Autistic children's hand preferences: results from an epidemiological study of infantile autism

Can cerebral lateralisation explain heterogeneity in language and increased non-right handedness in autism? A literature review

BACKGROUND

Autism is characterised by phenotypic variability, particularly in the domains of language and handedness. However, the source of this heterogeneity is currently unclear.

AIMS

To synthesise findings regarding the relationship between language, handedness, and cerebral lateralisation in autistic people and consider how future research should be conducted in order to progress our understanding of phenotypic variability.

METHODS AND PROCEDURES

Following a literature search and selection process, 19 papers were included in this literature review. Studies using behavioural, structural, and functional measures of lateralisation are reviewed.

OUTCOMES AND RESULTS

The studies reviewed provided consistent evidence of differential cerebral lateralisation in autistic people, and this appears to be related to between-group differences in language. Evidence relating this to handedness was less consistent. Many of the studies did not include heterogeneous samples, and/or did not specify the language process they investigated.

CONCLUSIONS AND IMPLICATIONS

This review suggests that further research is needed to fully understand the relationship between cerebral lateralisation and phenotypic variability within autism. It is crucial that future studies in this area include heterogeneous samples, specify the language process they are investigating, and consider taking developmental trajectories into account.

Crossed Eye/Hand Laterality and Left-Eyedness Predict a Positive 24-Month Outcome in Alcohol-Dependent Patients

BACKGROUND

Available predictors of hospital readmission following withdrawal in alcohol-dependent patients are limited. However, such parameters are needed to optimize individualized treatment strategies. This study investigated whether crossed eye/hand laterality, eyedness, and handedness may predict outcomes in alcohol dependence.

METHODS

The prospective study included 200 early-abstinent alcohol-dependent inpatients (n[males] = 113, n[females] = 87) and 240 control subjects (n[males] = 133, n[females] = 107). We assessed eyedness and handedness using the hole-in-the-card and Shimizu tests and documented alcohol-related readmissions over 12 and 24 months.

RESULTS

Crossed eye/hand laterality and left-eyedness were associated with a reduced risk for alcohol-related readmission (12-month: odds ratios [OR] = 0.41, p = 0.008, OR = 0.42, p = 0.004; 24-month: OR = 0.57, p = 0.097, OR = 0.47, p = 0.016), fewer median readmissions (12-month: 0 vs. 1, p = 0.005, 0 vs. 1, p = 0.005; 24-month: 1 vs. 2, p = 0.014, 1 vs. 2, p = 0.006), and more mean days to the first readmission (12-month: 270 vs. 209, p = 0.007, 269 vs. 207, p = 0.003; 24-month: 462 vs. 335, p = 0.039, 461 vs. 323, p = 0.005). They also interacted with treatment and alcohol drinking history to predict the outcome. In sex-specific analyses, most of these effects remained significant in males but not in females. Handedness alone did not significantly predict outcome. Moreover, the laterality markers did not significantly differ between alcohol-dependent patients and control subjects.

CONCLUSIONS

Determining crossed eye/hand laterality and eyedness may help to individualize relapse prevention in the future. Both are easily accessible predictors of alcohol-related readmission following inpatient withdrawal treatment.

Handedness and the risk of glioma

Gliomas are the most common type of malignant primary brain tumor and few risk factors have been linked to their development. Handedness has been associated with several pathologic neurological conditions such as schizophrenia, autism, and epilepsy, but few studies have evaluated a connection between handedness and risk of glioma. In this study, we examined the relationship between handedness and glioma risk in a large case-control study (1849 glioma cases and 1354 healthy controls) and a prospective cohort study (326,475 subjects with 375 incident gliomas). In the case-control study, we found a significant inverse association between left handedness and glioma risk, with left-handed persons exhibiting a 35% reduction in the risk of developing glioma [odds ratio (OR) = 0.65, 95% confidence interval (CI) 0.51-0.83] after adjustment for age, gender, race, education, and state of residence; similar inverse associations were observed for GBM (OR = 0.69, 95% CI 0.52-0.91), and non-GBM (OR = 0.59, 95% CI 0.42-0.82) subgroups. The association was consistent in both males and females, and across age strata, and was observed in both glioblastoma and in lower grade tumors. In the prospective cohort study, we found no association between handedness and glioma risk (hazards ratio = 0.92, 95% CI 0.67-1.28) adjusting for age, gender, and race. Further studies on this association may help to elucidate mechanisms of pathogenesis in glioma.

