1 Behavioral Interventions Behav. Intervent. 17: (2002) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: /bin.115 USING HABIT REVERSAL TO TREAT CHRONIC VOCAL TIC DISORDER IN CHILDREN Douglas W. Woods* and Michael P. Twohig University of Wisconsin Milwaukee, USA In the present study, a nonconcurrent multiple baseline design was used to evaluate the effectiveness of simplified habit reversal in three children diagnosed with chronic vocal tic disorder. In two children, vocal tics were substantially reduced. In a third child, tics were not reduced, and the addition of a supplemental contingency management program was ineffective. Despite these mixed results, the treatment was viewed as acceptable to the children s parents in all cases as measured by a standard index of treatment acceptability. Implications of these findings are discussed. Copyright # 2002 John Wiley & Sons, Ltd. INTRODUCTION A vocal tic is a sudden, rapid, and repetitive vocalization (American Psychiatric Association (APA), 2000). Although different tic disorders (i.e. Tourette s syndrome and transient tic disorder) may also include vocal tics as part of their symptomology, individuals diagnosed with chronic vocal tic disorder (CVT) must exhibit one or more vocal tics (with no motor tics) that occur many times per day for at least one year (APA, 2000). The prevalence estimates of chronic tic disorder range from 2.9 to 18% of the population with the disorder being more common in boys (Findley, 2001). However, such figures represent combined estimates for chronic vocal and chronic motor tic disorders. The prevalence for CVT as a separate diagnostic category remains unclear. A variety of behavioral interventions have been used to treat CVT, including differential reinforcement for the absence of tics (Wagaman, Miltenberger, & Williams, 1995), shaping with negative reinforcement (Alexander et al., 1973), and habit reversal plus cognitive therapy (Fuata & Griffiths, 1992). Although all of the studies reported success with their respective interventions, each presented data on only one subject, and only the Wagaman et al. (1995) study contained procedures for experimental control. Clearly, there is a paucity of research on the behavioral treatment of CVT. * Correspondence to: Douglas W. Woods, Department of Psychology, University of Wisconsin Milwaukee, Box 413, Milwaukee, WI 53201, USA. Contract/grant sponsor: University of Wisconsin Milwaukee Graduate School Research Committee. Copyright # 2002 John Wiley & Sons, Ltd.
2 160 D. W. Woods and M. P. Twohig One of the most promising interventions for CVT is habit reversal (Azrin & Nunn, 1973). Habit reversal was originally developed as a large, multi-component treatment package; however, more recent research has resulted in a simplification of the procedure. This simplified version, commonly referred to as simplified habit reversal (SHR), has been found to be as effective as the full procedure (Miltenberger, Fuqua, & McKinley, 1985). Typically, components of SHR include awareness training, competing response training, and social support. Research on SHR as a treatment for Tourette s syndrome and chronic motor tic disorder has demonstrated that the procedure is effective in reducing a variety of motor tic topographies (see, e.g., Woods, Miltenberger, & Lumley, 1996; Woods & Miltenberger, 1995, 1996; Miltenberger, Fuqua, & Woods, 1998). Unfortunately, studies evaluating the use of habit reversal or SHR to treat vocal tics in persons with Tourette s syndrome or CVT have been scarce. In one of the few studies to address vocal tic symptoms with the entire habit reversal package, Fuata and Griffiths (1992) treated a chronic throat-clearing tic in a 28-year-old man. Cognitive therapy, which consisted of challenging irrational beliefs about the tics and developing coping statements, was also included. Results showed a reduction in the vocal tic, but the uncontrolled nature of the design and the inclusion of the additional components leaves in question the efficacy and independent contribution of SHR. Another study by Carr and Bailey (1996) evaluated the efficacy of awareness training and competing response practice as a treatment for a vocal tic in a child with Tourette s syndrome. Results of the study demonstrated that the intervention had a decelerating effect on tic frequency, but because the entire SHR package was not implemented it is difficult to come to firm conclusions about the efficacy of the procedure with vocal tics. Likewise, the child treated in the study had a diagnosis of TS, and not CVT, thus potentially limiting the generalizabilty of the findings to the CVT population. Summarizing the literature on the use of SHR to treat vocal tics in children with CVT, it appears that SHR is promising, but research does not exist to fully support its clinical implementation. The purpose of the present study was to evaluate the efficacy of SHR as a treatment for CVT in children. METHOD Participants Larry Larry was a seven-year-old African-American male who had been engaging in a chronic coughing/throat clearing tic for 1 year. The tic was operationally defined as
