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Fulltext Reference-Free Assessment of Speech Intelligibility Using Bispectrum of an Auditory Neurogram

Hossain ME, Jassim WA, Zilany MS

PLoS One, 2016;11(3):e0150415.
PMID: 26967160 DOI: 10.1371/journal.pone.0150415

Sensorineural hearing loss occurs due to damage to the inner and outer hair cells of the peripheral auditory system. Hearing loss can cause decreases in audibility, dynamic range, frequency and temporal resolution of the auditory system, and all of these effects are known to affect speech intelligibility. In this study, a new reference-free speech intelligibility metric is proposed using 2-D neurograms constructed from the output of a computational model of the auditory periphery. The responses of the auditory-nerve fibers with a wide range of characteristic frequencies were simulated to construct neurograms. The features of the neurograms were extracted using third-order statistics referred to as bispectrum. The phase coupling of neurogram bispectrum provides a unique insight for the presence (or deficit) of supra-threshold nonlinearities beyond audibility for listeners with normal hearing (or hearing loss). The speech intelligibility scores predicted by the proposed method were compared to the behavioral scores for listeners with normal hearing and hearing loss both in quiet and under noisy background conditions. The results were also compared to the performance of some existing methods. The predicted results showed a good fit with a small error suggesting that the subjective scores can be estimated reliably using the proposed neural-response-based metric. The proposed metric also had a wide dynamic range, and the predicted scores were well-separated as a function of hearing loss. The proposed metric successfully captures the effects of hearing loss and supra-threshold nonlinearities on speech intelligibility. This metric could be applied to evaluate the performance of various speech-processing algorithms designed for hearing aids and cochlear implants.
Fulltext Genetic diversity of Nipah virus in Bangladesh

Rahman MZ, Islam MM, Hossain ME, Rahman MM, Islam A, Siddika A, et al.

Int J Infect Dis, 2021 Jan;102:144-151.
PMID: 33129964 DOI: 10.1016/j.ijid.2020.10.041

BACKGROUND: Nipah virus (NiV) infection, often fatal in humans, is primarily transmitted in Bangladesh through the consumption of date palm sap contaminated by Pteropus bats. Person-to-person transmission is also common and increases the concern of large outbreaks. This study aimed to characterize the molecular epidemiology, phylogenetic relationship, and the evolution of the nucleocapsid gene (N gene) of NiV.
METHODS: We conducted molecular detection, genetic characterization, and Bayesian time-scale evolution analyses of NiV using pooled Pteropid bat roost urine samples from an outbreak area in 2012 and archived RNA samples from NiV case patients identified during 2012-2018 in Bangladesh.
RESULTS: NiV-RNA was detected in 19% (38/456) of bat roost urine samples and among them; nine N gene sequences were recovered. We also retrieved sequences from 53% (21 out of 39) of archived RNA samples from patients. Phylogenetic analysis revealed that all Bangladeshi strains belonged to NiV-BD genotype and had an evolutionary rate of 4.64 × 10-4 substitutions/site/year. The analyses suggested that the strains of NiV-BD genotype diverged during 1995 and formed two sublineages.
CONCLUSION: This analysis provides further evidence that the NiV strains of the Malaysian and Bangladesh genotypes diverged recently and continue to evolve. More extensive surveillance of NiV in bats and human will be helpful to explore strain diversity and virulence potential to infect humans through direct or person-to-person virus transmission.
Fulltext In silico prediction of interaction between Nipah virus attachment glycoprotein and host cell receptors Ephrin-B2 and Ephrin-B3 in domestic and peridomestic mammals

Hoque AF, Rahman MM, Lamia AS, Islam A, Klena JD, Satter SM, et al.

Infect Genet Evol, 2023 Dec;116:105516.
PMID: 37924857 DOI: 10.1016/j.meegid.2023.105516

Nipah virus (NiV) is a lethal bat-borne zoonotic virus that causes mild to acute respiratory distress and neurological manifestations in humans with a high mortality rate. NiV transmission to humans occurs via consumption of bat-contaminated fruit and date palm sap (DPS), or through direct contact with infected individuals and livestock. Since NiV outbreaks were first reported in pigs from Malaysia and Singapore, non-neutralizing antibodies against NiV attachment Glycoprotein (G) have also been detected in a few domestic mammals. NiV infection is initiated after NiV G binds to the host cell receptors Ephrin-B2 and Ephrin-B3. In this study, we assessed the degree of NiV host tropism in domestic and peridomestic mammals commonly found in Bangladesh that may be crucial in the transmission of NiV by serving as intermediate hosts. We carried out a protein-protein docking analysis of NiV G complexes (n = 52) with Ephrin-B2 and B3 of 13 domestic and peridomestic species using bioinformatics tools. Protein models were generated by homology modelling and the structures were validated for model quality. The different protein-protein complexes in this study were stable, and their binding affinity (ΔG) scores ranged between -8.0 to -19.1 kcal/mol. NiV Bangladesh (NiV-B) strain displayed stronger binding to Ephrin receptors, especially with Ephrin-B3 than the NiV Malaysia (NiV-M) strain, correlating with the observed higher pathogenicity of NiV-B strains. From the docking result, we found that Ephrin receptors of domestic rat (R. norvegicus) had a higher binding affinity for NiV G, suggesting greater susceptibility to NiV infections compared to other study species. Investigations for NiV exposure to domestic/peridomestic animals will help us knowing more the possible role of rats and other animals as intermediate hosts of NiV and would improve future NiV outbreak control and prevention in humans and domestic animals.

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