Figure 1
Adaptive working memory training activities: Backwards Span Digits activity (A) and Following Instructions Objects activity (B) modified from Lau et al. (2023). Note, ISI = interstimulus interval.
Figure 2
Working memory measures used to calculate performance, maximum span and processing speed: Backwards Span – Digits version (A) and Letters version (B), Following Instructions – Objects version (C) and Letters version (D), and N-back (E), modified from Lau et al. (2023). Note. ISI = inter stimulus interval.
Table 1
Child Characteristics at Baseline.
| WORKING MEMORY TRAINING GROUP (n = 52) | ACTIVE CONTROL GROUP (n = 36) | GROUP DIFFERENCE p | |
|---|---|---|---|
| Age in years, mean (SD) | 9.43 (1.31) | 8.84 (1.07) | 0.02 |
| Female sex, n (%) | 23 (44.20) | 16 (44.44) | 0.95 |
| Primary caregiver highest level of education, n (%) | 0.70 | ||
| Completed high school | 2 (3.85) | 1 (2.78) | |
| University bachelor degree/diploma | 23 (44.23) | 16 (44.44) | |
| University postgraduate degree | 6 (11.54) | 7 (19.44) | |
| Not reported | 21 (40.39) | 12 (33.33) | |
| Secondary caregiver highest level of education, n (%) | 0.50 | ||
| Did not complete high school | 0 (0.00) | 1 (2.78) | |
| Completed high school | 4 (6.35) | 1 (2.78) | |
| University bachelor degree/diploma | 19 (30.16) | 14 (38.89) | |
| University postgraduate degree | 12 (19.05) | 6 (16.67) | |
| Not reported | 28 (44.44) | 14 (38.89) | |
| ADHD-RS-5 (raw score), mean (SD)1 | 9.25 (9.06) | 12.16 (10.96) | 0.36 |
| Raven’s SPM (raw score), mean (SD)2 | 34.77 (9.11) | 30.53 (9.77) | 0.60 |
[i] Note: 1One child in the control had ratings of clinical concern for ADHD-RS-5 and 2one child in each group had scores of clinical concern for the Raven’s SPM. Regressions and Chi-square tests were used to test group differences at baseline. Analyses adjusted for baseline age when testing group differences in scores for ADHD-RS-5 and Raven’s SPM. Abbreviations: ADHD-RS-5, ADHD Rating Scale-5 Home Version (18 items of inattention and hyperactivity/impulsivity symptoms rated on a 4-point scale by caregivers of children 5–17 years yield a total score ranging 0–54 with higher scores indicate greater symptoms. Scores >93rd percentile indicate clinical concern). Raven’s SPM, Raven’s Standard Progressive Matrices (a measure of fluid intelligence for individuals 6.5–80 years comprising five sets of 12 puzzles where the individual must identify the missing piece with the total score ranging 0–60 with higher scores indicating better fluid intelligence. Scores <7th percentile indicate clinical concern).
Table 2
Working Memory Scores at Baseline, Immediately Post-Intervention and 6-months Post-Intervention.
| WORKING MEMORY TRAINING GROUP | ACTIVE CONTROL GROUP | p | f2 | WORKING MEMORY TRAINING GROUP | ACTIVE CONTROL GROUP | p | f2 | WORKING MEMORY TRAINING GROUP | ACTIVE CONTROL GROUP | p | f2 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BACKWARDS SPAN DIGITS, MEAN (SD) | ||||||||||||
| BASELINE | IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | ||||||||||
| Performance | 7.60 (3.08) | 6.62 (3.19) | 0.48 | 0.01 | 7.59 (4.20) | 6.51 (3.80) | 0.94 | 0.00 | 9.00 (4.63) | 8.03 (3.38) | 0.88 | 0.00 |
| Maximum Span | 3.56 (0.85) | 3.24 (1.02) | 0.26 | 0.01 | 3.53 (1.14) | 3.20 (1.11) | 0.80 | 0.00 | 4.00 (1.44) | 3.60 (1.06) | 0.56 | 0.00 |
