Summary of findings'. 'Whole brain volume or volume of specific brain regions for early Alzheimer's disease dementia diagnosis in people with mild cognitive impairment.
| Whole brain volume versus volume of specific brain regions for early Alzheimer's disease dementia diagnosis in people with mild cognitive impairment | ||||||||
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Patient or population: people with mild cognitive impairment (MCI) Setting: memory clinics or registry data (e.g. ADNI) New test: volume of total hippocampus, medial temporal lobe, total entorhinal cortex, lateral ventricles, and whole brain. Volume measured with either quantitative manual or automated MRI technique Cut‐off value: not reported | ||||||||
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Number of results per 1000 participants tested (95% CI) Prevalence 30%. Typically seen in participants with MCI after 2 to 3 years of follow‐up |
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| Test | Number of participants (Number of studies) | True positives | False negatives | True negatives | False positives | Pooled sensitivity (95% CI) | Pooled specificity (95% CI) | Certainty of the evidence (GRADE) |
| Total hippocampus | 2209 (22) |
219 (192 to 240) |
81 (60 to 108) |
497 (455 to 539) |
203 (161 to 245) |
0.73 (0.64 to 0.80) |
0.71 (0.65 to 0.77) |
⊕⊕⊝⊝ Lowa,b |
| Medial temporal lobe | 1077 (7) |
192 (159 to 219) |
108 (81 to 141) |
455 (357 to 532) |
245 (168 to 343) |
0.64 (0.53 to 0.73) |
0.65 (0.51 to 0.76) |
⊕⊕⊕⊝ Moderatea,c |
| Lateral ventricles | 1077 (5) |
171 (147 to 195) |
129 (105 to 153) |
448 (413 to 490) |
252 (210 to 287) |
0.57 (0.49 to 0.65) |
0.64 (0.59 to 0.70) |
⊕⊕⊕⊝ Moderatea,c |
| Total entorhinal cortex | 529 (4) |
Meta‐analyses not conducted due to sparse and heterogeneous data | Range: 0.50 to 0.88 | Range: 0.60 to 1.00 | ⊕⊝⊝⊝ Very lowa,d | |||
| Whole brain | 424 (4) |
Meta‐analyses not conducted due to sparse and heterogeneous data | Range: 0.33 to 0.92 | Range: 0.41 to 1.00 | ⊕⊝⊝⊝ Very lowa,d | |||
| The table displays normalised number of participants within a hypothetical cohort of 1000 people at a prevalence of Alzheimer's disease (pre‐test probabilities) of 30%. We selected a prevalence value based on a prevalence observed in people with MCI after 2 to 3 years of follow‐up. We estimated confidence intervals based on those around the point estimates for pooled sensitivity and specificity. ADNI: Alzheimer's Disease Neuroimaging Initiative; CI: confidence interval; MCI: mild cognitive impairment; MRI: magnetic resonance imaging | ||||||||
| GRADE Working Group GRADES of evidence High certainty: we are very confident that the true effect lies close to the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||||
aRisk of bias: most studies were at high risk of bias for participant selection (registry data), or index test or both. We downgraded the certainty of the evidence by one level. bImprecision: wide 95% confidence intervals. We downgraded the certainty of the evidence by one level cImprecision: wide 95% confidence intervals, however upper limit for both sensitivity and specificity are below 0.75, which is a modest performance. We did not downgrade. dInconsistency and imprecision: sparse and inconsistent data. We downgraded the certainty of the evidence by one level both for inconsistency and imprecision.