Neural Processing of Speech Sounds in ASD and First-Degree Relatives

Efficient neural encoding of sound plays a critical role in speech and language, and when impaired, may have reverberating effects on communication skills. This study investigated disruptions to neural processing of temporal and spectral properties of speech in individuals with ASD and their parents and found evidence of inefficient temporal encoding of speech sounds in both groups. The ASD group further demonstrated less robust neural representation of spectral properties of speech sounds. Associations between neural processing of speech sounds and language-related abilities were evident in both groups. Parent-child associations were also detected in neural pitch processing. Together, results suggest that atypical neural processing of speech sounds is a heritable ingredient contributing to the ASD language phenotype.

Autism spectrum disorder and congenital heart disease: a narrative review of the literature

Individuals born with congenital heart disease (CHD) are at an increased risk of developing neurodevelopmental disorders. Despite this, studies are limited in their investigation of autism spectrum disorder in the context of CHD. This review provides an overview of the literature examining autism spectrum disorder in CHD and discusses strengths, limitations, and future directions. Recent efforts have been made to extrapolate the association between CHD and symptoms of autism. Findings suggest that the core features of autism spectrum disorder are also implicated in children with CHD, namely social-cognitive weaknesses, pragmatic language differences, and social problems. Compared to norm-referenced samples, separate studies have identified divergent and overlapping neuropsychological profiles among both patient groups, yet there are no studies directly comparing the two groups. There is emerging evidence of prevalence rates of autism diagnosis in CHD showing an increased odds of having autism spectrum disorder among children with CHD relative to the general population or matched controls. There also appears to be genetic links to this overlap, with several genes identified as being tied to both CHD and autism. Together, research points to potentially shared underlying mechanisms contributing to the pathophysiology of neurodevelopmental, neuropsychological, and clinical traits in CHD and autism spectrum disorder. Future investigation delineating profiles across these patient populations can fill a significant gap in the literature and aid in treatment approaches to improve clinical outcomes.

Childhood Academic Performance: A Potential Marker of Genetic Liability to Autism

Autism spectrum disorder (ASD), a heritable neurodevelopmental disorder, confers genetic liability that is often expressed among relatives through subclinical, genetically-meaningful traits, or endophenotypes. For instance, relative to controls, parents of individuals with ASD differ in language-related skills, with differences emerging in childhood. To examine ASD-related endophenotypes, this study investigated developmental academic profiles among clinically unaffected siblings of individuals with ASD (n = 29). Lower performance in language-related skills among siblings mirrored previously-reported patterns among parents, which were also associated with greater subclinical ASD-related traits in themselves and their parents, and with greater symptom severity in their sibling with ASD. Findings demonstrated specific phenotypes, derived from standardized academic testing, that may represent childhood indicators of genetic liability to ASD in first-degree relatives.

[Formula: see text] A cross-cultural study of visual attention in autism spectrum disorder

Differences in visual attention have been documented in ASD, and appear linked to clinical symptoms. However, most research has been conducted in Western cultures. Because striking differences in visual attention patterns have been documented in other cultures, it is important to understand how culture may influence attentional patterns in ASD. This study compared differences in visual attention in ASD across Western and East Asian cultures, where differences in attention to contextual and global information have been repeatedly demonstrated, to investigate potential culturally-specific ASD phenotypes. One hundred thirty-two total participants included individuals with ASD (n = 24) and controls (n = 47) from Hong Kong (HK), along with a previously studied group of age- and IQ-comparable participants from the United States (n = 26 ASD; n = 35 control). Gaze was tracked while participants completed two narrative tasks that differed in social-emotional complexity. Proportions of fixations to face, bodies, and setting were examined across groups using linear mixed-effect models and a series of growth curve models. Cultural differences were found across tasks and groups. Both the ASD and control HK groups attended more to global contextual setting information, more to the body regions, and less toward faces of characters compared to US groups. Growth curve models indicated that these differences attenuated over time in certain stimuli. ASD-related effects were only observed in the more complex stimuli depicting characters with ambiguous facial expressions. Findings indicate a notable cultural influence on visual attention patterns in ASD, and underscore the importance of stimuli complexity in differentiating cultural versus diagnostic effects on attentional styles.

P-070 Comparison of Microfluidic Sperm Sorting (MFSS) versus Physiological Intracytoplasmic Sperm Injection (PICSI) versus Density Gradient versus Swim Up in high DNA fragmentation index sperm samples

Study question

To evaluate the effectiveness of using Microfluidic Sperm Sorting (MFSS) over other technique in patient with high DNA fragmentation index (DFI) sperm samples?

