietze, Foster, & Friedman, 1974). Response-contingent stimulation involves the provision of stimulation contingent upon a child's behavior, whereas response-independent stimulation involves the provision of stimulation that is noncontingent or nondependent upon a child's behavior. Findings from studies indicate that noncontingent stimulation at least initially elicits child attention and increased behavior responding, but that children habituate to the response-independent stimulation the longer it is available. In contrast, response-contingent stimulation elicits and maintains child behavior responding for longer periods of time and is often associated with positive social-emotional behavior following contingency detection and awareness (see e.g., Dunst, 2003). The purpose of the analyses in this brief report was to determine the relative efficiency of response-contingent and response-independent stimulation on child operant learning and two concomitant child behavior (visual attention and affective behavior). The analyses were completed on data collected as part of a study promoting teachers' use of contingency games as a form of early childhood intervention with young children with multiple disabilities and profound developmental delays (Raab, Dunst, Wilson, & Parkey, 2007). During the baseline condition of the study, teachers were observed using noncontingent stimulation to elicit child behavior. The effect appeared to be behavior suppression rather than behavior enhancement. The extent to which this observation was confirmed in a secondary analysis of the study data was the focus of this report. The conduct of the original study was guided by a conceptual and operational framework that postulated both immediate and extended benefits of contingency learning opportunities (Dunst et al. …

Recent advances in the treatment of stuttering: A theoretical perspective

Prolonged speech and its variants are widely used in the behavioral treatment of stuttering. Unlike these approaches, which depend on clinician-prescribed speech pattern changes, two behavioral treatment regimens, one for children and another for adults, recently developed at the Australian Stuttering Research Center, promote self-monitoring of speech as a means of controlling stuttering. In these programs, the clients themselves modify their speech in subtle and variable ways to gain control over stuttering and, in that, they appear to be similar to a well-known experimental technique for suppressing stutters known as response contingent stimulation. The present paper provides an integrated explanation for the effectiveness of both clinician-directed as well as client-initiated speech pattern modifications and, in the process, develops a new model of stuttering. It also shows why client-generated speech patterns changes potentially produce faster and more lasting improvement than those changes prescribed by a clinician. Learning outcomes: The reader will learn about: (1) two hypothesized methods of preparing utterance motor plans—speech concatenation and speech construction; (2) how behavioral treatment programs make use of speech construction to promote fluency in persons who stutter; (3) why therapy procedures based on cognitively driven speech construction produce faster and superior results than those based on motorically driven speech construction; and (4) the empirical evidence that suggests that speech concatenation is the source of stuttering.

The obscure object of desire: 'nearly, but clearly not, like me': contingency preference in normal children versus children with autism.

The author describes the central role of contingency detection in early socioemotional development. It has been proposed (Gergely & Watson, 1999) that infants are innately equipped with a complex perceptual mechanism, the "contingency detection module," which functions to establish the primary representation of the bodily self as well as the later orientation toward reactive social objects. According to the "contingency switch" model, the target value of the module that is initially genetically set to preferentially explore perfectly response-contingent stimulation is "switched" at around 3 months toward a preference for less-than-perfect social contingencies. It is hypothesized that the primary cause of childhood autism is a genetic defect, due to which the normal process of switching contingency preference at around 3 months does not take place. Preliminary results from an experimental study to test this model are reported. The study contrasts the preferential reactions of normal children and children with autism to perfect versus imitative (high-but-imperfect) contingencies. The results provide support for the contingency switch hypothesis of the etiology of childhood autism.

Changes in linguistic variables during operant, laboratory control of stuttering in children

Response contingent stimulation (RCS) is known to reduce stuttering in many cases. Time-out (TO) from speaking after stuttering is a particularly effective form of RCS. However, the mechanism underlying the TO effect is unknown. The demonstrated value of operant methods in the clinical control of stuttering in young children warrants renewed interest in exploring why pausing for a short time after stuttering would reduce the frequency of stuttering. In this study, selected linguistic measures were made for two school-age boys whose stuttering reduced during TO in a laboratory study. One boy showed a clear reduction in verbal output, accompanied by a reduction in lexical diversity, but the other boy showed no changes in linguistic measures. This finding is of interest because, in a previous acoustic analysis of the same speech samples, the first boy showed no changes in acoustic speech measures of duration while the second boy did show changes in acoustic speech measures of duration. This raises the possibility that people who stutter may change their verbal output in response to TO, but in different ways. Although the present data do not establish a causal relationship between alterations in verbal output and reductions in stuttering, they raise the need for further research that might explain why TO might control stuttering.

Reapproaching Mahler: new perspectives on normal autism, symbiosis, splitting and libidinal object constancy from cognitive developmental theory.

