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Papadatou-Pastou M, Sampanis P, Koumzis I, Stefanopoulou S, Sousani D, Tsigkou A, Badcock NA. Cerebral laterality of writing in right- and left- handers: A functional transcranial Doppler ultrasound study. Eur J Neurosci 2022; 56:3921-3937. [PMID: 35636946 DOI: 10.1111/ejn.15723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 02/20/2022] [Accepted: 04/29/2022] [Indexed: 11/30/2022]
Abstract
The cerebral lateralization of written language has received very limited research attention in comparison to the wealth of studies on the cerebral lateralization of oral language. The purpose of the present study was to further our understanding of written language lateralization, by elucidating the relative contribution of language and motor functions. We compared written word generation with a task that has equivalent visuomotor demands but does not include language: the repeated drawing of symbols. We assessed cerebral laterality using functional transcranial Doppler ultrasound (fTCD), a non-invasive, perfusion-sensitive neuroimaging technique in 23 left- and 31 right-handed participants. Findings suggest that the linguistic aspect of written word generation recruited more left-hemispheric areas during writing, in right-handers compared to left-handers. This difference could be explained by greater variability in cerebral laterality patterns within left-handers or the possibility that the areas subserving language in left-handers are broader than in right-handers. Another explanation is that the attentional demands of the more novel symbol copying task (compared to writing) contributed more right-hemispheric activation in right-handers, but this could not be captured in left-handers due to ceiling effects. Future work could investigate such attentional demands using both simple and complex stimuli in the copying condition.
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Affiliation(s)
- Marietta Papadatou-Pastou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece.,Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Panagiotis Sampanis
- Psychology Department, School of Social Sciences, Birmingham City University, The Curzon Building, Birmingham, United Kingdom
| | - Ioannis Koumzis
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
| | - Sofia Stefanopoulou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
| | - Dionysia Sousani
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
| | - Athina Tsigkou
- School of Education, National and Kapodistrian University of Athens, Athens, Greece
| | - Nicholas A Badcock
- School of Psychological Science, University of Western Australia,, Crawley, Western Australia, Australia.,Department of Cognitive Science, ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, 16 University Avenue, North Ryde, New South Wales, Australia
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2
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Burgund ED. Task-domain and hemisphere-asymmetry effects in cisgender and transmale individuals. PLoS One 2021; 16:e0260542. [PMID: 34874973 PMCID: PMC8651105 DOI: 10.1371/journal.pone.0260542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 11/11/2021] [Indexed: 11/25/2022] Open
Abstract
The present research examined the extent to which transmale individuals’ functional brain organization resembles that of their assigned sex or gender identity. Cisgender-female, cisgender-male, and transmale participants, who were assigned female sex but did not have a female gender identity, were compared in terms of effects that have been observed in cisgender individuals: task-domain effects, in which males perform better than females on spatial tasks and females perform better than males on verbal tasks; and hemisphere-asymmetry effects, in which males show larger differences between the left and right hemispheres than females. In addition, the present research measured participants’ intelligence in order to control for potential moderating effects. Participants performed spatial (mental rotation) and verbal (lexical decision) tasks presented to each hemisphere using a divided-visual field paradigm, and then completed an intelligence assessment. In the mental-rotation task, cismale and transmale participants performed better than cisfemale participants, however this group difference was explained by intelligence scores, with higher scores predicting better performance. In the lexical-decision task, cismale and transmale participants exhibited a greater left-hemisphere advantage than cisfemales, and this difference was not affected by intelligence scores. Taken together, results do not support task-domain effects when intelligence is accounted for; however, they do demonstrate a hemisphere-asymmetry effect in the verbal domain that is moderated by gender identity and not assigned sex.
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Affiliation(s)
- E. Darcy Burgund
- Department of Psychology, Macalester College, Saint Paul, Minnesota, United States of America
- * E-mail:
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3
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Richardson T. No association between adult sex steroids and hand preference in humans. Am J Hum Biol 2021; 34:e23605. [PMID: 33949024 DOI: 10.1002/ajhb.23605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND There is ongoing debate about the effects of hormones on the lateralization of the developing brain. In humans, there are conflicting theories of how testosterone during development should affect lateralization. Empirical studies linking prenatal and postnatal testosterone levels to hand preference (a proxy for lateralization) are similarly mixed. Links between hand preference and health may also suggest a mediating role of steroid hormones such as testosterone and estradiol. Studies to date of adult steroid hormones and handedness have been hindered by samples that contain small numbers of non-right-handers. RESULTS In the largest study of the phenomenon to date, I find that the testosterone (n = 7290) and estradiol (n = 3700) levels of left- and mixed-handed adults are no different to those of right-handers. All Bayesian 95% highest density intervals contained 0. DISCUSSION AND CONCLUSIONS The results have implications for studies that show elevated risk of hormonal-related mental and physical disorders in left-handed individuals.
