Tic Behavior Research Articles

Habit Reversal Training for Tic Disorders in Children and Adolescents

Chronic tic disorders, including Tourette's syndrome (TS), affect approximately .5% of children and adolescents. Although strong evidence exists supporting a neurobiological etiology, operant factors may play a role in the maintenance of tic behaviors. Pharmacological approaches remain the most commonly used intervention for chronic tic disorder in children and adults. Nevertheless, the unpredictable efficacy and serious side effects associated with medication along with parental concerns about long-term medication use in children underlie the need for nonpharmacological interventions for tics in this age group. This article reviews the rationale and evidence base for the use of habit reversal training (HRT), a multicomponent behavioral treatment package, as a treatment for childhood tics. Each of the primary treatment components of HRT is described and implementation is illustrated in case report format. A growing body of data suggests that HRT is a well-tolerated and efficacious intervention for tic disorders in this age group.

Crystallization Behavior of Co-Sputtered Amorphous Ti-C and Co-C Thin Films

Crystallization Behavior of Co-Sputtered Amorphous Ti-C and Co-C Thin Films

Clinical Significance of Tics and Attention-Deficit Hyperactivity Disorder (ADHD) in Children With Pervasive Developmental Disorder

The goal of this study was to examine the clinical significance of co-occurring tics and attention-deficit hyperactivity disorder (ADHD) as indicators of a more complex symptomatology in children with and without pervasive developmental disorder. Parents and teachers completed a Diagnostic and Statistical Manual of Mental Disorders-IV-referenced rating scale for 3- to 5- (n = 182/135) and 6- to 12- (n = 301/191) year-old children with pervasive developmental disorder and clinic controls, respectively. The percentage of children with tic behaviors varied with age: preschoolers (25%, 44%) versus elementary schoolchildren (60%, 66%) (parent and teacher ratings, respectively). For many psychiatric symptoms, screening prevalence rates were highest for the ADHD + tics group and lowest for the group with symptoms of neither, but the pattern of group differences varied by age group and informant. In general, there were few differences between the ADHD only and tics only groups. The pattern of ADHD/tic group differences was similar for both children with and without pervasive developmental disorder. We concluded that these findings support the notion that the co-occurrence of ADHD and tics is an indicator of a more complex psychiatric symptomatology in children with pervasive developmental disorder.

Clinical Significance of Tics and Attention-Deficit Hyperactivity Disorder (ADHD) in Children With Pervasive Developmental Disorder

The goal of this study was to examine the clinical significance of co-occurring tics and attention-deficit hyperactivity disorder (ADHD) as indicators of a more complex symptomatology in children with and without pervasive developmental disorder. Parents and teachers completed a Diagnostic and Statistical Manual of Mental Disorders-IV -referenced rating scale for 3- to 5- ( n = 182/135) and 6- to 12- ( n = 301/191) year-old children with pervasive developmental disorder and clinic controls, respectively. The percentage of children with tic behaviors varied with age: preschoolers (25%, 44%) versus elementary schoolchildren (60%, 66%) (parent and teacher ratings, respectively). For many psychiatric symptoms, screening prevalence rates were highest for the ADHD + tics group and lowest for the group with symptoms of neither, but the pattern of group differences varied by age group and informant. In general, there were few differences between the ADHD only and tics only groups. The pattern of ADHD/tic group differences was similar for both children with and without pervasive developmental disorder. We concluded that these findings support the notion that the co-occurrence of ADHD and tics is an indicator of a more complex psychiatric symptomatology in children with pervasive developmental disorder. ( J Child Neurol 2005;20:481-488).

Therapie der Tic-Störungen

Within the last decade therapeutic approaches to tic disorders are reflected in many new studies. The advent of novel neuroleptics and the more sophisticated behavioural therapeutic techniques may give new hope to children and adolescents with tic disorders. Hence, the progress in the field should be explored to find out the state of the art. A critical review of the empirically based literature and practical experience. Worldwide, drug treatment with clonidine and (from the group of novel antipsychotics) risperidone show the broadest empirical basis while in Europe benzamides have a good empirical clinical background. Behaviour therapy presents more and more helpful empirical data. Risperidone may become the first-line drug in treatment of tic disorders and behaviour therapy might be increasingly used within a multimodal treatment program.

Mechanical behavior of PACVD TiC–amorphous carbon composite layers

Hard composite layers consisting of TiC and amorphous carbon have been prepared by plasma-assisted chemical vapour deposition. It could be shown by high-resolution transmission electron microscopy (TEM) that nanocrystalline TiC particles are embedded in a matrix of amorphous carbon. Further TEM investigations revealed the occurrence of cracks in regular distances of approximately 400 nm. The stress state of TiC, amorphous carbon (a-C) and TiC/a-C layers was determined by the measurement of the substrate curvature in dependence on the layer thickness. High compressive stress was found for the TiC layers independent of the layer thickness, whereas a-C layers yielded only a low compressive stress. The stress difference of the two components is the reason for crack formation in the composite layers leading to a stress relaxation increasing with the layer thickness. Sliding tests with layers of compositions corresponding to the maximum hardness demonstrated a sliding and abrasive wear behavior comparable to that of PVD metal containing diamond-like carbon.

