Table 1.
Characteristics of studies included
| Reference | Study Samplea | Study Design Length of follow-up | MRI Magnet | Neuroimaging Outcome Measures | Cognition measured (test name) |
|---|---|---|---|---|---|
| Suo et al. [19] 2016 | Older adults with MCI N = 100 70.1 ± 6.7 years Completed MRI: N = 79 |
RCT Assessments at baseline and 6 months |
3 T | • Volumetric Structural MRI • Resting-state fMRI |
Global Cognition (ADAS-Cog) [41] ○ Memory Domain ○ Executive Function ○ Attention-Speed |
| Rosen et al. [18] 2011 | Older adults with MCI N = 12 74.34 ± 9.25 years Training N = 6 70.67 ± 10.58 years Control N = 6 78 ± 7.92 years |
RCT Assessments conducted on average 72 ± 26 days apart |
3 T | • Task-based fMRI • Incidental Auditory-Verbal Repetition paradigm |
Memory (Repeatable Battery for the Assessment of Neuropsychological Status: RBANS) [42] |
| Lampit et al. [16] 2015 | Healthy older adults: Subsample from Timecourse Trial N = 12 71.43 ± 7.48 years Training N = 7 72.3 ± 8 years Control N = 5 70.2 ± 6.7 years |
RCT Assessments at baseline, 3 weeks: Follow Up 1(FU1), 3 months: Follow Up 2 (FU2) Secondary analysis |
3 T | • Volumetric Structural MRI • Resting-state fMRI • Proton Magnetic Resonance Spectroscopy • DTI |
Global Cognition: Composite of memory and information processing speed (Mindstreams battery) [43] as well as executive function (Average Mindstreams Stroop Interference test for Inhibition [43] and Cambridge Neuropsychological Test Automated Battery (CANTAB) Stockings of Cambridge problems solving) [44, 45] |
| Belleville et al. [21] 2014 | Healthy community-dwelling older adults N = 40 69 ± 6.27 years Training group 1 N = 12 68.58 ± 8.16 years Training group 2 N = 14 69.57 ± 5.81 years Training group 3 N = 14 68.79 ± 5.13 years |
Quasi-experimental Pre-post Assessments 1 week before and 1 week after training |
3 T | • Task-based fMRI • Alphanumeric equation task • Visual detection task Tasks performed as single-task and dual-task |
Reaction Time (Alphanumeric equation task and visual detection task) Accuracy (Alphanumeric equation task and visual detection task) |
| Lin et al. [17] 2014 | Older adults with a history of a stroke N = 34 69.21 ± 4.93 years Training N = 16 62.4 ± 6.0 years Control N = 18 63.2 ± 5.7 years |
RCT Assessments at baseline and 10 weeks |
3 T | • Resting state fMRI | Memory (Wechsler Memory Scale) [46] Executive Function (Trail Making Test) [47] |
| Strenziok et al. [24] 2014 | Healthy older adults N = 42 69.21 ± 4.93 years Training group 1 N = 14 69.70 ± 6.9 years Training group 2 N = 14 68.52 ± 5.6 years Training group 3 N = 14 69.41 ± 2.3 years |
Quasi-experimental Pre-post Length of follow up: Not stated |
Not stated | • Resting-state fMRI • DTI |
Reasoning/Problem Solving (WAIS III Matrix Reasoning subtest, [48] Everyday problems Test, [49] Word Series and Letter Series Tests) [50] Episodic Memory (Wechsler Memory Scale Logical Memory Subtest) [51, 52] Spatial Working Memory (Information-processing Visuo-Spatial Delayed Match-to-Sample Test) [53, 54] Auditory Working Memory (Letter Number Sequencing subtest of WAIS III) [48] |
| Lövden et al. [23] 2010 | Healthy older adultsb: Subsample COGITO study N = 25 69.32 ± 3.12 years Training N = 12 68.9 ± 2.7 years Control N = 13 69.7 ± 3.5 years |
Quasi-experimental Pre-post Training: Pre-post MRI on average 179 ± 25.2 days apart Control: Pre-post MRI on average 184 ± 15.0 days apart |
1.5 T | • DTI | Spatial Working Memory (3-Back)c
Numerical Working Memory (Memory Updating)c Figural-Spatial Episodic Memory (Object-Position Memory)c Numerical Episodic Memory (Number-noun pairs)c Verbal Episodic Memory (Wordlist)c Perceptual Speed (Choice Reaction Task, Comparison tasks)c |
| Antonenko et al. [20] 2016 | Healthy older adults N = 25 69 ± 6 years |
Quasi-experimental Pre-post Assessments 1 day before (pre), 1 day after (post) and 1 month after (follow-up) trainingd |
3 T | • Volumetric Structural MRI • DTI |
Cued recall (3-alternative-forced-choice recall task (AFC); main outcome) [55] and recognition Episodic Memory control task (German Rey Auditory Verbal Learning Test) [56] |
| Heinzel et al. [22] 2014 | Healthy older adultsc
N = 19 65.95 ± 3.73 years |
Quasi-experimental Pre-post Subset of 15 older individuals performed pre-post MRI Length of follow up: Not stated |
3 T | • Volumetric Structural MRI • Task-based fMRI • N-back [57]: two runs (16 blocks/run) with 4 working memory loads (0, 1, 2, 3) • Functional Connectivity (PPI) |
Relative Working Memory Training gain (n-Back) [57] Short-term memory (Digit span Fwd and Bwd WAIS III) [51] Processing Speed (Digit Symbol WAIS III, [51] D2 Test [58]) Executive Functions: Verbal Fluency (Controlled Oral Word Association Test) [59] Inhibition (Stroop) [60] Abstract Reasoning (Raven’s SPM [61], Figural Relations subtest [62]) |
MRI Magnetic Resonance Imaging, DTI Diffusion Tensor Imaging, fMRI functional Magnetic Resonance Imaging, RCT Randomized Controlled Trial
aMean age ± standard deviation
bA sample of young adults was included in the study as well
cBehavioural outcomes only measured for intervention groups
dOnly cognitive assessments at one month follow-up (no MRI)