Table 1 Study and participant characteristics of the included studies
Study | Sample | Training | Outcomes | Prognostic factors | ||||
|---|---|---|---|---|---|---|---|---|
Study design Initial sample size for the experimental group Dropout and reasons | Age (years, M, SD) | Sex | Education(years, M, SD) | Description of memory training—content and frequency | Total length of training in minutes | Definition and method of assessment Timing of outcome assessment | Definition and methods | |
♂ | ♀ | |||||||
Pesce et al. [20] Stratified randomized study n = 30 n = 29 | 70.40 (7.00) | 14 | 15 | 9.60 (1.80) | Method of loci and general strategies. 24 weeks, 2 times a week for 1 h | 2880 | RAVLT, MMSE | Antioxidant levels assessed with the Biological Antioxidant potential Test; reactive oxygen metabolites derivative compounds assessed with the d-ROMs Test |
O'Hara et al. [9] Non-randomized, non-controlled longitudinal study n = 531 n = 419 due to several reasons at 5-year follow-up | 73.73(7.62) | 34 | 78 | 15.56 (2.79) | Method of loci. 2 weeks, 5 times a week for 2 h | 1200 | Number of words correctly recalled, number of words correctly recalled in order. Assessed at baseline and 5-year follow-up measurement | Pre-training, gain scores following training, age, education, reported use of mnemonic at follow-up, type of pre-training (standard vs. comprehensive) and length of training. |
Mohs et al. [21] RCT n = 68 n = n.a. | 78.30 (7.40) | 15 | 53 | 16.00 (2.70) | Structured memory training focusing on memory improvement and different strategies. Nine 90-min sessions | 810 | Verbal memory assessed with CVLT, non-verbal memory assessed with BFLT. Assessed 2 times at baseline, at post-test, 3 months and 6 months follow-up | Age, education, gender, subjective reported memory assessed with the MFI and the MFQ |
Kirchhoff et al. [22] Non-randomized, non-controlled longitudinal study n = 16 n = 2 due to technical difficulties | 72.00 (66–81) | 7 | 7 | 14.70 (2.90) | Memory strategy training and practice. 2 training sessions | Missing information | Memory retrieval using Remember/Know/New recognition memory decisions Assessed at pre-training and post-training | Hippocampal activity |
Kirchhoff et al. [23] Controlled trial n = 16 n = n.a. | 71.9 (66–81) | 8 | 8 | 14.8 (2.7) | Memory strategy training and practice 2 training sessions. | Missing information | Recognition memory using Remember/Know/New recognition memory decisions. Assessed at pre-training and post-training | Activity in prefrontal cortex, left lateral temporal cortex. |
RCT n = 22 n = 1 | 74.77 (6.57) | 8 | 13 | 18.77 (2.62) | Memory specificity training to improve the specificity of older adults’ retrieval of autobiographical memories by providing systematic practice. 4 weeks, once a week for 60 min | 240 | Autobiographical memory specificity. Assessed at pre-test, post-test, and 3 months follow-up. | Memory specificity assessed with MEPS, functional limitations assessed with FLP, self-rated depression assessed with HADS, independence assessed with IADL |
Andrewes et al. [26] RCT controlled for sex n = 20 n = 3 | 60–70 years | 10 | 10 | Some secondary schooling: n = 3 Secondary school + trade qualifications: n = 5 Complete secondary school: n = 6 Began tertiary school: n = 6 | Memory handbook training for face-name and prospective memory areas; independently implemented at home 4 weeks, 30 min per session | Missing information | Improvement in: Face-name Test, Laboratory Prospective Memory Assessment, Everyday Prospective Memory Assessment. Assessed at pre-test, post-test and 4-month FU | RAVLT, Warrington Forced-Choice Recognition for Faces, BDI, NART, Mattis Dementia Rating Scale. |
Anschutz et al. [27] Non-randomized, non-controlled longitudinal study n = 10 n = 1 due to severe illness | 73.50 (n.a.) | 2 | 7 | 10.70 (n.a.) | Method of loci No information on training duration and frequency | Missing information | Free-recall of two lists and recognition of two lists consisting of 12 nouns each. Assessed at pre-test and 34 months after finishing the training | Free-recall pre-test, free recall list 1, age |
Bissig and Lustig [28] Non-randomized, non-controlled longitudinal study n = 19 n = 1 due to low accuracy of studied words | 74.50 (6.10) | n.a. | n.a. | 18.00 (3.30) | Modified recollection training procedure 2 weeks, 4 sessions per day at 7 days | Missing information | Ranking: participants were ranked by final lag level (lag between lure repetitions). Assessed and adapted individually during each training performance | Age, crystallized intelligence |
