Relationship between Neurological Deficit and Intelligence Quotient in Children and Adolescents

Introduction. The relationship between developmental and mental deficits due to genetic or acquired causes is well established. However the possible relationship between neurological signs and intellectual development has not been sufficiently studied. Objective. We have conducted a transversal study to test the possible association between neurological signs and psychometrical measures in children and young adolescents. Patients and methods. 123 patients were neurologically explored (ages between 54-185 months), 36 girls and 87 boys. These subjects were neurologically and psychometrically tested during a period of 3 years. Contingency tables, chi squared tests, discriminant analysis and ROC curves were used for statistical analysis. This statistic allowed to establish the contingencies between neurological signs (presence or absence) and intelligence quotient (IQ) groups (low and normal scores). Results. The results showed a statistically significant relationship between IQ and the presence of 7 neurological signs (χ = 6,213; p = 0,013). The discriminant analysis classified correctly 77.2% of subjects. The ROC curves indicated a high sensitivity and specificity if subjects presented more than 3 neurological signs. The frequency analysis established the more discriminant neurological signs. Conclusions. The obtained results in children with learning and behavioural disabilities suggest comorbidity between low IQ and neurological signs. This association is more marked in the group of children than in the preand adolescent group. [REV NEUROL 2004; 38: 20-7]