| Basic Processing Speed | 1396.20 (368.87) | 1492.85 (618.72) | 0.98 | 0.00 | 1468.11 (479.21) | 1643.09 (473.68) | 0.50 | 0.01 | 1219.15 (323.48) | 1348.80 (331.11) | 0.52 | 0.01 |
| Cognitive Processing Speed | 1672.74 (488.10) | 1450.39 (497.74) | 0.02 | 0.08 | 1906.80 (1534.72) | 1698.71 (886.39) | 0.71 | 0.00 | 1425.57 (439.33) | 1398.37 (342.74) | 0.49 | 0.01 |
| BACKWARDS SPAN LETTERS, MEAN (SD) | ||||||||||||
| BASELINE | IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | ||||||||||
| Performance | 5.50 (2.44) | 5.00 (2.19) | 0.86 | 0.00 | 6.39 (3.30) | 5.66 (2.42) | 0.90 | 0.00 | 6.78 (2.83) | 5.91 (2.36) | 0.39 | 0.01 |
| Maximum Span | 2.88 (0.81) | 2.72 (0.88) | 0.91 | 0.00 | 3.16 (1.12) | 2.97 (0.79) | 0.60 | 0.00 | 3.34 (0.82) | 3.06 (0.73) | 0.31 | 0.01 |
| Basic Processing Speed | 1933.59 (634.04) | 1894.79 (515.96) | 0.25 | 0.02 | 1657.46 (499.58) | 1968.76 (614.34) | 0.12 | 0.03 | 1709.85 (561.23) | 1827.99 (472.22) | 0.92 | 0.00 |
| Cognitive Processing Speed | 1871.48 (553.58) | 1872.35 (654.26) | 0.94 | 0.00 | 1812.67 (385.60) | 1833.66 (504.96) | 0.94 | 0.00 | 1703.80 (472.43) | 1594.43 (440.50) | 0.12 | 0.04 |
| FOLLOWING INSTRUCTIONS OBJECTS, MEAN (SD) | ||||||||||||
| BASELINE | IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | ||||||||||
| Performance | 7.12 (2.19) | 5.72 (2.31) | 0.05 | 0.05 | 7.06 (2.42) | 5.80(2.32) | 0.15 | 0.03 | 7.44 (3.06) | 6.69 (2.45) | 0.75 | 0.00 |
| Maximum Span | 2.33 (0.62) | 1.89 (0.58) | 0.01 | 0.08 | 2.37 (0.76) | 1.94 (0.68) | 0.09 | 0.04 | 2.48 (0.86) | 2.26 (0.70) | 0.69 | 0.00 |
| Basic Processing Speed | 4820.88 (1445.40) | 5269.37 (1759.51) | 0.63 | 0.00 | 3478.83 (924.57) | 4222.04 (1422.01) | 0.03 | 0.06 | 3443.72 (984.84) | 3766.26 (1092.09) | 0.64 | 0.00 |
| Cognitive Processing Speed | 3199.25 (933.99) | 4240.08 (1968.37) | 0.01 | 0.12 | 2713.86 (860.50) | 3044.82 (939.46) | 0.43 | 0.01 | 2696.12 (698.30) | 3045.40 (1265.15) | 0.25 | 0.02 |
| FOLLOWING INSTRUCTIONS LETTERS, MEAN (SD) | ||||||||||||
| BASELINE | IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | ||||||||||
| Performance | 6.56 (1.41) | 5.66 (2.04) | 0.09 | 0.03 | 6.21 (2.13) | 5.71 (2.22) | 0.68 | 0.00 | 6.06 (2.08) | 5.66 (1.75) | 0.59 | 0.00 |
| Maximum Span | 2.00 (0.34) | 1.83 (0.57) | 0.31 | 0.01 | 2.25 (0.64) | 1.86 (0.49) | 0.01 | 0.08 | 2.00 (0.61) | 1.97 (0.57) | 0.89 | 0.00 |
| Basic Processing Speed | 3225.83 (1552.82) | 4111.80 (2748.91) | 0.20 | 0.02 | 3251.00 (1515.78) | 3598.16 (1623.54) | 0.79 | 0.00 | 2491.87 (845.85) | 2855.11 (984.83) | 0.37 | 0.01 |
| Cognitive Processing Speed | 2662.68 (763.73) | 3636.20 (2199.47) | 0.09 | 0.08 | 2809.44 (1480.79) | 3023.95 (1353.23) | 0.87 | 0.00 | 2369.98 (755.84) | 2228.71 (513.51) | 0.25 | 0.03 |
| N-BACK, MEAN (SD) | ||||||||||||
| BASELINE | IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | ||||||||||
| Performance | 13.19 (5.04) | 10.06 (5.55) | 0.06 | 0.04 | 14.80 (4.11) | 11.50 (5.38) | 0.02 | 0.07 | 16.10 (3.59) | 14.00 (4.34) | 0.08 | 0.04 |
| Cognitive Processing Speed | 1332.78 (329.55) | 1425.74 (417.39) | 0.23 | 0.02 | 1330.68 (321.82) | 1408.47 (374.46) | 0.46 | 0.01 | 1223.22 (283.39) | 1341.29 (360.36) | 0.28 | 0.01 |
[i] Note: p Group difference p-value, f2 Cohen’s effect size (small = 0.02, medium = 0.15, large = 0.35). Regressions and Chi-square tests were used to test group differences in working memory measures. Analyses adjusted for baseline age when testing group differences in scores.