Mechanical behavior of PACVD TiC–amorphous carbon composite layers

Hard composite layers consisting of TiC and amorphous carbon have been prepared by plasma-assisted chemical vapour deposition. It could be shown by high-resolution transmission electron microscopy (TEM) that nanocrystalline TiC particles are embedded in a matrix of amorphous carbon. Further TEM investigations revealed the occurrence of cracks in regular distances of approximately 400 nm. The stress state of TiC, amorphous carbon (a-C) and TiC/a-C layers was determined by the measurement of the substrate curvature in dependence on the layer thickness. High compressive stress was found for the TiC layers independent of the layer thickness, whereas a-C layers yielded only a low compressive stress. The stress difference of the two components is the reason for crack formation in the composite layers leading to a stress relaxation increasing with the layer thickness. Sliding tests with layers of compositions corresponding to the maximum hardness demonstrated a sliding and abrasive wear behavior comparable to that of PVD metal containing diamond-like carbon.

The influence of thermal annealing on residual stresses and mechanical properties of arc-evaporated TiC xN 1−x[formula omitted] thin films

We report the stress relaxation behavior of arc-evaporated TiC x N 1− x thin films during isothermal annealing between 350 and 900°C. Films with x= 0, 0.15, and 0.45, each having an initial compressive intrinsic stress σ int = −5.4 GPa, were deposited by varying the substrate bias V s and the gas composition. Annealing above the deposition temperature leads to a steep decrease in the magnitude of σ int to a saturation stress value, which is a function of the annealing temperature. The corresponding apparent activation energies for stress relaxation are E a =2.4 , 2.9, and 3.1 eV, for x= 0, 0.15, and 0.45, respectively. TiC 0.45N 0.55 films with a lower initial stress σ int = −3 GPa, obtained using a high substrate bias, show a higher activation energy E a =4.2 eV. In all the films, stress relaxation is accompanied by a decrease in defect density indicated by the decreased width of X-ray diffraction peaks and decreased strain contrast in transmission electron micrographs. Correlation of these results with film hardness and microstructure measurements indicates that the stress relaxation is a result of point-defect annihilation taking place both during short-lived metal-ion surface collision cascades during deposition, and during post-deposition annealing by thermally activated processes. The difference in E a for the films of the same composition deposited at different V s suggests the existence of different types of point-defect configurations and recombination mechanisms.

Tic Disorders, Trichotillomania, and Other Repetitive Behavior Disorders: Behavioral Approaches to Analysis and Treatment

Tic Disorders, Trichotillomania, and Other Repetitive Behavior Disorders: Behavioral Approaches to Analysis and Treatment

A cognitive-behavioral/psychophysiological model of tic disorders.

This article discusses current cognitive behavioral, as well as neurophysiological, accounts of the development and maintenance of tic behavior in chronic (simple or complex) tic disorders. A cognitive psychophysiological model is further elaborated, highlighting the reciprocal interplay of background cognitive and physiological factors preceding tic onset. According to the model, cognitive factors such as perfectionist concerns and heightened sensory awareness and self-attention, as well as physiological factors such as a high level of motor activation and accompanying elevated muscle tension, play a role in tic habits. Negative appraisals of tics and counter-productive coping strategies developed by clients as a means to suppress or to disguise the tic behavior may also locally reinforce tic onset. Neurochemical factors are viewed largely as concomitants of behavioral adaptations or compensations to the tic problem rather than as independent markers or precursors of tic onset. Clinically, the model emphasizes the role of cognitive-behavioral factors in tic onset, and suggests that tic management is best accomplished through cognitive behavioral interventions designed to prevent build up of both tension and pre-monitory urge in tic-affected muscles, rather than reverse the tic at the onset of the premonitory urge. The clinical validity of parts of the model is supported by recent experimental, psychometric and clinical studies. Other parts of the model remain speculative but at least yield testable predictions. A strength of the model is its ability to account for findings over diverse psychological and biological domains.

Tics, ADHD and Psychiatric Comorbidity

The prevalence of teacher-rated tic behaviors in 3006 school children, from preschool to adolescence, was determined in a study of comorbid psychiatric symptoms at State University of New York, Stony Brook, NY.