Summary answer

Microfluidic is not only correlated with better DNA integrity but also with the better reproductive outcome.

What is known already

DNA damage is unrecognisable in living sperm prior to insemination and an increased sperm DNA fragmentation index has been associated with lower fertilization rates, impaired embryo development and reduced pregnancy rates. Standard semen processing techniques are associated with centrifugation, which may induce reactive oxygen species and DNA damage.

In strategies to minimize sperm DNA fragmentation, Physiological ICSI can relatively reduce sperm DNA fragmentation by 67.9% (Parmegiani et al., 2010) while new technique Microfluidic sperm sorter technique also demonstrate sperm selection with significantly reduced DNA damage

Study design, size, duration

A prospective randomised study was conducted from 1st January 2019 to 1st December 2021. Four hundred patients were randomised by computer generated list and divided into 4 groups. Group A (n = 100) , in which sperm were processed by microfluidic sperm sorter (MFSS) while in group B (n = 100), sperm were selected by Physiological Intracytoplasmic Sperm Injection (PICSI), Group C (n = 100), sperm were processed by density gradient and Group D (n = 100), sperm were processed by swim-up technique.

Participants/materials, setting, methods

The study period included all normozoospermic patients with high DNA fragmentation index (>25%) while oligospermic, asthenozoospermic samples, patients with poor ovarian reserve and advanced age were excluded from the study. All A grade embryos were vitrified and transferred in frozen embryo replacement cycle. All the 3 groups were compared on the basis of fertilisation rate, day 3 grade A embryo development rate, clinical pregnancy rate and miscarriage rate.

Main results and the role of chance

Cycle characteristics (female age, length of stimulation, gonadotrophin dose, number of oocytes and number of transferred embryos) were similar among all 4 groups.

Among 4 groups, There was a statistically significant increase observed in Group A (Microfluidic Sperm Sorting), day 3 grade A embryo development rate (60% vs. 42% vs. 38% vs. 40%, p-0.016) and clinical pregnancy rate (62% vs. 46% vs. 41% vs 43%, p-0.049), while no statistical significant difference observed in fertilisation rate (82% vs. 78% vs. 76% vs. 78%, p-0.80) comparing group B, group C and group D. But significantly higher miscarriage rate (12% vs. 11% vs. 25%, 12%) observed in density gradient (Group C) technique.

Limitations, reasons for caution

Larger randomised control studies are needed to strengthen these results.

Wider implications of the findings

We have demonstrated that sperm sorted by microfluidic helps in selection of sperm with better DNA integrity over Physiological ICSI, Density Gradient and Swim-up techniues. Using it in routine practice can help in reducing the negative effect of reactive oxygen species and thus improve pregnancy rate and live birth rate.

Trial registration number

MCDH/2019/35

Cross-linguistic patterns of speech prosodic differences in autism: A machine learning study

Differences in speech prosody are a widely observed feature of Autism Spectrum Disorder (ASD). However, it is unclear how prosodic differences in ASD manifest across different languages that demonstrate cross-linguistic variability in prosody. Using a supervised machine-learning analytic approach, we examined acoustic features relevant to rhythmic and intonational aspects of prosody derived from narrative samples elicited in English and Cantonese, two typologically and prosodically distinct languages. Our models revealed successful classification of ASD diagnosis using rhythm-relative features within and across both languages. Classification with intonation-relevant features was significant for English but not Cantonese. Results highlight differences in rhythm as a key prosodic feature impacted in ASD, and also demonstrate important variability in other prosodic properties that appear to be modulated by language-specific differences, such as intonation.

A constellation of eye-tracking measures reveals social attention differences in ASD and the broad autism phenotype

Background

Social attention differences, expressed through gaze patterns, have been documented in autism spectrum disorder (ASD), with subtle differences also reported among first-degree relatives, suggesting a shared genetic link. Findings have mostly been derived from standard eye-tracking methods (total fixation count or total fixation duration). Given the dynamics of visual attention, these standard methods may obscure subtle, yet core, differences in visual attention mechanisms, particularly those presenting sub-clinically. This study applied a constellation of eye-tracking analyses to gaze data from individuals with ASD and their parents.

Methods

This study included n = 156 participants across groups, including ASD (n = 24) and control (n = 32) groups, and parents of individuals with ASD (n = 61) and control parents (n = 39). A complex scene with social/non-social elements was displayed and gaze tracked via an eye tracker. Eleven analytic methods from the following categories were analyzed: (1) standard variables, (2) temporal dynamics (e.g., gaze over time), (3) fixation patterns (e.g., perseverative or regressive fixations), (4) first fixations, and (5) distribution patterns. MANOVAs, growth curve analyses, and Chi-squared tests were applied to examine group differences. Finally, group differences were examined on component scores derived from a principal component analysis (PCA) that reduced variables to distinct dimensions.

