Open-Access Article on Precuneus Magnetic Stimulation for Alzheimer’s Disease
Koch, G., Casula, E. P., Bonnì, S., Borghi, I., Assogna, M., Minei, M., Pellicciari, M. C., Motta, C., D'Acunto, A., Porrazzini, F., Maiella, M., Ferrari, C., Caltagirone, C., Santarnecchi, E., Bozzali, M., & Martorana, A. (2022). Precuneus magnetic stimulation for Alzheimer's disease: A randomized, sham-controlled trial. Brain: A Journal of Neurology, 145(11), 3776–3786. https://doi.org/10.1093/brain/awac285
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What is the science?
In Alzheimer's disease (AD), pathological alterations occur in the Default Mode Network (DMN), including the precuneus, a region in the posterior cortex. The DMN is highly activated when people are awake and aware but are not pursuing any particular goal, thought, or task. The DMN is typically active when we direct attention inwards, as when we daydream, think about our day, and allow our minds to wander.
The precuneus exhibits early accumulation of amyloid plaques and neurofibrillary tangles, markers associated with AD pathology. These changes contribute to precuneal and DMN dysfunction. Research indicates that rTMS may restore cognitive function in mild AD cases over short durations.
What is the takeaway?
Repetitive Transcranial Magnetic Stimulation (rTMS) offers non-invasive therapeutic utility for AD by targeting the precuneus, potentially attenuating disease progression, and augmenting precuneal neural activity.
How did they do it?
The researchers cognitively assessed a cohort of 50 patients with mild to moderate AD before study commencement. They randomly assigned participants to the genuine rTMS experimental group or the sham rTMS control group. They administered intensive treatment five times weekly for 2 weeks, followed by weekly sessions for 22 weeks. They performed cognitive assessments at baseline, the 12-week midpoint, and the study's conclusion. They used single-pulse TMS with EEG to evaluate precuneus excitability and oscillations.
What Did They Find?
The researchers analyzed clinical and behavioral assessments and EEG-derived metrics. Although both groups cognitively declined, the experimental group exhibited smaller cognitive score decreases at the study's mid- and end-points. The experimental group's EEG readings confirmed enhanced precuneal activity at the study's conclusion.
What is the impact?
This groundbreaking study examined long-term rTMS effects, targeting the precuneus within the DMN in AD patients. Twenty-four weeks of precuneus rTMS delayed cognitive and functional decline in AD.
Glossary
Alzheimer's disease (AD): a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and behavioral changes, primarily affecting the elderly. It is marked by the accumulation of amyloid plaques and neurofibrillary tangles in the brain.
default mode network (DMN): task-negative circuit, active when we are reflective and deactivated when we attend to the environment.
precuneus: a region located in the medial aspect of the superior parietal lobule, part of the posterior cortex, involved in visuospatial processing, episodic memory, and self-related mental representations. It is a key component of the Default Mode Network.
repetitive transcranial magnetic stimulation (rTMS): a non-invasive neuromodulation technique that utilizes magnetic fields to stimulate neural activity in specific brain regions.
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