## 3 Results
### Study Characteristics
Moreover, most of the studies (N = 29, 66%) included females for over 50% of their samples (largest proportion was 81.25% in [98], and on the other hand, the smallest proportion was 9% [75]), and a single studied had only male participants [104]. It should be noted that there was no information for 4 studies [65; 70; 72; 79]. A total of 19 studies included participants suffering from ADHD, Mild Cognitive Impairment (MCI), schizophrenia, visual perceptual dysfunction, multiple sclerosis, fragile X syndrome, autism and overweight (adults), while the rest of studies (25) included healthy children, adults or older people. \begin{table}
\begin{tabular}{l c c} \hline \hline \multicolumn{1}{c}{**Study**} & **Game** & **Game Elements \({}^{*}\)** \\ \hline [PERSON] et al. [81] & BrainQuest & C, CM/CP, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [82] & [PERSON] & C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [83] & Space Fortress & AV, C, AP, PR, FB, DA \\ \hline [PERSON] et al. [84] & Game-based tasks & N/ST, C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [85] & Brain Fitness Program & N/ST, C, PR, LV, FB, DA \\ \hline [PERSON] et al. [86] & Recall the Game & N/ST, C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [87] & The Serious Game & N/ST, FB, DA \\ \hline [PERSON] et al. [88] & WM Training Game & N/ST, AP, DA \\ \hline [PERSON] et al. [42] & GAME & N/ST, C, AP, PR, LV, FB, DA \\ \hline [PERSON] and Band [89] & Luminosity & N/ST, AV, C, AP, DA \\ \hline [PERSON] et al. [90] & Computerized Interactive Remediation of & \\ Cognition—Training for Schizophrenia (CIRCuiTS) & N/ST, C, PR, LV, FB, DA \\ \hline [PERSON] et al. [91] & Timo’s Adventure & N/ST, AV, C, AP, PR, LV, FB \\ \hline [PERSON] et al. [92] & WM training: “Recall Them All” & N/ST, C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [93] & Towi video game & N/ST, AV, C, CM/CP, AP, FB \\ \hline [PERSON] et al. [94] & WM Training Game & N/ST, C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [95] & Game Show & C, AP, LV, DA \\ \hline [PERSON] et al. [96] & Find it, match it, solve it, complete it & ST, AP, PR \\ \hline [PERSON] et al. [97] & Mind Frontiers & N/ST, C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [98] & Cognitive Training Kit (COGNI-TRAcK) & C, PR, LV, FB, DA \\ \hline [PERSON] et al. [99] & CMI-APP & C, PR, LV, FB, DA \\ \hline [PERSON] et al. [100] & Fit Brains & C, AP, PR, LV, FB \\ \hline [PERSON] et al. [101] & [PERSON] game and Merry Snowballs game & C, AP, PR, LV, FB \\ \hline [PERSON] et al. [102] & Game-Based Auxiliary Training System (GBATS) & C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [103] & WM Training Game & C, AP, PR, LV, FB, DA \\ \hline [PERSON] et al. [104] & CCAT app & C, PR, LV, FB, DA \\ \hline \hline \end{tabular}  
*N/ST = Narrative/Stoytytelling; AV = Avatar; C = Conflict; CM/CP = Cooperation and Competition; AP = Action Points; PR = Progression; LV = Levels; FB = Feedback; DA = Difficulty Adjustment.  
\end{table} 
Table 2: _Cont._Regarding the outcomes that were reported, 19 studies presented data concerning participants' motivation and enjoyment in addition to the training domain outcomes, which were included in the majority of studies (N = 38), and only 6 studies focused exclusively on the effects in motivation and engagement outcomes, excluding any training domain outcomes. Data regarding the interventions' duration showed that there were cases with a single session (N = 4), which were cases for the assessment and screening of participants [63; 91; 93] for 18 months [77]. In general, the majority of studies (N = 25) ranged from 4 to 8 weeks in intervention duration. Thus, the total number of distinct sessions varied from 1-18 (N = 17) and 20 to 40 (N = 22), 2 studies supported the participants' free will to complete as many sessions as they liked [77; 88] and there was missing information for 2 studies [95; 101]. Session duration varied from 90 s [101] to 90 min [64].