Neurological diseases: Brain stimulation with 3D ultrasound offers hope
Researchers are working on a 3D ultrasound system to stimulate the brain and help with diseases such as epilepsy, Parkinson's and depression.
A "3D matrix ultrasound transducer" is intended to help with deep brain stimulation and thus help with neurological diseases such as Alzheimer's dementia.
(Image: Fraunhofer IBMT / Bernd Müller)
3D ultrasound is typically used for diagnostic purposes, but now the aim is to treat and at least alleviate diseases such as epilepsy, Parkinson's, depression, addiction or the consequences of strokes – without surgery. To this end, researchers at the Fraunhofer Institute for Biomedical Engineering (IBMT) in St. Ingbert are developing a special ultrasound system that uses 256 individually controllable ultrasound transducers to target individual points in deeper regions of the brain and stimulate them precisely by controlling the sound beam in 3D.
The Institute obtains the data required for the research from the results of a previous magnetic resonance imaging scan of the patient. The doctors then know which areas of the brain are responsible for the neuronal disease. With the position data that flows into the control software, "the ultrasound signals can be precisely aligned".
The transducer is placed on the head via a flexible pad. Patients are unaware of the treatment. According to current research, ultrasound is harmless due to its low intensity, and the hair does not have to be shaved off, but only treated with contact gel. "The ultrasound frequencies are in the low-frequency range below 1 MHz, for example at around 500 kHz," reads a press release. The researchers use "piezoelectric elements" for the transducer, which change their surface when voltage is applied and thus produce the ultrasound.
Deep stimulation with 3D sound signals
Scientists have been working on these and similar methods – such as electrical brain stimulation – for decades, but targeting specific areas as precisely as possible presents them with challenges. The research team led by Steffen Tretbar, together with industrial partners from Germany, the EU, the USA, Canada and Australia, have high hopes for the new method. "By individually controlling the 256 electronic channels, the ultrasound treatment becomes 3D-capable. The elements of the transducer are arranged like a chessboard and irradiate the desired area of the brain from different angles," says Tretbar.
The ultrasound device can be programmed "so that the beams are sent in a predefined sequence or follow certain movement patterns". In the future, it should be possible to set all parameters individually. One hope is to dissolve plaque in brain cells in Alzheimer's disease or to treat depression. "Researchers can use our technology platform to develop very different therapies and test them in clinical trials in the future," says Tretbar.
"Methods such as stimulation using externally applied magnetic fields do not yet produce optimal results due to the relatively low precision with which they act," writes IBMT. However, placing electrodes in the brain is invasive and risky. This was recently demonstrated by the case of a patient in whom the electrodes implanted by the company Neuralink became detached. He is the first patient with a brain-computer interface.
(mack)