Atypical lateralization of motor circuit functional connectivity in children with autism is associated with motor deficits

Background

Atypical lateralization of language-related functions has been repeatedly found in individuals with autism spectrum conditions (ASC). Few studies have, however, investigated deviations from typically occurring asymmetry of other lateralized cognitive and behavioural domains. Motor deficits are among the earliest and most prominent symptoms in individuals with ASC and precede core social and communicative symptoms.

Methods

Here, we investigate whether motor circuit connectivity is (1) atypically lateralized in children with ASC and (2) whether this relates to core autistic symptoms and motor performance. Participants comprised 44 right-handed high-functioning children with autism (36 males, 8 females) and 80 typically developing control children (58 males, 22 females) matched on age, sex and performance IQ. We examined lateralization of functional motor circuit connectivity based on homotopic seeds derived from peak activations during a finger tapping paradigm. Motor performance was assessed using the Physical and Neurological Examination for Subtle Signs (PANESS).

Results

Children with ASC showed rightward lateralization in mean motor circuit connectivity compared to typically developing children, and this was associated with poorer performance on all three PANESS measures.

Conclusions

Our findings reveal that atypical lateralization in ASC is not restricted to language functions but is also present in circuits subserving motor functions and may underlie motor deficits in children with ASC. Future studies should investigate whether this is an age-invariant finding extending to adolescents and adults and whether these asymmetries relate to atypical lateralization in the language domain.

Electronic supplementary material

The online version of this article (doi:10.1186/s13229-016-0096-6) contains supplementary material, which is available to authorized users.

Handedness in Children With Autism Spectrum Disorder

The left hemisphere is usually predominant in manual skills and language, suggesting a link between hand dominance and language. Studies of autism spectrum disorder show atypical handedness; however, few have examined language-handedness associations. Handedness, assessed by task performance, and standardized receptive and expressive language tests were completed in 110 autism spectrum disorder children (96 boys; M age = 8.3 years, SD = 3.8) and 45 typically developing children (37 boys; M age = 8.6 years, SD = 4.3), 3 to 17 years of age. The autism spectrum disorder group had a lower handedness score (was less strongly lateralized) than the control group. In the autism spectrum disorder group, there was a small effect of handedness on language; right-handers had better language than non-right-handers. Results suggest poorer language prognosis may be associated with left- or mixed-handedness in autism spectrum disorder.

Is strength of handedness reliable over repeated testing? An examination of typical development and autism spectrum disorder

Despite a lack of agreement concerning the age at which adult-like patterns of handedness emerge, it is generally understood that hand preference presents early in life and development is variable. Young children (ages 3-5 years) are described as having weak hand preference; however, older children (ages 7-10 years) display stronger patterns. Here, strength of hand preference refers to reliable use of the preferred hand. In comparison to their typically developing (TD) peers, individuals with autism spectrum disorder (ASD) are described as having a weak hand preference. This study aimed to extend the literature to assess three measures of handedness (Waterloo Handedness Questionnaire - WHQ, Annett pegboard - AP, and WatHand Cabinet Test - WHCT) in two repeated sessions. The first research question aimed to delineate if the strength of hand use changes across testing sessions as a function of age in typical development. Right-handed children reported a reliable preference for the right hand on the WHQ, similar to adults. A marginally significant difference was revealed between 3- to 4- and 5- to 6-year-olds on the AP. This was attributed to weak lateralization in 3- to 4-year-olds, where the establishment of hand preference by age 6 leads to superior performance with the preferred hand in 5- to 6-year-olds. Finally, for the WHCT, 3- to 4-year-olds had the highest bimanual score, indicating use of the same hand to lift the cabinet door and retrieve an object. It is likely that the task was not motorically complex enough to drive preferred hand selection for older participants. The second research question sought to determine if there is difference between (TD) children and children with ASD. No differences were revealed; however, children with ASD did display variable AP performance, providing partial support for previous literature. Findings will be discussed in light of relevant literature.

