Journal of Psychosomatic Research 76 (2014) 472–476
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Journal of Psychosomatic Research
Tourette patients' misbelief of a tic rebound is due to overall difficulties in reliable tic rating Kirsten R Müller-Vahl ⁎, Laura Riemann, Stefanie Bokemeyer Clinic of Psychiatry, Socialpsychiatry and Psychotherapy, Hannover Medical School, Germany
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Article history: Received 29 October 2013 Received in revised form 13 March 2014 Accepted 17 March 2014 Keywords: Tourette syndrome Tics Suppression Rebound Premonitory urge ADHD
a b s t r a c t Objective: While in clinical interviews the vast majority of patients with Tourette syndrome (TS) report about a tic rebound after voluntary tic suppression, in recent studies in children no paradoxical tic increase could be found. We hypothesized that in adult patients there is a tic rebound after tic suppression. Methods: We investigated the tic severity, premonitory urges and influence of attention deficit hyperactivity disorder (ADHD) before, during and after tic suppression in 22 adult patients with TS using both an objective video tic rating and subjective patient ratings for tics and premonitory urges. Results: According to the video rating, tic suppression resulted in a significant tic reduction, but no rebound. Patients also reported no tic rebound. They erroneously believed in an absolute tic reduction 20 and 30 min after suppression, but paradoxically felt no relative tic change. Premonitory urges remained unchanged. There was no correlation between premonitory urges and tic severity. The potency for tic inhibition did not correlate with premonitory urges and tic severity. ADHD did not influence tic inhibition. Conclusion: In adults with TS, there is no tic rebound after voluntary tic suppression. Patients also reported no rebound, but erroneously felt a tic reduction in the later course of the study. This misjudgement as well as patients' often reported (mis-)belief of a tic rebound may be caused by overall difficulties in reliable tic rating. Premonitory urges remained unchanged during tic suppression. Tic suppression was not influenced by attention deficits. Premonitory urges are no prerequisite of tic suppression. © 2014 Elsevier Inc. All rights reserved.
Introduction Tourette-syndrome (TS) is a neuropsychiatric disease defined by motor and vocal tics. Tics are often preceded by a premonitory urge and are temporarily suppressible. However, younger children (under the age of 10 years) often report that they do not feel an urge and are unable to suppress their tics [1,2]. Some (adult) patients feel that the premonitory urge is even more troublesome than the tics. Most patients report that they try to avoid tic suppression when possible, because they feel that voluntary tic suppression is exhausting, requires concentration, causes an increasing inner urge, and finally results in a temporarily overshooting tic increase [3]. In addition, patients often report that the premonitory urge not only increases during tic suppression, but also becomes unbearable and can only be abolished by the performance of a tic. Accordingly, most patients report that voluntary tic suppression causes only a postponement, but not an abolition of their tics [3]. For many years, these reports of patients, were not brought into question and resulted in the general excepted recommendation that patients with tics ⁎ Corresponding author at: Clinic of Psychiatry, Socialpsychiatry and Psychotherapy, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany. Tel.: +49 511 5323551; fax: +49 511 5323187. E-mail address: [email protected] (K.R. Müller-Vahl).
http://dx.doi.org/10.1016/j.jpsychores.2014.03.003 0022-3999/© 2014 Elsevier Inc. All rights reserved.
should avoid voluntary tic suppression. This conviction is also expressed in the results of a survey performed in 2004 demonstrating that 77% of medical doctors and psychologists experienced in tic disorders believed that tic suppression causes a tic rebound [4]. In contrast to these reports of patients, from recent studies it is suggested that – at least in children – voluntary tic suppression is not followed by a paradoxical tic increase [5–11]. These studies provided evidence that (1) tic suppression can be enhanced by reinforcement [7,8], (2) tics can be suppressed not only for a short period of time, but also for a time period of up to 40 min [6], (3) tic suppression results in a tic reduction of 70% [6,10], and (4) patients with attention problems are less able to suppress their tics [10]. This study was motivated by the following considerations: (1) we are running a large TS outpatient clinic and during the last years several hundred patients reported about a tic rebound and, therefore, we hardly could believe that there should be no tic rebound; (2) in none of the above mentioned studies a plausible explanation has been given, why patients should erroneously believe in a (non-existing) tic rebound; (3) all these studies have been performed in children, although (younger) children often report that they are unable to suppress their tics. On the one hand, one might speculate that in children there is no tic rebound because children are not able to suppress their tics sufficiently to cause a rebound. On the other hand, it can be hypothesized that there
K.R. Müller-Vahl et al. / Journal of Psychosomatic Research 76 (2014) 472–476
are differences between children and adults. Adults with persisting tics represent a specific subgroup of patients with unique characteristics and, therefore, results obtained in children can possibly not be generalized to adults; (4) most of the available studies have been performed in the context of clinical trials investigating the efficacy of behavioral therapy (such as habit reversal training) in patients with chronic tic disorders. This might have caused a methodological bias, since researchers understandably wished to find no tic rebound after suppression; and (5) it can be speculated that in some of the studies no tic rebound could be detected due to the small number of patients included, inappropriate assessment, and inadequate timing for tic rating. The aims of this study were to investigate for the first time in a larger group of adult patients with TS, whether voluntary tic suppression is followed by a tic rebound (either immediately or after a longer time period after tic suppression), causes an increased premonitory urge, and is influenced by comorbid attention deficit hyperactivity disorder (ADHD) using a sophisticated video protocol to measure tics at different time points. We hypothesized that in adult patients (1) voluntary tic suppression causes a tic reduction, (2) voluntary tic suppression results in a paradoxical tic rebound, and (3) premonitory urges increase during voluntary tic suppression. Methods Between 6/2010 and 1/2012, we investigated tic severity and premonitory urges before, during and after tic suppression in 22 adult patients (17 male, 5 female, mean age = 35.1 ± 10.7 years) with TS according to DSM-IV-TR. Patients were recruited from the TS outpatient Clinic of Psychiatry, Social psychiatry and Psychotherapy at the Hannover Medical School. Inclusion criteria were age 18–50 years, Yale Global Tic Severity Scale (YGTSS) total tic score (TTS) [12] ≥7, and self-reported ability for tic suppression. Exclusion criteria were the presence of significant comorbid medical conditions, other severe psychiatric disorders, age b 18 or N 50 years and YGTSS-TTS b7. Common comorbidities such as ADHD and obsessive-compulsive disorder (OCD) were no exclusion criteria. The study was approved by the local ethics committee. Subjects provided written informed consent before entering the study. To minimize bias, patients were not informed about the real aim of the study. Instead they were told that the study aims to investigate the degree of tic reduction during voluntary suppression. This instruction, in addition, should enhance the extent of tic suppression. The study consisted of three parts lasting about 60 min altogether: Part (I): Baseline before tic suppression. At baseline, the following measurements were performed: examiner tic rating according to the YGTSS, video rating according to the modified Rush Video-Based Tic Rating Scale (MRVS) [13] (for details see below), self-rating of tics according to a Visual Analogue Scale (VAS) (0–100, 0 = no tics, 100 = maximal tics), self-rating of premonitory urges according to the German version of the Premonitory Urge for Tics Scale (PUTS) [14], and assessments for ADHD including the DSM-IV symptom list [15], Conners Adult ADHD Rating Scale (CAARS) [16] and Wender-Utah-Rating-Scale (WURS-K) [17]. Part (II): Tic suppression. In the second study part, patients were asked to suppress their tics as much as possible for a time period of 10 min. As a reward for “optimal” tic suppression, a little present (chocolate) was promised. Just before the end of this tic suppression period, patients were asked to complete the VAS, PUTS and a VAS of Improvement (VAS-I) detecting relative changes in tic severity (−100%–+100%, 0% = no change) during “suppression” compared to “baseline”. In addition, tics were measured using the MRVS (for details see below).
