Tics and Tourette syndrome: An adult perspective
ABSTRACTTourette syndrome (TS) is a disorder characterized by childhood onset multiple motor and vocal tics often accompanied by features of obsessive compulsive disorder, attention deficit hyperactivity disorder (ADHD), or other behavioral manifestations. Tics may be simple or complex, and may include motor and vocal components. Abnormal function of the basal ganglia is thought to be an important underlying cause of tics and other movement disorders. Treatment of TS requires a thorough understanding of the phenomenology of the disease for the individual patient, and should focus on symptoms that are especially troubling. Some nonpharmacologic approaches may help to improve tic severity, including conditioning techniques, relaxation training, and hypnosis. Options for pharmacotherapy include dopamine blockers and depleters, benzodiazepines, central alpha-adrenergic blockers, and botulinum toxin. Many patients require therapy for comorbid conditions such as anxiety, depression, or ADHD. In case studies and small patient series, deep brain stimulation has been shown to markedly reduce tic severity and functional impairment associated with TS. While onset is most frequently in childhood, TS should not be considered exclusively a disorder of pediatric patients. The complications and comorbidities that are encountered in children and adolescents often persist into adulthood.
DEEP BRAIN STIMULATION
Deep brain stimulation (DBS) has been shown to improve TS in single-case studies and in small series, although the long-term benefit is unclear. Potential targets of stimulation include midline thalamic centromedian-parafascicular (CM-PF) nuclei, the ventralis oralis complex of the thalamus, motor and limbic globus pallidus pars interna (GPi), and the anterior limb of the internal capsule.30 In particular, stimulation of the sensorimotor GPi may ameliorate hyperkinetic states.
One report described the results of DBS implantation in a 15-year-old boy with TS who had not responded to several pharmacologic treatment options.31 Six months after implantation, the patient exhibited markedly improved tic severity as measured using the Yale Global Tic Severity Scale, including a 76% reduction in motor tic severity, 68% reduction in vocal tics, and a complete resolution of impairment.31
Published consensus criteria for the selection of suitable candidates for DBS include age greater than 25 years, chronic and severe tics with severe functional impairment for at least 12 months, tics that are frequent and noticeable in most situations most of the time, failure of conventional medical therapy, medical stability for 6 months, and willingness to participate in ongoing psychologic interventions.32 Exclusion criteria include the presence of another medical condition that could explain the tics, an unstable medical condition, being considered likely to benefit from psychologic interventions, psychosocial factors that may complicate the recovery process or make it difficult to assess outcome, and unwillingness to participate in ongoing treatment for psychosocial problems or risk factors. Other factors that should be considered include comorbidities, the variability in tic severity over time, the involvement of a multidisciplinary treatment team, results of a thorough neuropsychologic assessment, expertise of the surgical team, and access to imaging facilities for presurgical mapping and postsurgical evaluation.
SUMMARY AND CONCLUSIONS
Tourette syndrome is not uncommon among the adult population of a typical neurology practice, and should not be considered exclusively a pediatric diagnosis. Several treatment options are available, including behavioral approaches and several medications. Treatment should focus on the most disabling symptoms. Neuropsychologic assessment and psychiatric support may be necessary for some patients. The same comorbidities that are encountered in children are usually evident in adult patients as well. In medically refractory cases, DBS surgery may be helpful.