Results

No group differences emerged among standard, first fixation, and distribution pattern variables. Both the ASD and ASD parent groups demonstrated on average reduced social attention over time and atypical perseverative fixations. Lower social attention factor scores derived from PCA strongly differentiated the ASD and ASD parent groups from controls, with parent findings driven by the subset of parents demonstrating the broad autism phenotype.

Limitations

To generalize these findings, larger sample sizes, extended viewing contexts (e.g., dynamic stimuli), and even more eye-tracking analytical methods are needed.

Conclusions

Fixations over time and perseverative fixations differentiated ASD and the ASD parent groups from controls, with the PCA most robustly capturing social attention differences. Findings highlight their methodological utility in studies of the (broad) autism spectrum to capture nuanced visual attention differences that may relate to clinical symptoms in ASD, and reflect genetic liability in clinically unaffected relatives. This proof-of-concept study may inform future studies using eye tracking across populations where social attention is impacted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-022-00490-w.

P–612 Transdermal testosterone vs. Placebo (lubricant gel) pre-treatment in improving IVF outcomes in diminished ovarian reserve patients (POSEIDON group 3 and 4): a randomised controlled trial

Study question

To compare the efficacy of transdermal testosterone with placebo (lubricant gel) in improving IVF outcomes using GnRH antagonist protocol in POSEIDON group 3 and 4 patients.

Summary answer

Patients receiving pre-treatment with testosterone gel had higher mean number of oocytes retrieved and grade A embryos as compared to the patients receiving lubricant gel.

What is known already

Diminished ovarian reserve (DOR) is associated with suboptimal ovarian response, higher cycle cancellation rate and lower clinical pregnancy rate following IVF cycles. Various treatment regimens have been devised for management of such patients and use of adjuvants in the form of oral or transdermal androgen is one of them. Androgens improves follicular response to gonadotropin stimulation as well as increase FSH receptor expression in granulosa cells, in turn leading to better oocyte yield and pregnancy rate. Aim was to compare the effect of transdermal testosterone gel with placebo gel on ART outcome in DOR patients (POSEIDON Group 3 and 4).

Study design, size, duration

A prospective, randomised controlled trial was carried out from 1st September 2019 to 31st October 2020 at a tertiary infertility centre in India. 50 patients fulfilling the criteria of Group 3 and Group 4 of POSEIDON classification were included in the study. Patients with endocrine disorders (thyroid, prolactin), endometrioma, history of surgery on the ovaries, sensitivity to testosterone gel, male factor infertility and deranged liver and renal function tests were excluded.

Participants/materials, setting, methods

Enrolled patients were randomised into two groups of 25 patients each, one group was pretreated (TTG group) with transdermal testosterone gel, 12.5 mg/day from day 6th of previous cycle to day 2nd of stimulation cycle while patients in other group took lubricant gel for the same duration before stimulation with GnRH antagonist fixed protocol followed by fresh Day 3 transfer.

Main results and the role of chance

The baseline characteristics of the two groups were comparable. The primary outcome measures were the number of oocytes retrieved and number of grade A embryos formed (according to Istanbul consensus). The secondary outcome measures were implantation rate, clinical pregnancy rate, miscarriage rate and ongoing pregnancy rate. The mean number of oocytes retrieved in TTG group was 5±1.02 which was significantly higher than placebo group–3.5±1.2, (p < 0.001). The mean number of Grade A embryos were also significantly higher (4.78±0.54 vs 3.00±0.23, p < 0.001) in TTG group. The TTG group had higher implantation rate (28% vs 20%, p = 0.49), clinical pregnancy rate (32% vs 18%, p = 0.41), ongoing pregnancy rate (32% vs 16%, p = 0.38) and lower miscarriage rate (0% vs 20%, p = 0.38), however, these differences were not statistically significant.

Limitations, reasons for caution

The study was done at a single centre with small sample size, replication with more subjects and in different centers is needed.

Wider implications of the findings: Pre-treatment with testosterone gel in DOR patients improves ovarian response to stimulation and results in higher number of oocytes retrieved and good quality embryos resulting in improved clinical pregnancy rates. Transdermal testosterone is advantageous because of better bioavailability, easy application, patient friendly and less adverse effects.