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Part (III): Post suppression. After tic suppression had been stopped, tics were rated at four different times (immediately and after 10, 20 and 30 min) using the MRVS (for details see below). In addition, the VAS, PUTS, and VAS-I were used at three different time points (after 10, 20 and 30 min) to measure tics (self-rating) and premonitory urges. Protocol for MRVS The MRVS is regarded as the most objective examiner tic rating. The 10-minute film protocol includes full frontal body (far) and head and shoulders only (near) views with and without an examiner in the room lasting 2.5 min each. We standardized the protocol by using always the same order: a) near with examiner, b) near without examiner, c) far without examiner, and d) far with examiner. For tic rating, only two (far and near body view) 1-minute recordings with no examiner present are scored rating 5 domains: number of body areas involved, motor tic (MT) and vocal tic (VT) frequency and severity. We standardized the tic rating by selecting this 1-minute segment for tic rating from each 2.5-minute recording starting 0.5 min after the recording started (minute 0.5–1.5). Thus, during a study period of 30 min, the 10minute MRVS protocol can be performed a maximum of three times. For the sake of simplicity, we used the wording “tic rating was performed after 10, 20, and 30 min”. But strictly speaking, tic ratings according to the MRVS (as described above) were performed (1) from minute 3.0 to 4.0 (near without examiner) and 5.5 to 6.5 (far without examiner), (2) minute 13.0–14.0 and 15.5–16.5, and (3) minute 23.0– 24.0 and 25.5–26.5. In order, to measure tics in addition “immediately” after the end of the tic suppression period, we slightly modified the MRVS protocol: (1) tic rating was started directly after suppression was stopped (the examiner adjusted the video camera and instructed the patient to stop tic suppression exactly when she left the room), (2) tics were counted only once using the segment “near without examiner” (instead of using two segments far and near as described in the MRVS protocol), and (3) tics were counted only for 30 s (instead of 60 s as described in the MRVS protocol) and multiplied by 2 for further statistical analyses. All patients were informed about the video rating. First video documentation (baseline before tic suppression) was started 10 min before the first tic rating was done to ensure that the patients get used to the situation. Tic rating was performed by two of the authors (KMV, SB) who are experienced in tic rating and were blinded and not involved in the video recording. To avoid inter-rater bias, tic rating was done in a joint meeting and KMV rated MT and SB VT. If necessary, videos were watched several times and ratings were discussed. Inhibition potency As suggested recently by Ganos et al. [11] we calculated the inhibition potency (for both the TTS and the subscores MT and VT) as a measurement for tic inhibition. The inhibition potency was calculated as follows: (MRVS at baseline − MRVS during suppression) / MRVS at baseline. Statistics For statistical analyses, the generalized linear model (GLM) procedure of the IBM program package SPSS (version 21) was used. To test the primary hypothesis of a tic rebound, we analyzed the differences between group means for the different measurement occasions using analyses of variance (ANOVA). In case of a significant main effect, post-hoc tests were performed to compare the measurement occasions. Pearson coefficients were used to explore the correlation between different clinical (sub-)scores including MRVS, PUTS, VAS, VAS-I, and YGTSS. We explored the influence of comorbid ADHD on tics,
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Table 1 Tic severity, premonitory urges, and tic inhibition potency before, during and after tic suppression Tic severity
Inhibition potency
YGTSS
Baseline
Suppression
After suppression
30 s
10 min
20 min
30 min
Mean SD Range Mean SD Range P Mean SD Range P Mean SD Range P Mean SD Range P Mean SD Range P
MRVS
VAS
GS
TTS
MT
VT
TTS
MT
VT
55.29 22.94 10–94 – – – – – – – – – – – – – – – – – – – –
28.62 10.07 10–44 – – – – – – – – – – – – – – – – – – – –
15.62 4.91 7–24 – – – – – – – – – – – – – – – – – – – –
13.00 6.70 0–22 – – – – – – – – – – – – – – – – – – – –
9.31 4.78 0.00–14.00 5.18 4.63 0.00–15.00 0.001 9.21 4.85 0–16 0.92 9.24 4.41 1.5–16 0.90 9.02 5.02 0–16.5 0.22 8.90 4.87 0–16 0.27
2.19 1.09 0.00–3.33 1.39 1.05 0.00–3.83 b0.001 2.05 0.94 0–3 0.58 2.11 0.85 0.5–3.17 0.57 1.99 1.00 0–3.17 0.12 1.96 1.00 0–3.33 0.11
1.37 1.05 0.00–3.25 0.51 1.01 0.00–3.50 b0.001 1.53 1.24 0–3.5 0.54 1.45 1.30 0–3.5 0.65 1.33 1.22 0–3.5 0.81 1.42 1.28 0–4 0.71
49.67 22.27 5–90 17.62 12.31 0–45 b0.001 – – – – 50.90 24.24 5–100 0.76 41.88 21.61 10–85 b0.05 39.4 23.64 5–85 b0.05
VAS-I [%]
−62.00 30.67 −100.00–20.00 b0.001 – – – – 8.50 32.69 −45.00–80.00 0.40 −3.90 29.20 −60.00–40.00 0.33 −3.10 26.00 −50.00–50.00 0.37
TTS
0.48 0.08 −0.11–1.00
MT
1.84 0.21 −0.5–3.03
Premonitory urge VT
1.41 1.41 0.5–3.1
PUTS
27.81 5.06 14–35 28.74 4,71 20–38 n.s. – – – – 28.29 5.47 19–36 n.s. 27.52 6.56 14–38 n.s. 28.07 6.02 18–38 n.s.
YGTSS = Yale Global Tic Severity Scale, MRVS = Modified Rush Video Score, VAS = Visual Analogue Scale (0–100, 0 = no tics, 100 = maximal tics), VAS-I = Visual Analogue Scale of Improvement (−100%–+100%, 0% = no change), GS = global score, TTS = total tic score, MT = motor tic score, VT = vocal tic score, inhibition potency (calculated for TTS, MT, and VT) = (MRVS at baseline − MRVS during suppression) / MRVS at baseline, PUTS = Premonitory Urge for Tics Scale, SD = standard deviation, p = values compared to respective score at baseline.
