Leckman James F, Bloch Michael H, Scahill Lawrence, King Robert A
Yale Child Study Center, New Haven, CT 06510, USA.
J Child Neurol. 2006 Aug;21(8):642-9. doi: 10.1177/08830738060210081001.
Tourette syndrome is a neurodevelopmental disorder characterized by motor and vocal tics--rapid, repetitive, stereotyped movements or vocalizations. Tourette syndrome typically has a prepubertal onset, and boys are more commonly affected than girls. Symptoms usually begin with transient bouts of simple motor tics. By age 10 years, most children are aware of nearly irresistible somatosensory urges that precede the tics. These urges likely reflect a defect in sensorimotor gating because they intrude into the child's conscious awareness and become a source of distraction and distress. A momentary sense of relief typically follows the completion of a tic. Over the course of hours, tics occur in bouts, with a regular intertic interval. Tics increase during periods of 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, especially those that involve both heightened attention and fine motor or vocal control, as occur in musical and athletic performances. Over the course of months, tics wax and wane. New tics appear, often in response to new sources of somatosensory irritation, such as the appearance of a persistent vocal tic (a cough) following a cold. Over the course of years, tic severity typically peaks between 8 and 12 years of age. By the end of the second decade of life, many individuals are virtually tic free. Less than 20% of cases continue to experience clinically impairing tics as adults. 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 (ADHD), obsessive-compulsive disorder, depression, anxiety, and emotional instability--are often a greater source of impairment than the tics themselves. Emerging behavioral treatments of Tourette syndrome are based in part on an understanding of the moment-to-moment experience of somatosensory urges and motor response. With identification of specific genes of major effect and advances in our understanding of the neural circuitry of sensorimotor gating, habit formation, and procedural memory--together with insights from postmortem brain studies, in vivo brain imaging, and electrophysiologic recordings--we might be on the threshold of a deeper understanding of the phenomenology and natural history of Tourette syndrome.
抽动秽语综合征是一种神经发育障碍，其特征为运动性和发声性抽动——快速、重复、刻板的动作或发声。抽动秽语综合征通常在青春期前发病，男孩比女孩更易受影响。症状通常始于简单运动性抽动的短暂发作。到10岁时，大多数儿童会意识到抽动之前几乎无法抗拒的躯体感觉冲动。这些冲动可能反映了感觉运动门控的缺陷，因为它们侵入儿童的意识，成为分心和痛苦的来源。抽动完成后通常会有片刻的轻松感。在数小时内，抽动会阵发性发作，发作间隔规律。在情绪激动和疲劳时抽动会增加。抽动在性质上可能会变得“复杂”，且看似有目的性。抽动可以在短时间内被有意抑制，仅仅提及它们就能诱发抽动。在有目标导向的行为期间，尤其是那些需要高度注意力以及精细运动或发声控制的行为，如在音乐和体育表演中，抽动通常会减少。在数月的时间里，抽动会有起伏变化。新的抽动会出现，通常是对新的躯体感觉刺激源的反应，比如感冒后出现持续性发声抽动（咳嗽）。在数年的时间里，抽动严重程度通常在8至12岁达到峰值。到生命的第二个十年结束时，许多人的抽动几乎消失。不到20%的病例在成年后仍有临床意义上的抽动障碍。抽动很少单独出现，其他共存情况——如行为抑制障碍、对广泛感觉刺激的过敏、视觉运动整合问题、程序性学习困难、注意力缺陷多动障碍（ADHD）、强迫症、抑郁症、焦虑症和情绪不稳定——往往比抽动本身更易导致功能损害。抽动秽语综合征新出现的行为治疗方法部分基于对躯体感觉冲动和运动反应的即时体验的理解。随着主要效应特定基因的确定以及我们对感觉运动门控、习惯形成和程序性记忆神经回路理解的进展——再加上尸检脑研究、活体脑成像和电生理记录的见解——我们可能即将更深入地理解抽动秽语综合征的现象学和自然史。