Trial registration number

MCDH/2019/54

P–084 Microfluidic Sperm Sorting (MFSS) technique versus Physiological Intracytoplasmic Sperm Injection (PICSI) technique in high DNA fragmentation index sperm samples

Study question

To evaluate the effectiveness of using Microfluidic Sperm Sorting (MFSS) technique and Physiological Intracytoplasmic Sperm Injection (PICSI) technique in patient with high DNA fragmentation index (DFI) sperm samples.

Summary answer

Sperm selected by microfluidic sorting are associated with significant increase in day 3 grade A embryo development rate, clinical pregnancy rate over PICSI.

What is known already

DNA damage is unrecognisable in living sperm prior to insemination and an increased sperm DNA fragmentation index has been associated with lower fertilization rates, impaired embryo development and reduced pregnancy rates. Standard semen processing techniques are associated with centrifugation, which may induce reactive oxygen species and DNA damage. In strategies to minimize sperm DNA fragmentation, Physiological ICSI can relatively reduce sperm DNA fragmentation by 67.9% (Parmegiani et al., 2010) while new technique Microfluidic sperm sorter technique also demonstrate sperm selection with significantly reduced DNA damage.

Study design, size, duration

A prospective randomised study was conducted from 1st August 2019 to 31st December 2020. Two hundred patients were randomised by computer generated list and divided into 2 groups. Group A (n = 100) , in which sperm were processed by microfluidic sperm sorter (MFSS) while in group B (n = 100), sperm were selected by Physiological Intracytoplasmic Sperm Injection (PICSI) technique and morphologically normal motile sperm were injected by Intracytoplasmic sperm injection (ICSI) technique in all mature oocytes.

Participants/materials, setting, methods

The study period included all normozoospermic patients with high DNA fragmentation index (>25% ) while oligospermic, asthenozoospermic samples, patients with poor ovarian reserve and advanced age were excluded from the study. All A grade embryos were vitrified and transferred in frozen embryo replacement cycle. Both groups were compared on the basis of fertilisation rate, day 3 grade A embryo development rate , clinical pregnancy rate and miscarriage rate.

Main results and the role of chance

Cycle characteristics (female age, length of stimulation, gonadotrophin dose, number of oocytes and number of transferred embryos) were similar in both groups. Between the 2 groups, There was a significant increase observed in day 3 grade A embryo development rate (60% vs. 42%, p–0.016) and clinical pregnancy rate (62% vs. 46%, p–0.049), while no statistical significant difference observed in fertilisation rate (82% vs. 78%, p–0.80) and miscarriage rate ( 12% vs. 11%, p- 1). Limitations, reasons for caution: Larger randomised control studies are needed to strengthen these results.

Wider implications of the findings: We have demonstrated that sperm sorted by microfluidic helps in selection of sperm with better DNA integrity over Physiological ICSI. Using it in routine practice can help in reducing the negative effect of reactive oxygen species and thus improve pregnancy rate and live birth rate.

Trial registration number

MCDH/2019/31

The Phenotypic Profile Associated With the FMR1 Premutation in Women: An Investigation of Clinical-Behavioral, Social-Cognitive, and Executive Abilities

The FMR1 gene in its premutation (PM) state has been linked to a range of clinical and subclinical phenotypes among FMR1 PM carriers, including some subclinical traits associated with autism spectrum disorder (ASD). This study attempted to further characterize the phenotypic profile associated with the FMR1 PM by studying a battery of assessments examining clinical-behavioral traits, social-cognitive, and executive abilities in women carrying the FMR1 PM, and associations with FMR1-related variability. Participants included 152 female FMR1 PM carriers and 75 female controls who were similar in age and IQ, and screened for neuromotor impairments or signs of fragile X-associated tremor/ataxia syndrome. The phenotypic battery included assessments of ASD-related personality and language (i.e., pragmatic) traits, symptoms of anxiety and depression, four different social-cognitive tasks that tapped the ability to read internal states and emotions based on different cues (e.g., facial expressions, biological motion, and complex social scenes), and a measure of executive function. Results revealed a complex phenotypic profile among the PM carrier group, where subtle differences were observed in pragmatic language, executive function, and social-cognitive tasks that involved evaluating basic emotions and trustworthiness. The PM carrier group also showed elevated rates of ASD-related personality traits. In contrast, PM carriers performed similarly to controls on social-cognitive tasks that involved reliance on faces and biological motion. The PM group did not differ from controls on self-reported depression or anxiety symptoms. Using latent profile analysis, we observed three distinct subgroups of PM carriers who varied considerably in their performance across tasks. Among PM carriers, CGG repeat length was a significant predictor of pragmatic language violations. Results suggest a nuanced phenotypic profile characterized by subtle differences in select clinical-behavioral, social-cognitive, and executive abilities associated with the FMR1 PM in women.

