How is Tourette syndrome diagnosed

How is Tourette syndrome diagnosed

What features are necessary to make the diagnosis of Tourette syndrome (TS)? 

According to currently established criteria, the diagnosis of Tourette syndrome requires all of the following features: onset before age 21, multiple motor tics, one or more vocal tics, fluctuating course, and presence of tics for more than 1 year.

Tics that last less than 1 year are categorized as transient tic disorder (TTD).

TTD is estimated to occur in 5% to 24% of school children; there is no accurate way to predict whether TTD will evolve into Tourette syndrome.

Chronic motor tic disorder (CMTD) or chronic phonic tic disorder (CPTD) have the same criteria as Tourette syndrome, but patients only display either motor or phonic (vocal) tics. 

Tourette syndrome, defined by the motor manifestations, is three times more frequent in males, but when obsessive compulsive disorder (OCD) is included, the male preponderance becomes much less significant.

The onset is around age 7 years for facial tics with gradual progression in a rostrocaudal fashion.

The diagnosis is often delayed because of a tendency to misinterpret or not recognize the tics or behavioral problems as abnormal. Behavioral problems usually precede the onset of tics by 2 to 3 years. 

Sources

• Hanna PA, Jankovic J, Vincent A: Comparison of mouse bioassay and immunoprecipitation assay for botulinum toxin antibodies. J Neurol Neurosurg Psychiatry 66(5):612-616, 1999. 
• Ramirez-Castaneda J, Jankovic J: Long-term efficacy, safety, and side effect profile of botulinum toxin in dystonia: a 20-year follow-up. Toxicon 90:344-348, 2014. 
• Jankovic J: Botulinum toxin in clinical practice. J Neurol Neurosurg Psychiatry 75(7):951-957, 2004. 
• Mehanna R, Jankovic J: Botulinum neurotoxins as therapeutics. In Kostrzewa R (ed): Handbook of neurotoxicity. New York: Springer, pp. 553-590, 2014. 
• Jankovic J: Botulinum toxin in clinical practice. J Neurol Neurosurg Psychiatry 75(7):951-957, 2004. 
• Mehanna R, Jankovic J: Botulinum neurotoxins as therapeutics. In Kostrzewa R (ed): Handbook of neurotoxicity. New York: Springer, pp. 553-590, 2014. 
• Black KJ, Jankovic J, Hershey T, McNaught KS, Mink JW, Walkup J: Progress in research on Tourette syndrome. J Obsessive Compuls Relat Disord 3(4):359-362, 2014. 
• Jankovic J, Kurlan R: Tourette syndrome: evolving concepts. Mov Disord 26(6):1149-1156, 2011. 
• Fahn S, Jankovic J, Hallett M, Jenner P: Tics and Tourette syndrome. In Fahn S, Jankovic J: Principles and practice of movement disorders, Philadelphia: Churchill Livingstone, pp. 409-442, 2007. 
• Jankovic J, Kurlan R: Tourette syndrome: evolving concepts. Mov Disord 26(6):1149-1156, 2011.