[Cognitive functions in type 1 and type 2 diabetes. Meta-analysis].

INTRODUCTION: Diabetes has been repeatedly associated with a wide variety of cognitive impairments. AIM: To clarify the differences in cognitive dysfunctions between the two types of diabetes. METHOD: Metaanalysis was performed using databases of Medline, PubMed and ScienceDirect (3 studies with type 1 and 6 with type 2 diabetes). RESULTS: Adults with type 1 diabetes showed lower performance than control subjects in all fields. The effect size had the highest value in psychomotor activity (D = -0.69). The effect size was small for delayed verbal memory (D = -0.48), attention (D = -0.47), language (D = -0.44), visual processing (D = -0.35), immediate verbal memory (D = -0.30), working memory (D = -0.27) and executive functions (D = -0.26). Adults with type 2 diabetes showed lower performance than control subjects in all cognitive domains, except for working memory (D = +0.03). The effect size had the highest value in immediate verbal memory (D = -1.12), psychomotor activity (D = -0.82) and delayed verbal memory (D = -0.81). The effect size was moderate for general intellectual abilities (D = -0.68) and small for general memory (D = -0.37), attention (D = -0.35), language (D = -0.35), visual processing (D = -0.33) and executive functions (D = -0.33). CONCLUSION: Both types of diabetes are associated with reduced performance in numerous cognitive domains.