Epigenetics
Environmental risk factors
Maternal polycystic ovary syndrome (PCOS) is a risk for TS, ADHD and ASD \citep{30857571}
Review of the PANDAS controversy by Don Gilbert (
link)
\citet{30833232a}, using the National Health Insurance Research Database of Taiwan, analyzed 2261 TS patients and 20349 non-TS controls for the risk of traumatic brain injury (TBI). During follow-up, there was a significantly increased risk for TBI in TS patients compared to controls. Classic comorbidities such as ADHD, OCD and depression increased the risk for TBI, whereas the regular use of antipsychotic medication decreased it. These findings have important therapeutic implications.
Pathophysiology
Animal models
Pathological studies
Electrophysiology
"Spatio-temporal structure of single neuron subthalamic activity in Tourette Syndrome explored during DBS procedures" \citep{Vissani_2019}.
Cued voluntary eye blinking studied by EEG in people with and without tics \citep{31382238}.
Neuroimaging studies
SERT binding increased in people with TS+OCD \citep{30700759}
Boys with anxiety disorders have altered WM in the uncinate fasciculus \citep{30654645}
The ENIGMA-OCD group was able to use their very large data set to show that individual subject "mega-analysis" is superior to a site-wise meta-analysis \citep{30670959}. This result will guide the nascent ENIGMA-TS group.
fcMRI study \citep{31518769}
Pharmacological studies
Clinical and neuropsychological studies
Young adults with TS showed reduced accuracy in the second step of a reaching task, consistent with a model in which forward updating of a model of the movement is abnormal \citep{30561518}.
"A superior ability to suppress fast inappropriate responses in children with Tourette syndrome is further improved by prospect of reward" \citep{31103639}.
Other
Treatment
In a large study of manualized CBT in children with OCD, anxious and depressive symptoms improved substantially and was not linked to improvements in OCD severity [
10.1016/j.psychres.2019.04.021 ]. This result is one more argument in favor of psychotherapy for obsessions and compulsions, which are common in people with tics. A consensus report argues strongly for early intervention in OCD
\citep{30773387}. Since early-onset OCD is associated with tics
\cite{21820387}, a similar argument could be made for early intervention in tic disorders, especially since effective behavioral treatments without side effects are available. Studies of whether early intervention changes the course of tic disorders are needed.
Psychological interventions
One of the most interesting possibilities in delivering CBT for tics has come from the development of intrenet-based platforms, making these approaches available for a large numebr of patients, even in remote areas. The BIP-TIC platform, developped in Sweden, allows to use either HRT, ERP or a mixture of both online with a possible intervention of a therapist by phone or email. A first pilot study on 23 patients has shown encouraging results in a rater-blind parallel group trial (including a 12 month follow up) \citep{30772854}. A large (n= +200) UK-based study using this platform, and focussing on en ERP-based methodolody, called ORBIT, will commence shortly \citep{30610027}.
Medication
Neurosurgery