Author, date and country | Patient group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
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Carpenter et al. 2011 USA | - Elderly≥ 65;.ED physician discretion, English speaking, able to comply with data gathering, patient consent; excluded patients receiving mental status altering medications (antiemetic, benzodiazepines, narcotics) prior or during period, discharged prior to enrollment, critically ill, previously enrolled. - 169 enrolled, 163 included in analysis due to lack of data collection or refusal to participate further. - Mean age 78+/- 8 SD; 61% female, 49% were African Americans and 51% were Caucasian. | Prospective, cross-sectional | Measured sensitivity of screening tools, MMSE used as gold standard | - MMSE (gold standard ≤ 23) identified 60/163 (37%) patients with cognitive dysfunction - Delirium was identified in 9 – only by use of the CAM-ICU - Each screening instrument identified more patients with cognitive dysfunction than the MMSE. BAS, 65%; cAD8, 55%, O3DY, 66% and SBT, 43%. - Sensitivity of SBT, BAS, O3DY was 95%. SBT showed the largest agreement with the MMSE compared to the other instruments. - Each instrument had low specificities and would not be clinically helpful if positive. | - Convenience sample used – may reduce external validity - CAM-ICU tool has not been validated in the ED. - Screening tools were administered consecutively – risk of test-retest bias and test fatigue. MMSE (gold standard) was administered last. - MMSE suboptimal gold standard: sensitivity for mild cognitive impairment as low as 18%. |
Carpenter et. al. 2011 USA | 319 Elderly patients >65; non-critically ill, English speaking, receiving care in the ED for any reason. Excluded patients who received medication that may affect their mental status (narcotics, benzodiazepines, antiemetic) | Observational cross sectional cohort study | Sensitivity and specificity (95%CI) | SIS 74% (CI:68-80), 77% (74-80); cAD8 63% (53-72), 79%(73-85); pAD8 37% (28-46), 82% (77-86). | - Nonconsecutive convenience sampling. - Order of test administration not randomized or recorded - AD8 was administered to patients in 59% of cases and to caregivers 41% of cases. - MMSE not an ideal gold standard, also not sensitive for mild cognitive impairment - Unable to discriminate dementia from delirium with tests used - Did not assess reliability of SIS, AD8 and did not assess for selection bias between research assistants. - Cannot exclude a ‘learning phenomenon’ for the 3 item recall for the SIS and MMSE. Also 30 minute delay could have potentially allowed cognitive improvement or decline. - The SIS although superior only evaluates 2 realms (recall and orientation) of cognitive dysfunction. ED screening tools that evaluate different or additional domains may prove to be more accurate in cognitive dysfunction detection |
Combined abnormal SIS and cAD8 | sensitivity 89% (80-95), specificity 70% (63-73) | ||||
Abnormal SIS and cAD8 +LR | 19.9 (CI: 9.8-74.4) | ||||
ROC AUC | SIS: 0.83 (0.78-0.87); cAD8 0.74 (0.65-0.81); pAD8 0.67 (0.60-0.74) | ||||
Carpenter et. al. 2011 USA | Patients ≥ 65, English speaking and not prior use of sedating medications, abnormal MMSE scores. | Prospective cross sectional study | Sensitivity, specificity | - BAS Sen 72%(95% CI: 57-66), Spec 65% (44-82) - SBT: Sen 63% spec 88% (68-97) - cAD8: Sen 40% (34-41) Spec 89% (60-98) | - Study only looked at MCI, excluded patients with abnormal MMSE |
Monette et. al. 2001 Canada | 110 elderly patients, ≥66 years old. Exclusion criteria were as follows: blind, deaf, mute, aphasic, hospitalized the week prior to the interview, did not speak English or French, lived in a nursing home, too ill to be interviewed. Patients were interviewed within at least 6 hours of arriving to ED. | Reliability Study | Comparing CAM results obtained by lay interviewers to those obtained by geriatricians. Sensitivity, specificity | CAM administered by lay interviewers (compared to geriatricians) were 86% sensitive and 100% specific with excellent inter-observer reliability (kappa= 0.91) | - Focused on delirium ?applicable to other types of cognitive impairment. - Patients were recruited on weekdays, during the day and early evening shifts – this may have lead to the inclusion of patients that were generally lower acuity and less sick (spectrum bias). -Exclusion of patients who resided in a nursing home decreases this study’s external validity as an increasing number of patients that come into the ED will live in an assisted living or nursing facility. |
