Prenatal Androgen and Skills

Condition(s) studied

Investigational drug(s) / intervention(s)

Digit Ratio: The second (2D) and fourth (4D) finger lengths of the participants will be measured separately in both hands by a physiotherapist with over thirteen years of clinical experience.

Fine motor skills: Hand dexterity will be assessed using the Purdue Pegboard Test. The test will be administered according to standard procedure with participants seated at a table. Participants will be asked to place the pegs into the corresponding holes as quickly and accurately as possible within a specified time (30 seconds).

Tactile Discrimination: To perform the 2-point discrimination tests, the Baseline® two-point discriminator will be used. Measurements will be applied to the distal phalangeal pulp of the index finger on both hands while participants are seated in a comfortable position with their eyes closed.

Study summary

Due to the difficulties and risks of directly measuring prenatal hormone levels, biomarkers that indirectly reflect this exposure are used in research. In this context, the ratio of second to fourth finger length (2D:4D) is widely preferred because it is an easily applicable and non-invasive measurement. Evidence shows that 2D:4D stabilizes from the second trimester of pregnancy onward and exhibits strong sex differences across populations. The 2D:4D ratio is generally lower in men than in women. 2D is more strongly influenced by prenatal estrogen, while 4D is more strongly influenced by prenatal testosterone; this occurs during the first trimester of intrauterine fetal development. To our knowledge, studies examining the relationship between the 2D:4D ratio, an indirect indicator of prenatal androgen exposure, and dexterity and tactile discrimination are limited. Accordingly, the planned study aims to evaluate the relationship between the 2D:4D ratio and fine motor skills and tactile discrimination in healthy young adults.

Eligibility

Primary outcome measure(s)

• 2-point discrimination test — 12 months
  To perform 2-point discrimination tests, the Baseline® two-point discriminator will be used. Measurements will be applied to the distal phalangeal pulp of the index finger on both hands while participants are seated in a comfortable position with their eyes closed. The test will begin at a distance of 8 mm, allowing participants to perceive the stimulus as two points, and then the distance will be gradually reduced. After 5 mm, measurements will continue at 1 mm intervals. In each application, both contact points will be applied to the skin simultaneously and with equal pressure, and participants will be asked to indicate whether the perceived stimulus is a single point or two points.
• Digit Ratio — 12 months
  Measurements will be taken after participants' hands are placed on a flat surface with palms facing upwards. Finger length is defined as the distance from the midpoint of the proximal crease line where the finger joins the palm to the distal point of the fingertip. Measurements will be performed using a digital caliper with 0.01 mm accuracy, two separate measurements will be taken for each finger, and the average value will be recorded. Based on the obtained measurements, the 2D:4D finger ratio will be calculated by dividing the 2D length by the 4D length in both hands .
• Fine motor skills — 12 months
  The test will be administered according to standard procedure while participants are seated at a table. Participants will be asked to place the pegs into the corresponding holes as quickly and accurately as possible within the specified time (30 seconds). In the dominant and non-dominant hand tests, participants will be asked to place pegs with one hand for 30 seconds, while in the both-hand test, the simultaneous use of both hands will be evaluated. The number of correctly placed pegs for each subtest will be recorded, and higher scores will be considered as better fine motor skill performance.

Trial sites (1)

More Nigde Omer Halisdemir University trials in Turkey