A cross-cultural study showing deficits in gaze-language coordination during rapid automatized naming among individuals with ASD

Individuals with autism spectrum disorder (ASD) and their first-degree relatives demonstrate automaticity deficits reflected in reduced eye-voice coordination during rapid automatized naming (RAN), suggesting that RAN deficits may be a genetically meaningful marker of ASD language-related impairments. This study investigated whether RAN deficits in ASD extend to a language typologically distinct from English. Participants included 23 Cantonese-speaking individuals with ASD and 39 controls from Hong Kong (HK), and age- and IQ-comparable groups of previously-studied English-speaking individuals with ASD (n = 45) and controls (n = 44) from the US. Participants completed RAN on an eye tracker. Analyses examined naming time, error rate, measures of eye movement reflecting language automaticity, including eye-voice span (EVS; location of eyes versus the named item) and refixations. The HK-ASD group exhibited longer naming times and more refixations than HK-Controls, in a pattern similar to that observed in the US-ASD group. Cultural effects revealed that both HK groups showed longer EVS and more fixations than US groups. Naming time and refixation differences may be ASD-specific impairments spanning cultures/languages, whereas EVS and fixation frequency may be more variably impacted. A potential underlying mechanism of visual "stickiness" may be contributing to this breakdown in language automaticity in ASD.

The Impact of Learning and Memory on Performance Validity Tests in a Mixed Clinical Pediatric Population

OBJECTIVE

This study examined the degree to which verbal and visuospatial memory abilities influence performance validity test (PVT) performance in a mixed clinical pediatric sample.

METHOD

Data from 252 consecutive clinical pediatric cases (Mage=11.23 years, SD=4.02; 61.9% male) seen for outpatient neuropsychological assessment were collected. Measures of learning and memory (e.g., The California Verbal Learning Test-Children's Version; Child and Adolescent Memory Profile [ChAMP]), performance validity (Test of Memory Malingering Trial 1 [TOMM T1]; Wechsler Intelligence Scale for Children-Fifth Edition [WISC-V] or Wechsler Adult Intelligence Scale-Fourth Edition Digit Span indices; ChAMP Overall Validity Index), and intellectual abilities (e.g., WISC-V) were included.

RESULTS

Learning/memory abilities were not significantly correlated with TOMM T1 and accounted for relatively little variance in overall TOMM T1 performance (i.e., ≤6%). Conversely, ChAMP Validity Index scores were significantly correlated with verbal and visual learning/memory abilities, and learning/memory accounted for significant variance in PVT performance (12%-26%). Verbal learning/memory performance accounted for 5%-16% of the variance across the Digit Span PVTs. No significant differences in TOMM T1 and Digit Span PVT scores emerged between verbal/visual learning/memory impairment groups. ChAMP validity scores were lower for the visual learning/memory impairment group relative to the nonimpaired group.

CONCLUSIONS

Findings highlight the utility of including PVTs as standard practice for pediatric populations, particularly when memory is a concern. Consistent with the adult literature, TOMM T1 outperformed other PVTs in its utility even among the diverse clinical sample with/without learning/memory impairment. In contrast, use of Digit Span indices appear to be best suited in the presence of visuospatial (but not verbal) learning/memory concerns. Finally, the ChAMP's embedded validity measure was most strongly impacted by learning/memory performance.

Elevated Polygenic Burden for Autism Spectrum Disorder Is Associated With the Broad Autism Phenotype in Mothers of Individuals With Autism Spectrum Disorder

BACKGROUND

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental disorder that encompasses a complex and heterogeneous set of traits. Subclinical traits that mirror the core features of ASD, referred to as the broad autism phenotype (BAP), have been documented repeatedly in unaffected relatives and are believed to reflect underlying genetic liability to ASD. The BAP may help inform the etiology of ASD by allowing the stratification of families into more phenotypically and etiologically homogeneous subgroups. This study explores polygenic scores related to the BAP.

METHODS

Phenotypic and genotypic information were obtained from 2614 trios from the Simons Simplex Collection. Polygenic scores of ASD (ASD-PGSs) were generated across the sample to determine the shared genetic overlap between the BAP and ASD. Maternal and paternal ASD-PGSs were explored in relation to BAP traits and their child's ASD symptomatology.

RESULTS

Maternal pragmatic language was related to child's social communicative atypicalities. In fathers, rigid personality was related to increased repetitive behaviors in children. Maternal (but not paternal) ASD-PGSs were related to the pragmatic language and rigid BAP domains.

