Fenomenologia e história natural da síndrome de Tourette: breve resumo da pesquisa

Abstract

The phenomenology of Tourette syndrome is complex. Although overt motor and vocal tics are the defining features of Tourette syndrome, many individuals report experiencing sensory "urges," which are often difficult to describe. The natural history of this condition is also variable, with some individuals experiencing a marked reduction in tics by the end of the second decade of life while others go on to have a lifelong condition. The aim of this thesis was threefold: (1) to develop a valid and reliable clinical rating instrument; (2) to investigate the sensory phenomena associated with Tourette syndrome; and (3) to document the course of tic severity over the course of the first two decades of life. Each of these three studies involved groups of patients with Tourette syndrome or a chronic tic disorder and each of these studies has been published in a peer-reviewed journal. The Yale Global Tic Severity Scale (YGTSS) has excellent psychometric properties that have been independently replicated. It has also emerged as the most widely used clinician-rated tic severity scale in randomized clinical trials around the world. Sensory phenomena, particularly premonitory urges, are commonly reported among individuals with Tourette syndrome by the age of 10 years. There is considerable overlap with the sensory phenomena described by individuals with Obsessive-Compulsive Disorder. Tics usually have their onset in the first decade of life. They then follow a waxing and waning course and a changing repertoire of tics. As documented in the third study, for a majority of patients the period of worst tic severity usually falls between the ages of 7 and 15 years of age, after which tic severity gradually declines. This falloff in tic symptoms is consistent with available epidemiological data that indicate a much lower prevalence of Tourette syndrome among adults than children. This decline in tic severity has been confirmed in subsequent studies. In summary, incremental progress is being made in our efforts to characterize the phenomenology and natural history of Tourette syndrome. Revisions to the YGTSS should be considered. Significant advances have been made in measuring the premonitory urges associated with Tourette syndrome. The neurobiological underpinnings of the phenomenology and natural history of Tourette syndrome are currently underway in an effort to identify prognostic indicators.