Electrical and magnetic brain stimulation approaches have been developed by Australian researchers for persons suffering from treatment-resistant depression.
Patients will soon have access to more effective, individualized treatment for depression owing to research conducted by Associate Professor Andrew Zalesky and his team at the University of Melbourne in cooperation with the Queensland Neurostimulation Centre.
Zalesky and his team developed novel imaging techniques based on MRI scans of a patient's brain with a PhD in electrical engineering and formal training in applied mathematics.
“In simple terms, we’re using advanced brain imaging techniques to enable us to target the correct circuit to treat,” he told create. “Traditional approaches use a one-size-fits-all approach, and the problem with that is that we believe we end up targeting the wrong circuits in some patients.”
According to Zalesky, depressive symptoms may be caused by a disruption in communication between important brain regions. Traditional depression TMS (transcranial magnetic stimulation) or brain stimulation therapies all target the same location, regardless of the patient's symptoms or brain architecture.
“We know through neuroimaging studies that there’s extensive variation in brain circuitry, brain connectivity and brain networks across individuals,” he added. “The one-size-fits-all approach might target the wrong circuits in particular individuals — and we think that’s why some patients don’t respond well to treatment.”
How it works
“When it comes to the personalisation of brain stimulation therapy, the main engineering challenge is the low signal-to-noise ratio of functional MRI images. Separating noise from brain activity is a real challenge,” Zalesky said.
“To reliably map a person’s functional brain circuitry, we need to acquire lots of data. Typically, the patient would need to spend up to 30-50 minutes inside the MRI scanner for us to collect sufficient data to ensure that the brain network maps we reconstruct are reliable.”
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| Brain connections mapped with functional MRI. |
Some patients are unable to remain still for long periods of time in an MRI scanner.
“We’ve developed novel algorithms that allow us to reduce the amount of time that the patient needs to spend in the scanner — but with that minimal amount of data, we’re still able to reconstruct accurate and reliable brain maps that we can then use to inform the brain stimulation therapy,” he added.
“In a nutshell, the key innovation here is the novel image processing algorithms that we’ve developed to process the brain scans, which we can then use to reduce the time the patient spends in the scanner. Therefore, it makes it more comfortable for the patient and it makes personalisation of the therapy feasible.”
The method, which is being tested at the Queensland Neurostimulation Centre, also employs a TMS robot to offer their breakthrough in finding the best treatment coordinate.
“A coil delivers the stimulation to that precise point to the patient and if the patient moves their head during the treatment, the robot will then adjust the coil to compensate for that movement,” Zalesky explained.
“That way, we can be sure that therapeutic magnetic stimulation is delivered to the precise coordinate at all times.”
Engineering better therapeutics
Zalesky specializes in the field of systems neuropsychiatry, which focuses on understanding the brain as a whole through the relationships between distinct regions and how communication and interactions occur between them.
“We’ve moved from a reductionist approach where we’re focused on trying to understand the function of a specific region to a systems approach,” he remarked.
“The importance of that is that we know now that many neuropsychiatric and neurological disorders are actually disorders of altered brain connectivity."
“ For example, schizophrenia is associated with dysfunction and disruption to communication between multiple brain regions, particularly frontal and subcortical circuits. Similarly, with depression, neural circuits linking the limbic system with the frontal cortex show evidence of dysfunction, and we believe that altered interactions between these brain regions may in part result in the symptoms of depression.”
The Queensland Neurostimulation Clinic has been licensed to use the technology, which was recently approved by the Therapeutic Goods Administration in Australia. To date, around 30 patients have been treated.
“While a full clinical trial is needed to establish efficacy, most patients have reported excellent outcomes,” Zalesky added.
Some people only need one treatment, while others need maintenance treatments every 6 to 12 months. However, the researchers expect that their improved method will result in greater efficacy.