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Time of measurement
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premonitory urges, and tic suppression (YGTSS, VAS, PUTS, and inhibition potency) using Pearson correlations and analysis of variance. A p value b0.05 was considered significant. No correction for multiple testing was applied. Results Voluntary tic suppression resulted in a significant tic reduction (according to MRVS). There was no paradoxical tic increase after tic suppression: at no time of measurement after tic suppression (immediately, 10, 20, and 30 min), tic severity (TTS, MT, and VT according to MRVS) differed significantly from baseline (Table 1). Patients felt a tic decrease during suppression and an increase to baseline 10 min after suppression, but no rebound (according to VAS). They erroneously believed a tic reduction 20 and 30 min after suppression (VAS), but paradoxically felt no relative tic change at that time (VAS-I). PUTS remained unchanged during and after suppression (Table 1). There was no correlation between MRVS-TTS and YGTSS (for none of the scores), respectively, and PUTS. We found a positive correlation between YGTSS-TTS and VAS at baseline (r = 0.612, p = 0.007) and between PUTS and VAS-S 30 min after suppression (r = 0.497, p = 0.022). At no time of measurement there was a correlation between the inhibitory potency (for none of the scores) and PUTS, YGTSS, and VAS scores (Table 1). There was a positive correlation between the VAS-I and the VAS during (r = 0.496, p = 0.26) and 10 min after tic suppression (r = 0.44, p = 0.05), but not after 20 and 30 min. No other correlations were found between the VAS-I and other clinical (sub-)scores (VAS, PUTS, and MRVS). Nine patients (42.86%) fulfilled diagnostic criteria for ADHD (mean age = 33.78 years, 8 male, 1 female). There were no significant group differences between patients with and without ADHD regarding demographic (sex, age) and clinical (MRVS, PUTS, YGTSS, VAS, and inhibition potency) data. However, in patients with comorbid ADHD we found a trend towards a lesser inhibitory potency for total (p = 0.089) and vocal tics (p = 0.055), but not for motor tics. Furthermore, there were no correlations between ADHD and PUTS, YGTSS, VAS, and inhibition potency (neither for TTS (r = − 0.36, p = 0.17), nor for the subscores MT (r = − 0.25, p = 0.36) or VT (r = − 0.55, p = 0.3) of the inhibition potency).
Discussion In contrast to our hypothesis – but in line with recent small studies in children and adults [5–11] – we found no paradoxical tic increase after successful tic suppression (neither immediately nor in the later course) using an objective video tic rating. Since in this study only adult patients were included, it is unlikely that recent studies failed to detect a tic rebound only because of the inclusion of children, although children often report that they are unable to suppress their tics [2]. In contrast to patients' reports in clinical interviews, in this study the patients themselves reported no tic rebound. This discrepancy might be due to influences related to the artificial situation of a study (although the patients were unaware of the real aim of the study) or unusual and high concentration on tic rating. As demonstrated earlier [5–11], voluntary tic suppression resulted in a significant tic reduction (MRVS). Tic suppressibility was independent of tic severity, premonitory urge and comorbid ADHD. There was no correlation between tic severity and premonitory urges. Patients as well experienced a substantial tic reduction during suppression, but no paradoxical tic increase (VAS, VAS-I). However, when using an absolute tic self-rating (VAS), they erroneously believed that their tics were significantly reduced at 20 and 30 min after tic suppression. In contrast, when assessing relative tic changes (VAS-I), patients felt no change in tic severity compared to both baseline and 10, 20, and 30 min after tic suppression. Accordingly, we found a positive correlation between the VAS and VAS-I during and 10 min after tic suppression, but not at 20 and 30 min after tic suppression. Thus, patients' self-rating depends not only on the absolute severity of tics, but is highly influenced by the relative tic severity depending on the fluctuations of tics. These findings are completely in accordance with results obtained from a longitudinal study [18]. While all adult patients who still reported tics indeed showed tics on an objective video documentation, only half of the patients who considered themselves tic-free where correct and showed indeed no tics on the videotape. Interestingly, our findings confirm not only the general result by Pappert et al. [18] that subjective patient ratings differ from objective video rating, but also that patients report less tics than really existing. Although it is well-known that
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patient reports of tic frequency and severity may be not objective, so far, no conclusive explanation has been given for this phenomenon [5–11,18]. We hypothesize that patients' inaccuracy in tic rating including their misbelieve of a paradoxical tic increase after voluntary tic suppression can be most likely explained by the fact that patients' judgement is highly influenced by relative tic severity and depends not only on absolute severity of tics. Further studies are needed to disentangle this phenomenon. In clinical interviews the vast majority of patients states that voluntary tic suppression causes an increased premonitory urge that finally becomes unbearable [3]. In contrast, in this study, patients assessed that premonitory urges did not change during or at any time after tic suppression. Furthermore, our data corroborate recent results by Ganos et al. [11], demonstrating that the potency of tic inhibition is not influenced by tic severity or premonitory urge suggesting that premonitory urges are not a prerequisite of successful tic inhibition [11]. Of interest, there was even no correlation between tic self-rating (VAS) and the premonitory urge before, during and after tic suppression, except 30 min after suppression. Our results, therefore, further support the view that tics and premonitory urges constitute two parallel manifestations of the same disorder [11]. In accordance with recent studies in both children (n = 40) [19] and adults (n = 15) [11], but in contrast to other studies [14,20], we found no correlation between premonitory urges (according to PUTS) and tic severity (according to YGTSS). Although it is generally accepted that premonitory urges are “sensory phenomena preceding the tics”, it could be demonstrated that there is also a correlation between premonitory urges and obsessive compulsive symptoms [14,19,21]. It has been speculated that measurements for OCD unintentionally detect premonitory urges or that instruments for both OCD and premonitory urges detect shared underlying phenomena [19]. However, it has also been suggested that sensory phenomena include bodily and mental sensations and that the occurrence of different sensations depends on the diagnosis (OCD, TS or TS plus OCD) [22]. This assumption is reflected by the fact that until today there is no general accepted precise definition for “premonitory urges” and several different terms have been used such as sensory phenomena, sensory tics, just-right perceptions, feelings of incompleteness or discomfort, increased energy, pressure, and tension [19,21]. In contrast to results by Himle et al. [10] we found no correlation between attention problems and the inhibition potency suggesting that tic suppression is negatively influenced by ADHD. In addition, there was no correlation between ADHD and PUTS, YGTSS, and VAS. However, we found a weak trend towards a lesser inhibitory potency in patients with comorbid ADHD. The following limitations of the study