Altered orbitofrontal sulcogyral patterns in adult males with high-functioning autism spectrum disorders

Functions of the orbitofrontal cortex include diverse social, cognitive and affective processes, many of which are abnormal in autism spectrum disorders (ASDs). Recently, altered orbitofrontal sulcogyral patterns have been revealed in several psychiatric conditions, such as schizophrenia, indicating a possibility that altered orbitofrontal sulcogyral morphology reflects abnormal neurodevelopment. However, the presence of sulcal alterations in ASD remains unexplored. Using structural magnetic resonance imaging, subtypes of the 'H-shaped' sulcus (Type I, II and III, in order of frequency), posterior orbital sulcus (POS) and intermediate orbital sulcus were identified in each hemisphere of adult males with ASD (n = 51) and matched normal controls (n = 55) based on the study by Chiavaras and Petrides. ASD showed a significantly altered distribution of H-shaped sulcal subtypes in both hemispheres, with a significant increase of Type III. A significant alteration in the distribution of sulcal subtypes was also identified in the right hemisphere POS of ASD. Categorical regression analysis revealed that Type I and II expressions predicted a reduced total Autism-Spectrum Quotient score. Furthermore, Type I expression was associated with a reduced 'attention to detail' subscale score. The results demonstrate that altered sulcogyral morphology can be a marker for abnormal neurodevelopment leading to the increased risk of developing autism.

Psychological correlates of handedness and corpus callosum asymmetry in autism: the left hemisphere dysfunction theory revisited

Rightward cerebral lateralization has been suggested to be involved in the neuropathology of autism spectrum conditions. We investigated functional and neuroanatomical asymmetry, in terms of handedness and corpus callosum measurements in male adolescents with autism, their unaffected siblings and controls, and their associations with executive dysfunction and symptom severity. Adolescents with autism did not differ from controls in functional asymmetry, but neuroanatomically showed the expected pattern of stronger rightward lateralization in the posterior and anterior midbody based on their hand-preference. Measures of symptom severity were related to rightward asymmetry in three subregions (splenium, posterior midbody and rostral body). We found the opposite pattern for the isthmus and rostrum with better cognitive and less severe clinical scores associated with rightward lateralization.

An examination of handedness and footedness in children with high functioning autism and Asperger syndrome

Motor control deficits have been documented in children with high functioning autism and Asperger syndrome (HFA/AS), but the extent to which these disorders affect the children's footedness must be delineated. Twelve typically developing (TD) children and 12 children with HFA/AS, ages 6-9 years, were recruited. Motor control skills were assessed through a variety of footedness tasks to determine location and nature of impairment, regarding motor dominance. Overall, greater inconsistencies in dominance arose in children with HFA/AS, through disparities in measures of preference. Results will have broader implications for understanding motor impairments in children with HFA/AS as determined by comparing performance on footedness tasks, as well as for the design of interventions to account for these deficits.

Abnormal EEG lateralization in boys with autism

OBJECTIVE

Functional brain abnormalities associated with autism in 3-8-year-old boys were studied with EEG recorded under controlled experimental condition of sustained visual attention and behavioral stillness.

METHODS

EEG was recorded in two independent samples of boys with autism (BWA) from Moscow (N=21) and Gothenburg (N=23) and a corresponding number of age-matched typically developing boys (TDB). EEG spectral power (SP) and SP interhemispheric asymmetry within delta, theta and alpha bands were analyzed.

RESULTS

BWA comprised a non-homogeneous group in relation to theta and alpha SP. When four outliers were excluded the only between-group difference in absolute SP was a higher amount of prefrontal delta in BWA. BWA of both samples demonstrated atypical leftward broadband EEG asymmetry with a maximum effect over the mid-temporal regions. Concurrently, the normal leftward asymmetry of mu rhythm was absent in BWA.

