What are Neurodevelopmental Disorders?
Neurodevelopmental disorders (NDDs) affect the development of children and often appears in early childhood or infancy, with an estimated prevalence of 3-4% of children in the UK. They can interfere with the acquisition, retention, or application of specific skills or sets of information. They are typically marked by delayed development or impaired function in attention, learning, memory, perception, language, problem-solving, social interaction, or mobility. NDDs can have a variety of causes, such as genetic, environmental, and medical conditions. Some examples of NDDs include learning disabilities, autism, ADHD, intellectual disabilities, Tourette’s syndrome, cerebral palsy, and Rett syndrome.
Do all neurodevelopmental disorders need treatment?
One thing to consider is the need for treating NDDs. Celebrations of neurodiversity in the modern day shows a shift in the perception of NDDs over time. For example, the term ‘mental retardation’ used to be widely used but now this has shifted to ‘intellectual disability’, to help remove any negative connotations and misunderstandings. Similarly, autism used to be seen as a disease, but now differences between people are accepted and celebrated.
Some currently existing interventions for supporting individuals with NDDs include occupational therapy, behavioural therapy, skills learning, physical therapy, speech-language services, and medication. Many individuals with NDDs also have comorbid mental health conditions. Recent research indicates how TMS could also help support those with NDDs, by targeting the comorbid mental health conditions and/or elements of the NDDs themselves.
TMS and Autism Spectrum Disorder
Autism (ASD) is a spectrum condition that can be characterised by difficulties in social interaction and communication (e.g. verbal and non-verbal), restricted, repetitive and inflexible patterns of behaviour, executive dysfunction, and sensory abnormalities. Some current interventions for ASD include behavioural therapies (e.g. ABA), speech therapy, sensory therapy, occupational therapy, physical therapy, animal therapy, and music and art therapy. The research basis for TMS as a treatment for ASD symptoms is still very much in its infancy.
The few studies that have been published indicate that there is potential. Using both rTMS or iTBS (theta burst stimulation) over the dorsolateral prefrontal cortex or inferior parietal lobe has been found to help reduce repetitive-ritualistic behaviours, enhance selective attention and social functioning, and improve executive functioning deficits. There are also no identified risk factors for TMS-induced adverse effects that are specific to ASD, meaning that TMS is just as safe for individuals with ASD.
TMS and Attention Deficit Hyperactivity Disorder
ADHD can be characterised by a persistent pattern of inattention, hyperactivity and impulsivity, and a reduced quality of social, academic and occupational achievements. Symptoms typically present before the age of 12, and often persist into adulthood. Some current interventions for ADHD include medication, cognitive training, behavioural therapy, social skills training, and psychoeducation and family training. The research basis for the use of rTMS as a treatment for ADHD is conflicting, with some studies finding that rTMS can reduce symptoms, and others finding that rTMS doesn’t.
There is some evidence that the use of rTMS alongside medication could be a beneficial pairing for reducing ADHD symptoms. Transcranial direct stimulation (tDCS) is another non-invasive neuromodulation procedure that also affects brain activity. There is some research support that anodal tDCS could be more promising as a treatment for ADHD. However, more research is needed to establish this further.
TMS and Tourette’s Syndrome
Tourette’s syndrome is a condition that causes involuntary motor (e.g. eye blinking, eye darting, nose twitching, head jerking) and vocal tics (e.g. humming, sniffing, repeating words, and throat clearing). Some current interventions for Tourette’s syndrome include medication, behavioural therapy, and education for parents and schools.
The research basis for using TMS as a treatment for Tourette’s syndrome is also conflicting, but there is potential for rTMS to help reduce tics, as well as improve comorbid depression and anxiety. In these cases, using rTMS is preferable to using cTBS (theta burst stimulation), and a younger age during treatment is correlated with superior tic outcomes.
TMS and Other Neurodevelopmental Disorders
One study found that rTMS could improve sleep duration and sleep quality in children with Rett syndrome. However, they did not find any significant effects on degenerative changes.
There is also some research suggesting that TMS could also be beneficial as treatment for cerebral palsy, with improvements found in balance control, cognitive and learning abilities, and increased functional brain connectivity. It is suggested that combining rTMS with motor rehabilitation therapy could be a beneficial pairing for treatment.
In summary, the research basis for the use of TMS as a treatment for neurodevelopmental disorders is very much in its infancy. TMS looks promising for treating ASD with effects lasting post-treatment., and inhibitory TMS also has potential for reducing tic symptoms. For ADHD, anodal tDCS looks more promising than TMS. TMS could also be beneficial for dyslexia and cerebral palsy, but not for Rett syndrome. TMs is safe to use for patients with neurodevelopmental disorders, with most experiencing mild-to-none adverse effects, and only a few experiencing severe adverse effects. A lot of further research is needed to build up the research base even further, before TMS can be widely used as a treatment for neurodevelopmental disorders.
Smart TMS Bristol Practitioner