Comparing fixed‐amount and progressive‐amount DRO Schedules for tic suppression in youth with chronic tic disorders

Chronic tic disorders (CTDs) involve motor and/or vocal tics that often cause substantial distress and impairment. Differential reinforcement of other behavior (DRO) schedules of reinforcement produce robust, but incomplete, reductions in tic frequency in youth with CTDs; however, a more robust reduction may be needed to affect durable clinical change. Standard, fixed‐amount DRO schedules have not commonly yielded such reductions, so we evaluated a novel, progressive‐amount DRO schedule, based on its ability to facilitate sustained abstinence from functionally similar behaviors. Five youth with CTDs were exposed to periods of baseline, fixed‐amount DRO (DRO‐F), and progressive‐amount DRO (DRO‐P). Both DRO schedules produced decreases in tic rate and increases in intertic interval duration, but no systematic differences were seen between the two schedules on any dimension of tic occurrence. The DRO‐F schedule was generally preferred to the DRO‐P schedule. Possible procedural improvements and other future directions are discussed.     

A comparison of response cost and differential reinforcement of other behavior to reduce disruptive behavior in a preschool classroom

This study investigated the effectiveness of response cost and differential reinforcement of other behavior (DRO) in reducing the disruptive behaviors of 25 children in a preschool classroom. Using an alternating treatments design, disruptive behavior was reduced when the participants earned tokens for the absence of disruptive behavior (DRO) or lost tokens for the occurrence of disruptive behavior (response cost). Initially, DRO was more successful in reducing the number of disruptive behaviors; however, over time, response cost proved to be more effective.     

Treatment of vocal tics in children with Tourette syndrome: investigating the efficacy of habit reversal

Habit reversal was used to treat vocal tics in 5 children with Tourette syndrome. Vocal tics were reduced in 4 of the 5 children, the untreated motor tics did not increase, and treatment was acceptable to the children's parents.     

Creating tic suppression: comparing the effects of verbal instruction to differential reinforcement

The purpose of this study was to compare two methods designed to produce tic reduction in 4 children with Tourette's syndrome. Specifically, a verbal instruction not to engage in tics was compared to a verbal instruction plus differential reinforcement of zero-rate behavior (DRO). Results showed that the DRO-enhanced procedure yielded greater reductions in tic frequency.     

A comparison of fixed momentary differential reinforcement of other behavior to variable momentary differential reinforcement of other behavior to reduce challenging behavior

Differential reinforcement of other behavior (DRO) is commonly used to reduce behavioral excesses. Momentary DRO schedules involve delivery of reinforcement contingent upon the absence of the target behavior at a given moment. Two variations of momentary DRO exist: fixed-momentary (FM) DRO and variable-momentary (VM) DRO. In the current study, we directly compared FM-DRO and VM-DRO schedules to reduce challenging behavior maintained by automatic reinforcement exhibited by four children with autism spectrum disorder. The results suggest that both the DRO schedules were equally effective to reduce challenging behavior. A social validity measure showed that most caregivers rated the VM-DRO as a preferred schedule and noted the potential for FM-DRO schedule to become more discriminable over time, which could reduce its effectiveness. However, most caregivers also commented that the FM-DRO schedule was easier to implement.     

The effects of differential negative reinforcement of other behavior and noncontingent escape on compliance

The present study evaluated the effects of noncontingent escape and differential negative reinforcement of other behavior in reducing problem behaviors and increasing compliance in 2 children with disabilities. Results showed that both methods reduced problem behavior and increased compliance for both children.     

Examining the neural antecedents of tics in Tourette syndrome using electroencephalography

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by the occurrence of motor and vocal tics. TS is associated with cortical–striatal–thalamic–cortical circuit dysfunction and hyper-excitability of cortical limbic and motor regions that lead to the occurrence of tics. Importantly, individuals with TS often report that their tics are preceded by premonitory sensory/urge phenomena (PU) that are described as uncomfortable bodily sensations that precede the execution of a tic and are experienced as an urge for motor discharge. While tics are most often referred to as involuntary movements, it has been argued by some that tics should be viewed as voluntary movements that are executed in response to the presence of PU. To investigate this issue further, we conducted a study using electroencephalography (EEG). We recorded movement-related EEG (mu- and beta-band oscillations) during (1) the immediate period leading up to the execution of voluntary movements by a group of individuals with TS and a group of matched healthy control participants, and (2) the immediate period leading up to the execution of a tic in a group of individuals with TS. We demonstrate that movement-related mu and beta oscillations are not reliably observed prior to tics in individuals with TS. We interpret this effect as reflecting the greater involvement of a network of brain areas, including the insular and cingulate cortices, the basal ganglia and the cerebellum, in the generation of tics in TS. We also show that beta-band desynchronization does occur when individuals with TS initiate voluntary movements, but, in contrast to healthy controls, desynchronization of mu-band oscillations is not observed during the execution of voluntary movements for individuals with TS. We interpret this finding as reflecting a dysfunction of physiological inhibition in TS, thereby contributing to an impaired ability to suppress neuronal populations that may compete with movement preparation processes.     

