Handedness in systemic lupus erythematosus

Left-handedness and achievements in foreign language studies

Studies of brain lateralization lend support to the hypothesis that language-motor functions in left-handers are differently organized from those in right-handers. However, the implications of these differences regarding cognitive functioning are as yet subject to controversy. This concerns all hypotheses raised and empirical data collected over the years. Although it was suggested that left-handers are at higher risk of having language and reading deficits, empirical data from clinical and nonclinical populations are inconclusive at the present time. No effort, however, has been invested in examining possible differences in academic studies of foreign languages according to handedness. Here we report data indicating inferior achievements of left-handed native Hebrew speakers in studies of English as a foreign language. Left-handed pupils significantly more than right-handers were placed in lower level English classes and had more difficulties in applying orthographic-phonological mapping rules in reading English words and pseudowords. However, left-handers' difficulties in this task were not correlated with their performance in a word recognition task. It is thus suggested that the "common symptom" of poor word reading in left-handers indicates different processing failures in different left-handers, some of which impede the buildup of an internal representational system of mapping orthography to phonology and some of which concern mainly the precision of word production.

Is forced dextrality an explanation for the fall in the prevalence of sinistrality with age? A study in northern England

OBJECTIVES

The fall in the prevalence of left handedness with age has been attributed to either premature mortality or a cohort effect of forced dextrality. Evidence for forced dextrality was sought to differentiate between these competing theories.

DESIGN

6097 Edinburgh handedness inventories were used to calculate laterality quotients (LQ) with and without the questions relating to writing and drawing. These questions might be expected to be most influenced by forced dextrality.

SETTING

The study was performed in a small industrial town in Lancashire, UK.

PARTICIPANTS

Using the British family practitioner service where over 95% of the population are registered with a general practitioner a response rate of 82.17% was obtained with respect to the Edinburgh Inventory.

RESULTS

Questions about writing and drawing on the Edinburgh Inventory contributed to the positivity (right handedness) of the mean LQ, but equally across the ages. When a negative LQ was used to define left handedness the prevalence of left handedness fell from 11.2% at age 15 to 4.4% at age 70. Removal of the questions about writing and drawing caused the prevalence of left handedness to fall from 10.5% at age 15 to 4.95% at age 70.

CONCLUSIONS

Less than 20% of the fall in the prevalence of left handedness was accounted for by questions relating to writing and drawing. The fall in the prevalence of sinistrals in older age groups is not adequately explained by cohort effects of forced dextrality on the writing hand.

Is there really a syndrome involving the co-occurrence of neurodevelopmental disorder talent, non-right handedness and immune disorder among children?

This paper is the first large-scale attempt to test Geschwind and Galaburda's (1985a, 1985b, 1985c) hypothesis that there should be a four-way association among neurodevelopmental disorders (NDs), special talents, non-right handedness, and immune disorders. In a sample of 11,578 children, several two-way associations were found, but not those most strongly predicted by the theory. For example, non-right handedness was not associated with NDs considered to be secondary to left hemisphere dysfunction (e.g., articulation disorder, reading disability, verbal aptitude deficits). Instead, non-right handedness was associated with NDs that involve generalized brain damage (e.g. cerebral palsy, mental retardation, and seizures). One immune disorder (asthma) was associated with one ND (attention deficit disorder); immune disorder was not associated with non-right handedness. Less than 1% of this sample manifested the co-occurrence of any three or four of these markers. In sum, there was little evidence in support of the syndrome suggested by Geschwind and Galaburda (1985a, 1985b, 1985c).

Ambilaterality: definition from handedness preference questionnaires and potential significance

Defining handedness according to the results of preference questionnaires is operational. Most often, handedness is defined according to the extremes of the handedness range or equal divisions of the entire handedness range. These definitions may exclude ambilateral (ambidextrous) subjects from analysis or may fail to separate out subjects with intermediate handedness scores. Examples from the literature are presented to show that subjects with handedness scores in the weak right-handedness range may have characteristics that distinguish them from subjects in other segments of the handedness spectrum. Handedness studies should assess the middle handedness range using a scoring method which identifies subjects in this range.

Hand preference, immune system disorder and cognitive function among gay/bisexual men: the Multicenter AIDS Cohort Study (MACS)

This study evaluated the self-reported patterns of handedness among a large subsample (n = 1612) of the gay/bisexual men comprising the Multicenter AIDS Cohort Study (MACS). There was a small but significant elevation in left-handedness among gay/bisexual men compared to available normative data. However, there were no differences within the cohort in measures of immune function, self-reported autoimmune disorders, asthma, or hay fever, although there was an association between handedness and allergy. Performance on neuropsychological tests also did not differ as a function of handedness.

