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Gender differences in a variety of personality and emotional variables have frequently been reported (reviewed by Burton et al. 2007; Costa et al. 2001; Feingold 1994; Maccoby and Jacklin 1974; [...], One hundred seven university community participants (71 female, 36 male) were evaluated on the five personality factors (NEO-FFI), and finger lengths were measured to determine the ratio of the second to fourth digit (2D:4D). It is well-established that 2D:4D ratios are an index of prenatal androgenic activity. Sex differences were found such that the men had lower 2D:4D ratios than the women for both the left and right hands, and the women indicated greater Neuroticism than the men, as reported by others. Most interestingly, greater Openness was significantly associated with more female-typical (higher) 2D:4D ratios for the entire sample. This was significant for the male sample alone, and was found at a trend level in the female sample alone. Keywords 2D:4D * Digit ratio * Androgen * Personality * Sex differences

Two-button computer mouse users may exhibit sustained, static finger lifting behaviours to prevent inadvertent activations by avoiding finger pressure on the buttons, which leads to prolonged, static finger extensor muscle loading. One hundred graduate students were observed during normal computer work ill a university computer facility to qualify and quantify the prevalence of lifted finger behaviours and extended finger postures, as well as wrist/forearm and grip behaviour, during specific mouse activities. The highest prevalences observed were 48% of the students lifted their middle finger during mouse drag activities, and 23% extended their middle finger while moving the mouse. In addition, 98%, of the students rested their wrist and forearm (77%) or wrist only (21%) on the workstation surface, and 97% had an extended wrist posture (15[degrees]-30[degrees]) when using the mouse. Potential applications of these findings include future computer input device designs to reduce finger lifting behaviour and exposures to risk factors of hand/forearm musculoskeletal pain. Keywords: Finger behaviour; Computer mouse use; Finger lifting prevalence

The human hand is inherently complex and versatile. Its use in everyday activities requires its careful positioning relative to the arm and fine adjustments of the fingers to secure the [...]

The absorption of hand-transmitted vibration energy may be an etiological factor in vibration-induced disorders. The vibration power absorption density (VPAD) may be a better measure of energy than the total power absorption of the hand-arm system. The objectives of the present study are to develop a method to estimate the average absorption density in the fingers and to investigate its basic characteristics. Ten healthy male subjects were used in this study. The biodynamic response of the fingers in a power grip subjected to a broad-band random excitation was measured under three grip forces (15, 30, 50 N) and three push forces (35, 45, 50 N). The response was used to estimate the total finger energy absorption. The response, together with the finger volume, was also used to estimate the amount of tissue effectively involved in the absorption. Then, the average VPAD under constant-acceleration, constant-power density, constant-velocity vibration spectra, and 20 tool vibration spectra were calculated. The correlations between the VPAD and the unweighted and weighted accelerations (ISO 5349-1, 2001) were also examined. The VPAD depends on both the characteristics of the vibration spectrum and the biadynamic response of the finger-hand-arm system. The biodynamic response generally plays a more important role in determining the VPAD in the middle frequency range (31.5-400 Hz) than those at the low and high ends. The applied force significantly affected the VPAD. The finger VPAD was highly correlated to the unweighted acceleration. The average VPAD can be determined using the proposed experimental method. It can serve as an alternative tool to quantify the severity of the vibration exposure for studying vibration-induced finger disorders. [DOI: 10.1115/1.1992526]

ABSTRACT. The influence of different positions of the nonperforming (idle) fingers on the maximal force contraction of flexion (master) fingers during key pressing tasks was investigated. Ten participants performed maximal [...]

ABSTRACT. The authors performed a behavioral study of the complexity of left-hand finger movements in classical guitar playing. Six professional guitarists played movement sequences in a fixed tempo. Left-hand finger [...]

While professional musicians are generally considered to possess better control of finger movements than nonmusicians, relatively few reports have experimentally addressed the nature of this discrepancy in fine motor skills. For example, it is unknown whether musicians perform with greater skill than control subjects in all aspects of different types of fine motor activities. More specifically, it is not known whether musicians perform better than control subjects on a fine motor task that is similar, but not identical, to the playing of their primary instrument. The purpose of this study was to examine the accuracy of finger placement and accuracy of timing in professional musicians and nonmusicians using a simple, rhythmical, bilateral fingering pattern and the technology that allowed separate assessment of these two parameters. Professional musicians (other than pianists) and nonmusicians were given identical, detailed and explicit instructions but not allowed physically to practice the finger pattern. After verbally repeating the correct pattern for the investigator, subjects performed he task on an electric keyboard with both hands simultaneously. Each subject's performance was then converted to a numerical score. While musicians clearly demonstrated better accuracy in timing, no significant difference was found between the groups in their finger placement scores. These findings were not correlated with subjects' age, sex, limb dominance, or primary instrument (for the professional musicians). This study indicates that professional musicians perform better in timing accuracy but not spatial accuracy while executing a simple, novel, bimanual motor sequence.

