Tics are recurrent, sudden, non-rhythmic twitches. Can be in 1 muscle or muscle group, but can also be a more complex semi-purposeful movement, or even present as a bizarre gait. Typically affect face (eg blinking, grimacing), neck, shoulder. Can be more complex sequences of movements. Characteristics are:
- Tend to be situational, with stress making them worse.
- Initially they are suppressible, although depending on the situation this suppression can be virtually effortless! Usually though, suppression leads to rising anxiety and then a rebound in frequency.
- There is often a premonitory feeling.
- They can be suggestible.
Differential includes stereotypy, spasms, chorea.
Although tics can wax and wane over time, there is a general tendency to improve, and they are very unusual in adulthood.
Tics occur most commonly in boys. Usually they are transient, lasting for between 4 weeks and 1 year. A chronic tic disorder does exist distinct from Tourettes.
Vocal tics (clearing throat, yelps, coughs, sniffs, grunts) can occur in isolation, but a combination of vocal and motor tics suggests Tourette’s syndrome.
Tourette’s syndrome
Thought to affect 1% of children, so probably a lot subclinical! An inherited neuropsychiatric condition, it starts at a mean age of 7 but can be as young as 2yrs. Motor tics come first, about a year before vocal tics. Complex vocal tics may be seen but contrary to public understanding, most kids do not swear (coprolalia)!
Definition requires that motor and vocal/phonic tics are present (at some point) for at least a year, on a daily basis, with onset prior to 18yrs, in absence of substance misuse, medical condition or medication. The characteristic features of Tourette’s are:
- Echolalia – repeating phrases
- Palilalia – repeating other people’s words
- Coprolalia – swearing or abusive language. Involuntary, and causes distress to the patient, who will often try to conceal the outburst by coughing, etc.
- Copropraxia – making obscene gestures
- Palipraxia – imitating other people’s gestures
Tics wax and wane, evolve over months. Can be self harming eg scratching, rubbing, head banging, punching, poking, stabbing oneself (see also obsessive compulsive co-morbidity below).
In some patients, there is a non-obscene compulsion to shout socially inappropriate things (NOSI). Often worsens around puberty. 50% abate after puberty, but mostly just better self-management?
Differential is basal ganglia or cerebellar abnormality eg post-encephalitis, Huntingtons. Investigations only necessary where unusual deterioration or progression of symptoms.
Co-morbidity
Pure tic disorder is unusual in Tourettes. 85% have comorbidity, most commonly:
- Obsessive Compulsive Disorder/Behaviour – less to do with cleanliness, more sexual/religious/violent themes, orderliness, symmetry, checking, counting, forced touching.
- Self-injurious behaviour is well described (see above)
- ADHD
- Conduct disorder, affective disorders more rarely.
The comorbidities are often more significant on school performance than the tics. Comorbidities are common in relatives, even if tics are not.
Treatment
Counselling is useful for self-esteem, anger management, and social functioning. Habit Reversal Training is effective but not widely available – officially 12 weekly hour sessions, need to recognize premonitory urges and then replace tic with controlled movement, or position self to prevent tic (eg chin on chest to prevent shouting).
Drug treatment may be considered eg self harming, but not much evidence for effectiveness. Traditional or atypical neuroleptics, or clonidine (esp where behaviour or sleep problems) used.
Deep brain stimulation being researched.
Prognosis
Tic frequency and severity decline with age in a large proportion of patients (59–85%).
Predictors of NOT improving include higher childhood tic severity, smaller caudate volumes and poorer fine motor control.
The presence of untreated comorbid psychopathology, such as ADHD and OCD, can adversely affect the long-term outcome of patients with TS.[Funct Neurol. 2012 Jan-Mar; 27(1): 23–27. ]
Tourettes Action parent support group.
[Stern, Curr Peds 2006:16:459]