The effects of extinction,noncontingent reinforcement and differential reinforcement of other behavior as control procedures

Several techniques have been used in applied research as controls for the introduction of a reinforcement contingency, including extinction, noncontingent reinforcement (NCR), and differential reinforcement of other behavior (DRO). Little research, however, has examined the relative strengths and limitations of these "reversal" controls. We compared the effects of extinction with those of NCR and DRO in both multi-element and reversal designs, with respect to (a) rate and amount of response decrement, (b) rate of response recovery following reintroduction of reinforcement, and (c) any positive or negative side effects associated with transitions. Results indicated that extinction generally produced the most consistent and rapid reversal effects, with few observed negative side effects.     

The role of adventitious reinforcement during differential reinforcement of other behavior: A systematic replication

Differential reinforcement of other behavior (DRO) is commonly used to decrease problem behavior by presenting reinforcers contingent upon the absence of a target response. Although it is well demonstrated that DROs decrease response rates, the processes producing these decreases are not well understood. The present study systematically replicated previous research assessing whether adventitious reinforcement of alternative behavior contributes to the effectiveness of DRO. We presented university students with two options on a computer and reinforced target responding on a variable-ratio schedule. Next, we compared decreases in target-response rates and any increases in alternative responding during DRO schedules versus yoked variable-time schedules or extinction probes. DRO schedules resulted in the lowest target-response rate and highest alternative-response rate. These findings generally provide some support for the adventitious reinforcement of “other” behavior.     

A double-blind,sham-controlled,trial of home-administered rhythmic 10-Hz median nerve stimulation for the reduction of tics,and suppression of the urge-to-tic,in individuals with Tourette syndrome and chronic tic disorder

Tourette syndrome (TS) and chronic tic disorder (CTD) are neurological disorders of childhood onset characterized by the occurrence of tics; repetitive, purposeless, movements or vocalizations of short duration which can occur many times throughout a day. Currently, effective treatment for tic disorders is an area of considerable unmet clinical need. We aimed to evaluate the efficacy of a home-administered neuromodulation treatment for tics involving the delivery of rhythmic pulse trains of median nerve stimulation (MNS) delivered via a wearable ‘watch-like’ device worn at the wrist. We conducted a UK-wide parallel double-blind sham-controlled trial for the reduction of tics in individuals with tic disorder. The device was programmed to deliver rhythmic (10 Hz) trains of low-intensity (1–19 mA) electrical stimulation to the median nerve for a pre-determined duration each day, and was intended to be used by each participant in their home once each day, 5 days each week, for a period of 4 weeks. Between 18th March 2022 and 26th September 2022, 135 participants (45 per group) were initially allocated, using stratified randomization, to one of the following groups; active stimulation; sham stimulation or to a waitlist (i.e. treatment as usual) control group. Recruited participants were individuals with confirmed or suspected TS/CTD aged 12 years of age or upward with moderate to severe tics. Researchers involved in the collection or processing of measurement outcomes and assessing the outcomes, as well as participants in the active and sham groups and their legal guardians were all blind to the group allocation. The primary outcome measure used to assess the ‘offline’ or treatment effect of stimulation was the Yale Global Tic Severity Scale–Total Tic Severity Score (YGTSS–TTSS) assessed at the conclusion of 4 weeks of stimulation. The primary outcome measure used to assess the ‘online’ effects of stimulation was tic frequency, measured as the number of tics per minute (TPM) observed, based upon blind analysis of daily video recordings obtained while stimulation was delivered. The results demonstrated that after 4-week stimulation, tic severity (YGTSS-TTSS) had reduced by 7.1 points (35 percentile reduction) for the active stimulation group compared to 2.13/2.11 points for the sham stimulation and waitlist control groups. The reduction in YGTSS–TTSS for the active stimulation group was substantially larger, clinically meaningful (effect size = .5) and statistically significant (p = .02) compared to both the sham stimulation and waitlist control groups, which did not differ from one another (effect size = −.03). Furthermore, blind analyses of video recordings demonstrated that tic frequency (tics per minute) reduced substantially (−15.6 TPM) during active stimulation compared to sham stimulation (−7.7 TPM). This difference represents a statistically significant (p < .03) and clinically meaningful reduction in tic frequency (>25 percentile reduction: effect size = .3). These findings indicate that home-administered rhythmic MNS delivered through a wearable wrist-worn device has the potential to be an effective community-based treatment for tic disorders.     