Margaret Mahler's seminal work on the psychological birth of the infant has generated more critical discussion than most other psychoanalytic theories of early development. But while the empirically, theoretically, and methodologically based criticisms of Mahler's theory are generally justified, her critics fail at times to consider some of the intriguing and creative insights that her theoretical formulations tried to capture. This paper attempts to reformulate these insights using the new conceptual tools that current cognitive developmental theory provides. Mahler's stage of normal autism is reconsidered in the light of contingency detection theory as an initial phase of primary preoccupation with self-generated perfectly response-contingent stimulation. Her concept of normal symbiosis is recast with the help of attachment theory's views on homeostatic regulation and the social biofeedback model of affect-reflective mirroring interactions with parents. Finally, her ideas about the development of splitting and libidinal object constancy are reconsidered according to recent theories of early representational development and mentalization.

Reapproaching Mahler: New Perspectives On Normal Autism, Symbiosis, Splitting and Libidinal Object Constancy From Cognitive Developmental Theory

Margaret Mahler's seminal work on the psychological birth of the infant has generated more critical discussion than most other psychoanalytic theories of early development. But while the empirically, theoretically, and methodologically based criticisms of Mahler's theory are generally justified, her critics fail at times to consider some of the intriguing and creative insights that her theoretical formulations tried to capture. This paper attempts to reformulate these insights using the new conceptual tools that current cognitive developmental theory provides. Mahler's stage of normal autism is reconsidered in the light of contingency detection theory as an initial phase of primary preoccupation with self-generated perfectly response-contingent stimulation. Her concept of normal symbiosis is recast with the help of attachment theory's views on homeostatic regulation and the social biofeedback model of affect-reflective mirroring interactions with parents. Finally, her ideas about the development of splitting and libidinal object constancy are reconsidered according to recent theories of early representational development and mentalization.

Integration of free pulses in electrical self-stimulation of the rat brain.

Frequency thresholds for electrical self-stimulation of the medial forebrain bundle were estimated in rats while low frequencies of pulses were applied continuously. When continuous pulses were delivered to the same electrode that received the 0.5-s trains of response-initiated stimulation, thresholds decreased by the free-pulse frequency (Experiment 1), consistently across current (Experiment 2). Estimates of the reward added by concurrent, response-contingent stimulation of the opposite electrode of a bilateral pair predicted the drop in threshold caused by the noncontingent pulses applied to the opposite hemisphere (Experiment 3), again, robustly across test current (Experiment 4). Continuous pulses restricted to times between self-initiated trains lost their effect (Experiment 5). The perception of reward was invariant despite changes in the overall activity of the self-stimulation substrate.

Choosing a treatment procedure for early stuttering: issues and future directions.

The new responsibility of speech-language pathologists to provide direct, early intervention for stuttering creates a further responsibility for them to choose justifiable treatment procedures for that intervention. This paper has two purposes. The first is to encourage clinicians to evaluate the conceptual and practical aspects of the treatments they use for early stuttering. The second purpose of the paper is to overview available early intervention procedures and consider the advantages, disadvantages, and prominent issues associated with each. The procedures considered are environment manipulation, prolonged speech, and response-contingent stimulation. It is concluded that clinicians have no cause to be satisfied with any currently available early intervention procedure. Further, it is concluded that (a) although anticipatory struggle theories have made a useful contribution to scholarship, their line of theoretical reasoning is questionable for clinical practice; (b) although theoretically sound for the purpose, variants of prolonged speech pose prohibitive conceptual and practical shortcomings if they are used to treat very young stuttering children; (c) despite its disadvantages, response contingent stimulation is the most conceptually and practically justifiable method for early intervention with stuttering.

A preliminary analysis of the ameliorative effects of time-out from speaking on stuttering.

Relatively few attempts have been made to systematically examine the processes responsible for the ameliorative effects of response-contingent stimulation (RCS) on stuttering. It was hypothesized that the reductions in stuttering that frequently accompany RCS are the result of the stutterer being encouraged to access extant fluent speech that may not be fully evident during "contingency-free" (CF) conditions. A preliminary analysis of the hypothesis was conducted by monitoring RCS and CF stuttering frequency and speaking rate in 20 adult stutterers before, during, and after a program of fluency training. Subjects were divided into "high" and "low" responders on the basis of their baseline response to the RCS procedure of time-out from speaking, after which they participated in a 32-hour program of fluency training aimed at minimizing stuttering. After showing a degree of relapse during a subsequent 6-mon follow-up, high and low responders were found to be equally affected by time-out. This result contrasted the differential response shown by the two groups during the baseline phase, and is consistent with the hypothesis that improvements in fluency during RCS may occur when stutterers access extant fluent speech that is not otherwise being fully utilized.

Response-contingent stimulation as a treatment for developmental failure in infancy

An 8-month-old infant with a developmental quotient of 1 1 2 months was given response-contingent stimulation using a pressure-sensitive pillow which turned an overhead mobile. The subject learned to control the mobile by kicking the pillow, and concurrently began smiling at both the mobile and her mother for the first time. After mastering three contingencies on arm, head, and leg movement, she displayed what appeared to be a Piagetian coordinated secondary circular reaction, in which one response provided 4 seconds of access to another contingency. Although the subject remains severely retarded, the results suggest that some forms of developmental delay may be treated at least in part as a failure to develop contingency awareness.