have to be addressed: (1) Although this is the largest study in adults with TS investigating changes in tic severity during and after voluntary tic suppression, the sample size was relatively small. (2) Albeit this seems rather unlikely, we cannot entirely rule out that a longer period of tic suppression would result in a paradoxical tic increase. One might also speculate that “naturalistic” tic suppression in the context of “real social situations” might result in different results. (3) We used an established video protocol to rate tic severity before, during and (at different time points) after tic suppression. According to this protocol a 1-minute segment from “the middle of the taping” shall be used for tic rating [13,23, 24]. For reason of standardization, we always selected a 1-minute segment starting 0.5 min after recording started. This procedure guaranteed that influences on tics caused by the adjustment of the video camera can be excluded and the examiner had definitely left the room. When rating tic severity “immediately after suppression” we decided to start the recording with the 2.5-minute “near” segment with the patient alone in the room. In addition, a 0.5-minute segment (multiplied by 2) was used for tic rating (instead of a 1-minute segment). These changes (MRVS) were made in order not to miss a short period of tic rebound immediately after tic suppression that would not
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have be detected when using the original MRVS protocol. In our opinion, this was the best possible approach to guarantee both standardization of recording and tic rating “immediately” after suppression. (4) The sample size of patients with comorbid ADHD was small and, therefore, our findings related to ADHD should be interpreted with caution. (5) For subjective patient rating of tics, we used a single-item VAS. VASs are well-established for the measurement of physical and psychological well-being and are fairly responsive to clinical changes [25]. We decided to use this very simple measurement for self-rating of tics, because in this study patients were ask to rate tic severity (and changes) several times during a short period of time and, therefore, it was inevitable to use a test that not only can be completed with the minimum of time, but also is responsive to changes. (6) We applied no correction for multiple testing. In summary, our results demonstrate that in adult patients, voluntary tic suppression results in a significant tic reduction, but not in a paradoxical tic increase. Our data provide substantial evidence that patients' often reported misbelief of a tic rebound is caused by an overall insufficiency in reliable tic rating. Self-rating of tics seems to be highly influenced by changes of tic severity over time. Since we found no correlation between tic severity, premonitory urges and tic inhibition, respectively, our results further corroborate the hypothesis that premonitory urges are not a prerequisite of successful tic inhibition. Competing interests The authors have no competing interests to report. Funding We received no financial and material support for this study. Acknowledgments We thank all patients for participating in this study. References [1] Leckman JF, Walker DE, Cohen DJ. Premonitory urges in Tourette's syndrome. Am J Psychiatry 1993;150:98–102. [2] Banaschewski T, Woerner W, Rothenberger A. Premonitory sensory phenomena and suppressibility of tics in Tourette syndrome: developmental aspects in children and adolescents. Dev Med Child Neurol 2003;45:700–3. [3] Müller-Vahl K. Klinische Kennzeichen von Tics. Tourette-Syndrom und andere Tic-Erkrankungen im Kindes- und Erwachsenenalter1. Auflage. . Berlin: Medizinisch Wissenschaftliche Verlagsgesellschaft; 2010 33–58.
[4] Marcks BA, Woods DW, Teng EJ, Twohig MP. What do those who know, know? Investigating providers' knowledge about Tourette's syndrome and its treatment. Cogn Behav Pract 2004;11:298–305. [5] Meidinger AL, Miltenberger RG, Himle M, Omvig M, Trainor C, Crosby R. An investigation of tic suppression and the rebound effect in Tourette's disorder. Behav Modif 2005;29:716–45. [6] Woods DW, Himle MB, Miltenberger RG, Carr JE, Osmon DC, Karsten AM, et al. Durability, negative impact, and neuropsychological predictors of tic suppression in children with chronic tic disorder. J Abnorm Child Psychol 2008;36:237–45. [7] Capriotti MR, Brandt BC, Ricketts EJ, Espil FM, Woods DW. Comparing the effects of differential reinforcement of other behavior and response-cost contingencies on tics in youth with Tourette syndrome. J Appl Behav Anal 2012;45:251–63. [8] Woods DW, Himle MB. Creating tic suppression: comparing the effects of verbal instruction to differential reinforcement. J Appl Behav Anal 2004;37:417–20. [9] Verdellen CWJ, Hoogduin CAL, Keijsers GPJ. Tic suppression in the treatment of Tourette's syndrome with exposure therapy: the rebound phenomenon reconsidered. Mov Disord 2007;22:1601–6. [10] Himle MB, Woods DW. An experimental evaluation of tic suppression and the tic rebound effect. Behav Res Ther 2005;43:1443–51. [11] Ganos C, Kahl U, Schunke O, Kühn S, Haggard P, Gerloff C, et al. Are premonitory urges a prerequisite of tic inhibition in Gilles de la Tourette syndrome? J Neurol Neurosurg Psychiatry 2012;83:975–8. [12] Leckman JF, Riddle MA, Hardin MT, Ort SI, Swartz KL, Stevenson J, et al. The Yale Global Tic Severity Scale: initial testing of a clinician-rated scale of tic severity. J Am Acad Child Adolesc Psychiatry 1989;28:566–73. [13] Goetz CG, Pappert EJ, Louis ED, Raman R, Leurgans S. Advantages of a modified scoring method for the Rush Video-Based Tic Rating Scale. Mov Disord 1999;14:502–6. [14] Woods DW, Piacentini J, Himle MB, Chang S. Premonitory Urge for Tics Scale (PUTS): initial psychometric results and examination of the premonitory urge phenomenon in youths with Tic disorders. J Dev Behav Pediatr 2005;26:397–403. [15] APA — American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders — DSM-IV-TR. 4th ed. Washington, DC: American Psychiatric Association; 2000 [Text Revision]. [16] Conners C, Erhardt D, Sparrow E. Conners' Adult ADHD Rating Scales. North Tonawanda, NY: Multi-Health Systems; 1999. [17] Retz-Junginger P, Retz W, Blocher D, Weijers HG, Trott GE, Wender PH, et al. Wender Utah rating scale. The short-version for the assessment of the attention-deficit hyperactivity disorder in adults. Nervenarzt 2002;73:830–8. [18] Pappert EJ, Goetz CG, Louis ED, Blasucci L, Leurgans S. Objective assessments of longitudinal outcome in Gilles de la Tourette's syndrome. Neurology 2003;61:936–40. [19] Steinberg T, Shmuel Baruch S, Harush A, Dar R, Woods D, Piacentini J, et al. Tic disorders and the premonitory urge. J Neural Transm 2010;117:277–84. [20] Crossley E, Seri S, Stern JS, Robertson MM, Cavanna AE. Premonitory urges for tics in adult patients with Tourette syndrome. Brain Dev 2014;36:45–50. [21] Crossley E, Cavanna AE. Sensory phenomena: clinical correlates and impact on quality of life in adult patients with Tourette syndrome. Psychiatry Res 2013;209:705–10. [22] Miguel EC, do Rosário-Campos MC, Prado HS, do Valle R, Rauch SL, Coffey BJ, et al. Sensory phenomena in obsessive–compulsive disorder and Tourette's disorder. J Clin Psychiatry 2000;61:150–6 [quiz 157]. [23] Goetz CG, Stebbins GT, Thelen JA. Talipexole and adult Gilles de la Tourette's syndrome: double-blind, placebo-controlled clinical trial. Mov Disord 1994;9:315–7. [24] Goetz CG, Tanner CM, Wilson RS, Shannon KM. A rating scale for Gilles de la Tourette's syndrome: description, reliability, and validity data. Neurology 1987;37:1542–4. [25] De Boer AGEM, van Lanschot JJB, Stalmeier PFM, van Sandick JW, Hulscher JBF, de Haes JCJM, et al. Is a single-item visual analogue scale as valid, reliable and responsive as multi-item scales in measuring quality of life? Qual Life Res 2004;13:311–20.
