TIC DISORDERS
DEFINITION:
A group of disorders characterized by sudden, involuntary,
repetitive, rapid, random, purposeless, and highly stereotyped
movements or vocalizations.
EPIDEMIOLOGY:
- incidence: most common of the movement disorders
- age of onset:
- mean of 7 years (from preschool to early school years)
- risk factors:
- familial (inheritance pattern not established)
- comorbid conditions:
- attention deficit disorder
- obsessive-compulsive disorder
- sleep disorders
- speech and language disorders
- learning disabilities
- impaired visual-motor skills
- impaired visual-perceptual performance
- disturbed auditory discrimination
- behavioural and emotional problems
TYPES:
CLINICAL FEATURES:
- commonly involve the head, face, and neck
- uncommonly involve the limbs and trunk
- usually present as a single tic which evolves into another
tic or two or more tics occurring simultaneously
- Types:
- involve a limited group of muscles of head & neck
- eye-blinking
- facial grimacing
- head-nodding
- neck-jerking
- shoulder-shrugging
2. Complex
- involve a group of muscles:
- facial gestures
- smelling an object
- raising hand to face
- copropraxia
- grooming behaviours
- hitting or biting self
- echokinesis
- hopping, jumping, leaping, skipping, stamping
- may involve a cluster of simple motor tics
- may be compulsive:
- touching objects, others, self
- arranging objects
2. Vocal Tics
- barking
- coughing
- grunting
- sniffing
- snorting
- throat-clearing
2. Complex
- sounds:
- animal noises, belching, hiccuping, high-pitched cries,
screaming
- words:
- coprolalia, echolalia, palilalia
3. Tic Characteristics
- wax and wane
- involuntary and not caused by stress
- increase with anxiety, emotional stress, anger, excitement,
fatigue
- decrease with sleep, relaxation, and/or concentration
- briefly suppressible but may result in a "build-up"
- transient disorder (<1 year) vs chronic disorder (>1 year)
- can differentiate from other movement disorders:
- chorea, myoclonus, athetosis, dystonia, hemibalism, tremor
- tic severity scales available
- also sensory tics:
- uncomfortable sensations - tickle, irritation, temperature
change, unusual feelings
4. Comorbid Conditions
- in 20-60% of Tourette's Syndrome
- may precede onset of tics by 2-3 years
- may be more common or severe in those with severe tics
- more prevalent in males with Tourette's Syndrome
2. Obsessive-Compulsive Disorder
- in 28-67% with Tourette's Syndrome
- obsessions:
- fears of harm, contamination, etc
- compulsions:
- ordering and arranging habits
- checking, counting, or decontamination rituals
3. Sleep Disorders
- sleepwalking, night terrors, nightmares, talking in sleep,
restlessness, difficulty falling asleep
4. Learning Disabilities
- in 33-50% of Tourette's Syndrome
- may be related to impaired visual-motor,
visual-perceptual, and/or auditory discrimination skills,
dyslexia
5. Other Behavioural Problems
- 5-20 times more common in Tourette's Syndrome
- anxiety, depression, hostility
- inappropriate sexual thoughts or behaviour
- conduct disorders, discipline problems, mania, panic
attacks, phobias, stuttering, neuroses
INVESTIGATIONS:
- all tests are usually normal
- no investigations are diagnostic as diagnosis is clinical
MANAGEMENT:
- determine whether or not the major source of distress is due
to the tics or comorbid problems and develop an individualized
multimodal management programme
2. Psychological
- individual and family counselling
- education of family, peer, school teachers
- detailed psychoeducational testing for comorbid conditions,
(i.e., learning disabilities, impaired visual-motor skills)
3. Medical
- benefits:
- suppresses tics in 80-85% of patients
- risks:
- no evidence therapy modifies eventual outcome
- 50% have moderate to severe side effects
- indications for:
- Chronic Motor or Vocal Tic Disorder
- Tourette's Disorder
- - (no indication for treating Transient Tic Disorder)
- social and academic disabilities
- dopamine antagonist used since 1961
- start at 0.25-0.50mg po qhs
- increase by 0.5mg po q4-5d till therapeutic benefit then
switch to bid (same total dose)
- if no response by 6 mg/day unlikely to respond
- side effects:
- lethargy, dysphoria, depression, weight gain
- blunted cognitive function with impaired school
performance
- extrapyramidal manifestations (<10% of patients)
- acute dystonic reaction
- oculogyric crisis, torticollis
- orobuccolingual dyskinesia +/- choreiform movements
of limbs
- rare reactions
- parkinsonian, akisthesia, tardive dyskinesia,
withdrawal emergent syndrome (occurs with reduction of
dose)
2. Pimozide
- postsynaptic blocker of D2 receptors
- equally as effective as haloperidol but more side
effects
- side effects:
- extrapyramidal manifestations (10-15% of patients)
- prolong QT interval on ECG
- contraindicated in those with prolonged QT syndrome
or arrhythmias
4. Comorbid Problems
- behavioural or educational approaches
- treatment with methylphenidate, dextroamphetamine, or
pemoline may exacerbate tics
- desipramine
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