Postdoc, Mind research and imaging center, national cheng kung university
Alpha rhythm is believed to be related to relaxation behavior on cortical inhibition. Numerous studies have reported neurofeedback training (NFT) of alpha rhythm on enhancement of working memory. However, the effect of alpha NFT on episodic memory remains largely unknown. Moreover, there is largely obscure on prominent location of alpha wave of an NFT. The present study aims to explore promising topological location for NFT of alpha rhythm and effect on episodic memory. Episodic memory was evaluated in terms of the picture recognition task. NFT of twelve sessions were conducted within three weeks. In the NFT, amplitude of alpha wave was significantly and progressively elevated in the alpha group but has no change in the control group. Accuracy of the picture recognition task was significantly higher in the alpha group compared to the control group. Furthermore, twenty-nine participants (83%) of the alpha group, “Responder”, revealed that alpha amplitude of 12th session was 1.5-fold of alpha amplitude of the first session. Topographic distribution of alpha rhythm was prominent over the frontoparietal region in 86.2% of responders, and 13.8% of responders primarily showed alpha rhythm in the occipital region. Frontoparietal-dominated responders had significantly higher accuracy of the picture recognition task compared to the control group, but occipital-dominated responders showed no difference. The present study showed that amplitude of alpha rhythm was trainable and had enhancement on episodic memory after NFT. Our findings suggest that enhancement of alpha rhythm over the frontoparietal region has great enhancement on episodic memory.
Abstract: Neurofeedback training (NFT) of the alpha rhythm has been used for several decades but is still controversial in regards to its trainability and effects on working memory. Alpha rhythm of the frontoparietal region are associated with either the intelligence or memory of healthy subjects and are also related to pathological states. In this study, alpha NFT effects on memory performances were explored. Fifty healthy participants were recruited and randomly assigned into a group receiving a 8–12‐Hz amplitude (Alpha) or a group receiving a random 4‐Hz amplitude from the range of 7 to 20 Hz (Ctrl). Three NFT sessions per week were conducted for 4 weeks. Working memory was assessed by both a backward digit span task and an operation span task, and episodic memory was assessed using a word pair task. Four questionnaires were used to assess anxiety, depression, insomnia, and cognitive function. The Ctrl group had no change in alpha amplitude and duration. In contrast, the Alpha group showed a progressive significant increase in the alpha amplitude and total alpha duration of the frontoparietal region. Accuracies of both working and episodic memories were significantly improved in a large proportion of participants of the Alpha group, particularly for those with remarkable alpha‐amplitude increases. Scores of four questionnaires fell in a normal range before and after NFT. The current study provided supporting evidence for alpha trainability within a small session number compared with that of therapy. The findings suggested the enhancement of working and episodic memory through alpha NFT. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc.
Pub.: 01 Apr '16, Pinned: 31 Jul '17