CONCLUSIONS

The abnormal broadband EEG asymmetry in autism may point to a diminished capacity of right temporal cortex to generate EEG rhythms. The concurrent lack of normal leftward asymmetry of mu rhythm suggests that abnormalities in EEG lateralization in autism may be regionally/functionally specific.

SIGNIFICANCE

The data provide evidence for abnormal functional brain lateralization in autism.

Handedness, eyedness and nasal cycle in children with autism

OBJECTIVE

Autism is referred to as cerebral lateralization abnormality. In this study, the possible relationships among handedness, eyedness and nasal cycle in autism have been investigated.

MATERIALS AND METHODS

Thirty-seven children with autism and 20 controls were included in the study. The patient group included 27 boys and 10 girls who ranged in age from 5 to 20 years. For hand preference, hand used to write and throw a ball was accepted as dominant hand. For eye preference or dominance, eye used to look through keyhole of a door was accepted as dominant eye. Nasal dominance was assessed by a method of measuring the nasal airflow.

RESULTS

The rates of left-handedness and left-eyedness were higher in children with autism compared to normal populations. A majority of children with autism had left nasal dominance.

CONCLUSION

Autism and early language impairment may be associated with left handedness, eyedness and nasal dominance.

Atypically diffuse functional connectivity between caudate nuclei and cerebral cortex in autism

Background

Autism is a neurodevelopmental disorder affecting sociocommunicative behavior, but also sensorimotor skill learning, oculomotor control, and executive functioning. Some of these impairments may be related to abnormalities of the caudate nuclei, which have been reported for autism.

Methods

Our sample was comprised of 8 high-functioning males with autism and 8 handedness, sex, and age-matched controls. Subjects underwent functional MRI scanning during performance on simple visuomotor coordination tasks. Functional connectivity MRI (fcMRI) effects were identified as interregional blood oxygenation level dependent (BOLD) signal cross-correlation, using the caudate nuclei as seed volumes.

Results

In the control group, fcMRI effects were found in circuits with known participation of the caudate nuclei (associative, orbitofrontal, oculomotor, motor circuits). Although in the autism group fcMRI effects within these circuits were less pronounced or absent, autistic subjects showed diffusely increased connectivity mostly in pericentral regions, but also in brain areas outside expected anatomical circuits (such as visual cortex).

Conclusion

These atypical connectivity patterns may be linked to developmental brain growth disturbances recently reported in autism and suggest inefficiently organized functional connectivity between caudate nuclei and cerebral cortex, potentially accounting for stereotypic behaviors and executive impairments.

Learning disability

Learning disability is common, affecting 1-2.5% of the general population in the Western world, and encompasses many different conditions. It usually leads to major functional impairment and lifelong need for support and interventions, not the least important of which are medical and health-care services. Rapid progress is being made in the understanding of the cause and pathogenesis of many learning disability syndromes, and these advances are likely to improve targeted interventions in the next decade. Many countries have abolished a learning disability specialty for medical professionals, but there is a great need to revive this niche of medical knowledge. We know little about quality of life and effects on families of people with learning disability, and research is needed to address these issues.

Asperger's disorder in the emergency psychiatric setting

Asperger's syndrome (AS) is a pervasive developmental disorder that may be unrecognized, especially if signs of other psychiatric disorders coexist. The objectives of this paper are: 1) to ascertain the prevalence of AS in the emergency psychiatric setting; and 2) to describe features of AS which may help to differentiate these patients from patients with psychotic disorders. Among 2500 patients admitted to a psychiatric intensive care unit, 5 (0.2%) received a diagnosis of AS, for the first time. Besides impairment of social interaction, common features were the following: male gender, left handedness, obsessive-compulsive symptoms, cognitive hyper-abilities, violent behavior, sense of humor, low WAIS total score, high WAIS verbal/performance score ratio, unusual, restricted interest and clumsiness. Comorbid schizophrenia is difficult to rule out in these patients. Psychotic symptoms should not be overvalued in making the diagnosis when specific features of AS are present.

