The Relationship Between Finger Ratio and Development in Infants

Официальное название

The Relationship Between Digit Ratio and Motor Development and Sensory Processing in Infants

Обзор

One of the most prominent indicators of prenatal androgen exposure is considered to be the ratio of second and fourth finger lengths (2D:4D). The 2D:4D finger ratio refers to the ratio of the length of the second finger (2D; index finger) and the fourth finger (4D; ring finger). Evidence suggests that 2D:4D is developmentally stable and stabilizes from the second trimester of pregnancy. It has been reported that the 2D:4D ratio correlates positively with estrogen and negatively with testosterone. In both sexes, prenatal testosterone levels are inversely related by a 2D:4D ratio, which does not change with age. Androgens can have direct trophic effects on target cells or indirectly affect neuronal growth through neurotrophic mediators released locally by steroid-sensitive neuronal or glial cells. Prenatal testosterone can have long-term organizational effects on the structure and function of various body systems (e.g., cardiovascular and musculoskeletal systems) that are important for physical activity and exercise.

Подробное описание

One of the most prominent indicators of prenatal androgen exposure is considered to be the ratio of second and fourth finger lengths (2D:4D). The 2D:4D finger ratio refers to the ratio of the length of the second finger (2D; index finger) and the fourth finger (4D; ring finger). Evidence suggests that 2D:4D is developmentally stable and stabilizes from the second trimester of pregnancy. It has been reported that the 2D:4D ratio correlates positively with estrogen and negatively with testosterone. In both sexes, prenatal testosterone levels are inversely related by a 2D:4D ratio, which does not change with age.

From a gender perspective, differences have been found in the basic motor skills of boys and girls. Boys have greater object control skills than girls. Gender is one of the most studied variables in motor development. Many longitudinal studies show that boys perform better in gross motor skills such as running and jumping, while girls are more successful in fine motor tasks such as drawing or manipulating small objects. Sensory processing involves the capacity to receive, interpret, organize, and respond to sensory input from both one's own body and the external environment. Sensory processing disorders can be observed in infants due to the immaturity of their systems. There are very few studies on measuring finger length in the early stages of newborns. To our knowledge, the relationship between intrauterine androgen exposure (2D:4D) and motor development and sensory processing has not yet been investigated. Therefore, the planned study aims to evaluate the 2D:4D finger ratio in 12-18-month-old infants and to examine the relationship between this ratio and motor development and sensory processing.

Вмешательства

• Поведенческое Digit Ratio
  The lengths of the second (2D) and fourth (4D) fingers will be measured separately on each hand. Measurements will be taken with the baby's hands placed flat on a surface with palms facing upwards. Finger length will be defined as the distance from the midpoint of the proximal crease at the base of the finger to the distal end of the finger. A digital caliper with a precision of 0.01 mm will be used, and two separate measurements will be taken for each finger, with the average value recorded. Ba
• Поведенческое Motor development
  The Peabody Developmental Motor Scale-2 (PDMS-2) is planned to be used to assess motor development. The PDMS-2 test is designed to identify developmental delays in children aged 0-72 months. It is used to evaluate children's motor development with separate tests and rating scales for both gross and fine motor skills.
• Поведенческое Sensory processing functions
  The Test of Sensory Functions in Infants was planned for use to assess babies' sensory development. The TSFI is frequently used to evaluate the sensory processing functions of infants aged 4-18 months. It is used to determine whether and to what extent a baby has a sensory processing problem. It consists of 24 items. The TSFI requires the baby to be stimulated and interact with various materials. The total score ranges from 0-49, and the test has normative values for different age groups. Althou

Первичные конечные точки

• Sensory processing [Срок оценки: 12-18 months]
• Motor development [Срок оценки: 12-18 months]
• Digit Ratio [Срок оценки: 12-18 months]

Критерии участия

Критерии включения

• Term infants (37-40 weeks),
• Infants aged 12-18 months

Критерии исключения

• Preterm infants,
• Infants with congenital infections or proven genetic changes,
• Infants and mothers diagnosed with metabolic, neurological, and genetic diseases,
• Maternal diabetes,
• Intrauterine growth retardation,
• Infants with a history of hand-related surgery,
• Children whose parents did not volunteer to study

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Модель наблюдения

Другое

Центры проведения

Turkey (Türkiye) · 1 центр

• Nigde Omer Halisdemir University — Niğde

Публикации

• Cay M, Gurel S. The relationship between mothers' second and fourth finger lengths (2D:4D) and anthropometric measurements (height, weight, head circumference, and 2D:4D) of the newborns. Am J Hum Biol. 2022 May;34(5):e23700. doi: 10.1002/ajhb.23700. Epub 2021 Nov 9. PMID 34751980
• Ernsten L, Korner LM, Heil M, Schaal NK. The association between 2D:4D digit ratio and sex-typed play in children with and without siblings. Sci Rep. 2024 Jul 2;14(1):15231. doi: 10.1038/s41598-024-65739-1. PMID 38956189
• Paukner A. Digit ratio (2D:4D) and its behavioral correlates in infant rhesus macaques (Macaca mulatta). Dev Psychobiol. 2020 Nov;62(7):992-998. doi: 10.1002/dev.21917. Epub 2019 Sep 12. PMID 31512755

Идентификаторы

NCT: NCT07525726 · Digit ratio and development

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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