3 Habit reversal of chronic vocal tics 161 loud and soft coughing and clearing of the throat. Previous medical evaluations had shown no specific organic origin for the persistence of the behavior, thus a diagnosis of CVT was provided. In addition to CVT, Larry had been diagnosed with attention deficit hyperactivity disorder (ADHD) and standardized psychological assessments suggested he also exhibited oppositional behavior but was functioning in the average range of intelligence on the Wechsler Abbreviated Scale of Intelligence (WASI; described below). Travis Travis was a 16-year-old Caucasian male who had been engaging in throat clearing and grunting tics since the age of 8. Previous evaluations by ear, nose, and throat specialists suggested no known organic origin for the behaviors. In addition to CVT, Travis had a diagnosis of attention deficit hyperactivity disorder, which was confirmed by standardized psychological assessments. Travis was functioning in the average range of intelligence on the WASI. Rick Rick was a nine-year-old Caucasian male who had been engaging in two vocal tics for 2 years. Independent evaluations by the first author and a pediatric neurologist confirmed the diagnosis of CVT. Rick had exhibited no motor tics prior to participation in the study. Rick s vocal tics included a rapid but forceful exhale of air through the nose and a rapid sniffing sound from the nose. Standardized psychological assessments suggested that Rick had no additional behavioral concerns, and was functioning in the average range of intelligence on the WASI. Data Collection All data on tic occurrence were collected via in-home videotaped assessments. All videotaped assessment sessions were conducted in a situation identified by the child s parent(s) as the one most likely to produce high levels of tics. The situation identified as most conducive to tic expression across all children was being alone. Each assessment was 15 min in length and approximately one to three assessments per week were taken throughout baseline and post-treatment phases. Rick s and Travis s assessments were videotaped by their parents due to their distance from the university, and Larry s assessments were recorded by an undergraduate student trained in direct observation procedures. In all cases, the child was left in the room by himself while the recordings were being made.
4 162 D. W. Woods and M. P. Twohig The assessments were scored by undergraduate students trained in direct observation procedures. A 10 s partial-interval scoring method was used and produced a percentage of intervals with vocal tics as the dependent variable. Seventeen per cent of the assessment sessions were scored for interobserver agreement by a second trained observer. Interobserver agreement was calculated by counting the number of intervals in which the observers agreed that a vocal tic had occurred or agreed that a vocal tic had not occurred and dividing this number by the total number of intervals. Overall agreement across all children was 98%. Measures Wechsler Abbreviated Scale of Intelligence (WASI; Psychological Corporation, 1999) The WASI is a norm-referenced abbreviated intelligence test designed to provide IQ estimates for individuals aged The WASI produces a full scale IQ score with a mean of 100 and a standard deviation of 15. To obtain the estimated IQ score a twoor four-subtest version can be administered. The two-subtest version was administered in this study. The two-subtest version has demonstrated excellent reliability along with acceptable content, concurrent, and construct validity. Treatment Evaluation Inventory Short Form (TEI-SF, Kelley, Heffer, Gresham, & Elliott, 1989) The TEI-SF is a nine-item inventory completed by the parents which measures treatment acceptability. Each item is rated on a five-point Likert scale. The ratings for the nine items are summed and a total score is presented. Possible scores range from 9 to 45 with higher scores indicating greater treatment acceptance. Scores over 27 indicate a more favorable than unfavorable view of treatment. The TEI-SF has shown good internal consistency and has proven to be a valid measure of treatment acceptability. Procedure A nonconcurrent multiple baseline design was used to evaluate the effectiveness of SHR as a treatment for CVT in children. During the initial assessment, participants and their parents were informed of the procedures and provided their informed consent. Next, the children completed the WASI and the parents and children were interviewed to determine their eligibility for the study. To be eligible for participation, the children had to (i) have an IQ above 70, (ii) have engaged in a
5 Habit reversal of chronic vocal tics 163 chronic vocal tic for over 1 year, (iii) be willing to be videotaped in their home, (iv) express a desire to stop their vocal tic, and (v) have the ability to follow instructions according to parental report. After the initial assessment, the in-home recording began. Recording continued until a stable baseline (three consecutive assessment sessions with data points showing no downward trend) was achieved. At this point, SHR was implemented according to a currently existing treatment manual (see Woods, 2001, for a detailed description of the treatment). Treatment occurred across three weekly sessions. The first treatment session lasted one hour, and in this session the child was taught SHR, which consisted of awareness training, competing response training, and social support training. To increase awareness, the child was taught to describe and detect occurrences of his tic. After the child was able to describe the tic accurately (with feedback provided by the therapist), he was asked to acknowledge