To deliver ultrasound from the transducer into the human head, a good acoustic coupling is essential. BrainSonix provides specialized acoustic coupling pads (gel pads) that facilitate efficient ultrasound transmission. These pads are placed between the transducer and the scalp. They serve two purposes: (1) to bridge the gap and conform to the contours of the head, eliminating any air spaces (since air would reflect ultrasound) and (2) to provide a controlled medium through which ultrasound travels before entering the skull. In practice, we apply a bit of standard ultrasound gel to both sides of the pad – on the concave side that touches the transducer and on the patient side – then sandwich the pad in between. The combination of the pad material and gel on both sides ensures good conduction of ultrasound from the transducer into the skin (with minimal reflection or loss).

BrainSonix offers two types of coupling pads: transmit pads and blocking (sham) pads. The transmit pads are made of an acoustically & visually transparent material that allows the ultrasound waves to pass through into the head with very low attenuation.

In contrast, the blocking pads (used for sham controls) use a patented design that contains an internal structure that reflects or absorbs the ultrasound, preventing it from reaching the brain. These are sold as a set with a transmit pad, both of which are visually opaque. This means that both pads in this set look and feel identical to the touch – even the person administering the treatment cannot distinguish them visually. This was a deliberate design to enable blinded studies: a technician can place a pad on the transducer without knowing if it’s the active or sham version, thereby maintaining placebo control conditions. The BrainSonix team pioneered this solution, creating the industry’s first truly effective ultrasound sham pad (patent pending) in 2023. These pads address a major challenge in focused ultrasound trials: normally, when ultrasound is on, a participant might hear a hum or feel a slight vibration, which could tip them off that they are receiving the real stimulation. With our sham pads, even though the device may operate and make sound, no ultrasound energy actually enters the head, and the participant experiences the same sensor cues either way – thus achieving a true placebo control condition.