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Affiliation(s)
- Thomas Richardson
- School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK
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Richards G, Beking T, Kreukels BPC, Geuze RH, Beaton AA, Groothuis T. An examination of the influence of prenatal sex hormones on handedness: Literature review and amniotic fluid data. Horm Behav 2021; 129:104929. [PMID: 33454315 DOI: 10.1016/j.yhbeh.2021.104929] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 01/27/2023]
Abstract
Competing theories have posited roles for foetal androgen exposure in the development of human handedness. However, due to practical and ethical considerations, few studies have used hormonal measures to examine this possibility. The current paper reviews this literature and reveals a generally inconsistent pattern of results. We also present data from a longitudinal study of prenatal sex hormone exposure and subsequent handedness. More specifically, we examine correlations between testosterone and estradiol measured from second trimester amniotic fluid and hand preference (Dutch language version of the Edinburgh Handedness Inventory) and hand skill asymmetry (pegboard task) measured at 15 years of age. Prenatal sex hormone exposure was not associated with the direction of hand preference in either males or females. However, in females, high levels of prenatal testosterone were associated with weaker lateralisation of hand skill, and high levels of prenatal estradiol were associated with weaker hand preference. In addition, high levels of prenatal testosterone were associated with increased task duration (i.e., slow hand speed) for the right and left hands of males. The pattern of results observed here is not entirely consistent with any of the main theories linking sex hormones with handedness, suggesting that an association between these variables may be more complex than initially thought.
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Affiliation(s)
- Gareth Richards
- Newcastle University, School of Psychology, Ridley Building 1, Queen Victoria Road, Newcastle upon Tyne NE1 7RU, UK; University of Cambridge, Autism Research Centre, Department of Psychiatry, Douglas House, 18b Trumpington Road, Cambridge CB2 8AH, UK.
| | - Tess Beking
- University of Groningen, Faculty of Behavioural and Social Sciences, Department Clinical & Developmental Neuropsychology, Grote Kruisstraat 2/1, 9712 TS Groningen, the Netherlands; Amsterdam University Medical Center, location VUmc, Department of Medical Psychology, Center of Expertise on Gender Dysphoria, PO Box 7057, 1007 MB Amsterdam, the Netherlands; University of Groningen, Groningen Institute for Evolutionary Life Sciences, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Baudewijntje P C Kreukels
- Amsterdam University Medical Center, location VUmc, Department of Medical Psychology, Center of Expertise on Gender Dysphoria, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Reint H Geuze
- University of Groningen, Faculty of Behavioural and Social Sciences, Department Clinical & Developmental Neuropsychology, Grote Kruisstraat 2/1, 9712 TS Groningen, the Netherlands
| | - Alan A Beaton
- Swansea University, Department of Psychology, School of Human & Health Sciences, Swansea SA2 8PP, UK; Aberystwyth University, Department of Psychology, Aberystwyth SY23 3UX, UK
| | - Ton Groothuis
- University of Groningen, Groningen Institute for Evolutionary Life Sciences, Nijenborgh 7, 9747 AG Groningen, the Netherlands
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Yuksel T, Sizer E, Durak H. 2D:4D ratios as an indicator of intrauterine androgen exposure in children who stutter. Early Hum Dev 2019; 135:27-31. [PMID: 31228858 DOI: 10.1016/j.earlhumdev.2019.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 11/15/2022]
Abstract
AIM We aimed to explore whether there is a relationship between stuttering and digit ratio (2D:4D), which is thought to be a marker of prenatal testosterone exposure. METHODS We evaluated a total of 90 children who stutter (CWS; n = 40 mild-to-moderate and n = 50 severe stutters) and 40 healthy peers (CWNS) as controls. We used the Clinical Global Impression-Severity (CGIS) scale to measure the severity of stuttering. We measured the lengths of index finger (2D) and ring finger (4D) of both hands directly and divided to calculate 2D:4D ratio. The difference between the right and the left hand 2D:4D ratio (DR-L) was also calculated. RESULT Significant difference was found in right 2D:4D and the mean DR-L between the CWS and CWNS groups. Right 2D:4D was significantly lower in stuttering boys than in control boys, and in stuttering girls than control girls. Also, DR-L was significantly lower in stuttering boys than control boys. In ANOVA, there were significant differences between the mild-to-moderate, severe stuttering and control groups in terms of right 2D:4D and DR-L. Right hand 2D:4D and DR-L decreased from controls to severe stutterers. CONCLUSION Our results suggest that lower right 2D:4D and DR-L were related to the presence and severity of stuttering in children, i.e. CWS had lower 2D:4D and DR-L than CWNS. Further large-scale prospective studies are needed to clarify the reliability of 2D:4D ratio as an indicator of fetal sex hormone exposure level and its relation with the presence and severity of stuttering in children.
