Older adults get episodic memory boosting from noninvasive stimulation of prefrontal cortex during learning

Great example of exactly what we’re up against. The study in the previous post found no effect on Working Memory in older adults targeting dorsolateral prefrontal cortex (dlPFC). This study did find a positive effect on Episodic Memory in older adults targeting left lateral prefrontal cortex (PFC).

Episodic memory displays the largest degree of age-related decline, a process that is accelerated in pathological conditions like amnestic Mild Cognitive Impairment (aMCI) and Alzheimer’s Disease (AD). Previous studies have shown that the left lateral prefrontal cortex (PFC) contributes to the encoding of episodic memories along the life span. The aim of this randomized, double-blind, placebo-controlled study was to test the hypothesis that anodal tDCS over the left lateral PFC during the learning phase would enhance delayed recall of verbal episodic memories in elderly individuals. Older adults learned a list of words while receiving anodal or placebo (sham) tDCS. Memory recall was tested 48 hours and 1 month later. The results showed that anodal tDCS strengthened episodic memories, an effect indicated by enhanced delayed recall (48 hours) compared to placebo stimulation (Cohen’s d effect size=1.01). The observation that PFC-tDCS during learning can boost verbal episodic memory in the elderly opens up the possibility to design specific neurorehabilitation protocols targeted to conditions that affect episodic memory such as MCI.