[2D:4D finger ratio and language development]. / Indice digital D2:D4 y desarrollo del lenguaje.

INTRODUCTION: A possible hormonal influence in language development has been suggested in the recent years. The 2D:4D finger ratio is an indirect measure for prenatal androgen exposure. It is negatively related to prenatal testosterone and positively related to prenatal estrogen, resulting in a lower ratio for men and a larger ratio for women. It can be explored in children as young as 2 years old. AIM: To study if an association exists between the 2D:4D finger ratio and language development (vocabulary) and/or language problems. SUBJECTS AND METHODS: The lengths of the second digit (index finger) (2D) and the fourth digit (ring finger) (4D) were measured in 97 preschoolers and the Language Development Survey was administered to the parents. RESULTS: A weak negative correlation between language development (vocabulary) and right 2D:4D ratio was found in both sexes for children aged 4 or less years, significant only in boys. A strong negative correlation between language articulation problems and right 2D:4D ratio in both sexes for children aged 3 or less years, and a lower negative correlation between articulation problems and right 2D:4D ratio were found for boys aged 4 or less years. CONCLUSION: Findings suggest an important role for testosterone in language development (vocabulary) and a possible influence on articulation problems, probably through higher testosterone levels.

Validity and reability of the CBCL/6-18. Includes DSM scales.

INTRODUCTION: The Child Behavior Checklist (CBCL/6-18) is the most commonly used parent-completed instrument that assesses child and adolescent psychopathology. It has been used in epidemiology and clinical studies. The last version contains DSM-oriented subscales. OBJECTIVE: Investigate the psychometric properties of the CBCL/6-18 and develops a valid and reliable Mexican version. METHOD: Psychologists and child psychiatrists adapted the Spanish version of CBCL/6-18, and a back translation was done by a native English speaker. Discrepancies in the adaptation were solved by consensus. The checklist was applied to children in the community and to outpatients from a psychiatric children hospital. Reliability was evaluated by estimating internal consistency (Cronbach's alpha) on all scales: retest at one week was evaluated with intraclass correlation coefficients (ICC). A ROC curve was performed to estimate a cut-off which correctly identified children from the clinically referred patients and children recruited in the community (non-referred). Mean differences for the groups were calculated with the Student's t test. RESULTS: The Mexican version of the CBCL/6-18 showed that the Cronbach's alpha coefficient was 0.90 for internalizing problems, 0.94 for externalizing problems and 0.97 for the total problem scale. The ICC was 0.97 for the total problem scale. Significant differences were found between the mean score in broad band, narrow and the new DSM/oriented scales. CONCLUSIONS: The Mexican version of CBCL/6-18 is a reliable and valid screening instrument for clinical and epidemiologic use.