The paradigms are the experimental tasks that are used to map the brain through functional Magnetic Resonance Imaging. Its previous validation is essential to guarantee a successful record of the cognitive activity. A paradigm of abstract reasoning formed by a task of semantic and visual analogies was validated in young-adults between 18 and 30 years in the city of Cuenca-Ecuador. The paradigm was programmed in PsychoPy 3, a free software for neuroscience experiments. The results indicated that the experimental paradigm was understandable and easy to solve. It was also found that the average response time in the semantic reasoning task was significantly lower than the average resolution time of the visual reasoning task. Therefore, it was possible to establish the number of stimuli and their average exposure time needed for a functional Magnetic Resonance Imaging.
validation
Validación de un paradigma de razonamiento abstracto para Resonancia Magnética funcional (RMf). Validation of an abstract reasoning paradigm for functional magnetic resonance (fMR).
Capacidad Diagnóstica y Validación Preliminar del Test del Reloj, Versión de Cacho a la Orden, para Enfermedad de Alzheimer de Grado Leve en Población Chilena
Background: To perform a study with discriminant power and validity using the Clock drawing Test by instruction (CDTI) in patients with mild Alzheimer’s disease (MAD).
Materials and Methods: Phase I diagnostic test study. We included a healthy control arm of 58 elderly people and 40 cases with mild Alzheimer’s disease. All participants were examined and diagnosed by clinical consensus. The MMSE, CDTI and clinical record were obtained.
Results: There were significant differences between the study groups regarding cognitive tests’ performance when comparing age and education, but no differences were found when comparing gender. ANCOVA test showed no significant effect exerted by the demographic variables on cognitive performance in any group. The sensitivity (CTO=84% vs MMSE=79,3%), specificity (92,5% vs
82,5%) and diagnostic utility of the CDTO were higher than one’s resulting form the MMSE (=0,90, p=0,000). The combined use of both
instruments increased diagnostic capacity. The best cutoff point for the diagnosis of mild dementia was ≤6 points in CDTO and ≤23 in
MMSE. Both instruments correlated statistically.
Conclusions: The CTO is a useful test and can discriminate between cognitively healthy subjects and patients with EAL when appliying the “to order” criteria from Cacho’s version.
