Neurología (English Edition) (Nov 2023)
Diagnostic accuracy and predictive validity of combined use of Fototest and Mini-Cog in cognitive impairment
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. Resumen: Introducción: El Fototest y el Mini-Cog incluyen todos los dominios que debieran formar parte de una evaluación cognitiva. Nuestro objetivo es evaluar la utilidad diagnóstica del uso conjunto de ambos instrumentos para el diagnóstico de deterioro cognitivo (DC). Métodos: Estudio Fase III de evaluación de pruebas diagnósticas con dos muestras independientes, ESTUDIO (448 sujetos), dividida aleatoriamente en dos dataset (BASE 80%, TEST 20%), y EXTERNA (61 sujetos). Prueba index: Fototest y Mini-Cog aplicados consecutivamente; prueba de referencia: evaluación cognitiva formal. Se evalúa la UD del uso combinado y escalonado de los modelos Simple (Comb-Simple), Regresión Logística (Comb-RL) y Árbol Aleatorio (Comb-AA) para identificar DC (GDS ≥ 3). Se realiza un análisis exploratorio en BASE seleccionando los criterios que maximizan la Exactitud; la evaluación se realiza en las muestras TEST y EXTERNA mediante un análisis preespecificado con los criterios seleccionados. Resultados: La UD de los modelos combinados en BASE (Comb-Simple 88.3 (88.5−91.4) [Exactitud (LI95%-LS95%)], Comb-RL 91.6 (88.2−94.3) y Comb-AA 95.2 (92.5−97.2)) es significativamente superior a la de Mini-Cog y Fototest (81.6 (77.1−85.4) y 84.9 (80.8−88.5) respectivamente); estos resultados son replicados en TEST (Comb-Simple 88.9 (Exactitud), Comb-RL 95.6 y Comb-AA 92.2) y EXTERNA (Comb-Simple 91.8, Comb-RL 90.2 y Comb-AA 88.5). La aplicación escalonada mantiene la misma UD pero requiere menos tiempo (197.3 ± 56.7 vs 233.9 ± 45.2, p < 0.0001). Conclusiones: El uso conjunto del Fototest y el Mini-Cog requiere menos de cuatro minutos y mejora la UD de ambos instrumentos. El uso escalonado es más eficiente porque manteniendo la misma UD requiere menos tiempo de aplicación.