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Journal of Psychosomatic Research
Tourette patients' misbelief of a tic rebound is due to overall difficulties in reliable tic rating Kirsten R Müller-Vahl ⁎, Laura Riemann, Stefanie Bokemeyer Clinic of Psychiatry, Socialpsychiatry and Psychotherapy, Hannover Medical School, Germany
a r t i c l e
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Article history: Received 29 October 2013 Received in revised form 13 March 2014 Accepted 17 March 2014 Keywords: Tourette syndrome Tics Suppression Rebound Premonitory urge ADHD
a b s t r a c t Objective: While in clinical interviews the vast majority of patients with Tourette syndrome (TS) report about a tic rebound after voluntary tic suppression, in recent studies in children no paradoxical tic increase could be found. We hypothesized that in adult patients there is a tic rebound after tic suppression. Methods: We investigated the tic severity, premonitory urges and influence of attention deficit hyperactivity disorder (ADHD) before, during and after tic suppression in 22 adult patients with TS using both an objective video tic rating and subjective patient ratings for tics and premonitory urges. Results: According to the video rating, tic suppression resulted in a significant tic reduction, but no rebound. Patients also reported no tic rebound. They erroneously believed in an absolute tic reduction 20 and 30 min after suppression, but paradoxically felt no relative tic change. Premonitory urges remained unchanged. There was no correlation between premonitory urges and tic severity. The potency for tic inhibition did not correlate with premonitory urges and tic severity. ADHD did not influence tic inhibition. Conclusion: In adults with TS, there is no tic rebound after voluntary tic suppression. Patients also reported no rebound, but erroneously felt a tic reduction in the later course of the study. This misjudgement as well as patients' often reported (mis-)belief of a tic rebound may be caused by overall difficulties in reliable tic rating. Premonitory urges remained unchanged during tic suppression. Tic suppression was not influenced by attention deficits. Premonitory urges are no prerequisite of tic suppression. © 2014 Elsevier Inc. All rights reserved.
Introduction Tourette-syndrome (TS) is a neuropsychiatric disease defined by motor and vocal tics. Tics are often preceded by a premonitory urge and are temporarily suppressible. However, younger children (under the age of 10 years) often report that they do not feel an urge and are unable to suppress their tics [1,2]. Some (adult) patients feel that the premonitory urge is even more troublesome than the tics. Most patients report that they try to avoid tic suppression when possible, because they feel that voluntary tic suppression is exhausting, requires concentration, causes an increasing inner urge, and finally results in a temporarily overshooting tic increase [3]. In addition, patients often report that the premonitory urge not only increases during tic suppression, but also becomes unbearable and can only be abolished by the performance of a tic. Accordingly, most patients report that voluntary tic suppression causes only a postponement, but not an abolition of their tics [3]. For many years, these reports of patients, were not brought into question and resulted in the general excepted recommendation that patients with tics ⁎ Corresponding author at: Clinic of Psychiatry, Socialpsychiatry and Psychotherapy, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany. Tel.: +49 511 5323551; fax: +49 511 5323187. E-mail address: [email protected] (K.R. Müller-Vahl).
http://dx.doi.org/10.1016/j.jpsychores.2014.03.003 0022-3999/© 2014 Elsevier Inc. All rights reserved.
should avoid voluntary tic suppression. This conviction is also expressed in the results of a survey performed in 2004 demonstrating that 77% of medical doctors and psychologists experienced in tic disorders believed that tic suppression causes a tic rebound [4]. In contrast to these reports of patients, from recent studies it is suggested that – at least in children – voluntary tic suppression is not followed by a paradoxical tic increase [5–11]. These studies provided evidence that (1) tic suppression can be enhanced by reinforcement [7,8], (2) tics can be suppressed not only for a short period of time, but also for a time period of up to 40 min [6], (3) tic suppression results in a tic reduction of 70% [6,10], and (4) patients with attention problems are less able to suppress their tics [10]. This study was motivated by the following considerations: (1) we are running a large TS outpatient clinic and during the last years several hundred patients reported about a tic rebound and, therefore, we hardly could believe that there should be no tic rebound; (2) in none of the above mentioned studies a plausible explanation has been given, why patients should erroneously believe in a (non-existing) tic rebound; (3) all these studies have been performed in children, although (younger) children often report that they are unable to suppress their tics. On the one hand, one might speculate that in children there is no tic rebound because children are not able to suppress their tics sufficiently to cause a rebound. On the other hand, it can be hypothesized that there
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are differences between children and adults. Adults with persisting tics represent a specific subgroup of patients with unique characteristics and, therefore, results obtained in children can possibly not be generalized to adults; (4) most of the available studies have been performed in the context of clinical trials investigating the efficacy of behavioral therapy (such as habit reversal training) in patients with chronic tic disorders. This might have caused a methodological bias, since researchers understandably wished to find no tic rebound after suppression; and (5) it can be speculated that in some of the studies no tic rebound could be detected due to the small number of patients included, inappropriate assessment, and inadequate timing for tic rating. The aims of this study were to investigate for the first time in a larger group of adult patients with TS, whether voluntary tic suppression is followed by a tic rebound (either immediately or after a longer time period after tic suppression), causes an increased premonitory urge, and is influenced by comorbid attention deficit hyperactivity disorder (ADHD) using a sophisticated video protocol to measure tics at different time points. We hypothesized that in adult patients (1) voluntary tic suppression causes a tic reduction, (2) voluntary tic suppression results in a paradoxical tic rebound, and (3) premonitory urges increase during voluntary tic suppression. Methods Between 6/2010 and 1/2012, we investigated tic severity and premonitory urges before, during and after tic suppression in 22 adult patients (17 male, 5 female, mean age = 35.1 ± 10.7 years) with TS according to DSM-IV-TR. Patients were recruited from the TS outpatient Clinic of Psychiatry, Social psychiatry and Psychotherapy at the Hannover Medical School. Inclusion criteria were age 18–50 years, Yale Global Tic Severity Scale (YGTSS) total tic score (TTS) [12] ≥7, and self-reported ability for tic suppression. Exclusion criteria were the presence of significant comorbid medical conditions, other severe psychiatric disorders, age b 18 or N 50 years and YGTSS-TTS b7. Common comorbidities such as ADHD and obsessive-compulsive disorder (OCD) were no exclusion criteria. The study was approved by the local ethics committee. Subjects provided written informed consent before entering the study. To minimize bias, patients were not informed about the real aim of the study. Instead they were told that the study aims to investigate the degree of tic reduction during voluntary suppression. This instruction, in addition, should enhance the extent of tic suppression. The study consisted of three parts lasting about 60 min altogether: Part (I): Baseline before tic suppression. At baseline, the following measurements were performed: examiner tic rating according to the YGTSS, video rating according to the modified Rush Video-Based Tic Rating Scale (MRVS) [13] (for details see below), self-rating of tics according to a Visual Analogue Scale (VAS) (0–100, 0 = no tics, 100 = maximal tics), self-rating of premonitory urges according to the German version of the Premonitory Urge for Tics Scale (PUTS) [14], and assessments for ADHD including the DSM-IV symptom list [15], Conners Adult ADHD Rating Scale (CAARS) [16] and Wender-Utah-Rating-Scale (WURS-K) [17]. Part (II): Tic suppression. In the second study part, patients were asked to suppress their tics as much as possible for a time period of 10 min. As a reward for “optimal” tic suppression, a little present (chocolate) was promised. Just before the end of this tic suppression period, patients were asked to complete the VAS, PUTS and a VAS of Improvement (VAS-I) detecting relative changes in tic severity (−100%–+100%, 0% = no change) during “suppression” compared to “baseline”. In addition, tics were measured using the MRVS (for details see below).