Reading disability, immune disorders and non-right-handedness: twin and family studies of their relations

Geschwind and colleagues discussed associations among learning disorders, immune disorders and non-right-handedness. In this study, we examined the associations between reading disability (RD) and both immune disorders (ID) and non-right-handedness (NRH) in family and twin samples (total N = 1731 cases) identified through an RD proband. We also conducted co-segregation analyses to ascertain the degree to which NRH, ID and RD were biologically related. There was little evidence for an overall association between RD and NRH. There was not convergent evidence across all four samples for an association between RD and ID, although we did find an association between RD and ID in two of four samples. Nor was there strong support for a subtype where RD and NRH, or RD and ID, co-segregate in families. These data suggest that the associations postulated by Geschwind and colleagues are not robust in RD samples, although we cannot completely rule out the possibility of an RD plus ID subtype.

Handedness is not related to self-reported disease incidence

A hand preference inventory and a disease questionnaire were administered to a sample of 743 undergraduate students. The incidence of left-handedness was not related to the report of any of the diseases surveyed. Among right-handers, preference scores were slightly lower (less right-handed) in those reporting drug allergies or migraine. These data provide no support for the argument that handedness and immune disorders are related.

Sex-dependent association between immune function and paw preference in two substrains of C3H mice

Asymmetry in brain modulation of the immune system has been previously described in mice. Paw preference is known to be associated with immune reactivity but the respective roles of sex and genetic background in this association remain to be elucidated. In this work, male and female mice of the C3H/He and C3H/OuJIco substrains were selected as right- and left-handers. Mitogen-induced lymphoproliferation and natural killer cell activity were then tested. Left-handed female mice of both C3H substrains exhibited higher mitogenesis than right-handers but no association between paw preference and NK cell activity was found in females. Conversely, in males of both substrains, right-handers showed enhanced NK cell activity compared to left-handers but no association between paw preference and mitogenesis was observed in males. Only small differences in the strength, but not in the direction, of the association between paw preference and immune functions were observed between the two C3H substrains. These results show that the association between paw preference and immune reactivity in mice varies according to the immune parameters tested and is a sex-dependent phenomenon in which the genetic background may be involved.

Hand preference in homosexual men

The present study examined the distribution of hand preference and its relationship to immune system functioning and performance on neuropsychological tests in a sample of 993 homosexual men from the Multicenter AIDS Cohort Study comprising 502 HIV-1 seronegatives, 436 asymptomatic HIV-1 seropositives, and 55 men with diagnoses of AIDS or AIDS Related Complex. The prevalence of left-handedness in all of the groups (13.1-14.5%) was consistent with prior published reports of prevalent left-handedness in the general population. The distribution of hand preference scores (on a 5-item self-report questionnaire) was J-shaped and shifted to the right as in the general population. There were no differences between right- and left-handers in the immune system parameter of CD4 counts, nor was there any increase of self-reported allergies among the left-handers. We found a significantly larger number of 'outliers' on the neuropsychological measures for left-handers than for right-handers, both for HIV-1 seronegatives and seropositives. These results failed to replicate Lindesay's (1987) report of a leftward shift in manual preference among homosexual men, and failed to support Geschwind and Galaburda's (1985b) hypothesis of a link between homosexuality, handedness and autoimmune disorder. The differences between right- and left-handers on neuropsychological measures, independent of HIV-1 serostatus, are discussed in terms of Satz's (1972) model of pathological left-handedness.

Strain-dependent association between immune function and paw preference in mice

The relationship between immune function and the preferred direction of behavioral asymmetry was examined in several mouse strains. Mixed leukocyte reaction, natural killer cell activity, cytotoxic T lymphocyte response and lymphoproliferation in response to mitogens were investigated in animals with left or right paw preference. From the 7 strains and substrains examined, it appeared that differences in immune function between left and right pawed mice, when present, vary in directionality. Thus, in C3H/HeJ and 129/J, left pawed mice had higher immune responses than right pawed mice, whereas in C3H/HeNCr MTV- and BALB/cJ animals, the reverse was found. In C3H/HeNCr MTV+, C57BL/6J and Collin's heterogenous control population for the high/low asymmetry lines, no differences between animals with left or right paw preference were found. The statistical significance of these differences were not uniform for all the immune parameters studied. These data indicate that the association between immune function and preference for using the left versus right paw is a strain-dependent phenomenon and may suggest that the inconsistent evidence for an association between immune deficiency and left-handedness could be due to genetic heterogeneity among subpopulations.

Immune and autoimmune diseases in dyslexic children

One hundred and five dyslexic and 105 control children were compared for frequency of immune diseases, autoimmune diseases, and non-right-handedness in the light of the Geschwind-Behan (1982) "testosterone hypothesis". The results showed significantly more immune- and autoimmune-diseases int he dyslexic group. There were no differences between the groups in the frequency of non-right-handedness. There were no interactions with gender, although there were more non-right-handed boys than girls in the total sample. Mothers of children who were dyslexic experienced significantly more negative life-events during pregnancy, they also experienced the pregnancy as more difficult, and they had more spontaneous abortions. In conclusion, the results support some aspects of the "testosterone hypothesis", but they also point to a more complex pattern of interaction between the factors that still remain unanswered.

