Publications by authors named "Alexandre Nikolaev"

6 Publications

  • Page 1 of 1

Neuroanatomical Correlates of Macrolinguistic Aspects in Narrative Discourse in Unilateral Left and Right Hemisphere Stroke: A Voxel-Based Morphometry Study.

J Speech Lang Hear Res 2021 May 12;64(5):1650-1665. Epub 2021 Apr 12.

Linguistics Department, School of Humanities, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.

Background A growing body of literature has demonstrated the importance of discourse assessment in patients who suffered from brain injury, both in the left and right hemispheres, as discourse represents a key component of functional communication. However, little is known about the relationship between gray matter density and macrolinguistic processing. Purpose This study aimed to investigate this relationship in a group of participants with middle-low to low socioeconomic status. Method Twenty adults with unilateral left hemisphere ( = 10) or right hemisphere ( = 10) chronic ischemic stroke and 10 matched (age, education, and socioeconomic status) healthy controls produced three oral narratives based on sequential scenes. Voxel-based morphometry analysis was conducted using structural magnetic resonance imaging. Results Compared to healthy controls, the left hemisphere group showed cohesion impairments, whereas the right hemisphere group showed impairments in coherence and in producing macropropositions. Cohesion positively correlated with gray matter density in the right primary sensory area (PSA)/precentral gyrus and the pars opercularis. Coherence, narrativity, and index of lexical informativeness were positively associated with the left PSA/insula and the superior temporal gyrus. Macropropositions were mostly related to the left PSA/insula and superior temporal gyrus, left cingulate, and right primary motor area/insula. Discussion Overall, the present results suggest that both hemispheres are implicated in macrolinguistic processes in narrative discourse. Further studies including larger samples and with various socioeconomic status should be conducted. Supplemental Material https://doi.org/10.23641/asha.14347550.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1044/2020_JSLHR-20-00500DOI Listing
May 2021

Evaluating three stuttering assessments through network analysis, random forests and cluster analysis.

J Fluency Disord 2021 Mar 9;67:105823. Epub 2020 Dec 9.

School of Languages and Cultures, University of Sheffield, Sheffield S3 7RA, UK, and Department of Languages, University of Helsinki, Helsinki FI-00014, Finland. Electronic address:

Purpose: In stuttering, cognitive and behavioural variables interact in nonlinear fashion. These variables can be assessed by instruments which evaluate perceived impact of stuttering and stuttering severity. We applied three statistical methods in combination to the analysis of three assessment protocols to discover relationships within and between the tests to better understand variations in behavioural and social aspects of stuttering.

Methods: Scores from Stuttering Severity Index (SSI-IV), Overall Assessment of the Speaker's Experience of Stuttering scale (OASES), and Unhelpful Thoughts and Beliefs About Stuttering scale (UTBAS), collected from 26 participants were compared using three statistical methods: network analysis, random forests, and cluster analysis.

Results: Network analysis demonstrated that SSI-IV only weakly interacts with a quality of life index (OASES) and a self-perception and belief systems index (UTBAS). Random forest analyses revealed the last two measures relate strongly to each other. The results from cluster analysis suggest a) a possible regrouping of OASES items and b) a possible use of one UTBAS scale instead of the three.

Conclusion: A combination of three statistical methods allowed us to evaluate the three assessments in more depth. The lack of interaction between the SSI-IV on the one hand, and OASES and UTBAS on the other, suggests that the network of the three commonly used stuttering assessments may be fractured in a non-productive way. A potential gap may exist for an assessment tool that would link behavioural and social aspects of stuttering.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jfludis.2020.105823DOI Listing
March 2021

Production of Inflected Novel Words in Older Adults With and Without Dementia.

Cogn Sci 2020 08;44(8):e12879

Institute of Clinical Medicine, Neurology, University of Eastern Finland.

While cognitive changes in aging and neurodegenerative disease have been widely studied, language changes in these populations are less well understood. Inflecting novel words in a language with complex inflectional paradigms provides a good opportunity to observe how language processes change in normal and abnormal aging. Studies of language acquisition suggest that children inflect novel words based on their phonological similarity to real words they already know. It is unclear whether speakers continue to use the same strategy when encountering novel words throughout the lifespan or whether adult speakers apply symbolic rules. We administered a simple speech elicitation task involving Finnish-conforming pseudo-words and real Finnish words to healthy older adults, individuals with mild cognitive impairment, and individuals with Alzheimer's disease (AD) to investigate inflectional choices in these groups and how linguistic variables and disease severity predict inflection patterns. Phonological resemblance of novel words to both a regular and an irregular inflectional type, as well as bigram frequency of the novel words, significantly influenced participants' inflectional choices for novel words among the healthy elderly group and people with AD. The results support theories of inflection by phonological analogy (single-route models) and contradict theories advocating for formal symbolic rules (dual-route models).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cogs.12879DOI Listing
August 2020

Demographic Effects on Longitudinal Semantic Processing, Working Memory, and Cognitive Speed.

