# Combining Stimulation Protocols to Probe Memory Consolidation—Commentary on Hausdorf et al. 2025

## TL;DR

This commentary discusses a study finding that combining two brain stimulation methods during sleep does not improve memory consolidation, unlike when used separately.

## Contribution

The commentary provides new insights into why combined stimulation protocols may not enhance memory consolidation.

## Key findings

- Combining closed-loop acoustic stimulation with tDCS during sleep does not improve memory consolidation.
- The study contrasts with previous findings where each stimulation method alone showed benefits.
- Potential explanations for the lack of combined effect are proposed.

## Abstract

A recent study by Hausdorf et al. reported that combining closed‐loop acoustic stimulation with transcranial direct current stimulation during sleep does not improve memory consolidation. This contrasts with past studies that reported a beneficial effect of each method individually. In this commentary, I discuss the relevance of the study in the current literature and offer potential explanations for this absence of effect.