Source	Search strategy	Hits retrieved
ALOIS (www.medicine.ox.ac.uk/alois) [Date of most recent search: 31 May 2018]	Basic search: COG [Studies within ALOIS are coded COG if the intervention is a cognitive‐based intervention]	Jan 2015: 31 Jul 2015: 4 Feb 2016: 2 Jul 2016: 0 May 2018: 1
MEDLINE In‐process and other non‐indexed citations and MEDLINE 1950‐present (Ovid SP) [Date of most recent search: 31 May 2018]	1. “cognitive stimulation”.ti,ab. 2. cognitive ADJ3 train*.ti,ab. 3. “cognitive exercis*”.ti,ab. 4. “brain train*”.ti,ab. 5. (memory adj3 train*).ti,ab. 6. “memory rehab*”.ti,ab. 7. “memory enhance*”.ti,ab. 8. “poetry‐based stimulation”.ti,ab. 9. “cognitive flexibility”.ti,ab. 10. “brain exercis*”.ti,ab. 11. “cognitive rehab*”.ti,ab. 12. “mnemonic train*”.ti,ab. 13. CST.ti,ab. 14. (mental adj3 activit*).ti,ab. 15. “cognitive intervention*”.ti,ab. 16. “cognitive motor intervention*”.ti,ab. 17. “cognition based intervention*”.ti,ab. 18. “cognitive enrich*”.ti,ab. 19. Cognitive Therapy/ mt 20. or/1‐19 21. *aging/ 22. Aged 23. “Aged, 80 and over” 24. Middle Aged 25. Age Factors 26. *Cognition/ 27. *Cognition Disorders/ 28. Memory/ 29. Memory Disorders/ 30. Brain/ 31. Mild Cognitive Impairment/ 32. Executive Function/ 33. (cognit* ADJ3 (func* OR declin* OR reduc* OR impair* OR improve* OR deficit* OR progress* 34. OR perform*)).ti,ab. 35. “mental perform*”.ti,ab. 36. memory.ti,ab. 37. “executive function*”.ti,ab. 38. MCI.ti,ab. 39. AAMI.ti,ab. 40. ACMI.ti,ab. 41. ARCD.ti,ab. 42. CIND.ti,ab. 43. (nMCI OR aMCI OR mMCI OR MCIa).ti,ab. 44. Dementia/ 45. Alzheimer Disease/ 46. dement*.ti,ab. 47. alzheimer*.ti,ab. 48. “old* age*”.ti,ab. 49. elderly.ti,ab. 50. “middle age*”.ti,ab. 51. “old*adults”.ti,ab. 52. seniors.ti,ab. 53. “senior citizens”.ti,ab. 54. “community dwelling”.ti,ab. 55. pensioners.ti,ab. 56. or/21‐55 57. randomized controlled trial.pt. 58. controlled clinical trial.pt. 59. randomized.ab. 60. placebo.ab. 61. drug therapy.fs. 62. randomly.ab. 63. trial.ab. 64. groups.ab. 65. or/57‐64 66. exp animals/ not humans.sh. 67. 65 NOT 66 68. 67 AND 56 AND 20 [all results] 69. (“cognitive stimulation” OR “cognitive training”).ti. 70. *Cognition 71. *Aging/ 72. and/69‐71 73. 72 AND 57 [‘no brainer’ results ‐ directly sent to core author team] 74. 68 NOT 73 [results minus ‘no brainer’ results ‐ for the crowd to screen]	Jan 2015: 1455 Jul 2015: 70 Feb 2016: 303 Jul 2016: 423 May 2018: 703
Embase 1974‐24 January 2018 (Ovid SP) [Date of most recent search: 31 May 2018]	1. aging/ 2. aged/ 3. middle aged/ 4. mild cognitive impairment/ 5. elderly.ti,ab. 6. MCI.ti,ab. 7. AAMI.ti,ab. 8. ACMI.ti,ab. 9. ARCD.ti,ab. 10. CIND.ti,ab. 11. (nMCI or aMCI or mMCI or MCIa).ti,ab. 12. "old* age*".ti,ab. 13. elderly.ti,ab. 14. "middle age*".ti,ab. 15. "old* aadults".ti,ab. 16. seniors.ti,ab. 17. "senior citizens".ti,ab. 18. "community dwelling".ti,ab. 19. pensioners.ti,ab. 20. ("aged sample" or "aged population" or "older sample" or "older population").ti,ab. 21. "CDR 0.5".ti,ab. 22. (cognit* adj3 (func* or declin* or reduc* or impair* or improve* or deficit* or progress* or perform* or abilit*)).ti,ab. 23. or/1‐22 24. *cognition/ 25. memory/ or episodic memory/ 26. executive function/ 27. attention/ 28. "mental