Left-handedness and myasthenia gravis

In two separate studies comparing the handedness of patients suffering from myasthenia gravis with matched controls, no evidence was found to support the Geschwind Behan hypothesis of an association between autoimmune disease and left-handedness. Counter to prediction both studies found marginally lower incidences of left-handedness in myasthenics, and when combined with the similar result of Cosi et al. (Cortex 24, 573-577, 1988) the difference was highly statistically significant. The personality of myasthenics, as assessed by the Eysenck Personality Questionnaire (EPQ), and in particular the psychoticism scale, which has been postulated to be related to androgen levels, was not significantly different from controls. However, assessment of sex-roles using the Bem Sex Role Inventory suggested that female myasthenics were more masculine than controls.

The testosterone hypothesis: Assessment since Geschwind and Behan, 1982

The Geschwind hypothesis proposes a causal interaction among non-right-handedness, immune disorders, and learning disabilities, including dyslexia, via the intrauterine action of the male hormone testosterone. Some epidemiologic studies have supported at least a statistical association among the three traits; others have not. The associations between learning disorders and immune disease and between learning disorders and non-righthandedness appear to be better supported than that between immune disorders and non-right-handedness. However, none of data thus far accumulated are conclusive because it is not clear that the samples studied have been truly representative.The neuropathologic evidence, both in autopsy studies in human dyslexics and in animal models of developmental cortical abnormalities, are consistent with but not diagnostic of immunological pathology. Mechanisms are discussed by which an abnormal immune system could thus injure the developing brain, with an emphasis placed on abnormal maternal-fetal interactions, including maternal autoimmune disease and maternal-fetal incompatibility. A genetic origin is also possible in which the maternal role is less significant.

Neuropsychological correlates of serum lymphocytotoxic antibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by frequent neuropsychiatric (NP) manifestations. At least two different pathogenetic mechanisms have been proposed for NP-SLE, including vasculitis and antibodies against neuronal antigens, the latter as expressed by the presence of brain cross-reactive lymphocyte antibodies. We have previously reported a high prevalence of cognitive dysfunction in SLE which can remain subclinical and which cannot be accounted for on the basis of disease activity, general distress, or steroid medication. In the present study, we undertook the same extensive, standardized neuropsychological testing in 98 consecutive female SLE patients in order to evaluate central nervous system functioning in relation to serum lymphocyte antibodies which were measured at the time of neuropsychological testing by a microcytotoxicity test. A significant association was observed between the presence of serum lymphocytotoxic antibodies (LCA) and cognitive impairment in patients with SLE. The pattern of impairment which predominated in the LCA-positive patients involved deficits in anteriorly associated, primarily visuospatial functions. These findings support the hypothesis of localization of a particular antigen-antibody interaction in the brain in SLE, suggesting the existence of immunological control mechanisms for normal brain functioning.

Altered cerebral dominance in an atopic population

Handedness was assessed in 853 subjects, 424 from an allergy office practice and 429 from a health screening clinic, using a modified Oldfield Handedness Inventory. Subjects also responded to a survey ascertaining both personal and family histories of allergy-related problems and left-handedness. A significant left-handed shift in mean laterality quotient and an increased incidence of left-handedness was found in participants from the allergy office and in subjects who considered themselves to be affected by allergy, allergic rhinitis, and/or asthma. Controlling for nonatopic responders from the allergy office and possibly atopic responders from the health screening clinic, mean laterality quotients were 66.4 +/- 51.6 vs 79.4 +/- 42.1 (p less than .001) and the incidence of left-handedness was 12.1% vs 6.8% (p less than .05). Mean laterality quotient of 125 asthmatics was 65.1 +/- 54.0, and 16 (12.8%) were left-handed. The mean percentage of left-handed children of 79 asthmatic parents was found to be increased: 16.7 +/- 26.3% vs 10.3 +/- 21.2% of children of 198 nonatopic parents (p less than .02). This was attributable to left-handed children of asthmatic women, 18.6 +/- 29.0% (p less than .01), but not asthmatic men. Both autonomic neurologic dysfunction and disordered immunoregulation typify atopic disease. Our results can be interpreted to reflect this duality and lend support to Geshwind's hypothesis of a relationship between cerebral dominance and immunologic set resulting from common developmental influences.

Systemic lupus erythematosus: learning disability in the male offspring of female patients and relationship to laterality

Systemic lupus erythematosus (SLE) is a multisystemic disease that predominates in women during the childbearing years. One system frequently affected is the central nervous system. Seizures and psychoses are criteria useful in the diagnosis of SLE. The effects of this disease on disorders of learning and handedness in both patients and first degree relatives are the subject of the present report. Dyslexia and other disorders of learning were present in 45% (24/55) of male offspring of female SLE patients. Ten percent of male siblings of female SLE patients were learning-impaired. Dyslexia and other disorders of learning are also common in women with SLE (dyslexia 12.5%) and men with SLE where the proband is one of two or more cases of SLE in the same family (dyslexia 27.6%). Tests for handedness in the lupus population indicated that there were slightly more patients (mostly women) (p = 0.08) who were lefthanded by the Oldfield laterality test compared to normal volunteers. Handedness did not correlate with the degree of dyslexia in either the patients or their first degree relatives.