occurrences of therapist-simulated tics until he was 80% accurate. Next the participant was asked to acknowledge occurrences of his own tics until 80% accuracy was achieved. This same process of description and detection was repeated with the antecedents to the tics. Typical antecedents involved a slight move of the head prior to the vocalization or a vague urge or tension in the throat preceding the tic. Therapist simulations were conducted only with the overt antecedents. Competing response training was implemented after awareness training. During competing response training, the child was taught to engage in a competing response for one minute contingent on an occurrence of the tic or one of the antecedents. In this study, the competing response was diaphragmatic breathing. After the breathing was demonstrated for the child by the therapist, the child learned to do the breathing through instruction, prompting, and feedback from the instructor. After the breathing was being done correctly, the instructions for its use were given to the child and he was asked to practice it contingent on the tics or antecedents until 80% accuracy was achieved. The final portion of the first treatment session involved social support training. In this component, the child demonstrated the correct use of the competing response procedure for his primary caregiver. The primary caregiver was then instructed to praise the child for correctly implementing the competing response contingent on the vocal tic or its antecedents. Likewise, the caregiver was instructed to prompt the child to use the competing response if he or she witnessed the child engaging in the vocal tic but not using the competing response. These behaviors were modeled by the therapist. The caregiver was then asked to practice with the child while receiving feedback from the therapist, until praising and prompting was occurring with 80% accuracy. At this point, the initial 1 hour therapy session was concluded with instructions to the child and his parents to continue the SHR procedures outside of therapy whenever a tic or antecedent presented itself.
6 164 D. W. Woods and M. P. Twohig The next two treatment sessions were 30 min in length and involved a review of the treatment procedures covered in the first session. During these booster sessions, the child was asked to explain and demonstrate the procedure. Correct explanations and demonstrations were praised and incorrect explanations or demonstrations were reviewed according to the protocol used in the first treatment session. After the second 30 min booster session, treatment was completed. Post-treatment video recording started after the first treatment session and continued through the remaining treatment sessions until a stable trend (i.e. three consecutive data points with no downward trend in the data) was achieved. At the end of the post-treatment recording the children s caregiver was asked to complete the TEI-SF. For Travis and Rick, three months after the last post-treatment data point was recorded, two additional recordings were conducted within one week of each other to determine the maintenance of the intervention. RESULTS Tic Occurrence Larry During baseline, Larry s vocal tics occurred during a mean of 25.3% of the intervals. Upon implementation of SHR, Larry s vocal tics decreased, but then soon increased to baseline levels for a mean of 22.5%. Larry s mother reported that he was not compliant with the procedures. To address this, a reinforcement program (as recommended by Woods (2001) was implemented (see Figure 1), in which Larry received a checkmark on a chart each time he correctly engaged in a competing response with or without parental prompting. A total of five checkmarks obtained at the end of each day could be exchanged for a choice of reinforcers from a reinforcer menu generated by Larry and his mother. Reinforcers included preferred activities or items. The token economy was in effect for the remainder of the study, but despite a small decrease immediately after its implementation, it had little effect on the tics or his mother s report of treatment compliance. Travis During baseline, Travis s vocal tics occurred during a mean of 9.95% of the intervals. After starting treatment, Travis s tics decreased to a mean of 3.6% of intervals. At the 3 month follow-up, his tics were ocurring during 7.3% of the intervals, but the variability in their occurrence made it difficult to ascertain whether follow-up gains were maintained over baseline levels.
7 Habit reversal of chronic vocal tics 165 Figure 1. Per cent of intervals with vocal tics across assessment sessions and participants. Rick During baseline, Rick s vocal tics occurred during a mean of 91.7% of the intervals. Upon implementation of habit reversal, Rick s vocal tics decreased drastically (M ¼ 23.9%). A 3 month follow-up showed that the decrease in the percentage of intervals with vocal tics was still present (M ¼ 10.5%). Interestingly, after the treatment was completed, but still during the post-treatment data collection phase, Rick s parents reported the development of a motor tic involving a rapid jerking of the head. His parents reported that this tic had never been seen before and did not occur on the videotaped assessments. To address the motor tic, habit reversal (Woods, 2001) was applied in one 30 min session. Rick s parents reported that the tic quickly disappeared and did not return.
