Attention-deficit hyperactivity disorder (AD/HD) and fluctuating asymmetry (FA) in a college sample: an exploratory study

Right-left digit ratios, a novel form of asymmetry: Patterns of instability in children and relationships to platelet counts and hospitalization in adults with COVID-19

High right minus left (R-L) asymmetry of digit ratios has been reported to be linked to hospitalization for COVID-19. Here we examined the developmental patterns of this novel form of asymmetry in children and further explored their relationships to platelet counts and hospitalization for COVID-19 in adult patients. We considered ratios calculated from four digits (2D, 3D, 4D, 5D) in: (i) a sample of healthy participants aged 2 years to 18 years (n = 680, 340 males) and (ii) 96 adult patients (42 males) hospitalized for COVID-19 and 100 controls (53 males). The protocol for (ii) included a questionnaire and laboratory test results. In sample (i) of the six unsigned digit ratio asymmetries, those which included 5D had the highest mean asymmetry with the greatest between-individual variation and they were unstable over the age range of 2 years to 18 years. In sample (ii) patients showed higher asymmetries than controls in four ratios (2D:4D, 2D:5D, 3D:5D, 4D:5D) and a sum of asymmetries of the two independent ratios (2D:4D+3D:5D) correlated positively with platelet counts and hospitalization. Conclusion: Means and SDs of digit ratio asymmetry that include the 5th digit are high and age-unstable. Digit ratio asymmetry, particularly 5th digit ratio asymmetry and a composite measure of 2D:4D + 3D:5D asymmetry, may be positively linked to high platelet counts in COVID-19 patients and to an elevated risk of hospitalization.

REAC neuromodulation treatments in subjects with severe socioeconomic and cultural hardship in the Brazilian state of Pará: a family observational pilot study

PURPOSE

The purpose of this preliminary observational study was to evaluate the usefulness of a humanitarian initiative, aimed at improving the neuropsychological and behavioral attitude of children with severe socioeconomic and cultural hardship, in the Brazilian state of Pará. This humanitarian initiative was realized through the administration of two neuromodulation protocols, with radioelectric asymmetric conveyor (REAC) technology. During several years of clinical use, the REAC neuromodulation protocols have already proved to be effective in countering the effects of environmental stress on neuropsycho-physical functions.

PATIENTS AND METHODS

After the preliminary medical examination, all subjects were investigated with the Strengths and Difficulties Questionnaire (SDQ), including the impact supplement with teacher's report. After the SDQ, they received the neuromodulation treatment with REAC technology named neuro postural optimization (NPO), to evaluate their responsiveness. Subsequently, every 3 months all subjects underwent a treatment cycle of neuropsycho-physical optimization (NPPO) with REAC technology, for a total of three cycles. At the end of the last REAC-NPPO treatment cycle, all subjects were investigated once again with the SDQ. For the adequacy of the data, the Wilcoxon and the Signs tests were used. For the subdivision into clusters, the Kruskal-Wallis test was applied for the adequacy of the procedure. For all the applied tests, a statistical significance of p<0.5 was found.

RESULTS

The results showed that the REAC-NPO and REAC-NPPO neuromodulation protocols are able to improve the quality of life, the scholastic and socialization skills, and the overall state of physical and mental health in children of a family with severe socioeconomic and cultural hardship.

CONCLUSION

The REAC-NPO and REAC-NPPO neuromodulation protocols, due to their non-invasive characteristics, painlessness, and speed of administration, can be hypothesized as a treatment to improve the overall state of physical and mental health in a large number of people with socioeconomic and cultural discomfort.

Morphology and Behavior: Phrenology Revisited

Research conducted by evolutionary psychologists and biologists shows that subtle individual differences in body morphology can be related to surprising and important differences in human behavior and reproductive success. The authors summarize recent work on these effects as they relate to fluctuating asymmetry, facial attractiveness, finger digit morphology, sexually dimorphic differences in body configuration, and head circumference. Examples include the discovery that women who have sex with bilaterally symmetrical men report more orgasms; men with attractive faces have higher quality sperm; the length of the index finger in relation to the ring finger is related to verbal fluency, spatial ability, and the risk of autism; women with an hourglass figure have more regular menstrual cycles and are more fertile; and the sound of a person's voice predicts his or her sexual behavior.

