Increasing Brain Gamma Activity Improves Episodic Memory and Restores Cholinergic Dysfunction in Alzheimer's Disease.
Ann Neurol
; 92(2): 322-334, 2022 08.
Article
en En
| MEDLINE
| ID: mdl-35607946
ABSTRACT
OBJECTIVE:
This study aimed to assess whether non-invasive brain stimulation with transcranial alternating current stimulation at gamma-frequency (γ-tACS) applied over the precuneus can improve episodic memory and modulate cholinergic transmission by modulating cerebral rhythms in early Alzheimer's disease (AD).METHODS:
In this randomized, double-blind, sham controlled, crossover study, 60 AD patients underwent a clinical and neurophysiological evaluation including assessment of episodic memory and cholinergic transmission pre and post 60 minutes treatment with γ-tACS targeting the precuneus or sham tACS. In a subset of 10 patients, EEG analysis and individualized modelling of electric field distribution were carried out. Predictors to γ-tACS efficacy were evaluated.RESULTS:
We observed a significant improvement in the Rey Auditory Verbal Learning (RAVL) test immediate recall (p < 0.001) and delayed recall scores (p < 0.001) after γ-tACS but not after sham tACS. Face-name associations scores improved with γ-tACS (p < 0.001) but not after sham tACS. Short latency afferent inhibition, an indirect measure of cholinergic transmission, increased only after γ-tACS (p < 0.001). ApoE genotype and baseline cognitive impairment were the best predictors of response to γ-tACS. Clinical improvement correlated with the increase in gamma frequencies in posterior regions and with the amount of predicted electric field distribution in the precuneus.INTERPRETATION:
Precuneus γ-tACS, able to increase γ-power activity on the posterior brain regions, showed a significant improvement of episodic memory performances, along with restoration of intracortical excitability measures of cholinergic transmission. Response to γ-tACS was dependent on genetic factors and disease stage. ANN NEUROL 2022;92322-334.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Enfermedad de Alzheimer
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Memoria Episódica
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Estimulación Transcraneal de Corriente Directa
Tipo de estudio:
Clinical_trials
/
Prognostic_studies
Límite:
Humans
Idioma:
En
Año:
2022
Tipo del documento:
Article