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Part (III): Post suppression. After tic suppression had been stopped, tics were rated at four different times (immediately and after 10, 20 and 30 min) using the MRVS (for details see below). In addition, the VAS, PUTS, and VAS-I were used at three different time points (after 10, 20 and 30 min) to measure tics (self-rating) and premonitory urges. Protocol for MRVS The MRVS is regarded as the most objective examiner tic rating. The 10-minute film protocol includes full frontal body (far) and head and shoulders only (near) views with and without an examiner in the room lasting 2.5 min each. We standardized the protocol by using always the same order: a) near with examiner, b) near without examiner, c) far without examiner, and d) far with examiner. For tic rating, only two (far and near body view) 1-minute recordings with no examiner present are scored rating 5 domains: number of body areas involved, motor tic (MT) and vocal tic (VT) frequency and severity. We standardized the tic rating by selecting this 1-minute segment for tic rating from each 2.5-minute recording starting 0.5 min after the recording started (minute 0.5–1.5). Thus, during a study period of 30 min, the 10minute MRVS protocol can be performed a maximum of three times. For the sake of simplicity, we used the wording “tic rating was performed after 10, 20, and 30 min”. But strictly speaking, tic ratings according to the MRVS (as described above) were performed (1) from minute 3.0 to 4.0 (near without examiner) and 5.5 to 6.5 (far without examiner), (2) minute 13.0–14.0 and 15.5–16.5, and (3) minute 23.0– 24.0 and 25.5–26.5. In order, to measure tics in addition “immediately” after the end of the tic suppression period, we slightly modified the MRVS protocol: (1) tic rating was started directly after suppression was stopped (the examiner adjusted the video camera and instructed the patient to stop tic suppression exactly when she left the room), (2) tics were counted only once using the segment “near without examiner” (instead of using two segments far and near as described in the MRVS protocol), and (3) tics were counted only for 30 s (instead of 60 s as described in the MRVS protocol) and multiplied by 2 for further statistical analyses. All patients were informed about the video rating. First video documentation (baseline before tic suppression) was started 10 min before the first tic rating was done to ensure that the patients get used to the situation. Tic rating was performed by two of the authors (KMV, SB) who are experienced in tic rating and were blinded and not involved in the video recording. To avoid inter-rater bias, tic rating was done in a joint meeting and KMV rated MT and SB VT. If necessary, videos were watched several times and ratings were discussed. Inhibition potency As suggested recently by Ganos et al. [11] we calculated the inhibition potency (for both the TTS and the subscores MT and VT) as a measurement for tic inhibition. The inhibition potency was calculated as follows: (MRVS at baseline − MRVS during suppression) / MRVS at baseline. Statistics For statistical analyses, the generalized linear model (GLM) procedure of the IBM program package SPSS (version 21) was used. To test the primary hypothesis of a tic rebound, we analyzed the differences between group means for the different measurement occasions using analyses of variance (ANOVA). In case of a significant main effect, post-hoc tests were performed to compare the measurement occasions. Pearson coefficients were used to explore the correlation between different clinical (sub-)scores including MRVS, PUTS, VAS, VAS-I, and YGTSS. We explored the influence of comorbid ADHD on tics,
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Table 1 Tic severity, premonitory urges, and tic inhibition potency before, during and after tic suppression Tic severity
Inhibition potency
YGTSS
Baseline
Suppression
After suppression
30 s
10 min
20 min
30 min
Mean SD Range Mean SD Range P Mean SD Range P Mean SD Range P Mean SD Range P Mean SD Range P
MRVS
VAS
GS
TTS
MT
VT
TTS
MT
VT
55.29 22.94 10–94 – – – – – – – – – – – – – – – – – – – –
28.62 10.07 10–44 – – – – – – – – – – – – – – – – – – – –
15.62 4.91 7–24 – – – – – – – – – – – – – – – – – – – –
13.00 6.70 0–22 – – – – – – – – – – – – – – – – – – – –
9.31 4.78 0.00–14.00 5.18 4.63 0.00–15.00 0.001 9.21 4.85 0–16 0.92 9.24 4.41 1.5–16 0.90 9.02 5.02 0–16.5 0.22 8.90 4.87 0–16 0.27
2.19 1.09 0.00–3.33 1.39 1.05 0.00–3.83 b0.001 2.05 0.94 0–3 0.58 2.11 0.85 0.5–3.17 0.57 1.99 1.00 0–3.17 0.12 1.96 1.00 0–3.33 0.11
1.37 1.05 0.00–3.25 0.51 1.01 0.00–3.50 b0.001 1.53 1.24 0–3.5 0.54 1.45 1.30 0–3.5 0.65 1.33 1.22 0–3.5 0.81 1.42 1.28 0–4 0.71
49.67 22.27 5–90 17.62 12.31 0–45 b0.001 – – – – 50.90 24.24 5–100 0.76 41.88 21.61 10–85 b0.05 39.4 23.64 5–85 b0.05
VAS-I [%]
−62.00 30.67 −100.00–20.00 b0.001 – – – – 8.50 32.69 −45.00–80.00 0.40 −3.90 29.20 −60.00–40.00 0.33 −3.10 26.00 −50.00–50.00 0.37
TTS
0.48 0.08 −0.11–1.00
MT
1.84 0.21 −0.5–3.03
Premonitory urge VT
1.41 1.41 0.5–3.1
PUTS
27.81 5.06 14–35 28.74 4,71 20–38 n.s. – – – – 28.29 5.47 19–36 n.s. 27.52 6.56 14–38 n.s. 28.07 6.02 18–38 n.s.
YGTSS = Yale Global Tic Severity Scale, MRVS = Modified Rush Video Score, VAS = Visual Analogue Scale (0–100, 0 = no tics, 100 = maximal tics), VAS-I = Visual Analogue Scale of Improvement (−100%–+100%, 0% = no change), GS = global score, TTS = total tic score, MT = motor tic score, VT = vocal tic score, inhibition potency (calculated for TTS, MT, and VT) = (MRVS at baseline − MRVS during suppression) / MRVS at baseline, PUTS = Premonitory Urge for Tics Scale, SD = standard deviation, p = values compared to respective score at baseline.
