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Repeated sessions of electrical stimulation to brain networks associated with memory improved verbal learning in some Alzheimer's disease patients for up to eight weeks in a preliminary trial led by UT Southwestern Medical Center researchers. The findings, published in The Journal of Prevention of Alzheimer's Disease , indicate that while future trials are needed, neurostimulation shows early promise as a treatment for Alzheimer's and other neurodegenerative disorders, such as Lewy body dementia. The small trial tested the effectiveness of transcranial direct current stimulation (tDCS), which sends an electrical current through electrodes affixed to the scalp to alter the functioning of targeted brain regions .
The study was rigorously performed with results of two doses of tDCS compared with a control group. Unlike Alzheimer's medications that target plaques and protein tangles in the brain that disrupt mental abilities , tDCS doesn't alter brain pathology. Instead, its purpose is restoring damaged neural pathways to improve cognitive functioning.
"Around one-third of the active treatment groups experienced clinically meaningful improvements in verbal learning in this pilot trial," said lead author Christian LoBue, Ph.D., Associate Professor of Psychiatry and Neurological Surgery at UT Southwestern and an Investigator in the Peter O'Donnell Jr.
Brain Institute. "That's quite remarkable and mirrors the success rates for some of the earliest neuromodulation trials that led to Food and Drug Administration approval for treating depression. It's a very encouraging starting point.
" Researchers focused on applying tDCS to patients' dorsal anterior cingulate cortex, an area in the frontal lobe involved in the brain's memory network, to determine whether the device could improve learning and the consolidation of information stored in long-term memory. Twenty-five patients with Alzheimer's disease from cognition specialty clinics in the Dallas-Fort Worth area took part in the study, receiving either neurostimulation for 20 minutes on 10 days during the two-week trial, or a sham treatment with no electrical current. Participants in the neurostimulation group received current levels that caused tingling, itching, or prickling sensations on their scalps.
They took tests to measure memory and other high-level information processing skills before their first tDCS treatment and immediately after their last one. One-third of the neurostimulated patients showed clinically meaningful improvement in verbal learning—their ability to recall a series of words soon after hearing them—versus none in the control group. For those who improved after receiving a lower current, effects persisted for eight weeks, pointing to the technique's promise as a potential treatment.
Additionally, 25% of patients who received neurostimulation at a lower current and 33% who received a higher current showed clinically meaningful improvements in their abilities to rapidly produce words, such as naming objects and actions. This compared with none in the control group showing meaningful improvement. Variations in cranial anatomy are normal, and Alzheimer's patients display differing patterns of brain atrophy.
The research team said disparities in responses to tDCS could have resulted from underlying anatomical differences, and future trials could include brain imaging and customized placement of neurostimulation devices tailored to each individual's cranial anatomy. Dr. LoBue stressed that the findings are preliminary and will need further investigation.
"While we didn't see changes in their ability to form long-lasting memories in this trial, the area of the brain we've focused on could be a promising target for controlling a very debilitating set of Alzheimer's symptoms," Dr. LoBue noted. "We're at a critical starting point for understanding the possibilities.
" More information: Christian LoBue et al, High definition transcranial direct current stimulation as an intervention for cognitive deficits in Alzheimer's dementia: A randomized controlled trial, The Journal of Prevention of Alzheimer's Disease (2025). DOI: 10.1016/j.
tjpad.2024.100023.
