Associations Between the 2D:4D Proxy Biomarker for Prenatal Hormone Exposures and Symptoms of Developmental Language Disorder.

PURPOSE

Relative lengths of the index (2D) and ring (4D) fingers in humans represent a retrospective biomarker of prenatal hormonal exposures. For this reason, the 2D:4D digit ratio can be used to investigate potential hormonal contributions to the etiology of neurodevelopmental disorders. This study tested potential group differences in 2D:4D digit ratios in a sample of boys with and without developmental language disorder (DLD) and examined the strength of associations between 2D:4D digit ratio and a battery of verbal and nonverbal measures.

METHOD

A group of 29 boys affected by DLD and a group of 76 boys with typical language abilities participated (age range = 5;6-11;0 years). Scanned images were used to measure finger lengths. Language measures included the core language subtests from the Clinical Evaluation of Language Fundamentals-Fourth Edition (Semel, Wiig, & Secord, 2003), a nonword repetition task, a sentence recall task, and the Test of Early Grammatical Impairment (Rice & Wexler, 2001).

RESULTS

Significant group differences indicated lower 2D:4D digit ratios in the group with DLD. Modest associations were found between 2D:4D digit ratios and some Clinical Evaluation of Language Fundamentals-Fourth Edition subtests.

CONCLUSIONS

Prenatal hormone exposures may play a role in the etiology of some language symptoms.