ABSTRACT
Background: Hand preference is perhaps the most obvious behavioral asymmetry observed in humans and is related to cerebral dominance. Animal and human studies have shown that cerebral cortex has a definite role in regulation of cardiovascular autonomic activity. Each hemisphere exhibits differential control over dynamics of heart especially the sympathetic activity is controlled by right hemisphere insula in particular. Hence, the present study was conducted to evaluate influence of cerebral dominance (handedness) on cardiovascular responses such as heart rate (HR) and blood pressure (BP) indices to autonomic stressor tests in the left and right hander adolescents. Aims and Objectives: The aim of the study was to evaluate the differences in cardiovascular responses in the left and right handers to autonomic stressor tests. Materials and Methods: The present cross-sectional study was conducted in 35 right and 35 left hander students of age group 16–20 years. Autonomic stressor tests used in the study were handgrip dynamometry and cold pressor test (CPT). Results: The right and left handers had similar baseline values of BP and HR. All the subjects responded to Autonomic function tests by increased BP and HR from baseline. The absolute BP values and change in BP from baseline were significantly higher in the left than right handers both during and after the tests. HR values showed significant differences in peak values during both the tests. Visual analog score was similar during CPT in both groups. Conclusion: The HR and BP responses to autonomic stressor tests are higher in the left handers than right handers supports the fact that the right hemisphere has more influence on sympathetic activity of heart.
ABSTRACT
The 2D:4D is thought as a biomarker for prenatal androgen exposure. Some studies have reported a significant difference between the sexes. Earlier studies reported variations in different ethnic and geographic groups. 2D:4D is related to several medical conditions including cardiovascular diseases (CVD) and metabolic syndrome (MetS). The present study investigated the relationships between hand preference, ratio of the index finger (2nd digit: 2D) and ring finger (4th digit: 4D) lengths (2D:4D), height, waist-to-height ratio (WHtR), waist circumference (WC) and weight, body mass index (BMI) in a Turkish population. The study comprised 118 healthy subjects (68 males and 50 females). 2D and 4D finger lengths and some anthropometric traits (height, weight, WC) were measured. The BMI and WHtR were calculated. Hand preference was determined by using a questionnaire (Edinburgh handedness inventory). Geschwind scores were calculated to evaluate the degree of hand preference. The mean age was 26.74 (female 27.86, male 25.89). The right hand 2D:4D was found significantly lower in males (0.9797) than in females (0.9922) (p< 0.001), but the left hand 2D:4D was insignificant. Significant correlations (negative) were observed between the 2D:4D (both left and right) and WHtR; the 2D:4D ratio (both left and right) and WC in males. However, in females, these correlations were insignificant. The R2D:4D was sexually dimorphic in a Turkish population. There were significant differences between strong right (SR) and weak left (WL) in terms of the R2D:4D. However only 5 subject's hand preference was found WL. Therefore, further studies are needed to determine the relationships between hand preference and R2D:4D in Turkish population. Further studies are needed to determine whether a larger sample population alters these possible associations between the ratio of 2D:4D and other investigated traits in a Turkish population.
El 2D:4D está pensado como un biomarcador para la exposición prenatal de andrógenos. Algunos estudios han reportado una diferencia significativa entre sexos. Estudios anteriores informaron variaciones en diferentes grupos étnicos y geográficos. 2D:4D está relacionado con varias afecciones médicas que incluyen enfermedades cardiovasculares (ECV) y síndrome metabólico (MetS). El presente estudio investigó las relaciones entre la preferencia de la mano, la proporción del dedo índice (2º dígito: 2D) y el dedo anular (4º dígito: 4D), longitudes (2D:4D), altura, relación cintura-altura (WHtR), circunferencia de cintura y peso (WC), e índice de masa corporal (IMC), en una población de Turquía. El estudio incluyó 118 sujetos sanos (68 hombres y 50 mujeres). Se midieron longitudes de dedos 2D y 4D y algunos rasgos antropométricos (altura, peso, WC). Se calcularon el IMC y el WHtR. La preferencia de la mano se determinó mediante el uso de una escala (Edinburgh Handedness Inventory). Las puntuaciones de Geschwind se calcularon para evaluar el grado de preferencia de la mano. La edad media fue de 26,74 años (femenino 27,86; masculino 25,89). La mano derecha 2D: 4D se encontró significativamente más baja en los hombres (0,9797) que en las mujeres (0,9922) (p <0,001), pero la mano izquierda 2D: 4D fue no significante. Se observaron correlaciones significativas (negativas) entre la 2D: 4D (izquierda y derecha) y WHtR y la relación 2D: 4D (izquierda y derecha) y WC en hombres. Sin embargo, en las mujeres, estas correlaciones fueron no significantes. El R2D: 4D fue sexualmente dimorfo en una población de Turquía. Hubo diferencias significativas entre la mano derecha fuerte (SR) y la mano izquierda débil (WL) en términos de R2D: 4D. Sin embargo, sólo se encontraron 5 preferencias de mano en el sujeto con WL. Por lo tanto, se necesitan más estudios para determinar las relaciones entre la preferencia de mano y R2D: 4D en la población de Turquía. Se necesitan más estudios para determinar si una muestra mayor altera estas posibles asociaciones entre la proporción de 2D: 4D y otros rasgos investigados en una población de Turquía.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Young Adult , Anthropometry/methods , Fingers/anatomy & histology , Functional Laterality , Turkey , Body Height , Body Weight , Body Mass Index , Waist CircumferenceABSTRACT
Research results with regard to handedness and dyslexia have been ambiguous. The present study investigated the relationship between handedness and dyslexia in secondary school students based on genetic (Right-Shift) and hormonal-developmental theories of handedness. A total of 135 students (45 dyslexics and 70 age- and sex-matched controls) participated in the study. Handedness was defined according to the Edinburgh Handedness Inventory. We developed several classifications that represented various levels of handedness. Both continuous and dichotomous classifications of handedness revealed a small but reliable increase in the proportion of non-right-handers among dyslexics, likely because of the increased proportion of dyslexics among pure left-handers. Dyslexics did not display precisely the same pattern of right and left responses as controls, with some differences at the extremes of the continuum. The present results provide empirical support for Annett's (1985) Right-Shift theory predictions. Additionally, the present study indicates that using a numerical scoring system or dichotomous classifications with restricted criteria that permit the measurement of several degrees of handedness appears to better determine hand preference than using broad classifications into handedness groups.