Relationship Between 2D:4D Finger Ratio and Proprioception

April 29, 2025 updated by: Onur Engin, Izmir Democracy University

Investigation of the Relationship Between 2D:4D Ratio and Proprioception

Background: 2D:4D ratio (the ratio of the length of the second digit to the length of the fourth digit) has been reported to be associated with muscle strength and physical performance, numerical competencies, spatial skills and cognitive abilities. However, the relationship between 2D:4D ratio and proprioception is not well-known, which was therefore aimed at investigating in current study. Methods: 2D:4D ratio (electronic digital calliper) and proprioception (Join position error is measure with Cervical Range of Motion instrument) were assessed in all individuals (n=35.7 ± 11.2 years).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

2nd (index) and 4th (ring) finger ratio, index finger (2nd finger) length to ring divided by the length of the fourth finger (4th finger) and is referred to in the literature as the "2D:4D ratio". The reference points for 2D:4D ratio measurement are the midpoint of the proximal ventral flexion bend of the finger and the distal end of the finger. 2D:4D ratio is a function of prenatal exposure to testosterone and estrogen levels and shows gender-related differences. A low 2D:4D ratio indicates that prenatal testosterone levels are high and estrogen levels are lower, while a high 2D:4D ratio indicates lower testosterone and higher estrogen exposure. For example, men's index fingers (2D) are longer than their ring fingers (4D), while in women the second finger is usually significantly shorter than or slightly shorter than or equal to the fourth finger. In recent years, several studies have been conducted on the biological and behavioral associations with the 2D:4D ratio. For example, a low 2D:4D ratio is often associated with increased physical strength, athletic performance, and risk-taking behavior, while a high 2D:4D ratio is associated with traits such as empathy and language skills. Proprioception, which refers to the ability to sense joint and body movement, as well as the movement of the body or body segments, is defined as the perception of its position in space. Proprioception plays a critical role for balance, coordination, and motor control. The 2D:4D ratio, influenced by hormonal changes, may affect proprioceptive functions, such as motor skills and hand-eye coordination. Some studies have found that individuals with low 2D:4D ratios perform better on tasks involving mental rotation of two- and three-dimensional objects. Testosterone exposure during the prenatal period is thought to increase the development of the right hemisphere of the brain. Proprioception, a person's ability to perceive body position and movements, can also be significantly influenced by the 2D:4D ratio. The ratio is influenced by both genetic factors and prenatal environmental influences. For example, human tool manipulation in the course of evolution contributed to the differentiation and specialization of brain areas associated with sensory and motor skills. Some research suggests that a low 2D:4D ratio may be linked to stronger motor skills and a better proprioceptive sense. This is because prenatal testosterone levels affect motor control and nervous system development, influencing hand-eye coordination. For example, individuals with a low 2D:4D ratio may show improved hand-eye coordination and performance in tasks requiring fine motor control. A study examined the relationship between hand morphometry (including 2D:4D ratio) and proprioception and found that haptic perception was closely related to proprioception. Lower 2D:4D ratios were associated with better physical strength and precise motor control. Additionally, lower 2D:4D ratios have shown an association with better arithmetic, visual, and spatial skills. However, there are no available studies that directly address the relationship between proprioception and the 2D:4D ratio. Therefore, more research is needed to understand the connection between proprioception and 2D:4D ratio. The aim of this study is to investigate the relationship between the 2D:4D ratio and proprioception in adult subjects.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
88

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey
      • Izmir, Turkey, 35140
        • Izmir Democracy University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Healthy adult individuals aged between 18 and 65 years, who volunteered to participate in the study. Participants had no sensory loss or severe neurological disorders affecting proprioception. Individuals with hand or cervical trauma history, congenital hand anomalies, or any condition preventing accurate 2D:4D measurement were excluded.

Description

Inclusion Criteria:

  • Age between 18 and 65 years
  • Agreeing to participate in the study.

Exclusion Criteria:

  • Individuals who have scars, finger deformities, and/or surgical interventions that would prevent accurate measurement of the 2D:4D ratio
  • Congenital hand anomalies
  • History of trauma involving the hand or cervical region were excluded from the study.
  • Having sensory loss or severe neurological disorder that would affect proprioception

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
assessment group
Finger length measurements(second digits and fourth digit) were made with acaliper. Range of motion (ROM) and joint position error measuremenst were made with a CROM device. Joint position error is assessed with neutral head positioning test and target head positioning test.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Finger length measurement and 2D:4D ratio calculation
Time Frame: baseline
The lengths of the second (2D) and fourth (4D) fingers on each hand were measured using an electronic digital caliper with a precision of 0.01 millimeters. Measurements were taken on the palmar surface of the hand, extending from the distal tip of the finger to the basal crease at the proximal end of the digit.The 2D:4D ratio was calculated separately for the right and left hands. To enhance the accuracy of the 2D:4D ratio measurements, each finger was measured three times during a single assessment session by the same investigator. The repeated measurements were not taken consecutively; instead, at least one other hand was measured between the first and second measurements of any given hand. This procedure was implemented to minimize the potential influence of recall bias on subsequent measurements.
baseline
Cervical Range of Motion
Time Frame: baseline
The cervical range of motion measurement was performed using a Cervical Range of Motion (CROM) device, which is a reliable and valid tool. The CROM unit is a mechanical instrument that measures cervical ranges by combining a magnetic reference with standard inclinometers. The individuals were told to sit comfortably with their hands on the armrest and their backs straight on the chair. The CROM unit was secured on the individuals' head by the physiotherapist. The CROM unit's magnetic yoke is positioned squarely around the neck with its arrow pointing directly north. Afterwards, physiotherapist asked individuals to perform cervical range of motion in all three directions: flexion- extension, lateral flexion and rotation.The maximum range of cervical flexion, extension, left and right rotation, and left and right lateral flexion was measured three times and averaged.
baseline
Repositioning to neutral head position (NHP)
Time Frame: baseline
For the NHP assessment, the individuals were asked to keep their head in the neutral head position, with their eyes closed. The deviations from the neutral (0) position in the sagittal (flexion-extension), frontal (lateral flexion), and transverse (rotation) planes were recorded using the CROM device.
baseline
Repositioning the head to a predetermined reference point (Target Head Position, THP)
Time Frame: baseline
For the assessment of THP, the target position will be defined as half of the maximum active range of motion measured during a standard cervical joint mobility assessment. While the patient's eyes are covered with an eye mask, the head will first be slowly positioned by the physiotherapist to the predetermined target angle and held in this position for five seconds for the patient to perceive. Subsequently, the head will be moved away from the target position, and the patient will be asked to actively reposition it to the original target. Each measurement will be repeated three times, and the mean deviation from the target angle will be recorded. Measurements will be conducted separately for flexion, extension, right rotation, left rotation, right lateral flexion, and left lateral flexion
baseline

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Izmir Democracy University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Onur Engin, Assist Prof, Izmir Democracy University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 29, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 24, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 9, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 22, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 29, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 1, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 1, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 29, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2025

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025/405

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

It was deemed appropriate to keep the data of the individuals participating in the study confidential

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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