Table 1.
Characteristics of the included studies.
| No. | Study | Diagnostic criteria for MCI | Sample size (E/C) | Interventions | Site for stimulation | Number of stimulation sessions | Stimulation frequency, stimulation intensity | Duration (minutes) |
Electrode | Follow-up time | Cognitive outcome measures |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Yan and Tao (2011) | Petersen diagnostic criteria | 12/13 | rTMS | Bilateral frontal poles (Fp1, Fp2) Bilateral middle temporal gyrus (T3, T4) |
800–1,000 pulses/day, once daily, 5 consecutive weekdays with interval of 1 month, totally 25 weekdays (sessions) | 13 Hz, 100% RMT (Fp1, Fp2); 1 Hz, 80–120% RMT (T3, T4) |
– | – | – | CMS (MQ): memory |
| 2 | Marra et al. (2012) | Subjective memory complaints and meeting clinical/neuropsychological criteria | 9/10 | rTMS | Left DLPFC (F3) | 40 trains/day, once daily, 5 consecutive weekdays per week, 2 weeks, totally 10 weekdays (sessions) | 10 Hz, 110% MT | – | – | Four weeks after treatment | RBMT: memory |
| 3 | Han et al. (2013) | Petersen diagnostic criteria | 20/18 | rTMS | Bilateral DLPFC (F3, F4) |
600 pulses/day, once daily, 5 consecutive weekdays per week, 8 weeks, totally 40 weekdays (sessions) | 20 Hz, 80% MT | – | – | – | Episodic memory test: episodic memory (long-term memory) |
| 4 | Drumond Marra et al. (2015) | Meeting clinical/neuropsychological criteria | 15/19 | rTMS | Left DLPFC (F3) | 2000 pulses/day, once daily, 5 consecutive weekdays per week, 2 weeks, totally 10 weekdays (sessions) | 10 Hz, 110% MT | – | – | One month after treatment | RBMT: memory |
| 5 | Long et al. (2018) | Petersen diagnostic criteria | 15/15 | rTMS | Left DLPFC (F3) | 1000 pulses/day, once daily, 5 consecutive weekdays per week, 2 weeks, totally 10 weekdays (sessions) | 15 Hz, 90% RMT | – | – | – | CMS (MQ): memory |
| 6 | Wen et al. (2018) | Petersen diagnostic criteria | 23/22 | rTMS | Left DLPFC (F3) | 400 pulses/day, once daily, 5 consecutive weekdays per week, 4 weeks, totally 20 weekdays (sessions) | 10 Hz, 80% RMT | – | – | One month after treatment | RBMT: memory |
| 7 | Wang et al. (2021b) | Guidelines for diagnosis and treatment of dementia and cognitive disorders in China | 19/20 | rTMS | Left DLPFC (F3) | 1,500 pulses/day, once daily, 10 consecutive days (sessions) |
10 Hz, 90% RMT | – | – | – | Auditory Verbal learning Test: immediate memory (working memory) |
| 8 | Hu et al. (2016) | Guidelines for diagnosis and treatment of dementia and cognitive disorders in China | 18/21 | tDCS | Right cerebellum | Once daily, 5 consecutive days (sessions) | – | 20 | 1.2 mA: 35 cm2 | – | WMS (Backwards Digit Span): working memory |
| 9 | Gomes et al. (2019) | Mayo clinic criteria | 29/29 | tDCS | Left DLPFC (F3) | Once daily, 2 days per week, totally 10 sessions | – | 30 | 2 mA: 25 cm2 | – | The Boston naming test: verbal memory (long-term memory) |
| 10 | Stonsaovapak et al. (2020) | The criteria of the MCI working group of the European Consortium on Alzheimer’s disease | 23/22 | tDCS | Right DLPFC (F4) | Once daily, 3 days per week, 4 weeks, totally 12 sessions | – | 20 | 2 mA: 25 cm2 | Eight weeks after treatment | CANTAB (DMS): visual memory (long-term memory) |
| 11 | Hu et al. (2020) | Meeting clinical/neuropsychological criteria | 20/20 | tDCS | Left DLPFC (F3) | Once daily, 5 days per week, 2 weeks, totally 10 days (sessions) | – | 20 | 1 mA: 9 cm2 | – | WMS (Backwards Digit Span): working memory |
| 12 | Gu et al. (2022) | Petersen diagnostic criteria and the diagnostic and statistical manual of mental disorders (DSM) | 20/20 | tDCS | Left middle temporal gyrus (T3) | Once daily, 5 days (sessions) | – | 20 | 2 mA: 35 cm2 | Four weeks after treatment | WMS (MQ): memory |
| 13 | Satorres et al. (2023) | Meeting clinical/neuropsychological criteria | 17/16 | tDCS | Left DLPFC (F3) | Once daily, 10 consecutive days (sessions) | – | 20 | 2 mA: 25 cm2 | – | TAVEC trial 1: immediate memory (working memory) |
E/C, experimental group/control group; rTMS, repetitive transcranial magnetic stimulation; Hz, Hertz; RMT, resting motor threshold; CMS, Clinical Memory Scale; MQ, memory quotient; DLPFC, dorsolateral prefrontal cortex; MT, motor threshold; RMBT, the Rivermead Memory Behavioural Test; tDCS, transcranial direct current stimulation; WMS, Wechsler Memory Scale; CANTAB, Cambridge Neuropsychological Test Automated Battery; DMS, Delayed Matching to Sample; TAVEC, Test de Aprendizaje Verbal Complutense.