Table 3
Moderated Multiple Regression Results for Change in Working Memory Performance From Baseline to Immediately and 6-months Post-intervention Predicted by Change in Maximum Span, Basic Processing Speed or Cognitive Processing Speed, and an Interaction Between the Change Score and Group.
| OUTCOME MEASURE/PREDICTOR | B [95% CONFIDENCE INTERVALS] | β | SE | f2 | B [95% CONFIDENCE INTERVALS] | β | SE | f2 |
|---|---|---|---|---|---|---|---|---|
| MAXIMUM SPAN | ||||||||
| IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Maximum span change | 3.01*** [2.40, 3.63] | 0.84 | 0.31 | 1.24 | 2.34*** [1.85, 2.83] | 0.73 | 0.25 | 1.14 |
| Change * Group | 0.06 [–0.71, 0.82] | 0.01 | 0.38 | 0.00 | 0.70* [0.13, 1.28] | 0.18 | 0.29 | 0.07 |
| Backwards Span Letters | ||||||||
| Maximum span change | 1.91*** [1.38, 2.43] | 0.72 | 0.26 | 0.67 | 1.87*** [1.14, 2.60] | 0.64 | 0.37 | 0.33 |
| Change * Group | 0.36 [–0.24, 0.96] | 0.11 | 0.30 | 0.02 | 0.57 [–0.27, 1.41] | 0.16 | 0.42 | 0.02 |
| Following Instructions Objects | ||||||||
| Maximum span change | 2.46*** [1.87, 3.05] | 0.78 | 0.30 | 0.88 | 2.71*** [2.09, 3.33] | 0.75 | 0.31 | 0.95 |
| Change * Group | –0.37 [–1.08, 0.34] | –0.09 | 0.36 | 0.01 | 0.35 [–0.44, 1.14] | 0.07 | 0.40 | 0.01 |
| Following Instructions Letters | ||||||||
| Maximum span change | 2.78*** [2.13, 3.43] | 0.81 | 0.33 | 0.95 | 2.12*** [1.50, 2.74] | 0.62 | 0.31 | 0.59 |
| Change * Group | –0.27 [–1.11, 0.58] | –0.06 | 0.42 | 0.01 | 0.36 [–0.56, 1.27] | 0.07 | 0.46 | 0.01 |
| BASIC PROCESSING SPEED | ||||||||
| IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Basic processing speed change | <–0.001 [–0.002, <0.001] | –0.13 | 0.00 | 0.01 | <0.001 [–0.001, 0.002] | 0.08 | 0.00 | 0.01 |
| Change * Group | <–0.001 [–0.002, 0.002] | –0.01 | 0.00 | 0.00 | –0.002 [–0.006, <0.001] | –0.19 | 0.00 | 0.03 |
| Backwards Span Letters | ||||||||
| Basic processing speed change | <–0.001 [–0.002, <0.001] | –0.16 | 0.00 | 0.01 | <–0.001 [–0.002, <0.001] | –0.14 | 0.00 | 0.01 |
| Change * Group | <0.001 [–0.001, 0.002] | 0.10 | 0.00 | 0.00 | <0.001 [–0.001, 0.001] | 0.04 | 0.00 | 0.00 |
| Following Instructions Objects | ||||||||
| Basic processing speed change | <–0.001 [<–0.001, <0.001] | –0.03 | 0.00 | 0.00 | <–0.001 [<0.001, <0.001] | –0.21 | 0.00 | 0.03 |
| Change * Group | <0.001 [<–0.001, <0.001] | 0.10 | 0.00 | 0.01 | <0.001 [<0.001, <0.001] | 0.08 | 0.00 | 0.00 |
| Following Instructions Letters | ||||||||
