ABSTRACT
INTRODUCTION: The Fototest and Mini-Cog include all the domains that are necessary in a cognitive assessment. This study aims to evaluate the diagnostic accuracy of the combined use of both instruments for detecting cognitive impairment. METHODS: We performed a phase III diagnostic accuracy study with 2 independent samples: STUDY, which included 448 participants randomly allocated to 2 datasets (BASE [80%] and TEST [20%]); and EXTERNAL, which included 61 participants. The index test was consecutive administration of the Fototest and Mini-Cog, and the reference test was formal cognitive assessment. We evaluated the diagnostic accuracy of two-step vs consecutive application of the tests and simple (Comb-Simple), logistic regression (Comb-LR), and random decision tree (Comb-RDT) models of their combined use for detecting cognitive impairment (Global Deterioration Scale score ≥ 3). We performed an exploratory analysis of the BASE dataset, selecting criteria that maximise accuracy; a pre-specified analysis was used to evaluate the selected criteria in the TEST and EXTERNAL datasets. RESULTS: The diagnostic accuracy (95% confidence interval) of the combined models in the BASE dataset (Comb-Simple: 88.3 [88.5-91.4]; Comb-LR: 91.6 [88.2-94.3]; Comb-RDT 95.2 [92.5-97.2]) was significantly higher than the individual values observed for the Mini-Cog and Fototest (81.6 [77.1-85.4] and 84.9 [80.8-88.5], respectively). These results were replicated in the TEST (Comb-Simple: 88.9; Comb-LR: 95.6; Comb-RDT: 92.2) and EXTERNAL datasets (Comb-Simple: 91.8; Comb-LR: 90.2; Comb-RDT: 88.5). Two-step application had the same diagnostic accuracy than consecutive application but required less time (mean [SD] of 197.3 s [56.7] vs 233.9 s [45.2]; P < .0001). CONCLUSIONS: Combined application of the Fototest and Mini-Cog takes less than 4 minutes and improves the diagnostic accuracy of both instruments. Two-step application is more efficient as it requires less time while maintaining the same diagnostic accuracy.
Subject(s)
Cognitive Dysfunction , Dementia , Humans , Cognitive Dysfunction/diagnosis , Dementia/diagnosis , Mental Status and Dementia TestsABSTRACT
INTRODUCTION: The Fototest and Mini-Cog include all the domains that are necessary in a cognitive assessment. This study aims to evaluate the diagnostic accuracy of the combined use of both instruments for detecting cognitive impairment. METHODS: We performed a phase iii diagnostic accuracy study with 2 independent samples: STUDY, which included 448 participants randomly allocated to 2 datasets (BASE [80%] and TEST [20%]); and EXTERNAL, which included 61 participants. The index test was consecutive administration of the Fototest and Mini-Cog, and the reference test was formal cognitive assessment. We evaluated the diagnostic accuracy of two-step vs. consecutive application of the tests and simple (Comb-Simple), logistic regression (Comb-LR), and random decision tree (Comb-RDT) models of their combined use for detecting cognitive impairment (Global Deterioration Scale score ≥ 3). We performed an exploratory analysis of the BASE dataset, selecting criteria that maximise accuracy; a pre-specified analysis was used to evaluate the selected criteria in the TEST and EXTERNAL datasets. RESULTS: The diagnostic accuracy (95% confidence interval) of the combined models in the BASE dataset (Comb-Simple: 88.3 [88.5-91.4]; Comb-LR: 91.6 [88.2-94.3]; Comb-RDT 95.2 [92.5-97.2]) was significantly higher than the individual values observed for the Mini-Cog and Fototest (81.6 [77.1-85.4] and 84.9 [80.8-88.5], respectively). These results were replicated in the TEST (Comb-Simple: 88.9; Comb-LR: 95.6; Comb-RDT: 92.2) and EXTERNAL datasets (Comb-Simple: 91.8; Comb-LR: 90.2; Comb-RDT: 88.5). Two-step application had the same diagnostic accuracy than consecutive application but required less time (mean [SD] of 197.3 s [56.7] vs. 233.9 s [45.2]; P<.0001). CONCLUSIONS: Combined application of the Fototest and Mini-Cog takes less than 4minutes and improves the diagnostic accuracy of both instruments. Two-step application is more efficient as it requires less time while maintaining the same diagnostic accuracy.