CONCLUSIONS

Associations emerged between parent and child phenotypes, with more associations emerging in mothers than in fathers. ASD-PGS associations emerged with BAP in mothers only, highlighting the potential for a female protective factor, and implicating the polygenic etiology of ASD-related phenotypes in the BAP.

A Unique Visual Attention Profile Associated With the FMR1 Premutation

Atypical visual attention patterns have been observed among carriers of the fragile X mental retardation gene (FMR1) premutation (PM), with some similarities to visual attention patterns observed in autism spectrum disorder (ASD) and among clinically unaffected relatives of individuals with ASD. Patterns of visual attention could constitute biomarkers that can help to inform the neurocognitive profile of the PM, and that potentially span diagnostic boundaries. This study examined patterns of eye movement across an array of fixation measurements from three distinct eye-tracking tasks in order to investigate potentially overlapping profiles of visual attention among PM carriers, ASD parents, and parent controls. Logistic regression analyses were conducted to examine whether variables constituting a PM-specific looking profile were able to effectively predict group membership. Participants included 65PM female carriers, 188 ASD parents, and 84 parent controls. Analyses of fixations across the eye-tracking tasks, and their corresponding areas of interest, revealed a distinct visual attention pattern in carriers of the FMR1 PM, characterized by increased fixations on the mouth when viewing faces, more intense focus on bodies in socially complex scenes, and decreased fixations on salient characters and faces while narrating a wordless picture book. This set of variables was able to successfully differentiate individuals with the PM from controls (Sensitivity = 0.76, Specificity = 0.85, Accuracy = 0.77) as well as from ASD parents (Sensitivity = 0.70, Specificity = 0.80, Accuracy = 0.72), but did not show a strong distinction between ASD parents and controls (Accuracy = 0.62), indicating that this set of variables comprises a profile that is unique to PM carriers. Regarding predictive power, fixations toward the mouth when viewing faces was able to differentiate PM carriers from both ASD parents and controls, whereas fixations toward other social stimuli did not differentiate PM carriers from ASD parents, highlighting some overlap in visual attention patterns that could point toward shared neurobiological mechanisms. Results demonstrate a profile of visual attention that appears strongly associated with the FMR1 PM in women, and may constitute a meaningful biomarker.

An Acoustic Characterization of Prosodic Differences in Autism Spectrum Disorder and First-Degree Relatives

This study examined prosody through characterization of acoustic properties of the speech of individuals with ASD and their parents, during narration. A subset of utterances were low-pass filtered and rated for differences in intonation, speech rate, and rhythm. Listener ratings were minimally related to acoustic measures, underscoring the complexity of atypical prosody in ASD. Acoustic analyses revealed greater utterance-final fundamental frequency excursion size and slower speech rate in the ASD group. Slower speech rate was also evident in the ASD parent group, particularly parents with the broad autism phenotype. Overlapping prosodic differences in ASD and ASD Parent groups suggest that prosodic differences may constitute an important phenotype contributing to ASD features and index genetic liability to ASD among first-degree relatives.

Physiological regulation and social-emotional processing in female carriers of the FMR1 premutation

The FMR1 gene is associated with a wide range of clinical and cognitive phenotypes, ranging from intellectual disability and autism symptoms in fragile X syndrome (caused by the FMR1 full mutation), to a more varied, and still poorly understood range of clinical and cognitive phenotypes among carriers of the gene in its premutation state. Because the FMR1 premutation is relatively common among women (as high as 1 in 150), investigations of its phenotypic impact could have broad implications for understanding gene-behavior relationships underlying complex human traits, with potential clinical implications. This study investigated physiological regulation measured by pupillary responses, along with fixation patterns while viewing facial expressions among women who carry the FMR1 premutation (PM group; n = 47), to examine whether the FMR1 gene may relate to physiological regulation, social-emotional functioning, and social language skills (where subclinical differences have been previously reported among PM carriers that resemble those documented in autism-related conditions). Relative to controls (n = 25), the PM group demonstrated atypical pupillary responses and fixation patterns, controlling for IQ. In the PM group, pupillary response and fixation patterns were related to social cognition, social language abilities, and FMR1-related variation. Results indicate a pattern of atypical attention allocation among women who carry the FMR1 PM that could reflect different emotion-processing strategies mediated by autonomic dysregulation and the FMR1 gene. These findings lend insight into the FMR1 gene's potential contributions to complex human traits such as social emotional processing and social language.

