Article

Tic symptom profiles in subjects with Tourette Syndrome from two genetically isolated populations.

Department of Psychiatry, University of California, San Diego, San Diego, California, United States
Biological Psychiatry (Impact Factor: 9.47). 03/2007; 61(3):292-300. DOI: 10.1016/j.biopsych.2006.02.009
Source: PubMed

ABSTRACT Tourette Syndrome (TS) has a complex etiology and wide variability in phenotypic expression. Identifying underlying symptom patterns may be useful for etiological and outcome studies of TS.
Lifetime tic and related symptom data were collected between 1996 and 2001 in 121 TS subjects from the Central Valley of Costa Rica and 133 TS subjects from the Ashkenazi Jewish (AS) population in the US. Subjects were grouped by tic symptoms using an agglomerative hierarchical cluster analysis. Cluster membership was tested for association with available ancillary information (age of onset, tic severity, comorbid disorders, medication treatment and family history).
Cluster analysis identified two distinct groups in each sample, those with predominantly simple tics (cluster 1), and those with multiple complex tics (cluster 2). Membership in cluster 2 was correlated with increased tic severity, global impairment, medication treatment, and presence of comorbid obsessive-compulsive symptoms in both samples, and with family history of tics, lower verbal IQ, earlier age of onset, and comorbid obsessive-compulsive disorder and attention-deficit/hyperactivity disorder in the AS sample.
This study provides evidence for consistent and reproducible symptom profiles in two independent TS study samples. These findings have implications for etiological studies of TS.

0 Followers
 · 
101 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tic disorders are heterogeneous, with symptoms varying widely both within and across patients. Exploration of symptom clusters may aid in the identification of symptom dimensions of empirical and treatment import. This article presents the results of two studies investigating tic symptom clusters using a sample of 99 youth (M age = 10.7, 81% male, 77% Caucasian) diagnosed with a primary tic disorder (Tourette's disorder or chronic tic disorder), across two university-based outpatient clinics specializing in tic and related disorders. In Study 1, a cluster analysis of the Yale Global Tic Severity Scale (YGTSS) identified four symptom dimensions: predominantly complex tics; simple head/face tics; simple body tics; and simple vocal/facial tics. In Study 2, these clusters were shown to be differentially associated with demographic and clinical characteristics. Findings lend support to prior research on tic phenomenology, help to organize treatment goals, and suggest symptom dimensions of tic disorders for further evaluation.
    Journal of Abnormal Child Psychology 04/2010; 38(6):777-88. DOI:10.1007/s10802-010-9410-5 · 3.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nucleation, growth, coalescence and separation are topological and shape changing events common to many physical problems including those aimed at modeling microstructural phase evolution. The common computational approaches to these problems rely on implicitly representing the geometric boundary of microstructural phases through level-sets and phase fields since explicit geometrical representations necessitate rediscretization in mesh or grid based solution approaches. In this paper, we develop an isogeometric explicit boundary tracking procedure that utilizes Non-Uniform Rational B-Splines (NURBS) to model both topology and shape changing events such as phase nucleation, growth, separation, and dissolution. The computational algorithms developed in the paper rely on a Constructive Solid Geometry (CSG)-inspired representation of phases that permits parametric immersion of void/inclusion phase boundaries in the underlying matrix phase. The representation also enables dynamically capturing topological and shape-changing events without modifying the underlying discretizations. The developed procedure is demonstrated through multiphysics examples that capture phase coalescence and separation caused by interactions of electrical field and surface energy under a constraint on mass conservation.
    Computer Methods in Applied Mechanics and Engineering 08/2011; 200(33):2594-2610. DOI:10.1016/j.cma.2011.04.002 · 2.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we consider the phase separation on general surfaces by solving the nonlinear Cahn–Hilliard equation using a finite element method. A fully discrete approximation scheme is introduced, and we establish a priori estimates for the discrete solution that does not rely on any knowledge of the exact solution beyond the initial time. This in turn leads to convergence and optimal error estimates of the discretization scheme. Numerical examples are also provided to substantiate the theoretical results.
    Computer Methods in Applied Mechanics and Engineering 07/2011; 200:2458-2470. DOI:10.1016/j.cma.2011.04.018 · 2.63 Impact Factor