8 166 D. W. Woods and M. P. Twohig Treatment Acceptability Parents for all three children found habit reversal to be an acceptable treatment for CVT at post-treatment. Travis s parents rated the procedure a 36 out of a possible 45 on the TEI-SF, and Rick s parents provided a rating of 39. Larry s parents rated the procedure a 30 out of a possible 45, indicating a positive view of treatment even though it was ineffective for Larry. Combined, these scores indicate that the procedure was found to be acceptable by the participants parents. DISCUSSION Prior research on the effectiveness of habit reversal as a treatment for tics has shown that the procedure is effective in reducing motor tics associated with chronic motor tic disorder and Tourette s syndrome. However, the effectiveness of the procedure for reducing vocal tics associated with CVT or TS remains unclear. In the present study, it was found that SHR was effective in producing immediate reductions in vocal tics associated with CVT for two of three children. Likewise, results showed that the children s caregivers found the treatment to be acceptable. Despite these positive results, a number of events occurring during the study are worthy of further discussion. First, the development of a motor tic in Rick during the course of SHR is of potential concern. Tic disorders are often viewed along a continuum of severity (i.e. transient tic disorder to Tourette s syndrome; Findley, 2001), and although Rick clearly had a diagnosis of CVT and not Tourette s syndrome (as confirmed by two separate evaluations) he developed a motor tic. Future research needs to experimentally determine whether or not habit reversal is capable of causing additional tics to develop in persons diagnosed with CVT. If it is found that habit reversal can cause other tics to occur, then the benefits of treatment must be weighed against the possible cost of producing more tics. Second, the research clearly shows that the SHR treatment manual tested in this study may not be sufficient to completely eliminate the tics associated with CVT and may not produce longer-term gains. As recommended by the Woods (2001) manual, a contingency management procedure was implemented to enhance the effectiveness of SHR. Unfortunately the procedure was ineffective for Larry, who had comorbid diagnoses of ADHD and oppositional behaviors. Future research should continue to evaluate best practices for treating CVT in children with comorbid psychiatric conditions. Perhaps it was the case that the oppositional behaviors required treatment before SHR could effectively be implemented. In addition, future research should investigate ways to promote the long-term maintenance of treatment gains found with SHR.
9 Habit reversal of chronic vocal tics 167 These findings are important for a number of reasons. First, this is the first study to demonstrate the efficacy of SHR as a treatment for CVT. To date, the literature on effective interventions for CVT has been sparse, leaving clinicians with little choice for empirically supported treatments. This study increases that body of literature. Second, the study points to potential concerns with habit reversal: the possible development of additional tics during the course of treatment and the treatment of children with comorbid psychiatric conditions. ACKNOWLEDGEMENTS This research was supported by a grant from the University of Wisconsin Milwaukee Graduate School Research Committee. The authors would like to thank Tim Roloff, Chris Flessner, Bryan Kroes, and the families that participated in the study. REFERENCES Alexander, A. B., Chai, H., Creer, T. L., Miklich, D. R., Renne, C. M., & Cardoso, R. A. (1973). The elimination of chronic cough by response suppression. Journal of Behavior Therapy and Experimental Psychiatry, 4, American Psychiatric Association (APA). (2000). Diagnostic and statistical manual of mental disorders (4th ed.). Text revision. Washington, DC: Author. Azrin, N. H., & Nunn, R. G. (1973). Habit reversal: a method of eliminating nervous tics and habits. Behaviour Research and Therapy, 11, Carr, J. E., & Bailey, J. S. (1996). A brief behavior therapy protocol for Tourette syndrome. Journal of Behavior Therapy and Experimental Psychiatry, 27, Findley, D. B. (2001). Characteristics of tic disorders. In D. W. Woods, & R. G. Miltenberger (Eds.), Tic disorders, trichotillomania, and other repetitive behavior disorders: Behavioral approaches to analysis and treatment (pp ). Norwell, MA: Kluwer. Fuata, P., & Griffiths, R. A. (1992). Cognitive behavioral treatment of a vocal tic. Behaviour Change, 9, Kelley, M. L., Heffer, R. W., Gresham, F. M., & Elliott, S. N. (1989). Development of a modified Treatment Evaluation Inventory. Journal of Psychopathology and Behavioral Assessment, 11, Miltenberger, R. G., Fuqua, R. W., & McKinley, T. (1985). Habit reversal with muscle tics: replication and component analysis. Behavior Therapy, 16, Miltenberger, R. G., Fuqua, R. W., & Woods, D. W. (1998). Applying behavior analysis to clinical problems: review and analysis of habit reversal. Journal of Applied Behavior Analysis, 31, Psychological Corporation. (1999). Wechsler Abbreviated Scale of Intelligence. San Antonio, TX: Author. Wagaman, J. R., Miltenberger, R. G., & Williams, D. E. (1995). Treatment of a vocal tic by differential reinforcement. Journal of Behavior Therapy and Experimental Psychiatry, 26,
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