Language processing skills linked to FMR1 variation: A study of gaze-language coordination during rapid automatized naming among women with the FMR1 premutation

The FMR1 premutation (PM) is relatively common in the general population. Evidence suggests that PM carriers may exhibit subtle differences in specific cognitive and language abilities. This study examined potential mechanisms underlying such differences through the study of gaze and language coordination during a language processing task (rapid automatized naming; RAN) among female carriers of the FMR1 PM. RAN taps a complex set of underlying neuropsychological mechanisms, with breakdowns implicating processing disruptions in fundamental skills that support higher order language and executive functions, making RAN (and analysis of gaze/language coordination during RAN) a potentially powerful paradigm for revealing the phenotypic expression of the FMR1 PM. Forty-eight PM carriers and 56 controls completed RAN on an eye tracker, where they serially named arrays of numbers, letters, colors, and objects. Findings revealed a pattern of inefficient language processing in the PM group, including a greater number of eye fixations (namely, visual regressions) and reduced eye-voice span (i.e., the eyes' lead over the voice) relative to controls. Differences were driven by performance in the latter half of the RAN arrays, when working memory and processing load are the greatest, implicating executive skills. RAN deficits were associated with broader social-communicative difficulties among PM carriers, and with FMR1-related molecular genetic variation (higher CGG repeat length, lower activation ratio, and increased levels of the fragile X mental retardation protein; FMRP). Findings contribute to an understanding of the neurocognitive profile of PM carriers and indicate specific gene-behavior associations that implicate the role of the FMR1 gene in language-related processes.

Links between looking and speaking in autism and first-degree relatives: insights into the expression of genetic liability to autism

Background

Rapid automatized naming (RAN; naming of familiar items presented in an array) is a task that taps fundamental neurocognitive processes that are affected in a number of complex psychiatric conditions. Deficits in RAN have been repeatedly observed in autism spectrum disorder (ASD), and also among first-degree relatives, suggesting that RAN may tap features that index genetic liability to ASD. This study used eye tracking to examine neurocognitive mechanisms related to RAN performance in ASD and first-degree relatives, and investigated links to broader language and clinical-behavioral features.

Methods

Fifty-one individuals with ASD, biological parents of individuals with ASD (n = 133), and respective control groups (n = 45 ASD controls; 58 parent controls) completed RAN on an eye tracker. Variables included naming time, frequency of errors, and measures of eye movement during RAN (eye-voice span, number of fixations and refixations).

Results

Both the ASD and parent-ASD groups showed slower naming times, more errors, and atypical eye-movement patterns (e.g., increased fixations and refixations), relative to controls, with differences persisting after accounting for spousal resemblance. RAN ability and associated eye movement patterns were correlated with increased social-communicative impairment and increased repetitive behaviors in ASD. Longer RAN times and greater refixations in the parent-ASD group were driven by the subgroup who showed clinical-behavioral features of the broad autism phenotype (BAP). Finally, parent-child dyad correlations revealed associations between naming time and refixations in parents with the BAP and increased repetitive behaviors in their child with ASD.

Conclusions

Differences in RAN performance and associated eye movement patterns detected in ASD and in parents, and links to broader social-communicative abilities, clinical features, and parent-child associations, suggest that RAN-related abilities might constitute genetically meaningful neurocognitive markers that can help bridge connections between underlying biology and ASD symptomatology.

Age-related changes in intrinsic function of the superior temporal sulcus in autism spectrum disorders

Currently, the developmental trajectories of neural circuits implicated in autism spectrum disorders (ASD) are largely unknown. Here, we specifically focused on age-related changes in the functional circuitry of the posterior superior temporal sulcus (pSTS), a key hub underlying social-cognitive processes known to be impaired in ASD. Using a cross-sectional approach, we analysed resting-state functional magnetic resonance imaging (fMRI) data collected from children, adolescents and adults available through the autism brain imaging data exchange repository [n = 106 with ASD and n = 109 typical controls (TC), ages 7-30 years]. The observed age-related changes of pSTS intrinsic functional connectivity (iFC) suggest that no single developmental pattern characterizes ASD. Instead, pSTS circuitry displayed a complex developmental picture, with some functional circuits showing patterns consistent with atypical development in ASD relative to TC (pSTS-iFC with fusiform gyrus and angular gyrus) and others showing delayed maturation (pSTS-iFC with regions of the action perception network). Distinct developmental trajectories in different functional circuits in ASD likely reflect differential age-related changes in the socio-cognitive processes they underlie. Increasing insight on these mechanisms is a critical step in the development of age-specific interventions in ASD.

