Monika began by welcoming us all to this webinar on Children. Dystonia and DBS organised by Dystonia Europe. She explained that we have 3 speakers, Sarah Perides Advanced Nurse Practitioner, Dr Margaret Kaminska both from the Evelina Children’s Hospital and Alfonso Fasana from the Toronto University Hospital. We had hoped to have a patient too but unfortunately they were not able to attend, hopefully they will attend a future webinar.
Alfonso Fasana was the moderator. He has worked in the field of movement disorders for a long time and has authored more than 500 scientific papers and been involved in many clinical trials.
He introduced the first speaker and told us a little of her history in working in the field of movement disorders.
Margaret Kaminska, consultant paediatric neurologist began by acknowledging that most of the audience if not all will already understand the role of DBS in dystonia. She explained that in movement disorders we have either too much or too little movement, hyperkinetic is too much movement hypokinetic is too slow movement. Dystonia is classed as hyperkinetic. She explained the different classes of movement disorders, dystonia which we all know about, chorea which is fast and random and myoclonus which is sudden and not rhythmic. In children all 3 can often be seen.
Cerebral palsy (CP) is the most common cause of childhood motor disability and out of 34 children with CP 87% had spasticity and 78% presented with dystonia. This was found while developing a hypertonia assessment tool.
Dystonia is a chronic condition and there is a long road to determining the best treatment for a child with dystonia. Most of the time it is a chronic condition and it is very rare for it to be treated and go away, as we all know, there is no cure. Margaret went on to explain there are various triggers that have to be taken into consideration when determining treatment, for example pain, reflux, constipation, the need for appropriate sitting and care equipment. They may need some physiotherapy, occupational therapy and speech and language therapy. The young patient may have difficulty communicating, which of course makes diagnosis and developing a treatment plan more difficult.
The most common medications used to treat childhood dystonia are baclofen and trihexyphenidyl but a lot of children have adverse reactions to these drugs.
Sometimes a lot of medication is needed to treat a child with dystonia. Margaret showed us a long list of medication that one 9 year old boy was taking, 11 different meds including morphine, poor young boy!
Obviously no-one wants their child to be on so much medication unless it proves to be successful.
This is where Deep Brain Stimulation (DBS) comes in. If medication or other therapies do not help then we can think about surgical intervention. Margaret showed us some pictures of the placement of electrodes in the brain. The neurosurgeons are always learning about electrode placement and the use of DBS, especially from colleagues around the world. It is also used to treat parkinsons, epilepsy, obsessive compulsive disorder (OCD), depression and tourettes but most often dystonia.
Improvement is measured using a scale called burke-fahn-marsden dystonia rating scale (BFMDRS) which is useful. It measures movement but does not measure function in life.
DBS is not a cure, it may reduce symptoms, for some people they will have such a reduction in symptoms they may feel they have been cured. However if the DBS is turned off the dystonia would come back.
Records show that about a third of children with inherited dystonia have a massive 76% improvement.
Margaret gave us the example of a child with cerebral palsy 1 year post DBS, they achieved their 5 goals which included dressing, washing their body, and sitting in a chair. Such basic functions that most people take for granted.
The best response to DBS is usually from those who have inherited dystonia. Other dystonias have a more modest response but that can still be meaningful.
They will have a brain MRI (Magnetic Resonance Imaging) before surgery to determine if there is any brain damage. The surgeon would want as little brain damage as possible for the DBS to be successful.
A further investigation into whether or not DBS could be useful include neurophysiology tests, SEP (somatosensory evoked potential test) and CMCT (central motor conduction time). I have to admit I had to look those terms up after the meeting, essentially they are looking at how signals travel along the nerves. When these are abnormal there is generally a poor response to DBS.
In the early days, the patient needed surgery each time the battery was changed. Nowadays the batteries last much longer and can be recharged by the patient/carer.
Margaret then went on to say that EEGs (brain scans) of deep structures in the brain through the DBS electrodes help practitioners to learn more about dystonia. It is also useful to record brain activity during events such as ‘bad dystonia’, I think this should be called ‘worse dystonia’ to me the term bad dystonia suggests there is a good dystonia!
She then showed us a graph of neuron activity which helped to place the electrode accurately and to determine the best level of stimulation. Another graph showed low brain activity when the patient was sleeping and high brain activity when the patient was awake. Maybe in time we will be able to control high activity moments better.
Margaret is not aware of any children younger than 2 years old having DBS, the youngest she has operated on was 32 months old.
There is a clear pathway from making the decision to perform DBS on a child or not to their post operative care.
Of course DBS in children is really teamwork involving neurologists, neurosurgeons, physiotherapists, occupational therapists, speech and language therapists etc.
Alfonso then introduced Sarah and gave us a brief rundown of her vast experience as a paediatric nurse within the Dystonia/DBS team.
Sarah gave us some really useful pre-surgical decision making tips e.g. make sure your child has a thorough assessment by a specialist team, make sure their goals are realistic, make sure you are as truthful as possible with your goals. Know that DBS is not a cure and it may take a while for the DBS to be effective.
She then gave us a summary of DBS which includes, brain surgery implanting 2 leads into a deep area in the brain called the global pallidus, wire that connects those leads to a battery powered stimulator.
This means a long General Anaesthetic for planning, scanning, placing leads and of course the surgery itself. The whole process can take 4 to 6 hours while the child is asleep.
There will be 2 small incisions and 2 small holes in the skull.
