Transcranial Direct Current Stimulation (tDCS)/Transcranial Alternating Current Stimulation (tACS)Original ArticleTranscranial Oscillatory Direct Current Stimulation During Sleep Improves Declarative Memory Consolidation in Children With Attention-deficit

- Slow oscillations (<1 Hz) during slow wave sleep support consolidation of declarative memory, and the application of transcranial oscillatory direct current stimulation (toDCS) at 0.75 Hz can enhance consolidation of declarative memory in healthy adults.
- Children with ADHD display altered slow EEG-activity during slow wave sleep and show deficits in the sleep associated consolidation of declarative memory.
- Applying toDCS during slow wave sleep in children with ADHD improved sleep-dependent consolidation of declarative memory to a level comparable to healthy controls.
- To our knowledge this is the first study reporting that in ADHD brain functions can be alleviated by toDCS.

BackgroundSlow oscillations (<1 Hz) during slow wave sleep (SWS) promote the consolidation of declarative memory. Children with attention-deficit/hyperactivity disorder (ADHD) have been shown to display deficits in sleep-dependent consolidation of declarative memory supposedly due to dysfunctional slow brain rhythms during SWS.ObjectiveUsing transcranial oscillating direct current stimulation (toDCS) at 0.75 Hz, we investigated whether an externally triggered increase in slow oscillations during early SWS elevates memory performance in children with ADHD. Methods: 12 children with ADHD underwent a toDCS and a sham condition in a double-blind crossover study design conducted in a sleep laboratory. Memory was tested using a 2D object-location task. In addition, 12 healthy children performed the same memory task in their home environment.ResultsStimulation enhanced slow oscillation power in children with ADHD and boosted memory performance to the same level as in healthy children.ConclusionThese data indicate that increasing slow oscillation power during sleep by toDCS can alleviate declarative memory deficits in children with ADHD.