Table 1.
Summary of the characteristics of studies included in the meta-analysis.
| Study (first author, year) | N | Gender (%male) |
Mean age (years) |
Duration | Add-on therapy | Diagnosis | Primary cognition outcome measures | Other cognitive measures | Mean cognitive score at baseline | Study design | Double-blind |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Howard et al. (2020) | 544 | 55.7 | 74.3(8.2) | 24 m | Minocycline | Alzheimer disease | MMSE | NR | MMSE:26.4 ± 1.9 | RCT | Yes |
| Bernard et al. (2019) | 520 | 30.3 | 71.1(7.3) | 24w | S47445 | Alzheimer disease | ADAS-cog | MMSE |
ADAS-cog: 23.6 ± 9.0 MMSE:19.7 ± 2.8 |
RCT | Yes |
| Lin et al. (2019) | 97 | 45.1 | 75.5(7.8) | 6w | Benzoate | Dementia | ADAS-cog | CDR, MMSE | ADAS-cog:29.3 ± 12.6 | RCT | Yes |
| Kouzuki et al. (2019) | 159 | 12.6 | 87.1(0.7) | 12w | Monosodium L-glutamate | Dementia | TDAS | GBSS |
TDAS:55.2 ± 3.6 GBSS:64.7 ± 3.9 |
RCT | No |
| Lin et al. (2014) | 60 | 38.3 | 70.2(8.5) | 24w | Benzoate | Alzheimer disease | ADAS-cog | CIBIC-plus, cognitive composite | ADAS-cog:15.3 ± 7.5 | RCT | Yes |
| Tsai et al. (2014) | 30 | 63.3 | 76.8(6.0) | 8w | Sarcosine | Parkinson’s disease with dementia | CASI | CASI, MMSE, CDR |
CASI:57.4 ± 23.9 MMSE:17.3 ± 6.7 CDR:2.2 ± 1.2 |
RCT | Yes |
| Chappell et al. (2007) | 181 | 47.5 | 74.5(9.0) | 11w | LY451395 | Alzheimer disease | ADAS-cog |
CIBIC, Trail Making Part A, Stylus Tapping Test (STT), Single Digit Modality Test (SDMT) |
ADAS-cog:19.4 ± 9.0 MMSE:20.3 ± 3.3 | RCT | Yes |
| Adair et al. (2001) | 43 | NR | NR | 6 m | NAC | Alzheimer disease | MMSE | Four separate batteriesa | MMSE:19.0 ± 3.7 | RCT | Yes |
| Tsai et al. (1999) | 17 | 64.7 | 72.2(7.3) | 4w | D-Cycloserine | Alzheimer disease | ADAS-cog | NR |
ADAS-cog:23.5 ± 9.0 MMSE:18.8 ± 5.3 |
RCT, crossover | Yes |
| Tsai et al. (1998) | 10 | 40.0 | 74.7(8.5) | 4w | D-Cycloserine | Alzheimer disease | ADAS-cog | MMSE |
ADAS-cog:25.5 ± 2.7 MMSE:20.0 ± 5.2 |
RCT, crossover | Yes |
| Schwartz et al. (1996) | 108 | 53.8 | 74.4(8.6) | 10w | D-Cycloserine | Alzheimer disease | NR | MMSE, DRS, Implicit memory performance of words | NR | RCT | Yes |
| Mohr et al. (1995) | 40 | NR | NR | 24w | Cycloserine | Alzheimer disease | Cognitive Drug Research Computerized Assessment System (CDR System) | Mattis Dementia Rating Scale (MDRS), CIBIC, Brief Cognitive Rating Scale (BCRS) | NR | RCT | Yes |
| Fakouhi et al. (1995) | 403 | 46.1 | 73.6(8.0) | 26w | Cycloserine | Alzheimer disease | Cognitive Drug Research (CDR) computerized test , DRS | MMSE | NR | RCT | Yes |
| Randolph et al. (1994) | 12 | 70.0 | 65.0(8.4) | 2w | D-Cycloserine | Alzheimer disease | ADAS-cog, RBAD | MMSE | MMSE:21.0 ± 3.3 | RCT, crossover | Yes |
ADAS-cog Alzheimer’s Disease Assessment Scale-cognitive subscale; CASI Cognitive Abilities Screening Instrument; CDR Clinical Dementia Rating; CIBIC-plus Clinician’s Interview-Based Impression of Change plus Caregiver Input; DRS Dementia Rating Scale; GBSS Gottfries–Bråne–Steen Scale; HVLT Hopkins Verbal Learning Task; MMSE Mini-Mental Status Examination; NR no reported; RBAD Repeatable Battery for the Assessment of Dementia; TDAS the Touch Panel-type Dementia Assessment Scale; WMS, Wechsler Memory Scale.
aBoston Naming Test, Gesture to Command, WMS Figure Reproduction(immediate), HVLT Recall (immediate), HVLT Recognition, Letter fluency, Category fluency, Judgment of Line Orientation.