“…Te center of the word-association frequency diagram illustrated the away from "BCI" and its composite words to "control," "performance" and "state," highlighting the shift in the review literature focus away from how BCI system operates and the move to the practical real-world application [4,26,27,29,35,37,90] (Figure 6). Tere is a district clustering in the 2018 onward diagram that is indicative of the focus center of research and is centered on "human," "user," and terms such as "cognitive" "process," "technology," and "response," terms associated with the application of BCI [29,40,44,97] (Figure 6). Early reviews focused on the methods and achieved greater performance with words such as "access pathways" [66], "alternative communication" [67], "biocompatibility" [43], "classifcation" [57], "cognitive tasks" [31], "control" [33], "motor imagery" [7,36,70,79], "neuroengineering" [19,43] "neuroimaging" [37], and "sensory-motor regions" [79], all of which show a focus on improving the understanding of brain function and how BCI systems are able to exploit this knowledge.…”