###### Abstract
However, in reality, components should be treated as the subset of mechanics, since they are the basis that drive the mechanics. In order to overcome the obstacle of the absence of a well-defined context for GEs, by searching the literature for the most commonly accepted terms, and also based on the findings from [48; 49; 50; 51; 52; 53; 54; 55], we decided to conclude GEs to the following nine: (a) Narrative/Sforytelling; (b) Avatar; (c) Conflict (challenge); (d) Cooperation and Competition; (e) Difficulty adjustment; (f) Feedback; (g) Levels; (h) Progression; and (i) Action Points. Gamification as a strategy has been developed over the last decade, and its effectiveness has been tested in numerous studies, as mentioned previously. The majority of studies have been heavily focused on the impact of gamification in cognitive performance, but fewer studies have actually tested the impact of certain GEs in a scientific framework. A possible explanation is that researchers have been developing computerized CT by simply converting traditional paper-and-pencil tasks to digital tasks by also adding arbitrary GEs, since there is a lack of scientific framework that dictates how to build electronic interventions. On the other hand, the introduction of gamification has been utilized as a tool to increase motivation and long-term engagement, and this aspect has been evaluated as well. Several reviews and meta-analyses on gamified computerized CT have been conducted, providing useful and interesting results. For example, in the systematic review by [PERSON] et al., which investigates the effect of gamification on process outcomes and on the training domain, they concluded that action points (rewards) and feedback are dominating the gamification landscape, but social features such as competition are underused [55]. Moreover, gamified tasks have been proven to be more motivating and demanding, but no effects on the training domain were found [55]. Similarly, in the study of [PERSON] et al., which tried to identify what GEs are being applied for cognitive training, assessment or rehabilitation, they reported the scoring system and narrative context as the most used GEs and a strong association between usability and six out of the seven GEs that were analyzed. An interesting finding was that using GEs that act as extrinsic motivation promotors can potentially jeopardize patients' long-term adherence to interventions, especially if associated with progressive difficulty [53]. In another meta-analysis, the effectiveness of computerized CT with game-like features in school-aged children with typical and atypical development was examined and showed that it can improve cognitive and behavioral performance in both populations, and it may help to make the training less burdensome for children, fostering motivation [56]. The work of [PERSON] et al. is likely one of the most known works regarding GEs, in which they aimed to explore and evaluate how gamification has already been used for CT and evaluation purposes. The authors reported that certain elements such as action points (rewards) and feedback are suitable for people with Attention-Deficit Hyperactivity Disorder (ADHD), who are especially responsive to immediate feedback and to the clear definition of goals and objectives, but mixed effects of gamification on task performance were reported [49]. In another systematic review by [PERSON] et al., regarding the investigation of training and transfer effects of computerized training on executive functions in children, results demonstrated a moderate effect size, and the transfer effect was more explicit in near-transfer conditions. Typically, developing children improved more during training, but the addition of GEs negatively affected the training and transfer effects [57]. On the other hand, there were meta-analyses which evaluated the impact of CT programs, such as the one by [PERSON] et al., in which they examined the use of commercial computerized cognitive games which targeted elderly people (>60 years old) without cognitive impairment.