Stuttering

Speech samples were collected from three adult male stutterers under six baseline conditions and 15 conditions believed to increase fluency. After moments of stuttering and filled pauses had been deleted from the samples, a speech pause analysis technique developed by Goldman-Eisler was used to measure the following speech pattern characteristics: mean phonation duration (i.e., the duration between pauses), pause proportion, articulation rate, fluent speech rate, mean sentence length, and percentage of syllables stuttered. Greater than 50% reduction in stuttering occurred in all but three conditions (Speak and Write, Relaxed, Alone with cards). Greater than 90% reduction occurred under Prolonged/DAF speech, Singing, Chorus reading, Shadowing, Slowing, Syllable-timed speech, and Response contingent stimulation. The data were examined for evidence of speech pattern characteristic changes which were associated with reduced stuttering. Lengthened mean phonation duration occurred consistently under four conditions: Chorus reading, Shadowing, Singing, and Prolonged/DAF. Slowed speech (lower overall rate, lower articulation rate, or increased pause proportion) occurred consistently in seven conditions: Prolonged/DAF, Slowing, Syllable-timed speech, Arm swing, Speak and write, Relaxed, and Singing. Only in Prolonged/DAF speech did lengthened phonation duration occur in conjunction with slowed speech. The results of this exploratory study suggest that stuttering may be reduced under different conditions by means of different strategies. Lengthened phonation and slowing were the predominant strategies used in those conditions investigated in this study. The results are consistent with those of effective treatment techniques. Theoretical accounts of the association between change in fluency and change speech pattern characteristics are discussed.

Pattern of rewarding stimulation affects the development of conditioned taste preferences

Research was undertaken to assess the importance of a response contingency on the development of conditioned taste preferences (CTPs). Water deprived rats implanted with lateral hypothalamic electrodes were given access to a lever which produced rewarding brain stimulation (response contingent rewarding stimulation) or had the stimulation administered at a rate determined by the experimenter (non-contingent rewarding stimulation) after drinking a novel tasting (coffee) solution. Consumption of the novel tasting solution was measured in a subsequent preference test. The results indicate that while response contingent stimulation produces reliable CTPs, non-contingent stimulation shows no evidence of inducing such preferences at any of the stimulation parameters employed. It was concluded that a reliable rate free measure of the rewarding aspects of brain stimulation could not be developed using non-contingent rewarding brain stimulation in conjunction with the CTP paradigm.

Learning to Control the Environment in Infancy

FINKELSTEIN, NEAL W., and RAMEY, CRAIG T. Learning to Control the Environment in Infancy. CHILD DEVELOPMENT, 1977, 48, 806-819. 34 infants participated in 3 experiments designed to examine the effects of response-contingent stimulation on subsequent performance in different learning tasks. Free operant and discriminative operant responding techniques were used to examine the proposition that experience with responsive stimulation would enhance an infant's subsequent learning performance. The results from the 3 experiments provide support for the central thesis. The mechanisms by which the transfer effects were obtained are discussed and an explanation concerning changes in attentional behavior is offered.

Effect of Vicarious Punishment on Stuttering Frequency

This investigation explored the effect of vicarious response-contingent stimulation on the frequency of stuttering. Twenty adult stutterers spoke for 20 minutes, then observed a speaker on a videotape for 10 minutes, and then spoke for an additional 20 minutes. In one condition the speaker on the videotape was a severe stutterer who experienced a dramatic reduction in stuttering under a contingent time-out procedure. In a second condition, the videotape speaker was a severe stutterer who received no experimental manipulations. In the third condition, the videotape speaker was a normal talker who received no experimental manipulations. All subjects participated in all three conditions. Twenty of the stutterers experienced a significant decrease in stuttering as a result of watching the videotape model who received contingent time-out. The subjects did not exhibit significant changes in stuttering after watching the severe stutterer who received no treatment or the normal talker.

Response-contingent positive stimulation of the part-word repetitions displayed by four stutterers

To assess the effect of response-contingent positive stimulation on the frequency of part-word repetitions displayed by stutterers, a single subject design was used. Four subjects were seen separately in an experimental session comprised of initial, experimental and final segments. During the experimental segment, money, the positive stimulus, was delivered contingent upon the occurrence of a part-word repetition. The data were analyzed statistically to determine the significance of differences in the frequency of part-word repetitions. This analysis did not demonstrate an effect of response-contingent positive stimulation on the part-word repetitions of any of the four subjects. The evidence obtained in this study supports the findings of previous research; some verbal behaviors of stutterers are unaffected by response-contingent stimulation. It appears necessary to investigate the effect of response-contingent stimulation on other separate behaviors as whole word repetition, phrase repetition, and hesitation for determination of their manipulability. The successful use of this procedure as a therapeutic treatment is dependent upon such a differential behavioral analysis.