Universal and language-specific connected speech characteristics of bilingual speakers with Alzheimer’s Disease: insights from case studies of structurally distinct languages

Purpose: Connected speech analysis has been effectively utilized for the diagnosis and disease monitoring of individuals with Alzheimer’s Disease (AD). Existing research has been conducted mostly in monolingual English speakers with a noticeable lack of evidence from bilinguals and non-English speakers, particularly in non-European languages. Using a case study approach, we characterized connected speech profiles of two Bengali-English bilingual speakers with AD to: determine the universal features of language impairments in both languages, identify language-specific differences between the languages, and explore language impairment characteristics of the participants with AD in relation to their bilingual language experience. Method: Participants included two Bengali-English bilingual speakers with AD and a group of age-, gender-, education- and language-matched neurologically healthy controls. Connected speech samples were collected in L1 (Bengali) and L2 (English) using a novel storytelling task (i.e., “Frog, where are you?”). These samples were analyzed using an augmented Quantitative Production Analysis and Correct Information Unit analyses for productivity, fluency, syntactic and morpho-syntactic features, lexical and semantic characteristics. Results: Irrespective of the language, AD impacted speech productivity (speech rate and fluency) and semantic characteristics in both languages. Unique language-specific differences were noted on syntactic measures (reduced sentence length in Bengali), lexical distribution (fewer pronouns and absence of reduplication in Bengali) and inflectional properties (no difficulties with noun or verb inflections in Bengali). Among the two participants with AD, the individual who showed lower proficiency and usage in L2 (English) demonstrated reduced syntactic complexity and morpho-syntactic richness in English. Conclusion: Evidence from these case studies suggest that language impairment features in AD are not universal across languages, particularly in comparison to impairments typically associated with language breakdowns in English. This study underscores the importance of establishing connected speech profiles in AD for non-English speaking populations, especially for structurally different languages. This would in turn lead to the development of language-specific markers that can facilitate early detection of language deterioration and aid in improving diagnosis of AD in individuals belonging to underserved linguistically diverse populations

Connected speech characteristics of Bengali speakers with Alzheimer’s Disease: evidence for language-specific diagnostic markers

Background & Aim: Speech and language characteristics of connected speech provide a valuable tool for identifying, diagnosing and monitoring progression in Alzheimer’s Disease (AD). Our knowledge of linguistic features of connected speech in AD is primarily derived from English speakers; very little is known regarding patterns of linguistic deficits in speakers of other languages, such as Bengali. Bengali is a highly inflected pro-drop language from the Indo-Aryan language family. It is the seventh most spoken language in the world, yet to date, no studies have investigated the profile of linguistic impairments in Bengali speakers with AD. The aim of this study was to characterize connected speech production and identify the linguistic features affected in Bengali speakers with AD. Methods: Participants were six Bengali speaking AD patients and eight matched controls from the urban metropolis, Kolkata, India. Narrative samples were elicited in Bengali using the Frog Story. Samples were analyzed using the Quantitative Production Analysis and the Correct Information Unit analyses to quantify six different aspects of speech production: speech rate, structural and syntactic measures, lexical measures, morphological and inflectional measures, semantic measures and measure of spontaneity and fluency disruptions. Results & Conclusions: In line with the extant literature from English speakers, the Bengali AD participants demonstrated decreased speech rate, simplicity of sentence forms and structures, and reduced semantic content. Critically, differences with English speakers’ literature emerged in the domains of Bengali specific linguistic features, such as the pro-drop nature of Bengali and its inflectional properties of nominal and verbal systems. Bengali AD participants produced fewer pronouns, which is in direct contrast with the overuse of pronouns by English AD participants. No obvious difficulty in producing nominal and verbal inflections was evident. However, differences in the type of noun inflections were evident; these were characterized by simpler inflectional features used by AD speakers. This study represents the first of its kind to characterize connected speech production in Bengali AD participants and is a significant step forward towards the development of language-specific clinical markers in AD. It also provides a framework for cross-linguistic comparisons across structurally distinct and under-explored languages

Dune formation in dilute phase pneumatic transport system: PIV & PTV based analysis

