Tics

Tics are characterized by abrupt, repetitive movements (motor tics) or sounds (phonic tics)

• often the tic is preceded by a premonitory sensation of an urge, tension, discomfort, or other sensory phenomena

They usually involve the face and shoulders.

Presentation is commonly because the tic irritates a child's parent or a teacher, or the child is a victim of teasing.

• tics are most frequently associated with Tourette's syndrome
• tics have been reported to also occur in numerous different acquired and congenital neurological and neuropsychiatric disorders or following an exposure to a variety of drugs
• acute brain injury such as stroke, central trauma and peripheral injury has been associated with a variety of movement disorders, most frequently dystonia and tremor

Treatment

• seek specialist advice
• treatment options include (1):
  • clonidine is frequently considered the medication of first choice for the treatment of tics because of its low incidence of side effects and because it can also be of benefit in ameliorating comorbid attention deficit and hyperkinetic disorder (ADHD)
  • dopamine 2 (D2) receptor antagonists
    • studies have shown many neuroleptics, including haloperidol, pimozide, risperidone, ziprasidone, and olanzepine, to be effective in treating tics
  • clonazepam, and possibly other benzodiazepines, may be of benefit
  • presynaptic dopamine depletion
    • tetrabenazine is effective for treating tics, and although it does not cause tardive dyskinesia - however it may cause depression and parkinsonism

Notes:

• myoclonus or tics?
  • simple motor tics could be confused with myoclonus
  • all patients with tics are almost able to suppress them, even if only partially and temporarily, on request
    • this suppression is followed by a rebound phenomenon, which can be easily observed after the period of voluntary restraint. Such voluntary suppression is never observed for myoclonus
    • tics have patterned profile of muscle activation, which promotes more complex movement than myoclonus
      • even simple motor tics are often the combination of several brief muscle contractions which give rise to the so-called mimicking of normal coordinated movement
        • occasionally, the tic is preceded by premonitory sensations, and patients consider the tic as a voluntary way to obtain relief from these focal sensations - myoclonus is never associated with sensory phenomena
• botulinum toxin
  • in addition to the use of pharmacological agents with systemic effects, there is growing evidence to support the use of local injections of botulinum toxin for the treatment of motor and, sometimes, vocal tics

Reference:

1. Dooley JM. Tic disorders in childhood. Semin Pediatr Neurol. 2006 Dec;13(4):231-42.
2. Vercueil L. Myoclonus and movement disorders. Neurophysiol Clin. 2006 Sep-Dec;36(5-6):327-31