ProprioceptionNCT06953219
Relationship Between 2D:4D Finger Ratio and Proprioception
An observational study of Proprioception, run by Izmir Democracy University at 1 site in Turkey (Türkiye).
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Proprioception
- How many people
- 88 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 29 Jan 2025to 9 Apr 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
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.
Who may be able to join
- Age between 18 and 65 years
- Agreeing to participate in the study.
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Izmir Democracy University
Izmir, Izmır, 35140
About this study
Official title: 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).
Read the 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.
- Conditions
- Proprioception
- Keywords
- digit ratio, proprioception
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| 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 being measured
The primary outcome is the main question the study is designed to answer.
Finger length measurement and 2D:4D ratio calculation
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.
Measured: baseline
Cervical Range of Motion
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.
Measured: baseline
Repositioning to neutral head position (NHP)
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.
Measured: baseline
Repositioning the head to a predetermined reference point (Target Head Position, THP)
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
Measured: baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 May 2025
- Study start29 Jan 2025
- Primary completion24 Mar 2025
- Study completion9 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ProprioceptionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 88 participants (actual)
Sponsor and investigators
- Lead sponsor
- Izmir Democracy University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Onur Engin, Izmir Democracy University
- Investigators
- Onur Engin, Assist Prof, Principal investigator, Izmir Democracy University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06953219
- Sponsor's protocol ID
- 2025/405
- Status last verified
- Apr 2025
- First submitted
- 22 Apr 2025
- Last updated
- 1 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: It was deemed appropriate to keep the data of the individuals participating in the study confidential
Study at a glance
From the registry record, last updated by the sponsor on 1 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigation of the Relationship Between 2D:4D Ratio and Proprioception
- ClinicalTrials.gov ID
- NCT06953219
- Acronym / sponsor ID
- 2025/405
- Conditions
- Proprioception
- Keywords
- digit ratio, proprioception
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 88 participants (actual)
- Lead sponsor
- Izmir Democracy UniversityUniversity, hospital or other
- Study start
- 29 Jan 2025 (actual)
- Primary completion
- 24 Mar 2025 (actual)
- Study completion
- 9 Apr 2025 (actual)
- First posted
- 1 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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).
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 design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 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. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (2 listed)
- Age between 18 and 65 years
- Agreeing to participate in the study.
Key exclusion criteria (4 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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.
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.
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.
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
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 May 2025.
- Individual participant dataSharing planned: No. It was deemed appropriate to keep the data of the individuals participating in the study confidential
Related trials for Proprioception
Not yet recruitingObservational study
Microneurographic Assessment of Peripheral Nerves in Healthy Volunteers and Individuals With Sensory Dysfunction Caused by Inherited Mutations in the PIEZO2 Gene
PIEZO2-Deficiency Syndrome
Active, not recruiting
Comparative Effects of Vestibular Rehabilitation With and Without Cervical JPS Training in Stroke Patients
Stroke
Not yet recruiting
Spencer vs Positional Release Techniques for Chronic Subacromial Impingement
Chronic Subacromial Impingement Syndrome
Active, not recruiting
Comparative Effects of Sensorimotor Training and tACS on Upper Limb Function and Cervical Proprioception in Subacute Stroke
Sub-acute Stroke
Recruiting
Kinesio Taping in Young Adults With Thoracic Hyperkyphosis
Thoracic Hyperkyphosis
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Onur Engin, Assist Prof principal investigator
Izmir Democracy University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Proprioception, run by Izmir Democracy University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 1 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Finger length measurement and 2D:4D ratio calculation (time frame: baseline). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 May 2025.