Flow of gas-solid mixture through horizontal conveying section show a large variety of phenomena and is broadly classified into dilute and dense unstable regimes. Different types of instabilities are observed in the dense phase flow and are widely studied in literature; however, clustering instabilities are observed in the very dilute regime of flow with volume fraction ~0.001. A recent study has shown that regular, stable dune shaped clusters are formed in a small regime of the dilute phase of conveying. The dunes become unstable as the superficial gas velocity is decreased before it finally leads to the dense mode of conveying. The motivation of the current work is to investigate the velocity distribution on the surface of the stable and unstable dunes and thereby understand the cause behind the formation of the dunes in the conveying section. To that end, particle image and tracking velocimetry techniques are employed with the specific objective to determine the volume fraction and the velocity profile of the solid phase on the stable dune surface. A drastic change in the solid fraction within a few particle diameters from the dune surface suggests that PTV is more appropriate in the bulk whereas PIV is suitable for near surface investigation

Dune formation in dilute phase pneumatic transport system: PIV & PTV based analysis

Flow of gas-solid mixture through horizontal conveying section show a large variety of phenomena and is broadly classified into dilute and dense unstable regimes. Different types of instabilities are observed in the dense phase flow and are widely studied in literature; however, clustering instabilities are observed in the very dilute regime of flow with volume fraction ~0.001. A recent study has shown that regular, stable dune shaped clusters are formed in a small regime of the dilute phase of conveying. The dunes become unstable as the superficial gas velocity is decreased before it finally leads to the dense mode of conveying. The motivation of the current work is to investigate the velocity distribution on the surface of the stable and unstable dunes and thereby understand the cause behind the formation of the dunes in the conveying section. To that end, particle image and tracking velocimetry techniques are employed with the specific objective to determine the volume fraction and the velocity profile of the solid phase on the stable dune surface. A drastic change in the solid fraction within a few particle diameters from the dune surface suggests that PTV is more appropriate in the bulk whereas PIV is suitable for near surface investigation

SOFC Power Generation System by Bio-gasification

AbstractPower generation using SOFCs, is one of the technologies that can reduce emissions, allow fuel flexibility and achieve high efficiencies. Combining gasifiers with SOFCs would make it possible to extract energy from biomass with lower environmental impact compared to conventional fuel based systems. The hybrid SOFC-gasifier system is best suited for application in standalone systems. The present study shows the performance of a hybrid SOFC for different types of biomass feed. The gasifier reactions are simulated using AspenPlus and a 1D mathematical fuel cell model is used for calculating the SOFC performance. Amongst different biomass fuels chosen in our study, sugarcane bagasse shows best performance in hybrid SOFC. The electrochemical performance of the biomass fed hybrid SOFC is found to be less compared to a hydrogen fuelled system. The advantage of the hybrid system is that since energy generation is dependent on biomass feed, energy sustainability can be attained with proper policy and management

Study of contact resistance at the electrode-interconnect interfaces in planar type solid oxide fuel cells

Ohmic resistance at the interface of the electrode and the interconnect in Fuel Cells influences the overall performance of a cell. In the present work, contact resistances between interconnect and electrodes in planar type Solid Oxide Fuel Cells (SOFC) under various compression loads and at different temperatures are measured in laboratory scale experiments. The roughness of the electrode and interconnect surfaces is characterized and a mathematical model to determine the contact resistance at the interfaces with known morphology, is proposed. The experimental results are found to be in good agreement with the values obtained from the model. (C) 2013 Elsevier B.V. All rights reserved

L'énergie électrique en France en 1948.

Varon Henri. L'énergie électrique en France en 1948.. In: Annales de Géographie, t. 58, n°311, 1949. p. 270

Improvement in solid oxide fuel cell performance through design modifications: An approach based on root cause analysis