perform*".ti,ab. 29. memory.ti,ab. 30. dementia/ 31. Alzheimer disease/ 32. dement*.ti,ab. 33. alzheimer*.ti,ab. 34. or/24‐33 35. randomized controlled trial/ 36. controlled clinical trial/ 37. (randomly adj2 allocat*).ab. 38. (randomly adj2 divide*).ab. 39. randomi?ed.ab. 40. (controlled adj7 (study or design or trial)).ti,ab. 41. "double‐blind*".ti,ab. 42. "single blind*".ti,ab. 43. groups.ab. 44. or/35‐43 45. "cognitive stimulation".ti,ab. 46. (cognitive adj3 train*).ti,ab. 47. "cognitive exercis*".ti,ab. 48. "brain train*".ti,ab. 49. (memory adj3 train*).ti,ab. 50. "memory enhance*".ti,ab. 51. "memory rehab*".ti,ab. 52. "brain exercis*".ti,ab. 53. "cognitive rehab*".ti,ab. 54. "cognitive rehab*".ti,ab. 55. "mnemonic train*".ti,ab. 56. CST.ti,ab. 57. (mental adj3 activit*).ti,ab. 58. "cognitive intervention*".ti,ab. 59. "cognitive motor intervention*".ti,ab. 60. "cognition based intervention*".ti,ab. 61. "cognitive enrich*".ti,ab. 62. "reality orientation".ti,ab. 63. (memory adj2 game*).ti,ab. 64. or/45‐63 65. 23 and 34 and 44 and 64 66. ("cognitive stimulation" or "cognitive training").ti,ab. 67. cognition/ 68. (MCI or "mild cognitive impairment" or elderly or "old* adults" or "middle age*").ti. 69. 66 and 67 and 68 70. 35 and 69 71. 65 not 70	Jan 2015: 1289 Jul 2015: 163 Feb 2016: 380 Jul 2016: 268 May 2018: 796
PSYCINFO 1806‐January week 2 2018 (Ovid SP) [Date of most recent search: 31 May 2018]	1. exp Aging/ 2. exp Cognitive Impairment/ 3. "cognit* impair*".ti,ab. 4. MCI.ti,ab. 5. AAMI.ti,ab. 6. ACMI.ti,ab. 7. ARCD.ti,ab. 8. CIND.ti,ab. 9. (nMCI or aMCI or mMCI or MCIa).ti,ab. 10. "old* age*".ti,ab. 11. elderly.ti,ab. 12. "middle age*".ti,ab. 13. "old* adults".ti,ab. 14. seniors.ti,ab. 15. "senior citizens".ti,ab. 16. "community dwelling".ti,ab. 17. pensioners.ti,ab. 18. or/1‐17 19. randomi?ed.ti. 20. (randomly adj2 allocat*).ab. 21. (randomly adj2 divide*).ab. 22. RCT.ti,ab. 23. "double‐blind*".ti,ab. 24. "single blind*".ti,ab. 25. "randomi?ed trial".ab. 26. "randomi?ed control* trial".ab. 27. "random allocation".ab. 28. "controlled clinical trial".ti,ab. 29. (controlled adj4 (study or design or trial)).ti,ab. 30. or/19‐29 31. "cognitive stimulation".ti,ab. 32. (cognitive adj3 train*).ti,ab. 33. "cognitive exercis*".ti,ab. 34. "brain train*".ti,ab. 35. (memory adj3 train*).ti,ab. 36. "memory enhance*".ti,ab. 37. "memory rehab*".ti,ab. 38. "brain exercis*".ti,ab. 39. "cognitive rehab*".ti,ab. 40. "cognitive rehab*".ti,ab. 41. "mnemonic train*".ti,ab. 42. CST.ti,ab. 43. (mental adj3 activit*).ti,ab. 44. "cognitive intervention*".ti,ab. 45. "cognitive motor intervention*".ti,ab. 46. "cognition based intervention*".ti,ab. 47. "cognitive enrich*".ti,ab. 48. "reality orientation".ti,ab. 49. (memory adj2 game*).ti,ab. 50. or/31‐49 51. 18 and 30 and 50 52. *Cognition/ 53. (MCI or "mild cognitive impairment" or elderly or "old* adults" or "middle age*").ti. 54. ("cognitive stimulation" or "cognitive training").ti,ab. 55. 19 or 20 or 21 56. 52 and 53 and 54 and 55 57. 51 not 56	Jan 2015: 166 Jul 2015: 20 Feb 2016: 25 Jul 2016: 12 May 2018: 84
CINAHL (EBSCOhost) [Date of most recent search: 31 May 2018]		Jan 2015: 390 Jul 2015: 13 Feb 2016: 57 Jul 2016: 12 May 2018: 181