J Gerontol B Psychol Sci Soc Sci 2020 10;75(9):1850-1862

The Graduate Center of the City University of New York.

Objectives: To better understand and compare effects of aging and education across domains of language and cognition, we investigated whether (a) these domains show different associations with age and education, (b) these domains show similar patterns of age-related change over time, and (c) education moderates the rate of decline in these domains.

Method: We analyzed data from 306 older adults aged 55-85 at baseline of whom 116 returned for follow-up 4-8 years later. An exploratory factor analysis identified domains of language and cognition across a range of tasks. A confirmatory factor analysis analyzed cross-sectional associations of age and education with these domains. Subsequently, mixed linear models analyzed longitudinal change as a function of age and moderation by education.

Results: We identified 2 language domains, that is, semantic control and semantic memory efficiency, and 2 cognitive domains, that is, working memory and cognitive speed. Older age negatively affected all domains except semantic memory efficiency, and higher education positively affected all domains except cognitive speed at baseline. In language domains, a steeper age-related decline was observed after age 73-74 compared to younger ages, while cognition declined linearly with age. Greater educational attainment did not protect the rate of decline over time in any domain.

Discussion: Separate domains show varying effects of age and education at baseline, language versus cognitive domains show dissimilar patterns of age-related change over time, and education does not moderate the rate of decline in these domains. These findings broaden our understanding of age effects on cognitive and language abilities by placing observed age differences in context.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/geronb/gbaa080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759739PMC
October 2020

Lexical Decision Task for Studying Written Word Recognition in Adults with and without Dementia or Mild Cognitive Impairment.

J Vis Exp 2019 06 25(148). Epub 2019 Jun 25.

Feinberg School of Medicine, Northwestern University; Shirley Ryan AbilityLab.

Older adults are slower at recognizing visual objects than younger adults. The same is true for recognizing that a letter string is a real word. People with Alzheimer's disease (AD) or Mild Cognitive Impairment (MCI) demonstrate even longer responses in written word recognition than elderly controls. Despite the general tendency towards slower recognition in aging and neurocognitive disorders, certain characteristics of words influence word recognition speed regardless of age or neuropathology (e.g., a word's frequency of use). We present here a protocol for examining the influence of lexical characteristics on word recognition response times in a simple lexical decision experiment administered to younger and older adults and people with MCI or AD. In this experiment, participants are asked to decide as quickly and accurately as possible whether a given letter string is an actual word or not. We also describe mixed-effects models and principal components analysis that can be used to detect the influence of different types of lexical variables or individual characteristics of participants on word recognition speed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3791/59753DOI Listing
June 2019

Effects of morphological family on word recognition in normal aging, mild cognitive impairment, and Alzheimer's disease.

Cortex 2019 07 11;116:91-103. Epub 2018 Dec 11.

University of Eastern Finland, Kuopio, Finland; Kuopio University Hospital, Kuopio, Finland. Electronic address:

Reading a word activates morphologically related words in the mental lexicon. People with Alzheimer's disease (AD) or Mild Cognitive Impairment (MCI) often have difficulty retrieving words, though the source of this problem is not well understood. To better understand the word recognition process in aging and in neurodegenerative disorders such as MCI and AD, we investigated the nature of the activation of morphologically related family members in 22 Finnish speakers with AD, 24 with MCI, and 17 cognitively healthy elderly. We presented Finnish monomorphemic (base form) nouns in a single-word lexical decision experiment to measure the speed of word recognition and its relation to morphological and lexical variables. Morphological variables included morphological family size (separate for compounds and derived words) and pseudo-morphological family size (including the set of words that have a partially overlapping form but that do not share an actual morpheme, e.g., pet and carpet, or corn and corner). Pseudo-morphological family size was included to examine the influence of words with orthographic (or phonological) overlap that are not semantically related to the target words. Our analyses revealed that younger and elderly controls and individuals with MCI or AD were influenced by true morphological overlap (overlapping forms that also share meaning), as well as by the word's pseudo-morphological family. However, elderly controls and individuals with MCI or AD seemed to rely more on form overlap than young adults. This demonstrates that an increased reliance on form-based aspects of language processing in Alzheimer's disease is not necessarily due to a partial loss of access to semantics, but might be explained in part by a common age-related change of processes in written word recognition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cortex.2018.10.028DOI Listing
July 2019