Hand preferences in sign-learning students with autistic disorder

The purpose of the study was fourfold: (a) to document the hand preferences of nonspeaking individuals with autism as they produced signs and nonsign actions; (b) to find out if sign-language proficiency in such individuals is associated with directionality or consistency of signing hand preference; (c) to explore the link between hand preference for signing and standardised measures of cognitive and motor development; (d) to compare the hand preferences (sign and nonsign actions) of such individuals to sign-learning children with normal cognitive functioning. In this study, the hand preferences of 14 nonspeaking students with autistic disorder were determined from videotape records of their sign production and nonsign actions. In their sign production, four students strongly favoured their right hands, four had a distinct left-hand preference, and six did not significantly favour either hand. There was little evidence linking sign-language proficiency, cognitive maturity, or motor development to strongly lateralised signing or handedness in general in these students. Compared with the hand preferences of the children in the two comparison groups, the autistic students were markedly less lateralised with respect to signing, but not nonsign actions.

Hand preference and motor functioning in children with autism

This study examined three theories that have been proposed to explain the high rates of ambiguous hand preference in young children with autism. Twenty children with autism were matched with 20 children with developmental delays and 20 normally developing children. The groups were compared on measures of hand preference and motor skills. Results indicated that the lack of development of a hand preference in children with autism was not a direct function of their cognitive delay, as the children with developmental delays showed a dissimilar pattern of hand preference. The lack of a definite hand preference in the children with autism was also not due to a lack of motor skill development, as the children with developmental delays displayed similar levels of gross and fine motor skills without the accompanying lack of a definite hand preference. The finding that children with autism with a definite hand preference displayed better performance on motor, language, and cognitive tasks than children with autism who did not display a definite hand preference, however, provided support for the bilateral brain dysfunction hypothesis.

QEEG assisted neuropsychological evaluation of autism

The present case study utilizes neuropsychological procedures, quantitative electroencephalography (QEEG) and magnetic resonance imaging (MRI) to identify neural substrates of "autism" in a 25 year old Caucasian male. A priori hypotheses formed from a neuropsychological evaluation were supported by data from QEEG and MRI. Specifically, the neuropsychological evaluation was suggestive of left anterior deactivation and right frontal activation. Consistent with these results, QEEG data revealed relative activation of the right frontal region, while MRI results were suggestive of multiple small focal areas over the left frontal region and a teardrop shaped area of low attenuation across the right frontal region. The possible relation of right cerebral dysfunction and autism is discussed.

Hand preference and hand skill in children with autism

Hand preference and hand skill was assessed in two broad age groups of children with autism, children with learning disabilities, and control schoolchildren. The first group comprised children ages 3-5 years and the second group of children ages 11-13 years. Degree of handedness remained relatively stable across age groups, particularly within the autistic and learning-disabled populations. The main difference was between the subject groups, with the normal controls more lateralized than either the children with autism or children with learning disabilities. As with degree of handedness, consistency of handedness also differed significantly between subject groups with the normal controls more consistent in their hand preference than the other two groups. In addition, younger children were less consistent in their hand preference than older children. However, the present study found no evidence of a dissociation of hand skill and hand preference in children with autism compared to children with learning disabilities and normal developing children.

SPECT of the brain in childhood autism: evidence for a lack of normal hemispheric asymmetry

Autism is thought to be associated with abnormal hemispheric specialization and left-hemispheric dysfunction. Brain functional imaging using 133Xe-SPECT (single photon emission computed tomography) was used to measure left/right asymmetry and absolute values of regional cerebral blood flow (rCBF) in 18 children with autism aged from four to 17 years and 10 age-matched controls. All controls but only 10 children with autism were right-handed. The left-to-right indices, both hemispheric and regional, were positive in controls, indicating higher left than right rCBF values, but were negative in patients with autism. This inversion was statically significant for total hemispheres, sensorimotor and language-related cortex and was explained by a significant decrease of the left absolute rCBF values in these regions in the patients with autism. The inversion was independent of handedness, sex and age. These results confirm the existence of left-hemispheric dysfunction in childhood autism, especially in the cortical areas devoted to language and handedness, leading to anomalous hemispheric specialization.

