Clinical Features of Tourette Syndrome and Tic Disorders

Abstract

Background: Tourette syndrome (TS) is a neurodevelopmental disorder characterized by motor and vocal tics--rapid, repetitive, stereotyped movements or vocalizations lasting at least one year in duration. The goal of this article was to review the long-term clinical course of tics and frequently co-occurring conditions in children with TS.

Methods: We conducted a traditional literature search to locate relevant articles regarding long-term outcome and prognosis in TS and tic disorders.

Results: Tics typically have an onset between the ages of 4 and 6 years and reach their worst-ever severity between the ages of 10 and 12 years. By age 10 years, most children are aware of nearly irresistible somatosensory urges that precede the tics. A momentary sense of relief typically follows the completion of a tic. Over the course of hours, tics occur in bouts, with a regular inter-tic interval. Tics increase during periods of psychosocial stress, emotional excitement and fatigue. Tics can become "complex" in nature and appear to be purposeful. Tics can be willfully suppressed for brief intervals and can be evoked by the mere mention of them. Tics typically diminish during periods of goal-directed behavior. Over the course of months, tics wax and wane. By early adulthood, roughly three-quarters of children with TS will have greatly diminished tic symptoms and more than one-third will be virtually tic free.

Conclusion: Although tics are the defining aspect of TS, they are often not the most enduring or impairing symptoms in children with TS. Indeed in TS tics rarely occur in isolation, and other coexisting conditions--such as behavioral disinhibition, hypersensitivity to a broad range of sensory stimuli, problems with visual motor integration, procedural learning difficulties, attention-deficit hyperactivity disorder, obsessive-compulsive disorder, depression, anxiety, and emotional instability--are often a greater source of impairment than the tics themselves. Measures used to enhance self-esteem, such as encouraging independence, strong friendships and the exploration of interests, are crucial to ensuring positive adulthood outcome.

Figure 1.. Course of Tic Severity over the First Two Decades.

A. Data on the relative severity of tics are presented for 42 individuals with Tourette syndrome (A-D) [9]. The relative tic severity scale goes from 0 (no tics) to 5 (severe tics). Estimates from the patient and a respective parent were obtained independently. B. Box plot representing age when tic disorder symptoms were at their worst (N=46) [16].

Figure 2.. Tic Outcomes in Early Adulthood.

Tic severity in early adulthood (N=82). Adulthood tic severity class is defined by Yale Global Tic Severity Scale [Total Tic Score] (YGTSS): no tics (YGTSS: 0), minimal tics (YGTSS: 1–9), mild tics (YGTSS: 10–19), moderate or greater tics (YGTSS: ≥20). By contrast, all individuals had moderate or greater severity tics in childhood. Less than 5% of individuals reported having worse adulthood tics than in childhood. Adapted from Fig 2. in Bloch & Leckman [7].