Fluctuating asymmetry and developmental instability in sagittal craniosynostosis

OBJECTIVE

To determine whether premature sagittal craniosynostosis is associated with developmental instability in the skull by analyzing fluctuating asymmetry in skull shape.

DESIGN

Cranial shape was quantified by collecting coordinate data from landmarks located on three-dimensional reconstructions of preoperative computed tomography (CT) images of 22 children with sagittal craniosynostosis and 22 age-matched controls. A fluctuating asymmetry application of Euclidean distance matrix analysis (EDMA) was used to quantify and compare asymmetry in cranial shape using these landmark data.

RESULTS

In contrast to expectations, the sagittal craniosynostosis group did not show a statistically significant increase in the overall level of fluctuating asymmetry relative to the control group. However, we discerned statistically significant localized increases in fluctuating asymmetry in the sagittal craniosynostosis group at pterion and the anterior clinoid processes (alpha = .05). We also determined a significant correlation of fluctuating asymmetry values between the two groups (r = .71).

CONCLUSIONS

We conclude that there is no evidence of a role for system-wide developmental instability in the etiology of nonsyndromic sagittal craniosynostosis. However, the localized evidence of asymmetry at the anterior clinoid processes in the sagittal synostosis group suggests an association with the tracts of dura mater that attach there.

Attention deficit/hyperactivity disorder (ADHD) symptoms and digit ratios in a college sample

Diagnosticians recognize three subtypes of attention deficit/hyperactivity disorder (ADHD) if there are developmentally inappropriate levels (six or more symptoms) of Hyperactive-Impulsive behavior, or Inattentive behavior, or both (Combined), respectively. ADHD may partly reflect androgen dysfunction, and an arguable proxy for prenatal androgen exposure is the 2D:4D finger ratio set at least as early as week 9 in the fetus; this is lower in men than in women. We examined the relationship between digit ratios and ADHD symptoms representing the three phenotypes: ADHD/Combined as measured by "summarized" (Rasched) scales, i.e., 1) the short version of the Wender Utah Rating Scale (WURS) and a total symptom list derived from the DSM IV, and the subdivided DSM IV into 2) ADHD/Inattentive and 3) ADHD/Hyperactive-Impulsive inventories, in a sample of European-descent college students (135 female, 52 male) not selected for ADHD. All digit ratios were calculated excluding the thumb. There were significant sex differences for the 2D:4D digit ratios of both hands (RH and LH), and between the RH 3D:4D and between the LH 2D:3D ratio. In females, the more masculine the LH 2D:4D ratio, the more the ADHD/Combined symptoms (both WURS and DSM) and the more the ADHD/Inattentive symptoms and ADHD/Hyperactive-Impulsive symptoms. More masculine ratios also correlated between the total WURS and RH 2D:3D, RH 2D:4D, and LH 2D:3D; and between the inattentive DSM symptoms and LH 2D:5D, and between the ADHD/Hyperactive and Impulsive symptoms and RH 3D:4D.

Attention-deficit hyperactivity disorder and fluctuating asymmetry in another college sample

Attention deficit/hyperactivity disorder (AD/HD) represents a developmental lag that may be reflected in fluctuating asymmetry (FA), i.e., differences from perfect symmetry in traits that display bilateral symmetry. Burton et al. (2003 Am. J. Hum. Biol. 15:601-619) found a statistical trend for FA to increase (as dermatoglyphic index or as total index) as the behavioral measure for AD/HDness (Rasch logit values derived from the Wender Utah Rating Scale, or WURS) increased in males but not in females. The objective here was to do a similar study in an independently collected sample of college students (n = 222; 61 male, 161 female) not selected for AD/HD, looking at FA vs. symptoms for AD/HD based on Rasch versions of responses to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) (Barkley and Murphy 1998 Attention-Deficit Hyperactivity Disorder, New York: Guilford Press, p. 95-96) and the more comparable shortened WURS. FAs were lowest for body and ear height, and highest for eye width and nose width, and ranged from 0.01 +/- 0.001 (mean +/- SE) for foot and ankle widths to 0.13 +/- 0.01 in eye and nose widths for both sexes; the sexes did not differ significantly. Males displayed higher AD/HD symptom rates overall. There was a significant correlation between body FA and the WURS measure in females after Bonferroni correction (P = 0.002, r(2) = 0.058). Thus, AD/HD symptoms levels increased with an increase in body FA in female college students not selected for AD/HD.

