Using a kinematic analysis of different fetal arm movements recorded during ultrasonography, Italian researchers report that hand preference is well defined starting from 18 gestational weeks.
The team from SISSA of Trieste and University of Padua says it was able to foresee the motor preference observed in the same boys and girls at age nine. According to the study published last week in Scientific Reports, their predictions had an accuracy that ranged between 89% and 100% depending on the parameters used.
The researchers analyzed the movements of the hands of the fetuses at 14, 18, and 22 weeks of gestation using a 4D ultrasound scan, viewing the three dimensional image in real time and in movement, in 20-minute sessions. They studied three types of movements: two of greater precision, directed to the eyes and mouth, and one directed to the uterine wall, as a control. The results have shown that starting from the 18th week the fetuses execute significantly more quickly the movements requiring precision with the preferred hand.
The accuracy of the method used in this study opens new perspectives for its use in the clinical field, they report. Hand preference, they say, is due to the prevalence of one cerebral hemisphere, the contralateral one, over the other. This characteristic has sometimes been associated to pathologies that involve a cerebral asymmetry, such as depression, schizophrenia, and autistic spectrum disorders. Fetal kinematics could possibly be used to identify new markers that would allow intervention at an early stage.