Cable is passed from the top of the head and down to the placement of the battery.
Recovery does not involve intensive care, the child can be with their parents/carers immediately after surgery. They will be on a morphine infusion for the first night after surgery which keeps them calm and helps the recovery time.
Some children wake up really hungry, some feel sick, it just depends on the child. They will be in hospital for only about a week and then one more week resting at home then they can go back to school. Recovery is much quicker than I thought it would be!
Children who recover quickly are often well enough to visit tourist spots near the hospital before they go home, I am sure that is a welcome change for them and their parents/carers.
Sarah then went on to tell us about living with DBS, what happens when it is switched on? It is not a light bulb moment and changes are often very slow or even no change at all when it is first switched on. After that initial switch on the patient is sent home to get used to the stimulation, it can take months or even years to have a significant effect. Rechargeable batteries are used and charged with a charging device that can be held against the chest wall where the stimulator is. This can be difficult for the child depending on what their needs/disabilities are.
Each patient will have at least 6 follow up appointments to alter their stimulator, and to monitor their general health.
Patients stay with the clinic until they are 18, Sarah often finds it difficult to say goodbye after caring for them for many years.
She then told us about a few restrictions for DBS patients which include, trampolining, bungee jumping and contact sports or anything that will throw your head around.
As with all surgery there are sometimes complications and Sarah told us about:
Infections – 8% cases Haemorrhage under 1%
Hardware/technical malfunctions 15 – 20 %, would need further surgery.
Seizures – under 5%, Sarah has only seen this happen once and it stopped very quickly.
She then went on to say they can’t give anyone 100% guarantee that the patient will get the benefit that was hoped for and explained that DBS programming in children is challenging and time consuming. However, technology is developing and we can now do things that we couldn’t do 15 years ago! The stimulator can be programmed to suit the needs of each individual patient.
Both Margaret and Sarah gave really good presentations, sometimes over my head but mostly understandable. They spoke with care and even love for their patients and always want the best outcome.
Alfonso thanked the speakers then it was time for the questions. It has obviously been a really good webinar as we had lots of questions!
This is a summary of them:
- Dystonia and epilepsy, would DBS affect the epilepsy and can they be tackled together? This is not impossible but has to be very carefully considered. No evidence so far that DBS for Dystonia gives an improvement in their epilepsy.
- Difference between VNS and DBS – DBS electrodes go into brain tissue, targets are different for the VNS which stimulates the vagal nerve, and doesn’t go deep into the brain. Work differently but both use small electric currents.
- Child 8 has a rare genetic dystonia which involves different parts of the body and functions such as speech. Levodopa was good for but speech but had side effects.
- Would DBS be an option to help facial muscles and vocal chords. Sara – we never set speech improvements as a goal for DBS as we cannot see a change in clinic. Would not do DBS to improve speech alone as no evidence that it helps. Alfonso and Margaret both agree with Sarah. Margaret has seen some improvement in speech but this is very rare so it is never set as a goal for DBS.
- Is there any news on non-invasive stimulation? Margaret – unfortunately no option for viable therapy despite years of research. Can show some improvement for a while after external stimulation but it doesn’t last and needs to be repeated frequently, not practical.
- Electrodes in the brain do not cause any brain damage.
- Why are children operated on under GA, in children you don’t see an immediate effect so no benefit to them being awake, would also be frightening for them.
- Another neurologist asked about the success rate of clonidine, a drug which is beneficial in children with movement disorders. Margaret has a lot of experience of treating children with clonidine. Patients with severe dystonia may still need clonidine after DBS but a reduced dose. A few months later we can maybe wean them off the drug.
- Infection does not affect the performance of the stimulator. Would need to be treated of course.
- Margaret – Cochlear implants, very difficult to insert electrodes when a patient has cochlear implants, even difficult to do MRI scan. Should be possible but very difficult where implants are already in place.
- Cardio stimulator, Margaret would be worried about this and would need to consult with medtronic. Would there be any cross interference. Very difficult to say. Alfonso – in principle nothing is impossible but more investigations would be needed.
- For patients with existing conditions it may be possible to have DBS but great caution and investigations would be necessary.
- Does pubescence influence dystonia – Margaret – yes it does and it is difficult to manage, we just get them stabilised and then they move to adult services.
- Is there a difference in the procedure between verbal and nonverbal patients in the programming – Sarah – the programmer will get to know the patient and work with the family, the way you work is adapted but the programming procedure is the same.
- Is levodopa and/or botox etc reduced after the DBS Margaret – yes if successful the levodopa can be reduced, botox may not be needed at all or may need reduced injections/amounts. Treatment after DBS can change for upto 3 years post surgery.
- Are you aware of any genetic treatment studies – Margaret – no not at the moment.
- Are the guidelines for surgery changing and may allow more complex dystonias to be treated with DBS – Margaret – yes they are changing all the time – with each patient. More complex dystonias are accessing surgery worldwide.
Monika closed the meeting by thanking the speakers and moderator and told us that the webinar will be available on our you tube channel. Keep an eye on our podcasts too.
Well I hope you all agree it was a very interesting and worthwhile webinar, I have certainly learned more about treating children with DBS, it does sound daunting that very young children are having brain surgery, but in the capable hands of Magaret, Sara, Alfonso and their peers around the world I do believe the children are in very safe hands.
Gill Ainsley, Dystonia Europe Vice President and Secretary