Bråthen et al. [29] Controlled trial n = 126 n = 3 | Old: 73.40 (3.00) | Old: 29 | Old: 49 | Old: 14.70 (2.90) | Learning and practicing the Method of loci technique aiming to improve episodic memory performance 10 weeks, once a week + 8 weekly online home assignments | Missing information | Memory improvement: change in correct written recall of word list consisting of 100 nouns. Assessed at pre-test and post-test | Cortical volume, hippocampal volume, ALFF, fALFF |
Brooks et al. [8] RCT n = 224 Dropout not reported | 68.58 (7.05) | n.a. | n.a. | 15.33 (2.58) | Pre-training: imagery training, verbal elaboration and relaxation. Name-Face Mnemonic: three-step mnemonic Method of loci: method of loci for serial word recall. 2 weeks, 5 times a week for 120 min) | 1200 | Proper name recall task, word recall task (16 common words). Assessed at pre-test and post-test | Pretraining, pretest score, age, length of training, pretraining x length |
Clark et al. [30] Multi-site RCT (ACTIVE) n = n.a. n = n.a. | No demographics separately for the memory training groups were reported. | Memory training focused on improving verbal episodic memory through instruction and practice in strategy use 6 weeks, 10 60-min sessions | 600 | HVLT, RAVL, RBMT. Measured at baseline, immediate post-training, 1-;2-, 3-; 5-, and 10-year FU | Obesity, determined from BMI (in kg/m2) computed from measured height and weight data obtained at baseline | |||
Clark et al. [31] Multi-site RCT (ACTIVE) n = n.a. n = n.a. | No demographics separately for the memory training groups were reported. | Memory training focused on improving verbal episodic memory through instruction and practice in strategy use 6 weeks, 10 60-min sessions | 600 | Hopkins Verbal Learning Test, RAVL, RBMT. Measured at baseline, immediate post-training, 1-;2-, 3-; 5-, and 10-year FU | Education (self-reported as years of completed schooling) | |||
de Lange et al., [32] Controlled trial n = 76 n = 9 due to time constraints | 73.60 (3.00) | 25 | 51 | 15.00 (2.70) | Learning and practicing the Method of Loci technique aiming to improve episodic memory performance. 10 weeks, once a week + 8 weekly online home assignments | Missing information | Memory improvement: Word list recall | Interindividual variability in white matter microstructure |
de Lange et al., [33] Controlled trial n = 44 n = 0 | 73.30 (2.70) | 21 | 23 | 15.70 (3.10) | Learning and practicing the Method of Loci technique aiming to improve episodic memory performance. 10 weeks, once a week + 8 weekly online home assignments | Missing information | Memory improvement: word list test (100 words) | White matter microstructure |
Tomaszewski Farias et al. [34] Multi-site RCT (ACTIVE) n = n.a. n = n.a. | No demographics separately for the memory training groups were reported | Memory training focused on improving verbal episodic memory through instruction and practice in strategy use 6 weeks, 10 60-min sessions | 600 | Memory factor: Immediate recall HVLT, RAVLT, paragraph recall, RBMT | Instrumental activities of daily living, 18 questions of the Minimum Dataset Home Care scale | |||
Finkel and Yesavage [35] Controlled trial n = 77 n = 16 due to illness (n = 5), frustration (n = 7), bad weather (n = 2), no reason (n = 1) | 71.29 (6.31) | 30% | 70% | n.a. | Method of loci No information on training duration and frequency | Missing information | Memory improvement gain scores of a list of 16 common words recall | Age, education, MMSE score, depression score, neuroticism and extraversion scale of the NEO-PI |
Hampstead et al. [36] RCT n = 12 n = 1 due to ongoing disease | 73.20 (7.70) | n.a. | n.a. | 16.10 (3.40) | Object Location Assignment encoding and retrieval with mnemonic strategy from a cognitive rehabilitation program 2 weeks, 5 sessions + 1 follow-up session one month later | Missing information | Modified change score of Object Location Assignment accuracy | Medial temporal lobe volumetrics (hippocampus, amygdala, inferior lateral ventricles), standardized neuropsychological measures (RBANS Delayed Memory Index, TMT B) |
Hill et al. [37] Controlled trial n = 59 n = n.a. | 67.80 (7.50) | n.a. | n.a. | 5.80 (1.10) | Mnemonic training 2 weeks, twice a week for 120 min | 1680 | Recall performance in name-face recall | Rated confidence (perceived confidence in recalling the names of unfamiliar faces). |
Hill et al. [38] Non-randomized, non-controlled longitudinal study n = 102 n = n.a. | 75.40 (10.50) | 32 | 70 | n.a. | Name- and face and list-learning program using an imagery and judgment technique and method of loci method. 2 weeks, 7 times a week for 120 min | 1680 | Improvement in Name-Face recall, Improvement in List-Recall | MMSE. |