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Time of measurement
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premonitory urges, and tic suppression (YGTSS, VAS, PUTS, and inhibition potency) using Pearson correlations and analysis of variance. A p value b0.05 was considered significant. No correction for multiple testing was applied. Results Voluntary tic suppression resulted in a significant tic reduction (according to MRVS). There was no paradoxical tic increase after tic suppression: at no time of measurement after tic suppression (immediately, 10, 20, and 30 min), tic severity (TTS, MT, and VT according to MRVS) differed significantly from baseline (Table 1). Patients felt a tic decrease during suppression and an increase to baseline 10 min after suppression, but no rebound (according to VAS). They erroneously believed a tic reduction 20 and 30 min after suppression (VAS), but paradoxically felt no relative tic change at that time (VAS-I). PUTS remained unchanged during and after suppression (Table 1). There was no correlation between MRVS-TTS and YGTSS (for none of the scores), respectively, and PUTS. We found a positive correlation between YGTSS-TTS and VAS at baseline (r = 0.612, p = 0.007) and between PUTS and VAS-S 30 min after suppression (r = 0.497, p = 0.022). At no time of measurement there was a correlation between the inhibitory potency (for none of the scores) and PUTS, YGTSS, and VAS scores (Table 1). There was a positive correlation between the VAS-I and the VAS during (r = 0.496, p = 0.26) and 10 min after tic suppression (r = 0.44, p = 0.05), but not after 20 and 30 min. No other correlations were found between the VAS-I and other clinical (sub-)scores (VAS, PUTS, and MRVS). Nine patients (42.86%) fulfilled diagnostic criteria for ADHD (mean age = 33.78 years, 8 male, 1 female). There were no significant group differences between patients with and without ADHD regarding demographic (sex, age) and clinical (MRVS, PUTS, YGTSS, VAS, and inhibition potency) data. However, in patients with comorbid ADHD we found a trend towards a lesser inhibitory potency for total (p = 0.089) and vocal tics (p = 0.055), but not for motor tics. Furthermore, there were no correlations between ADHD and PUTS, YGTSS, VAS, and inhibition potency (neither for TTS (r = − 0.36, p = 0.17), nor for the subscores MT (r = − 0.25, p = 0.36) or VT (r = − 0.55, p = 0.3) of the inhibition potency).
Discussion In contrast to our hypothesis – but in line with recent small studies in children and adults [5–11] – we found no paradoxical tic increase after successful tic suppression (neither immediately nor in the later course) using an objective video tic rating. Since in this study only adult patients were included, it is unlikely that recent studies failed to detect a tic rebound only because of the inclusion of children, although children often report that they are unable to suppress their tics [2]. In contrast to patients' reports in clinical interviews, in this study the patients themselves reported no tic rebound. This discrepancy might be due to influences related to the artificial situation of a study (although the patients were unaware of the real aim of the study) or unusual and high concentration on tic rating. As demonstrated earlier [5–11], voluntary tic suppression resulted in a significant tic reduction (MRVS). Tic suppressibility was independent of tic severity, premonitory urge and comorbid ADHD. There was no correlation between tic severity and premonitory urges. Patients as well experienced a substantial tic reduction during suppression, but no paradoxical tic increase (VAS, VAS-I). However, when using an absolute tic self-rating (VAS), they erroneously believed that their tics were significantly reduced at 20 and 30 min after tic suppression. In contrast, when assessing relative tic changes (VAS-I), patients felt no change in tic severity compared to both baseline and 10, 20, and 30 min after tic suppression. Accordingly, we found a positive correlation between the VAS and VAS-I during and 10 min after tic suppression, but not at 20 and 30 min after tic suppression. Thus, patients' self-rating depends not only on the absolute severity of tics, but is highly influenced by the relative tic severity depending on the fluctuations of tics. These findings are completely in accordance with results obtained from a longitudinal study [18]. While all adult patients who still reported tics indeed showed tics on an objective video documentation, only half of the patients who considered themselves tic-free where correct and showed indeed no tics on the videotape. Interestingly, our findings confirm not only the general result by Pappert et al. [18] that subjective patient ratings differ from objective video rating, but also that patients report less tics than really existing. Although it is well-known that
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patient reports of tic frequency and severity may be not objective, so far, no conclusive explanation has been given for this phenomenon [5–11,18]. We hypothesize that patients' inaccuracy in tic rating including their misbelieve of a paradoxical tic increase after voluntary tic suppression can be most likely explained by the fact that patients' judgement is highly influenced by relative tic severity and depends not only on absolute severity of tics. Further studies are needed to disentangle this phenomenon. In clinical interviews the vast majority of patients states that voluntary tic suppression causes an increased premonitory urge that finally becomes unbearable [3]. In contrast, in this study, patients assessed that premonitory urges did not change during or at any time after tic suppression. Furthermore, our data corroborate recent results by Ganos et al. [11], demonstrating that the potency of tic inhibition is not influenced by tic severity or premonitory urge suggesting that premonitory urges are not a prerequisite of successful tic inhibition [11]. Of interest, there was even no correlation between tic self-rating (VAS) and the premonitory urge before, during and after tic suppression, except 30 min after suppression. Our results, therefore, further support the view that tics and premonitory urges constitute two parallel manifestations of the same disorder [11]. In accordance with recent studies in both children (n = 40) [19] and adults (n = 15) [11], but in contrast to other studies [14,20], we found no correlation between premonitory urges (according to PUTS) and tic severity (according to YGTSS). Although it is generally accepted that premonitory urges are “sensory phenomena preceding the tics”, it could be demonstrated that there is also a correlation between premonitory urges and obsessive compulsive symptoms [14,19,21]. It has been speculated that measurements for OCD unintentionally detect premonitory urges or that instruments for both OCD and premonitory urges detect shared underlying phenomena [19]. However, it has also been suggested that sensory phenomena include bodily and mental sensations and that the occurrence of different sensations depends on the diagnosis (OCD, TS or TS plus OCD) [22]. This assumption is reflected by the fact that until today there is no general accepted precise definition for “premonitory urges” and several different terms have been used such as sensory phenomena, sensory tics, just-right perceptions, feelings of incompleteness or discomfort, increased energy, pressure, and tension [19,21]. In contrast to results by Himle et al. [10] we found no correlation between attention problems and the inhibition potency suggesting that tic suppression is negatively influenced by ADHD. In addition, there was no correlation between ADHD and PUTS, YGTSS, and VAS. However, we found a weak trend towards a lesser inhibitory potency in patients with comorbid ADHD. The following limitations of the study