| Basic processing speed change | <–0.001 [<–0.001, <0.001] | –0.01 | 0.00 | 0.00 | <–0.001 [0.00, 0.00] | –0.05 | 0.00 | 0.00 |
| Change * Group | <–0.001 [<–0.001, <0.001] | –0.14 | 0.00 | 0.02 | <–0.001* [–0.001, <0.001] | –0.26 | 0.00 | 0.07 |
| COGNITIVE PROCESSING SPEED | ||||||||
| IMMEDIATELY POST–INTERVENTION | 6–MONTHS POST INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Group (training group) | 0.001* [<0.001, 0.003] | 0.68 | 0.00 | 0.12 | <0.001 [–0.004, 0.004] | 0.00 | 0.00 | 0.00 |
| Change * Group | –0.001 [<–0.001, <0.001] | –0.42 | 0.00 | 0.05 | <0.001 [–0.004, 0.005] | 0.06 | 0.00 | 0.00 |
| Backwards Span Letters | ||||||||
| Cognitive processing speed change | <–0.001 [–0.002, 0.001] | –0.06 | 0.00 | 0.00 | 0.002* [<0.001, 0.003] | 0.48 | 0.00 | 0.13 |
| Change * Group | <0.001 [–0.002, 0.002] | 0.09 | 0.00 | 0.00 | –0.001 [–0.003, <0.001] | –0.38 | 0.00 | 0.09 |
| Following Instructions Objects | ||||||||
| Cognitive processing speed change | <–0.001 [<–0.001, <0.001] | –0.12 | 0.00 | 0.01 | <–0.001* [–0.001, <0.001] | –0.35 | 0.00 | 0.19 |
| Change * Group | <–0.001 [<–0.001, <0.001] | –0.26 | 0.00 | 0.08 | <–0.001 [–0.001, <0.001] | –0.05 | 0.00 | 0.00 |
| Following Instructions Letters | ||||||||
| Cognitive processing speed change | <–0.001 [<–0.001, <0.001] | –0.24 | 0.00 | 0.04 | <0.001 [<0.001, <0.001] | 0.10 | 0.00 | 0.01 |
| Change * Group | <–0.001 [<–0.001, <0.001] | –0.15 | 0.00 | 0.02 | <–0.001 [–0.002, <0.001] | –0.33 | 0.00 | 0.13 |
| N-Back | ||||||||
| Cognitive processing speed change | –0.001 [–0.003, <0.001] | –0.16 | 0.00 | 0.01 | –0.001 [–0.003, <0.001] | –0.20 | 0.00 | 0.02 |
| Change * Group | 0.001 [–0.002, 0.004] | 0.11 | 0.00 | 0.01 | <0.001 [–0.002, 0.003] | 0.07 | 0.00 | 0.00 |
[i] Note: B unstandardised beta (negative value for an interaction indicates the training group had a lower score), SE standard error of the estimate, β standardised beta, f2 Cohen’s effect size (small = 0.02, medium = 0.15, large = 0.35), * p < 0.05, ** p < 0.01, *** p < 0.005. To apply Bonferroni corrections, significance levels of p = .004 (adjusting for 13 tests at each time-point) were calculated. Italics indicate non-significance after the Bonferroni correction was applied.
Table 4
Multiple Regression Results for Working Memory Performance, Capacity (Maximum Span) and Efficiency (Basic and Cognitive Processing Speeds) Scores Immediately and 6-months Post-intervention Predicted by Group, Covarying for Baseline Score and Age.
