Language in neurodevelopmental disorders
Language in neurodevelopmental disorders
Relations between intensionality, theory of mind and complex syntax in autism spectrum conditions
Around the age of 4 to 5 years old, typically developing children begin to successfully reason about what others know or believe and draw inferences regarding how these mental states will affect how a person behaves. This maturational milestone of metarepresentational abilities has been identified for both false-belief (FB) reasoning tasks as well as intensionality tasks. The aim of this study is to assess relations between these two metarepresentational capacities (FB reasoning and intensionality) and importantly their relation to maturation of embedded clauses among children with ASC and children with typical development. An important motivator for this study is evidence that there is a strong link among both these populations between performance on FB reasoning (Sally-Anne tasks) and linguistic maturation, in particular clausal embedding. This study aims to fine-grain the nature of the relation between complex syntax and metarepresentation by systematically assessing various clausal embedding types and expanding metarepresentation assessment to include intensionality tasks.
Question Comprehension in Autism Spectrum Conditions
Individuals with Autism Spectrum Conditions (ASC) have difficulties to initiate and follow a conversation as well as respect turn-taking. Understanding questions and answer them is essential for social interaction. In addition, prosody has a role in shaping questions to the point that there are languages such as Spanish where yes/no questions only differ from declaratives prosodically. As for wh-questions, ASC children understand them much later than typically developing (TD) children. They are also more difficult to answer than yes/no ones. The difficulty in answering wh-questions in simple and complex sentences in ASC should be clarified. They are used in the assessment of the understanding of false-belief (Sally-Anne task) and other explicit Theory of Mind (ToM) experiments. For this reason, the aim of this study is to assess the comprehension of different types of questions in ASC with and without intellectual disability in comparison to TD and individuals with intellectual disability.
Neural and cognitive correlates of absence of language
While anomalous language development and use is an important factor in many developmental disorders, a considerable proportion of Autism spectrum disorders (ASD) manifest in severe language deficits. Almost 30% of children on the spectrum do not develop phrase speech past five years of age: an outcome that persists across their lifetimes. Their comprehension of words tends to fall far behind their chronological ages while their understanding of instructions and grammatical structures, in turn, falls behind their receptive vocabulary. Importantly, language does not manifest in other modalities such as sign, gesture or written language. In absence of hearing, vision or severe motor difficulties such a failure of language development is striking.
What is the neural substrate of absense of language development? And what are its cognitive repercussions?
Our current research agenda consists of 3 studies designed to shed light on these questions. Two behavioral studies examine verbal or nonverbal cognition in this population and how these relate, and in particular which levels or varieties of nonverbal concepts or thought can develop when language appears to be absent. Finally, in a magnetic resonance paradigm, we investigate language network structural and functional architecture and its connectivity, linked to its subjacent behavioural-cognitive profile.
Language in neuropsychiatric disorders
Lexical-grammatical interface and referential anchoring in William syndrome
The speech of people with Williams Syndrome (WS) has been widely reported to be incoherent at the discourse level and characterized as a ‘cocktail party speech’; that is, it seems to be mainly oriented towards social interaction rather than actual content. In contrast with the majority of the literature, we tend to point to phrasal meaning processing rather than purely lexical meaning to be the base of coherence and truth problems. In other words, the discursive deficit that people with WS exhibit could be due to a lack of referential anchoring at the phrasal
level, in which grammar and lexicon interact. The core of the study is a comparison of electrophysiological response profiles in control participants and adult with WS for violations of semantic subcategorization restrictions at a grammatical level using EEG. We complement this study with an detailed analysis of fluency, semantic aspects and conversational aspects using a corpus of spontaneous speech.
Language in neurodegenerative dementia
Language and episodic memory: a linguistic analysis of language change across phases of Alzheimer's disease
While language and memory have both long been researched in Alzheimer’s disease (AD), few studies have examined them in conjunction. In the present study, we approach the connection of language and memory using AD as a model for the way the two constructs are interdependent when they deteriorate with disease progression. Specifically, we will examine linguistic changes in spontaneous speech samples elicited through a task requiring temporal displacement, which is critical for episodic memory as an early marker of cognitive decline in AD. Episodic memory has content that is personal and specific by nature, containing temporal, spatial, and personal information about events. Moreover, episodicity exists not only in the past but also in other non-present time frames. Thus, in a temporal displacement paradigm, we expect that people with AD have difficulties not only in recalling events, but also in future planning and imaginary scene construction. We will test this prediction in a cross- sectional analysis of people with varying degrees of progression of AD including prodromal stages (MCI, and the even earlier ‘subjective cognitive decline’ phase). The linguistic analysis will be complemented by neuroimaging data from structural MRI scans, which will allow us to relate linguistic changes to patterns of neuro-degeneration. Our hypothesis is that speech in people with AD will exhibit less definiteness, specificity, and temporal displacement in our tasks.
Linguistic comprehension in Huntington’s disease: the role of locality
Generally, authors claim that linguistic deficits attested in HD are due to motor symptomatology. However, following Hinzen et al. (2017) and Tovar et al. (2019) we argue that language changes may form an inherent part of the general cognitive decline seen in this disease and be even prior to the onset of motor symptoms (i.e. in presymtomatic population). Our main objective here is expanding these first approaches with a focus on a core principle of grammatical organization, locality, which I hypothesize to be distinctly impaired in this population. Concretely, I aim to study two specific linguistic processes: referential dependencies and constituent movements. In both of these, locality constraints are widely recognized to be involved. If I saw locality principles affected in HD, I could also eventually advance the understanding of their neural basis, since violations of such principles might relate to the neurodegeneration seen in HD.
Main researcher :
Language in Schizophrenia
Main completed projects:
(1) Language markers of Formal Thought Disorder (FTD): FTD is clinically manifest as disorganized speech, but its purely linguistic dimensions have not been well-researched. In a number of studies in both Spanish and English-speaking patients, we have found evidence that speech in FTD exhibits a reduction of definite noun phrases and more anomalous referential uses of these. This is particularly noteworthy since we had hypothesized definiteness to be a dimension of meaning that is inherently grammatically mediated. We therefore concluded that discourse in FTD manifests a linguistic problem, at the level of using grammar to configure specific forms of referential meaning. We have also documented anomalous patterns of dysfluency (pauses in specific syntactic positions), which distinguish patients from controls and patients without FTD. (2) As one of the first studies in this domain, we have subjected word-by-word literal transcriptions of hallucinated voice speech to a linguistic analysis. The analysis showed that voice speech, despite its often conversational setting, involves a reduction of first-person reference relative to non-first person reference. Moreover, in our group of very frequent voice hearers, voice speech exhibited virtually no connectivity at the grammatical level, whether in terms of grammatical connections between clauses or at the level of anaphoric noun phrases.
Our long-term aim is to understand the broader role of language in the neuropsychiatry of schizophrenia and the cognitive changes that take place in disorganized speech in FTD, anomalous speech perception in auditory verbal hallucinations, and language losing propositional or referential content in delusions.
In a sample of very frequent voice hearers (overlapping with the one of the above behavioural study), we investigate with fMRI, in cooperation with Pilar Salgado and Paola Fuentes from FIDMAG, how different forms of external speech are perceived by such patients and their control groups.