What makes someone tic?

Excessive blinking is blinking that seems more frequent or forceful than normal, involving one or both eyes.  Excessive blinking can be due to¹

1. Abnormalities to eyelids or front surface of eye (37%)
2. Ocular tic disorders (23%)
3. uncorrected refractive errors (need for glasses) (14%)
4. intermittent exotropia (occasional turning out of the eye, especially when in bright sunlight) (11%)

All of the above except (2) can be easily diagnosed and treated by an ophthalmologist.

What are tics?

Tics are repetitive muscular movements (motor tics) or utterances (vocal tics) that can be transient or persistent, local or widely generalised. About 13% of children have tics disorders and it starts to appear between ages 6-12 years². By the age of 7 years, approximately 5% of children have a history of such abnormal movement disorders. Tics may be a continuum from mild, simple, suppressible tics to chronic multiple, and complex ones. Complex tics involving both motor and vocal tics may be classified as Tourette syndrome. 90% of childhood ocular tics are transient (lasting less than one year) and resolve spontaneously³. Tics possess three key features⁴ that can help differentiate them from other movement disorders: (1) they are often preceded by a sensation and an irresistible urge to move known as premonitory urge; (2) they can be wilfully suppressed; and (3) they persist in all stages of sleep.

See video on Tourette Syndrome

So, what really causes tics?

There is no known cause but its onset is said to coincide with a temporarily stressful event in susceptible individuals. Children with tics usually present to a paediatrician with accompanying emotional disturbances. It is also highly hereditary and is thought to be autosomal dominant (the presence of only one gene is required to exhibit this disorder). One study concluded that ocular tics are not related to mothering behaviour. Tics may occur more frequently when a child is tired, stressed or excited.

Are there any treatments for tics⁵?

Tics can be diagnosed by neurologists and psychiatrists. It is important to note that tics often are not the worst problem and treatment is not always needed. Most treatments are purely symptomatic and that there are no known curative or preventive treatments. Furthermore, symptoms frequently improve or worsen over any period of time, even in untreated individuals. As such, apparent success or failure of any treatment may be coincidental.

1. Drug therapy : Most commonly Dopamine D2 receptor antagonist therapy
2. Habit reversal therapy

This therapy involves the application of a competing response whenever the patient notices either a tic or the urge to tic. Central to this is that the competing response must be paired with tic urges or tics, for benefits to be observed. Note that this is very different from simply telling the patient not to tic, or from "trying harder," neither of which is effective over the long run. Initially, heavy effort on the part of the patient may be needed. However, at long-term follow-up at least 50% of treated patients had greater than 75% reduction in overall tic severity, whether based on self-report of home tic counts or on blind review of a videotape filmed in the clinic. The effort expended by patients decreased dramatically as tic frequency declined, usually within the first few weeks of treatment.

My personal experience with tics

I remember having excessive blinking as a child, my mother used to nag at me to stop the blinking. But as I could recall, the blinking was involuntary and I could not control it. As a matter of fact, the constant nagging made things worse as I would try to avoid facing people for fear that they would see me tic. My mother said that it started when I was about 5 or 6 years old. It went away on its own before I turned 7 and I could remember vividly my sister said “You, you stopped blinking already!”. I was overjoyed that it finally went away, something that I had no control over. 

REFERENCES

1.       Ophthalmology. 2001 Sep;108(9):1556-61. Excessive blinking in childhood: a prospective evaluation of 99 children. Coats DK1, Paysse EA, Kim DS.

2.       Pediatrics. 1989 Jun;83(6):967-70. Functional blinking in childhood. Vrabec TR, Levin AV, Nelson LB.

3.       J AAPOS. 2004 Apr;8(2):171-4. Tic disorders in children with frequent eye blinking. Jung HY, Chung SJ, Hwang JM.

4.       Bntish Journal of Ophthalmology 1992; 76: 697-699. Eye movement tics F Shawkat, C M Harris; M Jacobs, D Taylor, E M Brett

5.       Medscape Practice Essentials: Tourette Syndrome and Other Tic Disorders http://emedicine.medscape.com/article/1182258-overview