Tics and psychiatric comorbidity in children and adolescents

This study examined comorbid psychiatric symptoms in a large, community-based sample of children and adolescents. The study sample comprised a total of 3006 school children: 413 preschool (3 to 5 years; 237 males, 176 females; mean age 4 years 2 months, SD 8 months), 1520 elementary school (5 to 12 years; 787 males, 733 females; mean age 8 years 2 months, SD 1 year 11 months), and 1073 secondary school children (12 to 18 years; 573 males, 500 females; mean age 14 years 4 months, SD 1 year 10 months), all of whom were attending regular education programs. Children were evaluated with a teacher-completed DSM-IV-referenced rating scale. The sample was divided into four groups: attention-deficit-hyperactivity disorder with tics (ADHD+tics), ADHD without tics (ADHD), tics without ADHD (T), and a comparison group i.e. neither ADHD nor tics (Non). The percentage of children with tic behaviors varied with age: preschool children (22.3%), elementary school children (7.8%), and adolescents (3.4%). Tic behaviors were more common in males than females, regardless of comorbid ADHD symptoms. For many psychiatric symptoms, screening prevalence rates were highest for the ADHD groups (ADHD+tics>ADHD>T>Non). However, obsessive-compulsive and simple and social phobia symptoms were more common in the groups with tic behavior. Findings for a community-based sample show many similarities with studies of clinically referred samples suggesting that teacher-completed ratings of DSM-IV symptoms may be a useful methodology for investigating the phenomenology of tic disorders.

Tribological behavior and wear mechanisms of Ti-C : H/TiC/TiCN/TiN/Ti coatings when sliding against steel, bronze and aluminum alloy rods

Tix%-C : H coatings of differing thicknesses and with various titanium concentrations were deposited on tungsten carbide disks by unbalanced magnetron sputtering. The mechanical properties, microstructure, and adhesion strength of these coating were measured. The tribology properties of the coatings against AISI 1045 steel, AA7075, AA6061 aluminum alloy, and bronze rods were tested by an oscillation sliding test machine with a line-contact wear mode under dry conditions. The microhardness of Tix%-C : H coatings increased with an increasing Ti concentration. The optimum coatings are composed of an intermediate layer of TiC/TiCN/TiN/Ti and a top layer of Tix%-C : H with x ≤ 20%. These coatings have an excellent wear resistance and a low friction coefficient when paired with a carbon steel or copper alloy. These pairs are marked by the mildly wear of the counterbodies of AISI 1045 steel and bronze. The coatings are less suitable for oscillation with the aluminum alloy under dry conditions due to severe adhesion damage.

Infection: a stimulus for tic disorders

The object of this study was to investigate the potential association of infections, especially group A hemolytic streptococcal infection, with the abrupt onset/exacerbation of tics or obsessive-compulsive behaviors. A structured clinical interview was used to evaluate 80 consecutive children, 5-17 years of age, with a diagnosis of tic disorder. Forty-two patients (53%) described a sudden, explosive onset or worsening of tic symptoms; 15 of these 42 had their exacerbation historically associated with an infection, nine of the 15 specifically with a streptococcal infection. Comparisons between those nine individuals and the remainder of the study population are presented. The results of this study reveal that descriptions of an abrupt tic onset or exacerbation are not uncommon in children with tic disorders; approximately 11% of children with tic disorders described abrupt changes of tic behavior within a 6-week period after a streptococcal infection.

Effect of thickness and carbon content on tribological behaviour and mechanical properties of Ti-C:H coatings

In this study Ti x% -C:H coatings are deposited with varying thicknesses and different ratios of x% titanium target “poisoning” on tungsten carbide (WC) substrate by Unbalanced Magnetron (UBM) sputtering process and Optical Emission Monitoring (OEM) control. According to our results, the coating microstructure, mechanical properties, Raman spectra, and wear resistance vary according to different x% levels. The films are tested against different counterbodies under dry and lubricated conditions by oscillation friction and wear tester (SRV). According to those results, films with 2.5 μm thickness and x=10% poisoning level tested against AISI 1045 steel under linear contact wear mode have excellent tribological properties. All of the Ti x% -C:H coatings sliding against 6061 Al counterbody produce severe adhesion damage between the contact surface. In addition, these coatings are inappropriate for high pressure point contact wear mode under dry and lubricated conditions.