| OUTCOME MEASURE/PREDICTOR | B [95% CONFIDENCE INTERVALS] | β | SE | f2 | B [95% CONFIDENCE INTERVALS] | β | SE | f2 |
|---|---|---|---|---|---|---|---|---|
| PERFORMANCE | ||||||||
| IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Group (training group) | –0.18 [–1.44, 1.08] | –0.02 | 0.63 | 0.00 | –0.02 [–1.67, 1.63] | 0.00 | 0.83 | 0.00 |
| Backwards Span Letters | ||||||||
| Group (training group) | –0.11 [–1.13, 0.91] | –0.02 | 0.51 | 0.00 | 0.51 [–0.52, 1.55] | 0.09 | 0.52 | 0.01 |
| Following Instructions Objects | ||||||||
| Group (training group) | 0.42 [–0.48, 1.31] | 0.08 | 0.45 | 0.01 | 0.02 [–1.18, 1.23] | 0.00 | 0.61 | 0.00 |
| Following Instructions Letters | ||||||||
| Group (training group) | 0.01 [–0.94, 0.96] | 0.00 | 0.48 | 0.00 | 0.13 [–0.73, 1.00] | 0.03 | 0.43 | 0.00 |
| N-Back | ||||||||
| Group (training group) | 1.64 [–0.03, 3.32] | 0.17 | 0.84 | 0.05 | 1.14 [–0.55, 2.83] | 0.14 | 0.85 | 0.02 |
| MAXIMUM SPAN | ||||||||
| IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Group (training group) | –0.06 [–0.42, 0.30] | –0.03 | 0.64 | 0.00 | 0.08 [–0.44, 0.61] | 0.03 | 0.26 | 0.00 |
| Backwards Span Letters | ||||||||
| Group (training group) | –0.10 [–0.45, 0.25] | –0.05 | 0.63 | 0.00 | 0.19 [–0.13, 0.50] | 0.12 | 0.16 | 0.02 |
| Following Instructions Objects | ||||||||
| Group (training group) | 0.19 [–0.10, 0.47] | 0.12 | 0.49 | 0.02 | –0.01 [–0.36, 0.34] | –0.01 | 0.17 | 0.00 |
| Following Instructions Letters | ||||||||
| Group (training group) | 0.30* [ 0.04, 0.56] | 0.25 | 0.47 | 0.07 | –0.01 [–0.27, 0.25] | –0.01 | 0.13 | 0.00 |
| BASIC PROCESSING SPEED | ||||||||
| IMMEDIATELY POST-INTERVENTION | 6-MONTHS POST-INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Group (training group) | –65.08 [–252.30, 122.13] | –0.07 | 452.62 | 0.01 | –41.83 [–171.06, 87.39] | –0.06 | 64.92 | 0.01 |
| Backwards Span Letters | ||||||||
| Group (training group) | –226.04* [–434.11, –17.96] | –0.20 | 477.61 | 0.06 | 9.70 [–195.00, 214.41] | 0.01 | 102.84 | 0.00 |
| Following Instructions Objects | ||||||||
| Group (training group) | –540.01* [–1039.64, –40.39] | –0.22 | 250.96 | 0.06 | –88.06 [–512.35, 336.23] | –0.04 | 213.16 | 0.00 |
| Following Instructions Letters | ||||||||
| Group (training group) | 107.11 [–540.03, 754.24] | 0.03 | 324.99 | 0.00 | –99.75 [–461.82, 262.33] | –0.05 | 181.87 | 0.00 |
| COGNITIVE PROCESSING SPEED | ||||||||
| IMMEDIATELY POST–INTERVENTION | 6–MONTHS POST INTERVENTION | |||||||
| Backwards Span Digits | ||||||||
| Group (training group) | –91.20 [–1014.85, 832.46] | –0.03 | 458.59 | 0.00 | –30.22 [–275.03, 214.59] | –0.04 | 121.76 | 0.00 |
| Backwards Span Letters | ||||||||
| Group (training group) | 55.94 [–252.27, 364.15] | 0.06 | 151.97 | 0.00 | 218.41 [ –68.72, 505.55] | 0.24 | 141.84 | 0.06 |
| Following Instructions Objects | ||||||||
| Group (training group) | –285.76 [–955.32, 383.80] | –0.15 | 328.71 | 0.02 | –415.22 [–1132.04, 301.59] | –0.19 | 354.67 | 0.03 |
| Following Instructions Letters | ||||||||
| Group (training group) | 901.38 [ –506.28, 2309.03] | 0.26 | 683.48 | 0.07 | 237.42 [–217.56, 692.39] | 0.21 | 219.94 | 0.05 |
| N-Back | ||||||||
| Group (training group) | –41.20 [–191.82, 109.42] | –0.06 | 75.67 | 0.00 | –59.47 [–192.70, 73.77] | –0.09 | 66.96 | 0.01 |
[i] Note: B unstandardised beta (negative value for an interaction indicates the training group had a lower score), SE standard error of the estimate, β standardised beta, f2 Cohen’s effect size (small = 0.02, medium = 0.15, large = 0.35), * p < 0.05, ** p < 0.01, *** p < 0.005. To apply Bonferroni corrections, significance levels of p = .003 (adjusting for 18 tests at each time-point) were calculated. Italics indicate non-significance after the Bonferroni correction was applied.
Figure 3
Mean highest span level trained on (and 95% CIs) for each training session in the adaptive working memory training group: Backwards Span Digits activity (A) and Following Instructions Objects activity (B).