The purpose of the present study is to investigate whether distribution patterns of the maximum fingertip force in all directions from 0 deg to 360 deg around the index fingertip are the same among subjects. Distributions of the maximum index fingertip force were measured at four finger postures for five subjects (healthy males, ages 21 to 25). It became apparent that distribution patterns of the fingertip force were very similar among subjects, through the application of an analysis of variance (level of significance: 5%) to the measurement results. In the production of the maximum fingertip force, Valero-Cuevas et al. [1998, 2000] reported that patterns of control signals for driving muscle forces were common among subjects. The results of the present study indicate that patterns of maximum fingertip force are also similar among subjects. Therefore, the possibility is high that the static transfer characteristic for index fingers from input (i.e., control signals to muscles) to output (i.e., the maximum fingertip force) is also common among subjects. [DOI: 10.1115/1.1468637]

There is indirect evidence that heightened exposure to early androgen may increase the probability that a girl will develop a homosexual orientation in adulthood. One such putative marker of early androgen exposure is the ratio of the length of the index finger (2D) to the ring finger (4D), which is smaller in male humans than in females, and is smaller in lesbians than in heterosexual women. Yet there is also evidence that women may have different sexual orientations at different times in their lives, which suggests that other influences on female sexual orientation, presumably social, are at work as well. We surveyed individuals from a gay pride street fair and found that lesbians who identified themselves as 'butch' had a significantly smaller 2D:4D than did those who identified themselves as 'femme.' We conclude that increased early androgen exposure plays a role in only some cases of female homosexuality, and that the sexual orientation of 'femme' lesbians is unlikely to have been influenced by early and rogens. KEY WORDS: androgen; sexual orientation; finger length ratios; lesbians.

Byline: R. Barkmann (1), W. Rohrschneider (2), M. Vierling (2), J. Troger (2), F. de Terlizzi (3), R. Cadossi (3), M. Heller (1), C.-C. Gluer (1) Keywords: Key words:Bone -- Children -- Growth -- Ultrasound Abstract: Quantitative ultrasound (QUS) of the finger phalanges is a useful tool in the assessment of disease- or age-related deterioration of bone. For studying the impact of juvenile diseases or growth disorders affecting the skeleton, a reference database for QUS parameters is needed. The aim of this study was to establish a calibrated reference database of parameters of transverse ultrasound transmission through juvenile finger phalanges. A total of 1328 children (650 females, 678 males ages 3--17 years) were measured in Heidelberg and Kiel in order to establish a German reference database. Highly significant gender-specific correlations (p&lt 0.0001) were found between the QUS parameters amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) versus age, body height and body mass index (BMI). For AD-SoS the correlation coefficients were R .sup.2= 0.64 against age in males and R .sup.2= 0.73 in females, R .sup.2= 0.60 against body height in males and R .sup.2= 0.68 in females, and R .sup.2= 0.19 against BMI in males and R .sup.2= 0.23 in females. For BTT the correlation coefficients were R .sup.2= 0.74 against age in males and R .sup.2= 0.79 in females, R .sup.2= 0.75 against body height in males and R .sup.2= 0.77 in females, and R .sup.2= 0.32 against BMI in males and R .sup.2= 0.35 in females. Age and height were the strongest determinants of QUS results. Gender-specific differences were observed in AD-SoS (significant for ages 11--14 years and for 150--170 cm body height) and in BTT (significant for ages 7 and 11--17 years and for 160--170 cm body height). Tables of QUS parameters versus age and height can serve as a basis for the evaluation of the impact of skeletal diseases or growth disorders on phalangeal QUS. Depending on the type of disease or growth disorder, measurement results can be compared with age- or height- specific reference data. In this way a simple and radiation-free assessment of juvenile skeletal disorders using quantitative ultrasound might be possible in the future. Author Affiliation: (1) Medizinische Physik, Klinik fur Diagnostische Radiologie, Universitatsklinikum Kiel, Kiel, DE (2) Padiatrische Klinik der Universitat Heidelberg, Heidelberg, Germany , DE (3) IGEA Biophysics Laboratory, Carpi, Italy, IT Article note: Received: 9 February 2001 / Accepted: 1 August 2001

Issues concerning the motor functioning of fingers and hand are examined, focusing on a study that compares force data for alternate finger tapping of the index and middle fingers and for one-finger tapping, as it applies to ergonomic research. Results indicate index finger has greater motor ability than the middle finger.

In ergonomics, handgrip has been perceived as one of the most important hand functions; however, other types of functions of the hand are also important to the ergonomist, such as finger and manual dexterity, on which few ergonomic studies have been done. This experiment involved 60 male and female college students whose performance (number of pegs placed into a board in 30 sec.) of finger dexterity were statistically significantly different between the right and left hands and between women and men. The interaction of hand and sex was significant.