The temporal dynamics of tics in Gilles de la Tourette syndrome

Background: Statistical characterization of tic behavior in Gilles de la Tourette syndrome (GTS) may provide insight into the dynamic functioning of the human central nervous system, as well as improve the quantitative assessment of tic symptom severity. Methods: Twenty-two medication-free GTS subjects underwent videotaping of their tics. The intervals between temporally adjacent tics were measured, and the statistical properties of these intervals were assessed through graphical representation of frequency distributions, autoregressive integrated moving average (ARIMA) modeling, spectral analysis, and construction of first return maps. Results: The frequency distribution of tic interval durations followed an inverse power law of temporal scaling. Spectral analyses similarly demonstrated that the spectral power density of tic interval duration scales inversely with frequency. ARIMA modeling suggested that the time series for tics are nonstationary as well as moving average processes. The first return maps demonstrated “burstlike” behavior and short-term periodicity in tics, and proved that successive tic intervals are not statistically independent. Graphic display of the time series confirmed short-term periodicity, and in addition suggested the presence of period doubling. Conclusions: These findings are suggestive though not conclusive evidence for the presence of a fractal, deterministic, and possibly chaotic process in the tic time series. These analytic methods provide insight into the temporal features of tics that commonly are described clinically (such as short-term bouts or bursting, and longer term waxing and waning), and they reveal certain important temporal features of tics that have not been clinically described. The methods may also prove useful in the improved characterization of tic symptom severity. Biol Psychiatry 1998;44:1337–1348 © 1998 Society of Biological Psychiatry

Static and dynamic erosion behavior of TiC coated graphite in high heat flux plasma

A high heat flux helium plasma has been used to irradiate TiC-coated graphite samples with a high substrate temperature up to 1800°C. A new technique of pulse biasing on the target with in situ optical spectroscopy gives dynamic erosion characteristics. The emission intensity of TiI spectral line corresponding to sputtered particle flux was observed to decrease as the temperature increases up to 1300°C. This behavior is explained in terms of self-sustaining coverage of the TiC surface with segregated carbon. Over 1300°C, the emission intensity increases with temperature. Pulse biasing gives also remarkable time evolution of TiI line emission intensity, which is strongly temperature-dependent. It is typically characterized by two time scales. These are discussed using the analysis of mass balance equations for carbon atoms. In addition, an initial overshoot of Ti erosion observed at very high temperature is modelled by a stoichiometric change of the TiC layer.

The thermal conductivity of metallic ceramics

Transition metal carbides, nitrides, and borides can be called metallic ceramics because they are electronically conductive and extremely hard. Their various applications include cutting and grinding tools, thermal-barrier coatings, diffusion-resistant thin films, interconnects, and superconductivity devices. In each case, the ability of the material to resist or permit heat flow is important. Because of the high concentration of nonmetal atom vacancies in the carbides and nitrides, the carriers of heat—conduction electrons and phonons (the quanta of lattice waves)—are severely scattered, and the thermal conductivity, K, is strongly affected, although differently in high- and low-temperature regions. Measurements of both the electrical and thermal conductivity of single-crystal metallic ceramics at low temperatures and the application of the Callaway formalism help explain the puzzling temperature dependence of K. The finding of a large peak in K of NbC just below its superconducting transition temperature confirms phonon-electron scattering and could lead to a thermal switch. The single-crystal thermal conductivity behavior of TiC and WC is used to interpret the measured K values for cemented carbides TiC/Ni-Mo and WC/Co through a broad temperature range.

SOCIAL AND EDUCATIONAL RESOURCES FOR PATIENTS WITH TOURETTE SYNDROME

Patients with Tourette syndrome may experience significant behavioral, academic, social, and vocational difficulty. Early diagnosis and a comprehensive treatment plan which includes the school and family may prevent exacerbation of tic symptoms and behavior problems. Since the extent of impairment frequently is unrelated to the severity of any observed or reported tics, clinicians evaluating a child or adolescent who presents with tics or a history of tics should include assessment of family dynamics, a description of any school-based or peer problems, and an evaluation for motor deficits as well as determination of whether features of any associated or comorbid disorders are present. The clinician provides vital services as an educator and advocate for the patient and as a guide in directing the family and patient to available social, educational, and vocational resources.

Preferential sputtering of carbides under deuterium irradiation — a comparison between experiment and computer simulation

The erosion behaviour of SiC, TiC and WC, i.e. sputtering yields and changes of surface composition due to preferential sputtering, is investigated under deuterium bombardment at room temperature in the energy range between 20 eV and 1.5 keV. Surface concentrations are measured by means of Auger Electron Spectroscopy and are compared both with concentrations calculated by using experimental sputtering yields of pure elements and with results obtained from TRIDYN computer simulations. Thus, the contribution of different factors to compositional changes, such as physical sputtering (TRIDYN), chemical erosion (experimental yields) and radiation induced solid state reactions, can be studied. It is found that the dominant erosion mechanism for carbides is physical sputtering at ion energies above about 5 times the threshold energy. A surface layer depleted of C is formed at lower ion energies due to preferential erosion of C. In SiC, this is due to chemical erosion of C. In TiC, evidence is given that, at lower ion energies, the surface composition is governed by bombardment induced solid state reactions between Ti and C. In WC, the large mass ratio between W and C results in preferential erosion of C due to threshold effects.