A review of developmental instability, parasitism and disease

Developmental instability is reflected in imprecise development caused by perturbations of the developmental process, while developmental stability reflects the ability to avoid or reduce such perturbations by developmental means. Developmental instability has been hypothesized to reflect overall individual condition, and asymmetric or otherwise aberrant individuals have thus been predicted to be particularly severely affected by disease and parasitism. An extensive review of the literature on animals, including humans, revealed consistent relationships between increased bilateral asymmetry and elevated risk of parasitism. Parasitism, including parasitism of mothers, is a cause of asymmetry as shown by a number of experiments, and asymmetric individuals are differentially susceptible to a range of different parasites. Extensive studies of humans have shown that asymmetric individuals also suffer disproportionately from a range of different diseases including mental diseases. Studies of transgenic organisms have now demonstrated that single genes associated with disease is a sufficient cause of increased asymmetry. A number of studies have also shown that activation of the immune system causes increased asymmetry in developing individuals, and that asymmetry and immunity show negative covariation. These findings may have important implications for the study of susceptibility of hosts to infectious disease.

Fluctuating asymmetry predicts human reactive aggression

Fluctuating asymmetry (FA) represents non-directional deviations from perfect symmetry in morphological characters. Prenatal stressors contribute to the imprecise expression of symmetrical phenotypes and display of agonistic behavior in children and adults. Because prenatal stress affects neurological function and overt behavior, and FA is often used as a marker for prenatal stress, we hypothesized that high FA would be associated with elevated levels of human reactive aggression. Data were collected from 100 males and females (average age = 20.1) on FA of 11 bilateral traits (second, third, fourth, and fifth digit length, palm height, wrist diameter, elbow width, ear height, ear width, foot breadth, and ankle circumference). Additional relationships were also investigated among FA, testosterone (T), and type of provocation to test a comprehensive aggression model. Experimental participants solicited donations for a fictitious charity organization via telephone and selected follow-up letters after the calls. High FA and T values were independently associated with elevated reactive aggression (force of terminating the call) under low provocation in males, and under high provocation in females. In the absence of phenotypical markers, i.e., FA and T, sex differences in response to provocation disappeared and a "passive-aggressive" response emerged. Both males and females selected hostile follow-up letters, but showed low reactive aggression when terminating the call under high provocation. This pattern was reversed under low provocation. Taken together, these data suggest that individuals' phenotype and intensity of provocation are important determinants of individual and sex differences in aggression.

Season of birth and fluctuating asymmetry

Fluctuating asymmetry (FA) refers to random, small deviations from perfect bilateral symmetry in morphological traits. These minor deviations from the ideal phenotype reflect environmental and genetic perturbations experienced during ontogeny. FA has been associated with negative health outcomes and many developmental disorders in humans. The prevalence of developmental disorders and adult health vary according to the month of birth, suggesting that seasonal stressors may leave enduring signs in the adult body, marked by high FA. The current study examined the relationship between FA and birth season. Data were collected for 205 males and females (average age = 20.39 years) on FA of 10 bilateral traits (second, third, fourth, and fifth digit length, palm height, wrist diameter, elbow width, ear height, foot breadth, and ankle circumference). Additional relationships were also investigated among FA, testosterone (T), and birth order. Results indicate that ear FA was lower for fall births compared to winter births in males. In females, palm FA was lower for fall births compared to those of the spring. FA of the digits was positively associated with T in males. Average FA, excluding the digits, decreased as the number of maternal siblings increased for both sexes. T concentrations in males were positively associated with the number of younger brothers. Our results generally confirm previous research on seasonal variation in adult longevity and neurological and psychiatric disorders, suggesting that winter and spring births are at risk for asymmetric developmental trajectory.