Kappa statistics | Kappa statistics for CAM vs. DSM IV: 0.97 (0.78-1.16), CAM vs. DSM-IIIR: 0.86 (0.43-1.12) and CAM vs. clinical impression: 0.94 (0.76-1.13) | ||||
Schofield et. al 2009 UK | 601 Patients ≥65 presenting to an inner city ED. Excluded patients unable to communicate, with learning disabilities, severe hearing disability, non-English speaking (with no interpreter). | Prospective comparison | Sensitivity, specificity, PPV,NPV: AMT4 | sensitivity 80% (CI: 0.75-0.85), specificity88% (CI 0.84-0.91) PPV 84 (CI 0.77-0.88) NPV 85 (CI 0.81-0.89) | - Used MMSE as gold standard. - Convenience sample may result in selection bias. - Carried out in United Kingdom, possible patient differences that may limit external validity to Canada. - Exclusion criteria limit external validity. - AMT4 scores were deduced from AMT – not separately obtained. - The research assistant administering the MMSE and AMT were not blinded to the results of the previous assessment, which may contribute to observer bias, threatening this study’s internal validity |
Sensitiviy/specificity,PPV,NPV: AMT | sensitivity 76% (CI 0.69-0.81), specificity 93% (CI: 0.90-0.96)PPV 90% (CI 0.84-0.93) NPV 83% (CI 0.79-0.87) | ||||
Sensitivity/Specificity: Judgment of admitting nurse | sensitivity 50.5% (CI 0.44-0.57) and specificity 98.6% (CI 0.96-1.00) | ||||
Wilber et. al 2008 USA | 352 Elderly ED patients ≥65. Excluded non English speaking, received medication that affect cognition, critically ill, uncooperative, and previously enrolled patients. | Prospective, cross sectional study | Sensitivity and specificity of SIS compared to MMSE. PPV and NPV | Sensitivity:63% (95% CI: 53-72%) Specificity: 81% (95% CI: 75-85%) PPV:60 (95% CI:50-69) NPV:83% (95% CI:77-87) | - Convenience sample – based on research assistant availability– risk of selection bias - 22% of patients refused to participate- risk of selection of unknown bias into study - Exclusion of non-English speaking patients reduces external validity. - Study conduced at 3 academic inner city ED, this limits external validity to non-urban centers. - Possible learning phenomenon with 3-item recall may account for differing sensitivity and specificities at different locations. - Study did not comment whether the 3 item recall list differed between the SIS and MMSE - SIS only assesses for temporal orientation and recall – may be unable to adequately detect cognitive impairment. - MMSE not ideal gold standard. |
Wilber et. al 2005 USA | 149 ED patients ≥65, excluded non-English speaking, un-cooperative or unwilling patients, medically unstable and those who received medications affecting mental status; average age 75. | Prospective randomized cross-sectional study. | - Compared sensitivity, specificity of SIS and Mini-Cog. Gold standard MMSE | - 23% of patients were cognitively impaired according to the MMSE - SIS sensitivity 94% (CI 73-100%) and specificity 86% (CI 74-94%) PPV 68% NPV: 98% - Mini-Cog sensitivity 75% (CI 48-93%) and specificity 85% (CI 73-93%) PPV 57% NPV 93% | - 21% of eligible patients refused to participate – may introduce selection bias and/or exclusion of severely cognitively impaired. - Exclusion of non-English speaking patients may limit external validity to all patient types. - Study conducted during convenient times when investigators were available – this may augment selection bias by limiting the number of mild or severely cognitively impaired that may during busy times in the ED. Introduces spectrum bias. - Conducted at community teaching hospital – may limit external validity to larger academic facilities. - MMSE administered after either SIS or Mini-Cog. - Wide confidence interval for SIS sensitivity due to small sample sizes. - Investigators administering the MMSE were not blinded to the results of the SIS or Mini-Cog. This undeniably introduces observer bias into the study. |
- Kappa statistics and ROC AUC calculated. | - Kappa statistic for the SIS and MMSE was 0.7. and Mini-Cog 0.5 - SIS agreed with MMSE 88% of the time and Mini-Cog 83% of the time - AUC for the ROC curve for SIS was 0.96 indicating excellent accuracy of this test. |