From local to global processing: the development of illusory contour perception

Global visual processing is important for segmenting scenes, extracting form from background, and recognizing objects. Local processing involves attention to the local elements, contrast, and boundaries of an image at the expense of extracting a global percept. Previous work is inconclusive regarding the relative development of local and global processing. Some studies suggest that global perception is already present by 8 months of age, whereas others suggest that the ability arises during childhood and continues to develop during adolescence. We used a novel method to assess the development of global processing in 3- to 10-year-old children and an adult comparison group. We used Kanizsa illusory contours as an assay of global perception and measured responses on a touch-sensitive screen while monitoring eye position with a head-mounted eye tracker. Participants were tested using a similarity match-to-sample paradigm. Using converging measures, we found a clear developmental progression with age such that the youngest children performed near chance on the illusory contour discrimination, whereas 7- and 8-year-olds performed nearly perfectly, as did adults. There was clear evidence of a gradual shift from a local processing strategy to a global one; young children looked predominantly at and touched the "pacman" inducers of the illusory form, whereas older children and adults looked predominantly at and touched the middle of the form. These data show a prolonged developmental trajectory in appreciation of global form, with a transition from local to global visual processing between 4 and 7 years of age.

Prevalence of taurodontism in premolars among patients at a tertiary care institution in Trinidad

OBJECTIVES

A study was undertaken to assess the prevalence of taurodontism in premolars in a group of adult dental patients in Trinidad and Tobago since there is no such data available for the region.

METHODS

Periapical and orthopantomograms of 1090 randomly selected patients were examined for the presence of an apically displaced pulp chamber without the usual constriction at the cementoenamel junction.

RESULTS

Prevalence of taurodontism in a sample of 1090 patients was 11.28%. Of the 5324 premolars examined, 4.79% were taurodonts. Prevalence of taurodontism was higher in males (6.46%) compared to females (3.66%). A Statistically significant difference (p < 0.0001) was observed in the prevalence of taurodontism in mandibular premolars compared to maxillary premolars (9.07% vs 0.56%).

CONCLUSION

Prevalence of taurodontism in premolars among Trinidadian patients, as assessed by radiographic study, was 4.79% and it was higher in the males compared to females. Significant differences were also observed between mandibular and maxillary premolars.

Statistical properties of the variation at linked microsatellite loci: implications for the history of human Y chromosomes

It has recently been suggested that observed levels of variation at microsatellite loci can be used to infer patterns of selection in genomes and to assess demographic history. In order to evaluate the feasibility of these suggestions it is necessary to know something about how levels of variation at microsatellite loci are expected to fluctuate due simply to stochasticity in the processes of mutation and inheritance (genetic sampling). Here we use recently derived properties of the stepwise mutation model to place confidence intervals around the variance in repeat score that is expected at mutation-drift equilibrium and outline a statistical test for whether an observed value differs significantly from expectation. We also develop confidence intervals for the time course of the buildup of variation following a complete elimination of variation, such as might be caused by a selective sweep or an extreme population bottleneck. We apply these methods to the variation observed at human Y-specific microsatellites. Although a number of authors have suggested the possibility of a very recent sweep, our analyses suggest that a sweep or extreme bottleneck is unlikely to have occurred anytime during the last approximately 74,000 years. To generate this result we use a recently estimated mutation rate for microsatellite loci of 5.6 x 10(-4) along with the variation observed at autosomal microsatellite loci to estimate the human effective population size. This estimate is 18,000, implying an effective number of 4,500 Y chromosomes. One important general conclusion to emerge from this study is that in order to reject mutation-drift equilibrium at a set of linked microsatellite loci it is necessary to have an unreasonably large number of loci unless the observed variance is far below that expected at mutation-drift equilibrium.

Geographic clustering of human Y-chromosome haplotypes

Five polymorphic markers on the Y-chromosome (mostly microsatellites) were typed in 121 individuals from 13 populations around the world. With these markers 78 different haplotypes were detected. Haplotypes present more than once tend to be shared by individuals from the same population or continent. A reconstruction of haplotype phylogeny also indicates significant geographic structure in the data. Based on the similarity of the haplotypes, population relationships were examined and found to be largely concordant with those obtained with other markers. Even though the sample size and the number of markers are small, there is very signficant clustering of the haplotypes by continent of origin.

Nucleoside phosphorylase 2 (Np-2) of mice

Isozyme patterns of nucleoside phosphorylase (NP) in 16 inbred strains, two recombinant inbred, one congenic, and three species of wild mice were studied. Evidence is provided for a genetic locus, Np-2, encoding an electrophoretic variant which is expressed exclusively in erythrocytes of certain inbred strains. This finding establishes the occurrence of genetic polymorphism of NP among inbred strains of mice. In addition, the Npla allele previously reported only in inbred strains has been observed in one of the species of wild mice (Mus musculus castaneus) studied.