Sensory system abnormalities in childhood dystonia
Research type
Research Study
Full title
Sensory system abnormalities in childhood dystonia / dystonic cerebral palsy – are sensory networks modulated by Deep Brain Stimulation?
IRAS ID
215381
Contact name
Verity M McClelland
Contact email
Sponsor organisation
King's College london
Duration of Study in the UK
3 years, 6 months, 0 days
Research summary
Research Summary
Dystonia is a disabling and painful motor disorder causing involuntary muscle contractions, twisting movements and abnormal postures. Childhood-onset dystonia often affects the whole body and is very severe.
Dystonia has no cure but symptoms can be improved by a technique called Deep Brain Stimulation (DBS). This involves using fine wires, called electrodes, to deliver electrical pulses to a specific group of nerve cells deep within the brain, called the Globus Pallidus interna.
DBS is more effective in some types of dystonia than others but we do not know why because a) we don’t yet know how DBS works and b) we don’t yet understand the mechanisms responsible for different types of dystonia, especially dystonia resulting from a brain injury during infancy (dystonic cerebral palsy).
One possible mechanism in adults with genetic dystonia is that abnormal perception of sensory inputs leads to distorted or excessive movements. However, this has not been investigated in dystonic cerebral palsy.I have found evidence of abnormal sensory pathways in some children with dystonia, particularly in dystonic cerebral palsy. My data suggest that such sensory deficits may be linked to outcome from DBS, but more powerful markers of outcome are still needed. I plan to take this forward by investigating whether measures of sensory processing within the brain are abnormal in children with different types of dystonia and whether these measures relate to outcome from DBS.
To investigate sensory processing I will use frequency analysis methods to detect changes in electroencephalogram (EEG) (brainwave) activity in relation to a sensory stimulus and a motor task. I will compare these measures in children with different types of dystonia and in children with good and poor outcome following DBS. The studies will be incorporated into the children’s clinical assessment pathway at Evelina Children’s Hospital.Summary of Results
Our research aims to find out how movement control in children/young people with dystonia differs from children/young people who do not have dystonia. This information is crucial for helping us to develop and adapt treatments for individual children/young people.
The aim of this particular study was to find out more about how the brain responds to sensory information related to movement, in children and young people with and without dystonia.
The study involved recording brain activity, using EEG (electroencephalogram) during a simple movement task controlled by a robotic device, which delivered brief wrist extension movements.
The EEG is a complex signal and contains rhythmic activity in different frequency bands. These different frequencies relate to different brain functions (Think of a radio – different radio stations are transmitted at different frequencies).
After the EEG had been recorded we analysed it in a particular way, looking at specific frequency bands - in particular a rhythm known as “mu”. Mu activity is a specific brain rhythm that changes in relation to movement or sensory stimulation. Changes in the level of mu activity reflect processing by the brain of incoming sensory information, especially information relating to movement (such as the position of our limbs or the degree of stretch or tension on a muscle at any given time).The findings from this study demonstrate that processing of sensory information, measured by assessing changes in the level of the brain’s mu rhythm in response to a small stretch stimulus at the wrist, is reduced in children with dystonia. Importantly, this finding was common across different types of dystonia (for example genetic dystonias and dystonic cerebral palsy) and across the whole age-range studied (5-21 years).
These new findings are important because they demonstrate an impairment of sensory processing and its development in young people with dystonia.
The observation that the impairment in mu modulation was a common phenomenon across different types of dystonia is also important as this could be used as a marker for monitoring or delivering therapy.
The full paper has been published open access (i.e. it is free for anyone to download) and can be found here: https://gbr01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fclick.pstmrk.it%2F3ts%2Fdoi.org%252F10.1016%252Fj.nicl.2021.102569%2FNBTI%2F8-i1AQ%2FAQ%2F0d10840c-e50d-442a-a96a-ca4a6dc94525%2F1%2F9bECH70jar&data=05%7C02%7Charrow.rec%40hra.nhs.uk%7C23306bb03a0a4907225408dc8bb7061c%7C8e1f0acad87d4f20939e36243d574267%7C0%7C0%7C638538865394957431%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=3UH%2BefoBt%2B4Ofa9gTM2bWcO7VTnFaYUjE8UZc8erVIQ%3D&reserved=0Note -The above summary was sent to the participants and their families with a thank you letter for taking part.
REC name
London - Harrow Research Ethics Committee
REC reference
17/LO/0439
Date of REC Opinion
5 May 2017
REC opinion
Further Information Favourable Opinion