Underestimation of Cognitive Impairment in Older Inpatients by the Abbreviated Mental Test Score versus the Montreal Cognitive Assessment: Cross-Sectional Observational Study
Bibliographic record
Abstract
Background/Aims: Cognitive impairment is prevalent in older inpatients but may be unrecognized. Screening to identify cognitive deficits is therefore important to optimize care. The 10-point Abbreviated Mental Test Score (AMTS) is widely used in acute hospital settings but its reliability for mild versus more severe cognitive impairment is unknown. We therefore studied the AMTS versus the 30-point Montreal Cognitive Assessment (MoCA) in older (≥75 years) inpatients. Methods: The AMTS and MoCA were administered to consecutive hospitalized patients at ≥72 h after admission in a prospective observational study. MoCA testing time was recorded. Reliability of the AMTS for the reference standard defined as mild (MoCA <26) or moderate/severe (MoCA <18) cognitive impairment was assessed using the area under the receiver-operating curve (AUC). Sensitivity, specificity, positive and negative predictive values of low AMTS (<8) for cognitive impairment were determined. Results: Among 205 patients (mean/SD age = 84.9/6.3 years, 96 (46.8%) male, 74 (36.1%) dementia/delirium), mean/SD AMTS was 7.2/2.3, and mean/SD MoCA was 16.1/6.2 with mean/SD testing time = 17.9/7.2 min. 96/205 (46.8%) had low AMTS whereas 174/185 (94%) had low MoCA: 74/185 (40.0%) had mild and 100 ( 54.0%) had moderate/severe impairment. Moderate/severe cognitive impairment was more prevalent in the low versus the normal AMTS group: 74/83 (90%) versus 25/102 (25%, p < 0.0001). AUC of the AMTS for mild and moderate/severe impairment were 0.86 (95% CI = 0.80–0.93) and 0.88 (0.82–0.93), respectively. Specificity of AMTS <8 for both mild and moderate/severe cognitive impairment was high (100%, 71.5–100, and 92.7%, 84.8–97.3) but sensitivity was lower (44.8%, 37.0–52.8, and 72.8%, 62.6–81.6, respectively). The negative predictive value of AMTS <8 was therefore low for mild impairment (10.9%, 5.6–18.7) but much higher for moderate/severe impairment (75.2%, 65.7–83.3). All MoCA subtests discriminated between low and normal AMTS groups (all p < 0.0001, except p = 0.002 for repetition) but deficits in delayed recall, verbal fluency and visuo-executive function were prevalent even in the normal AMTS group. Conclusion: The AMTS is highly specific but relatively insensitive for cognitive impairment: a quarter of those with normal AMTS had moderate/severe impairment on the MoCA with widespread deficits. The AMTS cannot therefore be used as a “rule-out” test, and more detailed cognitive assessment will be required in selected patients.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.010 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".