Gamma connectivity predicts response to intermittent theta burst stimulation in Alzheimer’s disease: a randomized controlled trial

There is growing evidence that neural network dysfunction is a likely proximate cause of cognitive impairment in Alzheimer’s disease and may represent a promising therapeutic target.

In this study, researchers investigated whether a course of intermittent theta burst stimulation (iTBS) could modulate functional connectivity and cognition in mild to moderate Alzheimer’s.

In a double-blind parallel randomized sham-controlled trial, 58 participants were randomized to either active or sham iTBS.

Stimulation was applied to the left dorsolateral prefrontal cortex, right dorsolateral prefrontal cortex, left posterior parietal cortex, and right posterior parietal cortex in every treatment session.

Neurobiological (electroencephalography), cognitive, and behavioral functional assessments were undertaken at baseline and end of treatment.

Cognitive and functional assessments were also conducted at 3- (blinded) and 6-month (active group only) follow-ups.

Active iTBS increased resting-state gamma connectivity and improved delayed recall on an episodic memory task.

Both baseline gamma connectivity and change in gamma connectivity predicted improved delayed recall following active treatment.

These findings support future research into iTBS for Alzheimer’s focusing on protocol optimization.

?

Hoy K.E., Emonson M.R.L., Bailey N.W., Rogers C., Coyle H., Stockman F., Fitzgerald P.B. Gamma connectivity predicts response to intermittent theta burst stimulation in Alzheimer's disease: a randomized controlled trial. Neurobiol Aging. 2023 Dec;132:13-23. doi: 10.1016/j.neurobiolaging.2023.08.006

Section snippets

Trial protocol

This was a double-blind parallel randomized sham-controlled trial. Participants were randomized to receive 21 sessions of either active or sham iTBS over a 6-week treatment course. Both raters and participants were blind to the treatment group. Although the research nurses administering treatments were aware of the participants’ treatment groups, they were not involved in any cognitive, functional, or EEG assessments and were counseled to avoid discussion of treatment-related aspects with …

Resting-state EEG: functional connectivity

Network-based statistics identified a network exhibiting greater gamma connectivity in the active group compared to the sham group at the?end of treatment in the eyes closed condition (p?=?0.055);?see Fig. 2. The identified network was widespread, encompassing frontal, parietal, and occipital regions both within and between hemispheres, with predominantly frontal-to-frontal connectivity and frontal to parietal/occipital connectivity. No other changes in gamma network activity were identified …

Discussion

The current study sought to investigate whether iTBS could successfully engage a proposed proximate therapeutic target in Alzheimer’s, namely dysfunctional neural connectivity. The primary hypotheses, that iTBS would significantly modulate resting-state connectivity and improve episodic memory, were supported. Specifically, a 6-week treatment course of iTBS significantly enhanced gamma connectivity and improved delayed recall for episodic memory. The active iTBS group showed a significant and …

?

--

Announcement: Membership to the Academy of Brain Stimulation is now open!

Join the ?????????????? ???? ?????????? ?????????????????????? as a ???????? ???????????? and gain exclusive access to a comprehensive educational library, featuring lectures, tutorials, interviews, and overviews of continuously updated, evidence-based clinical protocols.

Full membership also offers the opportunity to have your questions answered by leading TMS experts and to connect with a global network of brain stimulation professionals.

Visit our website for more information: https://brainstimulation-academy.com/