A novel brain stimulation technique has produced promising early results for improving memory in patients with Alzheimer’s disease. The technique is called ultrasound-guided transcranial pulse stimulation (TPS) and sending ultrashort – 3 nanosecond – ultrasound pulses 3mm to 5mm wide and 3cm long into different regions of the brain at intervals of between 200 and 300 milliseconds. The pulses are delivered using a handheld device which is placed over the skull in a precise location to target specific areas of the brain.
TPS offers several advantages over other brain stimulation techniques. Electrophysiological brain stimulation cannot achieve focal brain activation deep in the brain, transcranial magnetic stimulation is not sufficiently precise, and deep brain stimulation techniques require an invasive procedure. TPS can be used to stimulate specific areas of the brain including superficial layers and deep brain tissue without costimulation of unwanted areas of the brain. Guided by a magnetic resonance navigation system a neurologist can target the pulses on precise areas of the brain. TPS is also easy to administer and is non-invasive.
The study was conducted on 35 patients with probable AD, all of whom were receiving optimized standard treatments. Treatments were provided over a period of between 2 and 4 weeks and anatomical MRI scans were conducted before and after stimulation with TPS. The study was split between two treatment centers with one center using a navigated approach to target relevant areas of the brain with the second center running a non-navigated approach. 93% of patients experienced no side effects, and the other 7% only had mild side effects.
The early findings of the study are encouraging. The treatment resulted in increased neuromodulatory effects with memory improvements in Alzheimer’s patients lasting for up to 3 months. Patients’ cognitive states were assessed using the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychological battery after 3 months. The CERAD scores improved significantly for the memory and verbal components for patients at both treatment centers. At the first treatment center there was a decline in the score for figural performance, but the researchers believe that is because the center did not stimulate the occipitoparietal cortex, which is involved in visuospatial processing. The researchers also examined patients using an fMRI scan and the memory improvements correlated with improvements in brain networks.
While the results are certainly encouraging, the study was only conducted on a small number of patients and there was no control group. Consequently, it is too early to tell whether the new technique could have clinical applications.
You can read more about the study in the paper – Transcranial Pulse Stimulation with Ultrasound in Alzheimer’s Disease—A New Navigated Focal Brain Therapy – which was recently published in the journal Advanced Science. DOI: 10.1002/advs.201902583