The Ethiopian Cognitive Assessment battery in Schizophrenia (ECAS): a validation study

Abstract

Cognitive impairment is common in people with schizophrenia (PWS). To detect the presence and its consequences, cognitive measures with sound psychometric properties are needed. However, these are lacking especially in low-income countries. Hence, we developed the Ethiopian Cognitive Assessment battery in Schizophrenia (ECAS). In this study, we evaluated the psychometric properties of the ECAS in a cross-sectional study involving 350 PWS. Confirmatory factor analysis demonstrated a one-factor solution. ECAS score correlated significantly but weakly with a disability measure (r = -0.13, p = 0.02) and symptom dimensions of PANSS (r between -0.12 and -0.29, p < 0.05), except for positive symptoms (r = -0.10, p > 0.05). Years of education (β = 0.12, 95% CI (0.09, 0.14), p < 0.001), male sex (β = 0.22, 95% CI (0.05, 0.39)), age β = -0.02, 95% CI (-0.03, -0.01), and medication side effects (β = -0.03, 95% CI (-0.06, -0.01), p = 0.021) were significantly associated with the composite score of ECAS. The Item Response Theory analysis showed that the tool best functions among participants with moderate cognitive impairment (difficulty coefficient between -1.12 and 0.27). The Differential Item Functioning analyses showed that education had a positive contribution on Digit Symbol Substitution Test (MH OR = 2.64, 95% CI (1.34, 5.20)). The results showed that ECAS is valid in assessing cognition in PWS in low-resource settings.