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Affiliation(s)
- Tugba Yuksel
- Dicle University School of Medicine, Department of Child and Adolescent Psychiatry, Diyarbakir, Turkey.
| | - Esra Sizer
- Dicle University School of Medicine, Department of Child and Adolescent Psychiatry, Diyarbakir, Turkey
| | - Hasan Durak
- Dicle University School of Medicine, Department of Child and Adolescent Psychiatry, Diyarbakir, Turkey
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Tran US, Kossmeier M, Voracek M. Associations of Bisexuality and Homosexuality with Handedness and Footedness: A Latent Variable Analysis Approach. ARCHIVES OF SEXUAL BEHAVIOR 2019; 48:1451-1461. [PMID: 30498915 PMCID: PMC6594983 DOI: 10.1007/s10508-018-1346-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 02/10/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Non-right-handedness appears to be more common among bisexuals and homosexuals than among heterosexuals, which might be indirect evidence of effects of prenatal androgen exposure. Current data suggest higher prenatal testosterone levels among bisexual and homosexual women, but are inconclusive for men. This study examined the association between sexual orientation and non-right-handedness for sex differences and whether higher rates of mixed-handedness, rather than left-handedness, might be the driving factor. This allowed for more specific tests regarding the predictions of two competing theories of prenatal androgen exposure, the Geschwind-Galaburda theory and the callosal hypothesis, than in previous research. Being a potentially better indicator of cerebral lateralization than handedness, associations with footedness were also explored. To counter inconsistencies and shortcomings of previous research, we utilized two large discovery and replication datasets (ns = 2368 and 1565) and applied latent variable analysis to reliably classify lateral preferences (i.e., handedness, footedness). This maximized the statistical conclusion validity and allowed for direct tests of replicability. Sexual orientation was differentially associated with lateral preferences among men and women. Associations among women were consistent with predictions of the Geschwind-Galaburda theory, whereas among men they were consistent with predictions of the callosal hypothesis. The results were further consistent with models of homosexuality that suggest a role of parental epigenetic marks on sexually dimorphic fetal development. Research efforts should be increased with regard to footedness and epigenetic theories of homosexuality.
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Affiliation(s)
- Ulrich S Tran
- Department of Basic Psychological Research and Research Methods, School of Psychology, University of Vienna, 1010, Vienna, Austria.
| | - Michael Kossmeier
- Department of Basic Psychological Research and Research Methods, School of Psychology, University of Vienna, 1010, Vienna, Austria
| | - Martin Voracek
- Department of Basic Psychological Research and Research Methods, School of Psychology, University of Vienna, 1010, Vienna, Austria
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Mohammadi H, Papadatou-Pastou M. Cerebral laterality as assessed by hand preference measures and developmental stuttering. Laterality 2019; 25:127-149. [PMID: 31144576 DOI: 10.1080/1357650x.2019.1621329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The causes of developmental stuttering, a neurodevelopmental communicative disorder, have not been elucidated to date. Neuroimaging studies suggest that atypical cerebral laterality could be one of such causal factors. Moreover, handedness, a behavioural index for cerebral laterality, has been linked to stuttering and recovery from it. However, findings are conflicting, possibly due to sample selection procedures, which typically rely on self-reported stuttering, and to the fact that handedness is typically assessed with regards to its direction rather than degree. We investigated the possible relationship between handedness and stuttering. This is the first study where children who stutter (CWS) were selected using clinical criteria as well as speech samples and where a non-Western population was studied. Findings from 83 CWS aged 3-9 years (mean = 6.43, SD = 1.84) and 90 age- and sex-matched children who do not stutter (mean = 6.45, SD = 1.71) revealed no differences in their hand preference scores as evaluated by parent-completed Edinburgh Handedness Inventory, for both direction and degree. The severity of stuttering was not found to correlate with the degree of handedness. We suggest that parents and professionals not treat left- or mixed-hand preference as a reason for concern with regards to stuttering.
