European Society for the Study of Tourette Syndrome (ESSTS)
Posted in Courses & Conferences on 30th Sep 2019
Conference details: 15-17 May 2019, Hannover, Germany.
Report by: Jeremy Stern, Consultant Neurologist, St George’s Hospital.
Conflict of interest statement: None declared.
Conference organising committees usually aspire to a freshness in their programme that will be different to the last few annual meetings, with big breaking news and novel ideas for sessions. They aren’t always entirely successful but for this European Tourette Syndrome meeting the ESSTS officers and local organiser Kirsten Müller-Vahl did better than most. This will be a rather selective summary from that perspective. There are many published reviews covering progress in complex genetics and uncertain neurobiology, which were also covered.
Around 1% of children have Tourette Syndrome (TS) with higher rates in SEN education. Tics are more commonly seen in the context of transient tic disorders in up to 15-20% of boys, and in persisting chronic multiple tics. TS is defined by chronic multiple motor and at least one vocal tic which can be simple or complex. It is highly associated with other comorbidities including OCD and ADHD. Severity varies, many children improve but others have a lifelong intrusive condition.
Firstly, big news. 25 years ago Susan Swedo presented a hypothesis of immune mechanisms responding to Group A Streptococcal (GAS) infection causing a neuropsychiatric syndrome with movement disorders in children (PANDAS), analogous to Sydenham’s chorea, in association with anti-basal ganglia antibodies. PANDAS (now reclassified as PANS) is distinct from TS but since then in adult practice when dealing with apparently late or explosive onset TS we have tested ASO titres and anti-basal ganglia antibodies without the data to understand their clinical significance. Antibodies are seen in about 25% of children with TS. Streptococcal carriage is common in the population- is there a relationship between infection and the onset or exacerbation of TS in a more typical setting? Many strands of evidence have pointed to this question which has now been addressed by a major pan-European EU funded study, EMTICS. Children with TS (n=715) were followed prospectively and a group at risk of new onset, their siblings (n=260). The preliminary results gave a valuable negative result; there were 200 new GAS exposures but no indication these were preferentially associated with the new onset of tics in 60 cases, nor with exacerbations in already diagnosed children. EMTICS is a significant achievement which will yield other data and analyses. For now, whilst there remain controversial aspects to PANS which can exert a Lyme-like attraction to some parents and older patients, streptococcus does not appear to be relevant to typical TS and remains of doubtful relevance to most adult onset presentations.
A new idea was a session on “Is it time to rename Tourette’s”, a debate chaired by Andrea Cavanna who did not hesitate to launch into ‘…a rose by any other name’ at the first opportunity. There is a growing feeling that despite our attachment to the eponym and Gilles de la Tourette’s Salpêtrière pedigree (a definitive biography by Olivier Walusinski has recently been published) the name ‘Tourette’ is potentially an unhelpful distraction and a term like ‘tic spectrum disorder’ may be more appropriate both scientifically and in terms of reducing stigma. I favour this but we can think of examples of name changes in medicine not successfully destigmatising a condition. More interestingly there were people with TS at the meeting who spoke powerfully of ‘owning’ their condition and not wanting the label they had lived with through life to be taken away. This was also seen when the American Psychiatric Association left Asperger’s syndrome behind in the classification of autism (before it became known Asperger was a Nazi eugenicist). However, it is fair to consider whether this view is also representative of a family being given the diagnosis for the first time. The vote in favour of a name change was narrowly lost, the debate may continue.
A problem for adult neurologists is that drugs for tics are variable in efficacy although can be very useful – not unlike our medication options for essential tremor, dystonia or, for that matter, chronic migraine. The data for TS is generally poor and usually short term with clinical translation often disappointing for many patients. There has previously been a NIHR HTA assessment with meta-analysis of treatments in children, and now the AAN has published a comprehensive systematic review for children and adults including treatment and adverse effects and a practice guideline. The lead author Tamara Pringsheim presented these at the meeting. Both are worth reading and can’t be reproduced here but the quality of the existing data does lead to some anomalies. RCTs, obviously, are King so that the category of ‘low confidence in the evidence’ is shared by unused drugs like metoclopramide with an older option like pimozide which anecdotally may well have equal effectiveness to some in the ‘moderate confidence’ group (eg aripiprazole an often favoured first line drug, haloperidol, risperidone, clonidine). Only Comprehensive Behavioural Intervention for Tics (CBIT) was in the ‘high confidence’ group but is sadly underprovided. The Professor Mary Robertson prize for research contribution was this year won by Per Andrén for his published paper on a controlled trial of internet delivered behaviour therapy which is part of a wider data-driven movement to improve access to treatment.
Other clinical highlights included the first controlled trial by Dr Müller-Vahl of thalamic versus GPi deep brain stimulation (DBS) in 9 patients with bilateral dual stimulation with GPi seeming superior. There remains much uncertainty over patient and target selection and DBS is effectively not currently available for TS in the UK due to an NHSE commissioning decision.
The meeting included an interactive session on functional movement disorders. The explosion of interest in this area has perhaps come a little late to the TS clinical community and can be challenging as psychogenic movements share some characteristics of tics (suggestibility, distractibility) with important differences (lack of premonitory urge, usually less suppressibility). Our adult explosive-onset cases commonly appear to have varying degrees of functional components even when there also seem to be typical tics or a history of tics in childhood. “Tic attacks”, a category often made by the patients themselves can resemble dissociative seizures. This area will grow but may be reliant on opinion as much as objective signs.
The next ESSTS meeting will be held 3rd -5th June 2020 in Lausanne which also happens to be the place of Gilles de la Tourette’s death in 1904 from neurosyphilis.