The role of the cingulate cortex in the generation of motor tics and the experience of the premonitory urge-to-tic in Tourette syndrome

Tourette syndrome (TS) is a neurological disorder of childhood onset that is characterized by the occurrence of motor and vocal tics. TS is associated with cortical-striatal-thalamic-cortical circuit [CSTC] dysfunction and hyper-excitability of cortical limbic and motor regions that are thought to lead to the occurrence of tics. Individuals with TS often report that their tics are preceded by ‘premonitory sensory/urge phenomena’ (PU) that are described as uncomfortable bodily sensations that precede the execution of a tic and are experienced as a strong urge for motor discharge. While the precise role played by PU in the occurrence of tics is largely unknown, they are nonetheless of considerable theoretical and clinical importance as they form a core component of many behavioural therapies used in the treatment of tic disorders. Recent evidence indicates that the cingulate cortex may play an important role in the generation of PU in TS, and in ‘urges-for-action’ more generally. In the current study, we utilized voxel-based morphometry (VBM) techniques, together with ‘seed-to-voxel’ structural covariance network (SCN) mapping, to investigate the putative role played by the cingulate cortex in the generation of motor tics and the experience of PU in a relatively large group of young people with TS. Whole-brain VBM analysis revealed that TS was associated with clusters of significantly reduced grey matter volumes bilaterally within: the orbito-frontal cortex; the cerebellum; and the anterior and mid-cingulate cortex. Similarly, analysis of SCNs associated with bilateral mid- and anterior cingulate ‘seed’ regions demonstrated that TS is associated with increased structural covariance primarily with the bilateral motor cerebellum; the inferior frontal cortex; and the posterior cingulate cortex.     

Noncontingent reinforcement without extinction plus differential reinforcement of alternative behavior during treatment of problem behavior

The effects of noncontingent reinforcement (NCR) without extinction during treatment of problem behavior maintained by social positive reinforcement were evaluated for five individuals diagnosed with autism spectrum disorder. A continuous NCR schedule was gradually thinned to a fixed‐time 5‐min schedule. If problem behavior increased during NCR schedule thinning, a continuous NCR schedule was reinstated and NCR schedule thinning was repeated with differential reinforcement of alternative behavior (DRA) included. Results showed an immediate decrease in all participants’ problem behavior during continuous NCR, and problem behavior maintained at low levels during NCR schedule thinning for three participants. Problem behavior increased and maintained at higher rates during NCR schedule thinning for two other participants; however, the addition of DRA to the intervention resulted in decreased problem behavior and increased mands.     

On the definition of differential reinforcement of alternative behavior

Differential reinforcement of alternative behavior (DRA) has a long history as a behavioral treatment. The term has usually been defined in a manner that suggests one form of behavior (usually some appropriate alternative) is reinforced, while another form of behavior (usually problem behavior) is placed on extinction. In this paper, we will suggest that DRA should not require extinction, either procedurally or by definition. Ideally, problem behavior would be placed on extinction when possible; however, when problem behavior is not or cannot be placed on extinction, the procedure used is still DRA. Thus, we propose the following definition: Providing greater reinforcement, along at least one dimension, contingent on the occurrence of one form or type of behavior, while minimizing reinforcement for another form or type of behavior.     

Attention bias for social threat in youth with tic disorders: Links with tic severity and social anxiety

Many individuals with Tourette syndrome and chronic tic disorders (TS/CTDs) report poor social functioning and comorbid social anxiety. Yet limited research has investigated the role of cognitive factors that highlight social threats in youth with TS/CTD, and whether these biases underlie tic severity and co-occurring social anxiety. This study examined whether selective attention to social threat is enhanced young people with TS/CTDs compared to healthy controls, and whether attention biases are associated with tic severity and social anxiety. Twenty seven young people with TS/CTDs and 25 matched control participants completed an experimental measure of attention bias toward/away from threat stimuli. A clinician-rated interview measuring tic severity/impairment (YGTSS Total Score) and questionnaire measures of social anxiety were completed by participants and their parents. Young people with TS/CTD showed an attention bias to social threat words (relative to benign words) compared to controls but no such bias for social threat faces. Attention bias for social threat words was associated with increasing YGTSS Total Score and parent-reported social anxiety in the TS/CTDs group. Mediation analysis revealed a significant indirect path between YGTSS Total Score and social anxiety, via attention to social threat. Tentatively, these associations appeared to be driven by impairment rather than tic severity scores. Preliminary data suggests that youth with TS/CTD have enhanced attention to threat, compared to controls, and this is associated with impairment and social anxiety. Attention to threat could offer a cognitive mechanism connecting impairment and social anxiety, and so be a valuable trans-diagnostic treatment target.     

The effects of response cost in the treatment of aberrant behavior maintained by negative reinforcement

Positive reinforcement contingencies can sometimes be used to decrease problem behavior maintained by negative reinforcement (e.g., escape). In the current study, we evaluated the extent to which response cost (i.e., contingent removal of a preferred stimulus) would compete with the negative reinforcer maintaining destructive behavior. The response cost contingency reduced destructive behavior by 87% from baseline levels even though the negative reinforcement contingency (i.e., escape) remained in place.     

Treating excessively slow responding of a young man with Asperger syndrome using differential reinforcement of short response latencies

Fjellstedt and Sulzer-Azaroff (1973) used differential reinforcement of short latencies to decrease a child's latency to comply with instructions. We replicated this contingency with a young man diagnosed with Asperger syndrome across two tasks (question answering and math problem solving). We added a differential reinforcement contingency to teach the participant to discriminate between math problems that could be answered rapidly and those that required more time for accurate performance.