ISI Web of Science [includes: Web of Science (1945‐present); BIOSIS Previews (1926‐present); MEDLINE (1950‐present); Journal Citation Reports]; BIOSIS Previews [Date of most recent search: 31 May 2018]	("mild cognitive impairment" OR elderly OR "age* subjects" OR "old* adult*" OR "middle age*" OR MCI) AND TOPIC: ("randomly allocated" OR "random allocation" OR randomised OR randomized OR RCT OR "controlled trial" OR "double blind" OR "single blind") AND TOPIC: ("cognit* stim*" OR "cognit* train*" OR puzzle OR "brain train*" OR "cognit* exercis*" OR "brain exercis*" OR "memory exercis*" OR "brain gam*" OR "cognit* gam*" OR "memory gam*" OR sudoku OR crossword* OR "reality orientation") AND TOPIC: (cognition OR dementia OR memory OR "executive function" OR alzheimer*) Timespan: All years. Search language=Auto	Jan 2015: 333 Jul 2015: 44 Feb 2016: 108 Jul 2016: 35 May 2018: 408
LILACS (BIREME) [Date of most recent search: 31 May 2018]		Jan 2015: 4 Jul 2015: 0 Feb 2016: 0 Jul 2016: 0 May 2018: 0
CENTRAL (via CRSO) [Date of most recent search: 31 May 2018]	#1 MeSH descriptor: [Aged, 80 and over] explode all trees #2 MeSH descriptor: [Aged] explode all trees #3 MeSH descriptor: [Middle Aged] explode all trees #4 MeSH descriptor: [Mild Cognitive Impairment] explode all trees #5 "cognit* impair*" or MCI #6 elderly #7 "old* adults" #8 "old* age*" #9 "old* sample" #10 senior citizens #11 pensioners #12 seniors #13 #1 or #2 or #3 or #4 or #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 #14 MeSH descriptor: [Cognition] explode all trees #15 MeSH descriptor: [Dementia] explode all trees #16 cognit* #17 memory #18 "executive function*" #19 processing #20 "mental perform*" #21 dement* #22 alzheimer* #23 #14 or #15 or #16 or #17 or #18 or #19 or #20 or #21 or #22 #24 "cognitive stimulation" #25 "cognitive training" #26 "brain train*" #27 "brain gam*" #28 "memory train*" or "memory game*" #29 puzzle* #30 crossword* #31 sudoku* #32 "mental game*" #33 "mental agil*" #34 "cognitive exercis*" #35 "mental exercis*" #36 #24 or #25 or #26 or #27 or #28 or #29 or #30 or #31 or #32 or #33 or #34 or #35 #37 #13 and #23 and #36	Jan 2015: 274 Jul 2015: 11 Feb 2016: 57 Jul 2016: 4 May 2018: 210
Clinicaltrials.gov (www.clinicaltrials.gov) [Date of most recent search: 31 May 2018]		Jan 2015: 17 Jul 2015: 4 Feb 2016: 2 Jul 2016: 0 May 2018: 4
ICTRP Search Portal (http://apps.who.int/trialsearch) [includes Australian New Zealand Clinical Trials Registry; ClinicalTrilas.gov; ISRCTN; Chinese Clinical Trial Registry; Clinical Trials Registry – India; Clinical Research Information Service – Republic of Korea; German Clinical Trials Register; Iranian Registry of Clinical Trials; Japan Primary Registries Network; Pan African Clinical Trial Registry; Sri Lanka Clinical Trials Registry; The Netherlands National Trial Register] [Date of most recent search: 31 May 2018]		Jan 2015: 22 Jul 2015: 3 Feb 2016: 1 Jul 2016: 0 May 2018: 4
TOTAL before de‐duplication		Jan 2015: 3981 Jul 2015: 332 Feb 2016: 935 Jul 2016: 754 May 2018: 2390 TOTAL: 8392
TOTAL after de‐duplication		TOTAL: 6233
TOTAL after first assessment by the Crowd and CDCIG Information Specialists		Jan 2015: 604 Jul 2015: 60 Feb 2016: 164 Jul 2016: 73 May 2018: 190 TOTAL: 1091