Magnetically stimulating the brain might improve symptoms of autism and Asperger's syndrome
KENZO LOW could always look people in the eyes, but it hurt. "I felt a piercing intrusive sensation, like they were threatening me," he says. All that changed when he had a non-invasive form of brain stimulation. The idea was to see if it would alter any of his Asperger's symptoms. Several months afterwards, he noticed a positive change in the way he interacted with his aunt: "I could look at her the entire time she spoke to me without flinching or cringing inside."
Low is one of a handful of people participating in the first clinical trials to test whether transcranial magnetic stimulation (TMS) might boost social skills in people with autism spectrum disorders. As well as gaining insight into how an autistic person's brain functions, it is beginning to look as if certain facets of ASD might be treatable - assuming of course that a person wants such intervention.
Early results suggest that empathy and social functioning improve when a small area at the front of the brain is stimulated, while ability to communicate and concentration appear to be boosted when TMS is used to suppress activity in a different region of the brain.
"We're not proposing that this is likely to be a cure," says Paul Fitzgerald of the Monash Alfred Psychiatry Research Centre in Melbourne, Australia, who is leading the research that Low has been participating in. "But even if we only get short-term benefits, or they only occur in a small percentage of patients, it is really one of the first demonstrations that we can do something at a biological level that might be therapeutic."
TMS is a non-invasive technique that uses a magnetic coil to induce electric currents in the brain, which can either stimulate or suppress activity. Fitzgerald's team has been using a new form of TMS, which can penetrate up to 5 centimetres into the brain tissue, activating an area of the medial frontal cortex which is less active in people with ASD as they perform tasks related to social interaction.
In one trial, a 20-year old woman with Asperger's was given 15 minutes of TMS for nine days and her symptoms diminished on three scales used to assess the condition (The Journal of ECT, DOI: 10.1097/YCT.0b013e3181f07948). Like Low, she found it less uncomfortable making eye contact and felt more relaxed in social situations.
Intriguingly, Fitzgerald also has early findings to suggest that theory of mind, or the ability to attribute mental states to others, can be boosted or damped down in people without ASD - by stimulating or suppressing the same brain region. Fitzgerald's results in humans mirror recent findings in mice, which showed changes in social behaviour when the medial prefrontal cortex was either stimulated or suppressed using a technique called optogenetics, which switches brain cells on and off using light (Nature, DOI: 10.1038/nature10360).
Meanwhile, other groups have been using TMS to suppress brain activity in two different regions of the brain in people with ASD, with similarly encouraging results.
Manuel Casanova at the University of Louisville in Kentucky and his colleagues used TMS to suppress activity in the dorsolateral prefrontal cortex, an area of the brain involved in the integration of sensory processes, attention and other cognitive functions. Recent studies have suggested this area is impaired in people with autism.
The team studied a group of 16 people with high-functioning autism - those without learning difficulties - who were treated with TMS once a week for 12 weeks. They noticed a reduction in repetitive behaviours and irritability, and better concentration, compared with autistic people who didn't have the treatment (Journal of Neurotherapy, DOI: 10.1080/10874208.2010.501500).
As in Fitzgerald's study, some people responded better than others. Some children showed improvements at school and one started playing better chess, says team member Tato Sokhadze.
Lindsay Oberman at the Beth Israel Deaconess Medical Center in Boston and her colleagues have also noticed short-term improvements in the ability to name objects and recognise faces when an area of the brain involved in language processing is suppressed using TMS. In a small number of people with autism this has led to long-term changes (see "The emotional experience of a lifetime").
Everyone involved in these studies is anxious that no one thinks of TMS as a "cure" for autism. For a start, most of those studied so far have high-functioning autism and it's not clear if all people with autism would benefit. Also, none of the studies have looked at whether TMS can induce long-term changes in behaviour and what these long-term changes might be. "Stimulation can lead to improvements in certain skills, but we just looked at the improvements immediately afterwards," says Oberman, who has found that the brain of someone with autism responds differently to TMS than the brain of a neurotypical person. "We don't want to induce any kind of long-term change with the fear that something we think might lead to a benefit, might make them worse."
Even if TMS does prove its mettle as a therapy in autism, it is only ever likely to affect certain aspects of the condition, rather than making it go away, even if this was what an autistic person wanted. Low, who is 22 and training to be a doctor, says he still struggles with empathy and communication, even though being able to make comfortable eye contact means he's able to put more energy into reading people's facial expressions.
However, he says he is also glad that the majority of his Asperger traits remain intact. "I still feel pretty much like an Aspie, but with a reduction in daily anxiety. I definitely do not feel neurotypical at all."
