Acoustic regularities in infant-directed speech and song across cultures.

When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people from 187 countries, recruited via an English-language website, who guessed whether each vocalization was infant-directed. Their intuitions were more accurate than chance, predictable in part by common sets of acoustic features and robust to the effects of linguistic relatedness between vocalizer and listener. These findings inform hypotheses of the psychological functions and evolution of human communication.

Knowledge, gender, and guidance: Factors influencing Indian mothers responses to Attention Deficit Hyperactivity Disorder (ADHD).

In the current study, we examined the socio-demographic characteristics and attitudes of Indian mothers, their knowledge about behaviors related to Attention Deficit Hyperactivity Disorder (ADHD) and the relationship with ADHD diagnosis among their children. Previous research showed 11.3% of primary school children in India have been diagnosed with ADHD, yet little research has been conducted on how mothers perceive these behaviors. A survey was completed by 100 mothers with children aged between 4-12 years. The Centers for Disease Control (CDC) ADHD Checklist for Children was used to assess the presence of ADHD symptoms in Indian children. The surveys were analyzed to identify maternal ADHD knowledge, socio-demographic characteristics and attitudes associated with ADHD within the context of Indian culture using SPSS. It was determined that the gender of the child, the geographical location the mother was raised, willingness of mother to seek professional help, mother's knowledge on handling child's behavior and mother's knowledge on ADHD were significantly associated with ADHD. Further analyses revealed that a lack of knowledge of ADHD and handling child's behavior were most associated with anADHD diagnosis based on the CDCADHD checklist.

Development of Rapid Automatized Naming (RAN) in Simultaneous Kannada-English Biliterate Children.

RAN tests were administered to 600 typically developing children, 60 each from grade level one through grade ten (30 boys and 30 girls), who learn two distinct languages, English and Kannada simultaneously from the very first grade. The overall results were in accordance with similar previous studies in English and other European languages. The developmental trajectories were similar across the languages to a large extent; but the results also showed some differences across languages with respect to synchrony between the measures and the overall naming speed. Though some of the differences could be ascribed to the bilingual/biliterate culture and language use, there are enough scopes for future researches to examine these issues.

Association of SNPs of DYX1C1 with developmental dyslexia in an Indian population.

OBJECTIVE: DYX1C1 has been identified as a susceptible candidate gene for developmental dyslexia (DD); studies in various populations have yielded inconclusive results and the causal allele is unknown in the Indian population. On the basis of the initial association studies and the role of DYX1C1 in neuronal migration, we investigated the role of DYX1C1 in causing DD in an Indian population. MATERIALS AND METHODS: Ten single-nucleotide polymorphisms (SNPs) of DYX1C1 were genotyped in 210 cases with DD and 256 age-matched nondyslexic controls. Genotyping of these SNPs was carried with the MassARRAY technique using SpectroCHIP and analysed with MALDI-TOF MS. Single-marker and two-marker haplotype analyses were carried out and the χ-test, odds ratios, 95% confidence intervals and Yates correction were applied to identify the significance of the genotyped SNPs. RESULTS: A significant association was observed for the homozygous genotype (GG) of the SNP rs12899331 (3.12%) and individual allele frequency (P=0.039). Psycholinguistic tests showed an association between rs12899331 with dyslexic phenotypes such as word and nonword reading, syllable reversal task, spoonerism task and spelling. Two-marker haplotype analysis also showed a significant association for the markers G/C at rs12899331/rs1075938 (P=0.039) with the phenotypes rapid naming ability and phonological awareness, as well as with word reading, spelling and sentence repetition. CONCLUSION: The promoter SNP rs12899331 of DYX1C1 may contribute towards the manifestation of DD. This study supports the association of DYX1C1 with DD in an Indian population.

Lack of association between genetic polymorphisms in ROBO1, MRPL19/C2ORF3 and THEM2 with developmental dyslexia.

Developmental Dyslexia (DD) is a heritable, complex genetic disorder characterized by specific impairment in reading and writing ability that is substantially below the expected reading ability given the person's chronological age, measured intelligence and age-appropriate education. More than ten susceptible genes have been identified for DD. A Single Nucleotide Polymorphism (SNP) of these genes was found to be associated with various phenotypes of DD. To identify the role of SNPs of four candidate genes namely, MRPL19/C2ORF3, ROBO1 and THEM2 in an Indian population, we genotyped eight SNPs of these genes in 157 children with DD and 212 normal readers using a MassARRAY technique with a MALDI-TOF MS analyzer. Power analysis of some of these SNPs showed >80% of power. Chi-square test, Odds Ratios (ORs), 95% Confidence Intervals (CIs) and Bonferroni's correction were applied to identify the significance of the genotyped SNPs and haplotypes. Our study failed to show any association of SNPs and haplotypes of these genes with DD in an Indian population.

Analysis of genetic variants of dyslexia candidate genes KIAA0319 and DCDC2 in Indian population.

Developmental dyslexia (DD) is a heritable, complex genetic disorder associated with impairment in reading and writing skills despite having normal intellectual ability and appropriate educational opportunities. Chromosome 6p23-21.3 at DYX2 locus has showed the most consistent evidence of linkage for DD and two susceptible genes KIAA0319 and DCDC2 for DD at DYX2 locus showed significant association. Specific candidate gene-association studies have identified variants, risk haplotypes and microsatellites of KIAA0319 and DCDC2 correlated with wide range of reading-related traits. In this study, we used a case-control approach for analyzing single-nucleotide polymorphisms (SNPs) in KIAA0319 and DCDC2. Our study demonstrated the association of DD with SNP rs4504469 of KIAA0319 and not with any SNPs of DCDC2.

An examination of candidate gene SNPs for dyslexia in an Indian sample.

Developmental dyslexia (DD) is a complex neuro-genetic disorder associated with difficulty in learning to read despite adequate intelligence and educational opportunities. Studies in different populations have established associations between DD and single nucleotide polymorphisms (SNPs) in a number of candidate genes, including DYX1C1, KIAA0319 and DCDC2. In an ongoing DD study in India, we screened twenty SNPs located within the coding region of these three candidate genes by mass-ARRAY technique. At this point, there is no statistical evidence of association between the allelic variation in the three candidate genes and DD in our sample, although there might be some promising leads for future research that should involve a large and a better characterized sample.