For both technologies, there were evidence gaps related to population, intervention, comparators and outcomes. The committee concluded that there is potential benefit and some evidence to support recommending both digital therapies for people with chronic tic disorders and Tourette syndrome in the NHS with evidence generation, once appropriate regulatory approval is in place. The key evidence gaps were:
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Population: the relevant evidence for both technologies was around children and young people. There was limited evidence of the effects of using the technologies in adults. To get access to a diagnosis and treatment for adults with tic disorders is extremely difficult. The symptoms of tic disorders often fluctuate. Certain life events, such as periods of increased stress, can cause some adults with mild tics to experience severe symptoms if they cannot access treatment. So, more research is needed on the benefits and risks of using digital therapies in adults. The clinical experts also mentioned that people with attention deficit hyperactivity disorder, obsessive-compulsive disorder, autism spectrum disorder and intellectual disability are under-represented in the trial compared with clinical practice. This difference might be due to the measures used to assess comorbidities in the trial, rather than the population itself. People with these conditions could be disadvantaged by using digital technologies. More evidence is needed on using the technologies in people with comorbidities.
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Intervention: there was limited evidence particularly for Neupulse. The clinical experts suggested that evidence for Neupulse is required for a minimum of 6 months, and ideally 12 months follow up. For ORBIT, the EAG stated that having data from additional timepoints would support extrapolation of the effectiveness beyond 18 months. Further analysis of the data collected in the ORBIT‑UK trial is needed to reduce the uncertainty.
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Outcomes: evidence is lacking on the effect of digital therapies on quality of life. The EAG would like evidence that captures how a reduction in severity impacts quality of life or activity in daily life. The clinical experts explained that the connection between the objective measure of tics and quality of life is difficult. The EAG stated that the CHU‑9D (Child Health Utility 9D) reported in the ORBIT trial is the only available utility score for the modelled health states. The clinical experts suggested that considering outcome measures such as school and employment attendance, interviews with families and a qualitative survey may be beneficial. The process-evaluation study used during the ORBIT trial included both children and parents and carers. But, more children's reported response for their own health state is needed. It will be useful to have views from people with chronic tic disorders and Tourette syndrome and their parents and carers.
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Adverse events: more information related to the tolerability and comfort of using Neupulse is needed. The clinical experts also advised that more research is needed on the effects of stopping Neupulse.
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Cost and resource use: more evidence is needed on long-term costs needed to maintain long-term effectiveness. It would also be useful to know the training requirements, staff and resource use for Neupulse.