Rather than a voluntary movement, a tic is a movement which relieves a voluntary urge, and this is the key characteristic which differentiates a tic from another movement disorder.
Motor tics of the orofacial area include tongue protrusion, facial grimacing, blinking, and facial twitching and cheek sucking. Orofacial motor tics usually involve the peri-oral muscles (e.g. buccinator, orbicularis oris, tongue, and levator anguli oris).
Proposed Mechanism
The cortico-basal ganglia pathway is involved in normal motor control and implicated in multiple movement disorders, so a dysfuntion of this area will produce brief, repetitive muscle contractions. [1]
The most common and severe form of a multiple tic disorder is Tourette’s syndrome, which includes motor and vocal tics. This condition has been related with abnormalities within cerebro-basal ganglia circuits. [2]
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Treatment
Oral tics might impact patient functionality, since they could interfere with communication and social interaction.
1. Behavioral Therapy
If there is no actual change in the cerebro-basal circuits, some tics might be subject to voluntary inhibitory control. [3] Motor inhibition and attentional processing are tightly linked and both processes might rely on similar cognitive and neural mechanisms, providing the basis for tics inhibition with behavioral therapy. [4]
There has been some development in the application of technology for tic’s management, with interactive online treatments based on comprehensive behavioral interventions. [5] Some limitations for this type of approach are age of patients, tic severity, profile of comorbidities, treatment availability, cost, and insurance coverage. [6]
2. BoNT-A Injections
As with hyperactive tongue problems, there is a need to explore better when, where and to what degree BoNT-A may become useful in management of facial muscle, buccinator, orbicularis oris and tongue-based motor tics.
One paper reviewed the results of 450 patients who had various types of motor tics associated with Tourette’s syndrome who were treated with BoNT-A. [7] They used the Yale Global Tic Severity Scale and determined that BoNT-A in combination with baclofen was very effective, safe, and reliable in the treatment of tics associated with Tourette’s syndrome.
Another paper also described the effect of BoNT-A on 35 patients with long standing motor tics associated with the Tourette’s syndrome. [8] They reported that the patients rated their improvement with this treatment as a mean of 2.8 on a scale from 0 to 4.
A recent systematic review indicated that there is uncertainity about botulinum toxin effects in the treatment of focal motor and phonic tics, and the quality of the available evidence was categorized as very low. [9]
Related Reading: Chemodenervation Injections for Treating Oromandibular Dystonia
3. Controlling Alterations of Methylation Levels of Dopaminergic Genes
The blockade of the striatal dopamine-D2 receptors with dopamine receptor antagonists produces a tic-reducing effect. [10]
It has been proposed that if the alterations of methylation levels of dopaminergic genes are controlled, there will be a reduction of spontaneous fluctuations of tics. [11]
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References
[1] McCairn, K., Bronfeld, M., Belelovsky, K., & Bar-Gad, I. (2009). The neurophysiological correlates of motor tics following focal striatal disinhibition. Brain : A Journal of Neurology., 132(Pt 8), 2125-2138.
[2] McCairn, K., Iriki, A., & Isoda, M. (2013). Global dysrhythmia of cerebro-basal ganglia-cerebellar networks underlies motor tics following striatal disinhibition. The Journal of Neuroscience : The Official Journal of the Society for Neuroscience., 33(2), 697-708.
[3] Ganos, C., Rothwell, J., & Haggard, P. (2018). Voluntary inhibitory motor control over involuntary tic movements. Movement Disorders, Movement disorders , 2018.
[4] Hilt, P., & Cardellicchio, P. (2018). Attentional bias on motor control: Is motor inhibition influenced by attentional reorienting? Psychological Research Psychologische Forschung., Psychological research Psychologische forschung. , 2018.
[5] Conelea, C., & Wellen, B. (2017). Tic Treatment Goes Tech: A Review of TicHelper.com. Cognitive and Behavioral Practice.,24(3), 374-381.
[6] Fründt, O., Woods, D., & Ganos, C. (2017). Behavioral therapy for Tourette syndrome and chronic tic disorders. Neurology.,7(2), 148-156.
[7] Awaad Y. Tics in Tourette syndrome: new treatment options. Journal of Child Neurology, 1999 May, 14(5):316-9.
[8] Kwak CH; Hanna PA; Jankovic J. Botulinum toxin in the treatment of tics. Archives of Neurology, 2000 Aug, 57(8):1190-3.
[9] Pandey, S., Srivanitchapoom, P., Kirubakaran, R., & Berman, B. (2018). Botulinum toxin for motor and phonic tics in Tourette’s syndrome. The Cochrane Database of Systematic Reviews., 1, CD012285.
[10] Mogwitz, S., Buse, J., Wolff, N., & Roessner, V. (2018). Update on the pharmacological treatment of tics with dopamine-modulating agents. ACS Chemical Neuroscience., ACS chemical neuroscience. , 2018.
[11] Müller-Vahl, K., Loeber, G., Kotsiari, A., Müller-Engling, L., & Frieling, H. (2017). Gilles de la Tourette syndrome is associated with hypermethylation of the dopamine D2 receptor gene. Journal of Psychiatric Research., 86, 1-8.