ABSTRACT
INTRODUCTION: The AD8 is a brief informant-based questionnaire that may also be self-administered, and which aids in identifying cognitive impairment (CI). Our goal is to assess the diagnostic accuracy (DA) of a Spanish version of that questionnaire. MATERIAL AND METHODS: Cross-sectional study of a clinical sample of patient/informant dyads including 330 subjects with suspected CI or dementia (DEM) and 71 controls. We evaluated internal consistency (Cronbach's alpha) and validity (partial correlations with GDS stage, Fototest results and functional index measure [FIM]). We assessed DA for CI vs no CI (GDS stage 3-4) using the area under the ROC curve (AUC), and the cut-off with the highest Youden index was determined to be optimal. RESULTS: In the sample, 105 subjects had no CI, 99 had CI without DEM and 203 had DEM. Internal consistency was high (α 0.90, 95% confidence interval: 0.89-0.92), as were correlations with the GDS score (r=0.72, P<.001), Fototest results (r=-0.61, P<.001) and FIM (r=0.59, P<.001). The AUC for AD8 was 0.90 (95% confidence interval: 0.86-0.93), which was not significantly different from that of the Fototest (AUC 0.93, 95% confidence interval: 0.89-0.96). The optimal cut-off point was 3/4 with a sensitivity of 0.93 (95% confidence interval: 0.88-0.96) and a specificity of 0.81 (95% confidence interval: 0.72-0.88); 88.8% of the classifications were correct. Combined use of AD8 and the Fototest significantly improved the DA of both (AUC 0.96, 95% confidence interval: 0.93-0.98, P<.05). CONCLUSIONS: The Spanish version of the AD8 questionnaire preserves the psychometric qualities and DA of the original. Using this test in combination with the Fototest significantly increases the DA of both tests.
Subject(s)
Cognition Disorders/diagnosis , Surveys and Questionnaires , Aged , Aged, 80 and over , Cognition Disorders/psychology , Cross-Sectional Studies , Data Interpretation, Statistical , Female , Humans , Language , Male , Middle Aged , Neuropsychological Tests , Prospective Studies , ROC Curve , Reproducibility of ResultsABSTRACT
OBJECTIVE: Fototest is a short simple test, applicable to illiterate subjects and not influenced by educational level. The purpose of this study is to assess its validity for cognitive impairment (CI) and dementia (DEM) under routine clinical practice conditions. MATERIAL AND METHODS: A cross-sectional, multicentre and naturalistic study conducted in General Neurology clinics. The subjects were, over 60 years old, with a previously established diagnosis of no cognitive impairment (NoCI), cognitive impairment without dementia (CInoDEM), or dementia (DEM). The discriminant validity was assessed using the area under the ROC curve (AUC), sensitivity (Sn), specificity (Sp), and probability coefficients. Partial correlations were calculated, adjusted for age, sex and education level with Eurotest, verbal fluency test (VFT) and Global Deterioration Scale (GDS) score to evaluate the concurrent and construct validity. RESULTS: Nineteen neurologists included a total of 589 subjects: 361 NoCI, 106 CINoDEM and 122 DEM. The discriminant value was better for DEM (AUC 0.94 ± 0.02) than for CI (0.86 ± 0.02). For DEM the best cut-off point was 26/27 (Sn=0.88 [95% CI, 0.93-0.97], Sp=0.87 [95% CI, 0.84-0.90]); and for CI, 28/29 (Sn=0.71 [95% CI, 0.65-0.77], Sp=0.84 [95% CI, 0.80-0.88]). Fototest showed a high and significant correlation with Eurotest (r=0.70 ± 0.02), VFT (r=0.68 ± 0.02) and the GDS score (r=-0.77 ± 0.02). CONCLUSION: The Fototest showed adequate validity for CI and DEM in general Neurology clinics in an extensive and wide geographical area.