The effect of severe local cooling of the finger on the vasomotor activity of the arteriovenous anastomoses (AVAs) and other finger vessels was examined. Before cooling, blood velocity in both fingers showed the familiar large, closely correlated fluctuations caused by synchronous opening and closing of the AVAs. Results showed that these velocity fluctuations continued to be positively correlated with arterial blood velocity fluctuations in the control finger during cold-induced vasodilation.

The effect of local cooling from 35 to 19 degrees C on acral skin circulation in thermoneutral subjects was studied. Arterial blood velocity of the third finger in both hands were simultaneously recorded using ultrasound-Doppler systems. As expected, the constriction of the arteriovenous anastomoses (AVAs) caused large blood velocity fluctuations. From 35 to about 21.5 degrees C, the fluctuations were almost unchanged. However, at local temperatures below 21.5 degrees C, the velocities did not fluctuate which suggest sustained local closure of the AVAs.

Serial induction of stimuli in the fingers changes the neuronal specificity and somatosensory maps of the hand surface in adult owl monkey, trained to respond to particular stimulus sequence events. Synchronous application of remodelling stimuli to the fingers causes their integration whereas, asynchronous induction of stimuli causes their segregation. A terminal electrophysiological neuronal response mapping analysis reveals that conditioned monkeys have multiple-digit receptive fields.

A study to determine the quality of pull strength was conducted. Three types of pulls were explored, lateral pinch-pull, chuck pinch-pull and pulp pinch-pull. The subjects were coomposed of 70 college students. Results indicated that the lateral pinch-pull provided the greatest force. This type of pull requires a large surface of contact. The index finger pinch requires less space but generates weaker force.

E. A. Essock, W. K. Krebs, and J. R. Prather (1997) found that detection of grid patterns by the fingers was best for longitudinal, then oblique, and, last, horizontal orientations. They suggested that the anisotropy is due to the number of cortical neurons tuned to a stimulus orientation. The contribution of E. H. Weber (1834/1996) deserves mention. He found that the 2-point threshold on the arm was lower for horizontal than for longitudinal orientations. He (1852/1965) explained this by elongated 'sensory circles' - areas of skin served by single nerve fibers. The elongation followed the axis of the main sensory nerves (longitudinal in the arm). Horizontal acuity was finer because the stimulus interval covered more separate fibers. This account is similar to modern ideas on elongated receptive fields, although the locus is peripheral rather than central.

A study was conducted to estimate single- and multi-digit forces using electromyography obtained at standardized locations on the forearm. Results revealed that standardized methods are accurate in estimating finger forces in a variety of finger exertions in fixed postures and the accuracy depended upon the model used.

The present study was designed to examine the retention of relative force in the scaling of a serial force pattern in a finger-tapping sequence using an attenuated tap. On practice trials, i2 undergraduate students tapped a force plate connected to strain gauges that gave them feedback about the force. On test trials, participants recalled the force pattern (200 gm--200 gm-200 gm-100 gm) and the intertap interval (400 msec.) practiced during the practice period without the feedback (recalled task). Then, they adaptively produced a halved (halved task) or doubled force profile (doubled task) at the fixed intertap interval. Analyses showed that mean peak forces at the first three tap positions of the tapping sequence undershot the expected forces across all tasks. Hence, the ratios of the forces in Serial Positions 1:4, 2:4, and 3:4 were considerably lower than 2.0. This is a contextual effect suggesting that the last attenuated tap affected the first three taps of the tapping sequence. Thus, because the relative force of movements appears to be a weaker invariant feature than sequencing and relative timing for generalized motor program theory of Schmidt and Lee, this finding does not support the relative force for a generalized motor program.

To investigate the possible role of sensory function in conditions affecting sexual function, sensory thresholds were compared between young healthy men (n = 14, x age = 29.8), aging men (n = 15, x age = 67.3), and men suffering from diabetic impotence (n = 15, x age = 45.0). Using the psychophysical method of forced choice, vibrotactile and electrical stimulation thresholds were deterlmined in two separate sessions at two body sites: the fingertip and the ventral surface of the penis, just proximal to the glans. Vibrotactile penile thresholds (VTP) were lowest for young (Y) subjects and much hihher for both aging (A) and diabetic (D) subjects. Electrical stimulation of the penis (ESP) showed the same trends, although the differences only approached significance (p = 0.06). The vibrotactile finger threshold (VTF) was significantly higher for A subjects as compared with Y and D subjects, but there was no difference between the Y and D groups. Diabetic patients had significantly higher thresholds for electrical stimulation of the finger (ESF), in contrast to the VTF finding. Finger thresholds were significantly lower than penile thresholds for all groups, and the change in threshold from finger to penis was greater in both aging and diabetic than in young subjects. Age was positively correlated with thresholds for ESF, ESP, VTF, and marginally for VTP when all three groups were analyzed together. However, in general the results of threshold determinations could not be attributed merely to age. Based on a detailed questionnaire of sexuality, VTP was negatively correlated with sexual activity and both ESP and VTP were negatively correlated with erectile capacity. The data are consistent with a genital sensory role for age-related and diabetic changes in sexual function.