Objective: To determine whether performance in a virtual spatial navigational task is poorer in persistent postural perceptual dizziness (PPPD) patients than in healthy volunteers and patients suffering other vestibular disorders. Methods: Subjects were asked to perform three virtual Morris water maze spatial navigational tasks: (i) with a visible target, (ii) then with an invisible target and a fixed starting position, and finally (iii) with an invisible target and random initial position. Data were analyzed using the cumulative search error (CSE) index. Results: While all subjects performed equally well with a visible target, the patients with PPPD (n = 19) performed poorer (p < 0.004) in the invisible target/navigationally demanding tasks (CSE median of 8) than did the healthy controls (n = 18; CSE: 3) and vestibular controls (n = 19; CSE: 4). Navigational performance in the most challenging setting allowed us to discriminate PPPD patients from controls with an area under the receiver operating characteristic curve of 0.83 (sensitivity 78.1%; specificity 83.3%). PPPD patients manifested more chaotic and disorganized search strategies, with more dispersion in the navigational pool than those of the non-PPPD groups (standard distance deviation of 0.97 vs. 0.46 in vestibular controls and 0.20 in healthy controls; p < 0.001). Conclusions: While all patients suffering a vestibular disorder had poorer navigational abilities than healthy controls did, patients with PPPD showed the worst performance, to the point that this variable allowed the discrimination of PPPD from non-PPPD patients. This distinct impairment in spatial navigation abilities offers new insights into PPPD pathophysiology and may also represent a new biomarker for diagnosing this entity.

ResumenLa reciente estandarización en Chile de la Escala Wechsler de Inteligencia para Adultos (WAIS), en su cuarta versión, obliga a investigar el impacto que condiciones culturales y ambientales pueden tener sobre el rendimiento intelectual de las personas. El presente estudio comparó el desempeño de jóvenes provenientes de sectores rurales y urbanos de la región del Biobío, segmentados según nivel educativo de los padres como variable de aproximación al nivel socioeconómico. Los resultados muestran un efecto de interacción entre el nivel socioeconómico y el lugar de residencia. Comprensión verbal y memoria de trabajo son los constructos que reciben un mayor impacto del nivel socioeconómico. Se espera que futuros estudios contribuyan a la investigación de habilidades cognitivas en sectores rurales y socialmente deprivados de Chile. Palabras clave: ruralidad, habilidades cognitivas, Escala Wechsler de Inteligencia para Adultos y deprivación social. AbstractThe recent standardization of Wechsler Adult Intelligence Scale (WAIS) in its fourth version in Chile forces to test the impact that cultural and environmental conditions can have on people's intellectual performance. The present study compared the performance of young people from rural and urban areas of the Biobío region, segmented by parental education level as proxy variable to socioeconomic status. Results showed an interaction effect between socioeconomic status and place of residence. Verbal Comprehension and Working Memory are the constructs that received a higher impact of the socioeconomic status. Future studies are expected to contribute to research on cognitive abilities in rural and socially deprived sectors in Chile.

<b><i>Background:</i></b> The Montreal Cognitive Assessment (MoCA) is a sensitive screening instrument for mild neurocognitive disorder (mild NCD). However, cut-off scores and accuracy indices should be established using representative samples of the population. In this context, the aim of this study was to update the normative values, and diagnostic efficiency statistics of the MoCA to detect mild NCD in the Chilean population. <b><i>Methods:</i></b> This study included 226 participants from the north, center, and south of the country, classified into 3 groups: healthy elderly (HE; <i>n</i> = 113), mild NCD (<i>n</i> = 65), and major neurocognitive disorder (major NCD; <i>n</i> = 48). <b><i>Results:</i></b> The optimal cut-off score to discriminate mild NCD from HE participants was 20 points with a sensitivity of 82.8% and a specificity of 84.1%. The observed balance between sensitivity and specificity shows a good test performance either to confirm or discard a diagnosis. The cut-off between mild NCD and major NCD from HE participants was 19 points with 85.6% of sensitivity and 90.3% of specificity. <b><i>Conclusion:</i></b> Overall diagnostic accuracy can be considered as outstanding (AUC ≥0.904) when discriminating HE from both mild NCD and major NCD. These results showed that the MoCA is a suitable tool to identify mild NCD and major NCD.

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