Performance of the solid oxide fuel cell (SOFC) is significantly affected by ohmic and concentration losses. The ohmic losses increase with reduction in macroscopic and microscopic contact area at the interfaces of different components. On the other hand, the concentration losses depend on the distribution of fuel and oxidant over the active area. Present work aims to investigate the performance improvement through design modifications obtained from root cause analysis. The influence of the interfacial resistance (ohmic), both, in terms of the external compression load, i.e., the interaction at the microscopic level and macroscopic contact area, is minimised. The effect of the uniformity of the flow distribution on the performance of the scaled up SOFC is analysed. To these objectives, the base configuration is modified and the influence of the different modifications on the electrochemical performance is studied. At 0.7 V, the performance is observed to be enhanced by 62% through minimization of the contact resistance between interconnect and electrode. It is further improved by 100% with an increase in the apparent contact area for a given cell. Additional 50% enhancement in performance is observed by achieving better uniformity in the flow distribution. Overall similar to 212% enhancement in the performance is achieved with a design, which consists of all the modifications in one cell. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Importance of task selection for connected speech analysis in patients with Alzheimer’s disease from an ethnically diverse sample

Features of linguistic impairment in Alzheimer’s disease (AD) are primarily derived from English-speaking patients. Little is known regarding such deficits in linguistically diverse speakers with AD. We aimed to detail linguistic profiles (speech rate, dysfluencies, syntactic, lexical, morphological, semantics) from two connected speech tasks – Frog Story and picture description – in Bengali-speaking AD patients. The Frog Story detected group differences on all six linguistic levels, compared to only three with picture description. Critically, Frog Story captured the language-specific differences between the groups. Careful consideration should be given to the choice of connected speech tasks for dementia diagnosis in linguistically diverse populations

Connected speech profiles in bilinguals with AD (Dutta et al., 2024)

Purpose: Connected speech analysis has been effectively utilized for the diagnosis and disease monitoring of individuals with Alzheimer’s disease (AD). Existing research has been conducted mostly in monolingual English speakers with a noticeable lack of evidence from bilinguals and non-English speakers, particularly in non-European languages. Using a case study approach, we characterized connected speech profiles of two Bengali–English bilingual speakers with AD to determine the universal features of language impairments in both languages, identify language-specific differences between the languages, and explore language impairment characteristics of the participants with AD in relation to their bilingual language experience.Method: Participants included two Bengali–English bilingual speakers with AD and a group of age-, gender-, education-, and language-matched neurologically healthy controls. Connected speech samples were collected in first language (L1; Bengali) and second language (L2; English) using a novel storytelling task (i.e., Frog, Where Are You?). These samples were analyzed using an augmented quantitative production analysis and correct information unit analyses for productivity, fluency, syntactic and morphosyntactic features, and lexical and semantic characteristics.Results: Irrespective of the language, AD impacted speech productivity (speech rate and fluency) and semantic characteristics in both languages. Unique language-specific differences were noted on syntactic measures (reduced sentence length in Bengali), lexical distribution (fewer pronouns and absence of reduplication in Bengali), and inflectional properties (no difficulties with noun or verb inflections in Bengali). Among the two participants with AD, the individual who showed lower proficiency and usage in L2 (English) demonstrated reduced syntactic complexity and morphosyntactic richness in English.Conclusions: Evidence from these case studies suggests that language impairment features in AD are not universal across languages, particularly in comparison to impairments typically associated with language breakdowns in English. This study underscores the importance of establishing connected speech profiles in AD for non–English-speaking populations, especially for structurally different languages. This would in turn lead to the development of language-specific markers that can facilitate early detection of language deterioration and aid in improving diagnosis of AD in individuals belonging to underserved linguistically diverse populations.Supplemental Material S1. Existing studies exploring language in bilingual AD (based on Stilwell et al., 2016, and Calabria et al., 2017).Supplemental Material S2. Best Practice Guidelines for Reporting Spoken Discourse in Aphasia and Neurogenic Communication Disorders.Supplemental Material S3. A complete list and definitions of variables derived from the Quantitative Production Analysis (QPA) and Correct Information Unit (CIU) analyses.Dutta, M., Mello, T. M. D., Cheng, Y., Dash, N. S., Nandi, R., Dutt, A., & Bose, A. (2024). Universal and language-specific connected speech characteristics of bilingual speakers with Alzheimer’s disease: Insights from case studies of structurally distinct languages. Journal of Speech, Language, and Hearing Research, 67(4), 1143–1164. https://doi.org/10.1044/2024_JSLHR-23-00254</p