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Affiliation(s)
- Hiwa Mohammadi
- Department of Neurology & Sleep Disorders Research Center, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Marietta Papadatou-Pastou
- School of Education, Faculty of Primary Education, National and Kapodistrian University of Athens, Athens, Greece
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Hoppler S, Walther A, La Marca-Ghaemmaghami P, Ehlert U. Lower birthweight and left-/mixed-handedness are associated with intensified age-related sex steroid decline in men. Findings from the Men's Health 40+ Study. Andrology 2018; 6:896-902. [PMID: 29993200 PMCID: PMC6585816 DOI: 10.1111/andr.12516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 04/29/2018] [Accepted: 05/26/2018] [Indexed: 11/29/2022]
Abstract
In males, age‐related decline in free testosterone (T) and dehydroepiandrosterone (DHEA) by 2–3% per year has been reported. Estradiol (E2) and progesterone (P) seem to decrease as well, but to a lesser extent. Lower sex steroid levels in men have been related to physical and mental symptoms. Low birthweight and left‐/mixed‐handedness (L/MH) are indicators of an adverse fetal environment during pregnancy, and both have been linked to morbidity in later life. The aim of this study is to examine the relationship between lower birthweight as well as L/MH and age‐related sex steroid decline. In a cross‐sectional study design, saliva samples were collected under standardized conditions from healthy men for subsequent steroid hormone analysis using standard luminescence immunoassays. T (M = 67.57 pg/mL), DHEA (M = 247.91 pg/mL), E2 (M = 1.29 pg/mL), and P (M = 28.20 pg/mL) have been quantified leading to a final sample of 256 men providing complete data on sex hormones (MAge=57.8; SDAge = 10.8). Information on participants’ birthweight was obtained from birth reports (N = 134), and participants were asked about their handedness (right‐handed, left‐handed, mixed‐handed) (N = 256). Multivariate‐adjusted linear regression models relating each sex hormone individually and the principal component of declining steroid hormones (DSH)—an integrated hormonal parameter—with handedness and birthweight did not identify significant associations except for handedness and E2. Moderation analysis using robust regression accounting for bias due to influential data points detected a significant association between age and DSH for handedness (β = −0.0314, p = 0.040) but only a trend for birthweight (β = 0.0309, p = 0.073). For lower birthweight, a trend toward intensified age‐related sex steroid decline in men was observed, while for L/MH, a significant association with intensified age‐related sex steroid decline was identified. These results indicate that L/MH and potentially also lower birthweight might be considered as early risk factors for endocrine health in later life.
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Affiliation(s)
- S Hoppler
- Clinical Psychology and Psychotherapy, University of Zurich, Zurich, Switzerland
| | - A Walther
- Clinical Psychology and Psychotherapy, University of Zurich, Zurich, Switzerland.,University Research Priority Program - Dynamics of Healthy Aging, University of Zurich, Zurich, Switzerland.,Biological Psychology, TU Dresden, Dresden, Germany
| | | | - U Ehlert
- Clinical Psychology and Psychotherapy, University of Zurich, Zurich, Switzerland.,University Research Priority Program - Dynamics of Healthy Aging, University of Zurich, Zurich, Switzerland
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Mohammadi H, Joghataei MT, Rahimi Z, Faghihi F, Khazaie H, Farhangdoost H, Mehrpour M. Sex steroid hormones and sex hormone binding globulin levels, CYP17 MSP AI (-34T:C) and CYP19 codon 39 (Trp:Arg) variants in children with developmental stuttering. BRAIN AND LANGUAGE 2017; 175:47-56. [PMID: 28992603 DOI: 10.1016/j.bandl.2017.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 09/08/2017] [Accepted: 09/24/2017] [Indexed: 06/07/2023]
Abstract
Developmental stuttering is known to be a sexually dimorphic and male-biased speech motor control disorder. In the present case-control study, we investigated the relationship between developmental stuttering and steroid hormones. Serum levels of testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), oestradiol, progesterone, cortisol, and sex hormone binding globulin (SHBG), as well as the 2nd/4th digit ratio (2D:4D), an indicator of prenatal testosterone level, were compared between children who stutter (CWS) and children who do not stutter (CWNS). Moreover, two SNPs (CYP17 -34 T:C (MSP AI) and CYP19 T:C (Trp:Arg)) of cytochrome P450, which is involved in steroid metabolism pathways, were analysed between the groups. Our results showed significantly higher levels of testosterone, DHT, and oestradiol in CWS in comparison with CWNS. The severity of stuttering was positively correlated with the serum levels of testosterone, DHEA, and cortisol, whereas no association was seen between the stuttering and digit ratio, progesterone, or SHBG. The CYP17CC genotype was significantly associated with the disorder.
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Affiliation(s)
- Hiwa Mohammadi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Taghi Joghataei
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran; Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Zohreh Rahimi
- Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Faezeh Faghihi
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Habibolah Khazaie
- Sleep Disorders Research Center, Department of Psychiatry, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hashem Farhangdoost
- Department of Speech Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Masoud Mehrpour
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
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