México
It is important to understand learning disabilities (LD) because they are prevalent worldwide. Currently there is great controversy about LD definition, as some studies focus on the discrepancy between intelligence and academic skills, while others focus only on academic skill assessments. The DSM-IV-TR provides the most commonly used definition for LD, which includes specific learning disabilities (reading, writing, arithmetic) and unspecified learning disabilities. For specific one would expect a significant discrepancy between academic skills and IQ, in contrast, significant discrepancies should not be observed in the unspecified. The literature also reports comorbidities among LD types. The objective of this study was to evaluate reading, writing, and arithmetic task performance profiles in 127 public elementary school children. Based on DSM-IV-TR criteria, we determined academic skill profiles, the presence of LD, LD type, and potential comorbidities in our sample. Using normalized test scores for reading, writing, and arithmetic, we applied a hierarchical cluster analysis to identify academic skill patterns. The results showed the following clusters among school children: 1) children with normal academic skills (n = 80), 2) children with unspecified LD including deficiencies in all three academic processes (n = 27), and 3) children with specific reading LD including arithmetic and writing deficiencies (n = 20). These classification types may later help identify specific neuropsychological characteristics underlying a specific disability, and subsequently facilitate treatments. Key words: Learning disabilities, reading disabilities, LD subtypes, hierarchical-clusters.