Working Memory Training for Preschoolers at Risk of ADHD and Training Effects on Time Perception, ADHD Symptoms, and Academic Performance

verbal working memory (CMS- digit span)

时间窗: 5 weeks, immediately after the intervention

The number subtest from the Children Memory Scale (Cohen, 1997) was used to measure children's verbal working memory. The Numbers subtest included both digit span forward and backward tasks, for which the children were asked to recall digit sequences presented verbally in increasing length, either in the same order for Numbers Forward or in the reverse order for Numbers Backward. The total score was the sum of the scores for the forward and backward tasks.The raw score scale ranges from 0 to 30. A higher score indicates a better verbal working memory.

verbal working memory(CMS-digit span)

时间窗: before the intervention

The number subtest from the Children Memory Scale (Cohen, 1997) was used to measure children's verbal working memory. The Numbers subtest included both digit span forward and backward tasks, for which the children were asked to recall digit sequences presented verbally in increasing length, either in the same order for Numbers Forward or in the reverse order for Numbers Backward. The total score was the sum of the scores for the forward and backward tasks.The raw score scale ranges from 0 to 30. A higher score indicates a better verbal working memory.

non-verbal working memory(CMS - picture location)

时间窗: 5 weeks, immediately after the intervention

The picture location subtest from the Children Memory Scale (Cohen, 1997) was used to test participants' non-verbal working memory. Children were asked to look at pictures on a page for 2 seconds and to recall and indicate the pictures' locations by putting chips on the right places that matched the positions of the pictures showed. A score was given when the participant successfully matched the correct position of a picture.The raw score scale ranges from 0 to 30. A higher score indicates a better nonverbal working memory.

nonverbal working memory(CMS - picture location)

时间窗: before the intervention

The picture location subtest from the Children Memory Scale (Cohen, 1997) was used to test participants' non-verbal working memory. Children were asked to look at pictures on a page for 2 seconds and to recall and indicate the pictures' locations by putting chips on the right places that matched the positions of the pictures showed. A score was given when the participant successfully matched the correct position of a picture. The raw score scale ranges from 0 to 30. A higher score indicates a better nonverbal working memory.

Time perception: time discrimination

时间窗: 5 weeks, immediately after the intervention

A computerized task that examined participants' abilities in discriminating discrepancy between different durations of time (Gooch et al., 2011). A threealternative forced-choice (oddball) paradigm was used. On each trial, the child heard three 1000Hz tones, two of which were 1200ms long and a roving target which was at a different length (400ms, 700ms, and 1100ms - each repeated nine times). The child was required to choose which interval was "different" from the other two. Six easy trials of 100ms comparing with 1200ms were incorporated randomly during the experiment to evaluate the attention level of the participants.

Time perception: time reproduction

时间窗: 5 weeks, immediately after the intervention

A computerized lightbulb game was used to measure participants' abilities in recognizing and producing a designated period. The task was adapted from a similar task developed by Gooch and colleagues (2011). It was presented in a computer-game-like format where the child was asked to look at the red lightbulb that would appear on the screen and remember how long it had been left on (3s, 5s, 6s, 9s, 12s, and 15s). After, the child was asked to reproduce for the same length of duration. Immediately following this presentation the screen went blank and the participant was asked to "turn the yellow lightbulb on and leave it on" (use "ENTER" to turn on) for the same amount of time as it had been for the red lightbulb, and then use "SPACE" to turn off the light. Each target duration is presented twice in a randomized order for a total of 12 trials.

Time perception: time production

时间窗: 5 weeks, immediately after the intervention

Subjects were required to indicate the end of 3, 5, 12, and 20-s intervals (each produced twice) by saying "STOP" to indicate the end of the temporal duration.

Emotion situation knowledge measures.

时间窗: 5 weeks, immediately after the intervention

This task was developed by Garner et al. (1994) to measure children's ability to infer emotions from situational cues, and similar tasks have been used among preschoolers (Beaudoin et al. 2020; Gallant et al. 2020). Social situations commonly encountered by children were presented in pictures, with the facial expressions of the target characters left out (i.e., blank faces were shown). The children were asked to identify the feeling of the target character by either naming the emotion or pointing to the corresponding facial expression out of four options (happy, sad, angry, and afraid) given on the stimulus sheet. There were two sample items followed by 13 test items.

Working Memory Behavioural Manisfetation

时间窗: before the intervention

The Working Memory Subscale from the BRIEF-P is used to measure participants' daily behavioural manifestation of working memory reported by parents. The minimum raw score is 0 and maximum score is 17. A higher score indicates more severe deficits in working memory.

Theory of mind (ToM)

时间窗: 5 weeks, immediately after the intervention

Children's ToM will be measured by the ToM scale developed by Wellman and Liu (2004). The seven-item scale was designed for the experimental to adminster in order according to the difficulty of the task, with the Diverse Desire task as the easiest, and the Real-Apparent Emotion task as the most difficult. Participants will receive one point for each task passed successfully (range: 0-7).A higher score indicates a better ability of ToM.