have to be addressed: (1) Although this is the largest study in adults with TS investigating changes in tic severity during and after voluntary tic suppression, the sample size was relatively small. (2) Albeit this seems rather unlikely, we cannot entirely rule out that a longer period of tic suppression would result in a paradoxical tic increase. One might also speculate that “naturalistic” tic suppression in the context of “real social situations” might result in different results. (3) We used an established video protocol to rate tic severity before, during and (at different time points) after tic suppression. According to this protocol a 1-minute segment from “the middle of the taping” shall be used for tic rating [13,23, 24]. For reason of standardization, we always selected a 1-minute segment starting 0.5 min after recording started. This procedure guaranteed that influences on tics caused by the adjustment of the video camera can be excluded and the examiner had definitely left the room. When rating tic severity “immediately after suppression” we decided to start the recording with the 2.5-minute “near” segment with the patient alone in the room. In addition, a 0.5-minute segment (multiplied by 2) was used for tic rating (instead of a 1-minute segment). These changes (MRVS) were made in order not to miss a short period of tic rebound immediately after tic suppression that would not
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have be detected when using the original MRVS protocol. In our opinion, this was the best possible approach to guarantee both standardization of recording and tic rating “immediately” after suppression. (4) The sample size of patients with comorbid ADHD was small and, therefore, our findings related to ADHD should be interpreted with caution. (5) For subjective patient rating of tics, we used a single-item VAS. VASs are well-established for the measurement of physical and psychological well-being and are fairly responsive to clinical changes [25]. We decided to use this very simple measurement for self-rating of tics, because in this study patients were ask to rate tic severity (and changes) several times during a short period of time and, therefore, it was inevitable to use a test that not only can be completed with the minimum of time, but also is responsive to changes. (6) We applied no correction for multiple testing. In summary, our results demonstrate that in adult patients, voluntary tic suppression results in a significant tic reduction, but not in a paradoxical tic increase. Our data provide substantial evidence that patients' often reported misbelief of a tic rebound is caused by an overall insufficiency in reliable tic rating. Self-rating of tics seems to be highly influenced by changes of tic severity over time. Since we found no correlation between tic severity, premonitory urges and tic inhibition, respectively, our results further corroborate the hypothesis that premonitory urges are not a prerequisite of successful tic inhibition. Competing interests The authors have no competing interests to report. Funding We received no financial and material support for this study. Acknowledgments We thank all patients for participating in this study. References [1] Leckman JF, Walker DE, Cohen DJ. Premonitory urges in Tourette's syndrome. Am J Psychiatry 1993;150:98–102. [2] Banaschewski T, Woerner W, Rothenberger A. Premonitory sensory phenomena and suppressibility of tics in Tourette syndrome: developmental aspects in children and adolescents. Dev Med Child Neurol 2003;45:700–3. [3] Müller-Vahl K. Klinische Kennzeichen von Tics. Tourette-Syndrom und andere Tic-Erkrankungen im Kindes- und Erwachsenenalter1. Auflage. . Berlin: Medizinisch Wissenschaftliche Verlagsgesellschaft; 2010 33–58.
[4] Marcks BA, Woods DW, Teng EJ, Twohig MP. What do those who know, know? Investigating providers' knowledge about Tourette's syndrome and its treatment. Cogn Behav Pract 2004;11:298–305. [5] Meidinger AL, Miltenberger RG, Himle M, Omvig M, Trainor C, Crosby R. An investigation of tic suppression and the rebound effect in Tourette's disorder. Behav Modif 2005;29:716–45. [6] Woods DW, Himle MB, Miltenberger RG, Carr JE, Osmon DC, Karsten AM, et al. Durability, negative impact, and neuropsychological predictors of tic suppression in children with chronic tic disorder. J Abnorm Child Psychol 2008;36:237–45. [7] Capriotti MR, Brandt BC, Ricketts EJ, Espil FM, Woods DW. Comparing the effects of differential reinforcement of other behavior and response-cost contingencies on tics in youth with Tourette syndrome. J Appl Behav Anal 2012;45:251–63. [8] Woods DW, Himle MB. Creating tic suppression: comparing the effects of verbal instruction to differential reinforcement. J Appl Behav Anal 2004;37:417–20. [9] Verdellen CWJ, Hoogduin CAL, Keijsers GPJ. Tic suppression in the treatment of Tourette's syndrome with exposure therapy: the rebound phenomenon reconsidered. Mov Disord 2007;22:1601–6. [10] Himle MB, Woods DW. An experimental evaluation of tic suppression and the tic rebound effect. Behav Res Ther 2005;43:1443–51. [11] Ganos C, Kahl U, Schunke O, Kühn S, Haggard P, Gerloff C, et al. Are premonitory urges a prerequisite of tic inhibition in Gilles de la Tourette syndrome? J Neurol Neurosurg Psychiatry 2012;83:975–8. [12] Leckman JF, Riddle MA, Hardin MT, Ort SI, Swartz KL, Stevenson J, et al. The Yale Global Tic Severity Scale: initial testing of a clinician-rated scale of tic severity. J Am Acad Child Adolesc Psychiatry 1989;28:566–73. [13] Goetz CG, Pappert EJ, Louis ED, Raman R, Leurgans S. Advantages of a modified scoring method for the Rush Video-Based Tic Rating Scale. Mov Disord 1999;14:502–6. [14] Woods DW, Piacentini J, Himle MB, Chang S. Premonitory Urge for Tics Scale (PUTS): initial psychometric results and examination of the premonitory urge phenomenon in youths with Tic disorders. J Dev Behav Pediatr 2005;26:397–403. [15] APA — American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders — DSM-IV-TR. 4th ed. Washington, DC: American Psychiatric Association; 2000 [Text Revision]. [16] Conners C, Erhardt D, Sparrow E. Conners' Adult ADHD Rating Scales. North Tonawanda, NY: Multi-Health Systems; 1999. [17] Retz-Junginger P, Retz W, Blocher D, Weijers HG, Trott GE, Wender PH, et al. Wender Utah rating scale. The short-version for the assessment of the attention-deficit hyperactivity disorder in adults. Nervenarzt 2002;73:830–8. [18] Pappert EJ, Goetz CG, Louis ED, Blasucci L, Leurgans S. Objective assessments of longitudinal outcome in Gilles de la Tourette's syndrome. Neurology 2003;61:936–40. [19] Steinberg T, Shmuel Baruch S, Harush A, Dar R, Woods D, Piacentini J, et al. Tic disorders and the premonitory urge. J Neural Transm 2010;117:277–84. [20] Crossley E, Seri S, Stern JS, Robertson MM, Cavanna AE. Premonitory urges for tics in adult patients with Tourette syndrome. Brain Dev 2014;36:45–50. [21] Crossley E, Cavanna AE. Sensory phenomena: clinical correlates and impact on quality of life in adult patients with Tourette syndrome. Psychiatry Res 2013;209:705–10. [22] Miguel EC, do Rosário-Campos MC, Prado HS, do Valle R, Rauch SL, Coffey BJ, et al. Sensory phenomena in obsessive–compulsive disorder and Tourette's disorder. J Clin Psychiatry 2000;61:150–6 [quiz 157]. [23] Goetz CG, Stebbins GT, Thelen JA. Talipexole and adult Gilles de la Tourette's syndrome: double-blind, placebo-controlled clinical trial. Mov Disord 1994;9:315–7. [24] Goetz CG, Tanner CM, Wilson RS, Shannon KM. A rating scale for Gilles de la Tourette's syndrome: description, reliability, and validity data. Neurology 1987;37:1542–4. [25] De Boer AGEM, van Lanschot JJB, Stalmeier PFM, van Sandick JW, Hulscher JBF, de Haes JCJM, et al. Is a single-item visual analogue scale as valid, reliable and responsive as multi-item scales in measuring quality of life? Qual Life Res 2004;13:311–20.