The prevalence and origins of left hand preference in high risk infants, and its implications for intellectual, motor and behavioural performance at four and six years

This study investigates the origins of hand preference at 4 years in a cohort of 115 high risk and premature infants; the relationship between patterns of hand preference and intellectual, motor, temperament and behavioural status at 4 and 6 years; and evidence for brain injury in mediating the relationship between hand preference and development disorder. Increased left hand preference was independently associated with extreme prematurity, high neonatal risk, increased numbers of minor physical anomalies, lowered intellectual and motor abilities, and more difficult temperament. These findings supported the presence of intrauterine and neonatal pathological mechanisms leading to left hand preference in a small number of children. Neither poor function of the non dominant hand nor absence of a family history of left handedness could further define this pathological subgroup. Support for pathological mechanisms producing left handedness was found predominatly in the infants of high birth weight, whereas prevalence of left handedness was increased mainly among the extremely low birth weight infants. In this latter group the prevalence of left handedness was also increased among children of normal intelligence, suggesting that mechanisms other than brain damage lead to left hand preference in very premature infants.

Handedness in mental handicap: investigation into populations of Down's syndrome, epilepsy and autism

The handedness in three randomly sampled groups of people with learning disabilities consisting of patients with Down's syndrome, epilepsy, and autism were studied using a validated instrument. All subjects were controlled for neurological and other medical disorders. A statistically significant increase in left-handedness and ambiguous handedness compared with the general population was found in all groups. There was no significant difference in the rate of left-handedness between the three groups.

Causes and associations of severe and persistent specific speech and language disorders in children

Eighty-two school-age children with severe and persistent specific speech and language disorders were studied. 71 had specific developmental language disorders, three had structural malformations (cleft palate) and eight had disorders acquired after a period of normal language development, including five with Landau-Kleffner syndrome. The sex ratio was 3.8 boys to one girl. Nearly half had a family history of speech-language disorder, with one in 5.2 affected siblings. Aetiological factors were found in 26 per cent: 11 per cent prenatal, 3 per cent perinatal and 12 per cent postnatal. 21 per cent had had a seizure and 7 per cent had had seizures after the age of eight. 29 per cent were left-handed, 90 per cent were clumsy and 22 per cent first walked after 18 months. The complex origins of specific speech and language disorders are discussed.

Hand dominance of parents and other relatives of autistic children

Hand preferences of 219 mothers and 186 fathers of autistic children were assessed using the Annett Handedness questionnaire. Subgroups of 54 mothers and 57 fathers with a family history of language-related developmental disorders were identified. Parents also reported the handedness of other relatives. Mothers (but not fathers) in the main group were significantly more likely to be consistently right-handed than females in the general population, but this was not specifically associated with a family history of language problems. There was no evidence of an increased incidence of consistent left-handedness in either the whole group of parents or the subgroups. Reported handedness of other relatives showed no abnormal distribution in relation to a comparison group. The findings are discussed in relation to theories about genetic factors in language-related developmental disorders in general, and autism in particular.

Variables relating to the mental development of children with infantile autism

Among 54 variables studied in 194 autistic children, nine variables--meaningful words, pointing, eating without assistance, crane symptoms (maneuvers of letting a person manipulate an object by grasping his or her hand and bringing it close to the object), echolalia, changing clothes without assistance, speech loss (loss of once-emerged meaningful words before 30 months of age), establishment of toilet-training and diagnosis of MBD--were correlated significantly to the children's mental development levels with absolute values of Kendall's tau b over 0.2. A discriminant analysis showed that three positive correlates, i.e., meaningful words, pointing and echolalia, and a negative correlate, i.e., crane symptoms, were important in distinguishing between young autistics with and without unfavorable mental development and possible poor outcomes.