Leahy, Ridout, and Holland, [24] RCT n = 20 n = 1 due to unrelated health problems | 76.85 (5.27) | 6 | 14 | 17.75 (2.65) | Memory flexibility program 4 weeks, once a week for 60 min | 240 | Autobiographical memory specificity in the AMT. Assessed at pre-test, post-test, and 3 month FU. | Baseline cognitive flexibility measured with the verbal fluency sub-score of ACE-III. |
López-Higes et al. [39] RCT n = 50 n = 0 | ApoE 4 carriers: 71.64 (5.72) Non-carriers: 71.68 (5.65) | n.a. | n.a. | n.a. | Memory training consisting of cognitive stimulation, memory concepts, management of forgetting everyday experiences, meta-memory training 3 months, 30 90-min sessions | 2700 | Logical Memory and Word List from WMS-III | Apolipoprotein E genotyping |
McDougall et al., [40] RCT n = 135 Loss to post-test: n = 8 Loss to FU: n = 12 Loss to end of study: n = 8 | 74.69 (5.74) | 30 | 105 | 13.39 (3.90) | CBMEM-based intervention, based on the four components of self-efficacy theory 4 weeks, twice a week including 8 sessions and 4 booster sessions | 720 | HVLT-R, BVMT-R, RBMT. All outcome measures were administered at baseline, post-class (2 months after baseline), post-booster (6 months), post-classroom FU (14) and at the end of study (24 months) | Ethnicity, group assignment, time, education |
McDougall et al., [41] RCT n = 135 Loss to post-test: n = 8 Loss to FU: n = 12 Loss to end of study: n = 8 | 74.69 (5.74) | 30 | 105 | 13.39 (3.90) | CBMEM-based intervention, based on the four components of self-efficacy theory 4 weeks, twice a week including 8 sessions and 4 booster sessions | 720 | Relative gains in HVLT-R, RBMT All outcome measures were administered at baseline, post-class (2 months after baseline), post-booster (6 months), post-classroom FU (14) and at the end of study (24 months) | Age, education, racial/ethnic group |
Neely & Bäckman [42] RCT n = 23 n = n.a. | 73.00 (4.20) | 4 | 19 | 9.90 (3.10) | Encoding operations including interactive imagery and method of loci; attention training, relaxation training. Training was conducted in groups with 11–12 subjects, met twice a week for 5 consecutive weeks, each session lasted 1.5 h | 900 | Recall of concrete words, recall of objects, recall of subject-performed tasks, recall of abstract words Assessed at pre-test, post-test directly after training, 6 months FU | Pretest score for each dependent variable, MMSE score, age, years of education |
O’Hara et al., [43] Non-randomized, non-controlled longitudinal study n = 212 n = 113 | 74.00 (7.90) | 68 | 32 | 15.50 (2.70) | Memory training was not further described. Missing information on duration and frequency. | Missing information | BVRT, Logical Memory Test, Associate Learning Test, List-learning test. Assessed at baseline and FU 4-5 years after memory training. | Apolipoprotein E genotyping. |
Park et al. [7] RCT n = 39 n = n.a. | 69.81 (4.90) | 11 | 28 | 11.41 (4.31) | Multi-strategic memory training. 10 sessions once a week, each session lasted 1.5 h | 900 | Elderly verbal learning test of the EMS to assess verbal memory; Simple Rey Figure Test of the EMS to assess non-verbal memory. Assessed at pre-test and post-test (within 3 months after finishing the training) | All baseline values of the scores of neuropsychological tests, age, gender, years of education |
Rosi et al., [44] Non-randomized, non-controlled longitudinal study n = 44 n = n.a. | 68.73 (6.05) | n.a. | n.a. | 11.36 (3.50) | Memory training program. 6 weeks, once a week for 60 minutes. | 360 | Word list learning (memory practiced task), grocery list learning (memory non-practiced task), associative learning Assessed at pre-test and post-test. | Vocabulary test, Raven standard progressive matrices, listening span test, letter comparison, age |
Sandberg et al. [45] Non-randomized, non-controlled longitudinal study n = 112 n = 18 due to various reasons | 70.90 (6.70) | 38 | 56 | 11.90 (3.70) | Mnemonic training was based on the Swedish version of the number-consonant mnemonic task 5 times, twice a week | 600 | Number recall. Assessed at pre-test, post-test and FU | Three measures of episodic memory (free recall of concrete nouns, free recall of abstract nouns, paired-associate recall), three measures of working memory (listening span, two versions of computation span), nine measures of processing speed, two measures of verbal knowledge, depression (ZSRDS), vocabulary |