Intact reversed language-dominance but exaggerated cognate effects in reading aloud of language switches in bilingual Alzheimer’s disease.

Abstract

Objective: The current study investigated how Alzheimer’s disease (AD) affects production of speech errors in reading-aloud of mixed-language passages with language switches on cognates (e.g., family/familia), noncognates (e.g., people/gente), and function words (the/la). Method: Twelve Spanish-English bilinguals with AD and 22 controls read-aloud 8 paragraphs in 4 conditions: (a) English-default content switches, (b) English-default function switches, (c) Spanish-default content switches, and (d) Spanish-default function switches. Results: Reading elicited language intrusions (e.g., saying la instead of the), and several types of within-language errors (e.g., saying their instead of the). Reversed language-dominance effects were intact in AD; both patients and controls produced many intrusions on dominant language targets, and relatively fewer intrusions on nondominant language targets. The opposite held for within-language errors, which were more common with nondominant than dominant targets. Patients produced the most intrusion errors with cognate switch words (which best distinguished patients from controls in ROC curves of all speech error types), while controls had equal difficulty switching on cognate and function word targets. Conclusions: Reversed language-dominance effects appear to illustrate automatic inhibitory control over the dominant language, but could instead reflect limited resources available for monitoring when completing a task in the nondominant language. The greater sensitivity of intrusion errors with cognate than with function word targets for distinguishing patients from controls implies that language control may be aided by relatively intact knowledge of grammatical constraints over code-switching in bilinguals with AD.

[Retracted] Intestinal Flora Balance Therapy Based on Probiotic Support Improves Cognitive Function and Symptoms in Patients with Alzheimer’s Disease: A Systematic Review and Meta‐analysis

“…In addition, the hypothalamic-pituitary-adrenal (HPA) axis can affect the colonization and composition of intestinal flora by stimulating the secretion of adrenocortical hormones [ 12 ]. In turn, gut microbes and their metabolites can mediate neurophysiological processes including neurodevelopment, neurotransmission, immune activation of the central nervous system, and the integrity of the blood-brain barrier by regulating the maturation of microglia and astrocytes [ 13 ]. In the meanwhile, intestinal flora and their metabolites, such as short-chain fatty acids (SCFAs), γ -aminobutyric acid (GABA), and brain-derived neurotrophic factor (BDNF), have important effects on nerve inflammation, nerve injury, and brain behavior by regulating peripheral immune response [ 14 ].…”

Language Use in Deaf Children With Early-Signing Versus Late-Signing Deaf Parents

“…Thus, it might be more meaningful to consider speakers who are highly proficient in their later-acquired language (i.e., reversed dominance bilinguals) for comparison. Although there is a growing body of research on their language use and processing (e.g., Declerck et al, 2020;Gollan et al, 2020), research examining the effects of their language input on their children's language development is scarce. In one recent study, Stoehr et al (2019) asked whether language development in Dutch-German bilingual pre-schoolers has been influenced by the language input from their sequential bilingual mothers, who acquired Dutch in their adulthood, and have been using it dominantly in their daily lives.…”

Failure to stop autocorrect errors in reading aloud increases in aging especially with a positive biomarker for Alzheimer’s disease.

“…However, if autocorrect errors also increase in association with an increased accumulation of amyloid or Tau in the brain, it might suggest that decline in monitoring and executive control processes needed to stop autocorrection are affected by healthy aging and magnified by unidentified preclinical AD. In previous studies of reading aloud in bilinguals with AD (Gollan et al, 2017(Gollan et al, , 2020, and healthy aging monolinguals reading paragraphs without malapropisms (Gollan & Goldrick, 2019), function words elicited more errors than content words, a result we attributed to the difficulty of monitoring function words (Staub, Dodge, & Cohen, 2019). Thus, we hypothesized that errors on function word targets (e.g., saying "with" instead of "within" in "She'd try to be careful but she'd always end up within food on her clothes") might be more sensitive to aging and/or AD-related CSF biomarker levels than content word errors (e.g., saying "evolve" instead of "involve" in "As this technology continues to involve and I continue to get older .…”

“…Two recent studies demonstrated some promise along these lines using reading aloud of full paragraphs to elicit connected speech in cognitively healthy aging bilinguals versus in bilinguals with AD. Participants in these studies read aloud paragraphs written mostly in one language but with some switches into their other language; bilinguals with AD were more likely than controls to spontaneously translate language-switched words to avoid switching languages in their speech (Gollan, Li, Stasenko, & Salmon, 2020; Gollan, Stasenko, Li, & Salmon, 2017).…”