Overuse of familiar phrases by individuals with Williams syndrome masks differences in language processing.

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Sederias I, Krakovitch A, Stojanovik V, Zimmerer VC (2024). Overuse of familiar phrases by individuals with Williams syndrome masks differences in language processing. Journal of Child Language. Published online 2024:1-15. doi:10.1017/S0305000924000436

This work has been fun on so many levels. First, it connects my current research with my very early experiences with language sciences. Williams syndrome was often used as an example to illustrate how language functions as an independent cognitive “module” - or, even better, an “organ” - which doesn’t always behave like other functions of the brain/mind. I was academically raised with that belief, and now it was time to scrutinize it.

Second, the people with whom I worked were fantastic. This paper is based on a secondary data analysis conducted by two then-final-year undergraduate students, Ioana Sederias and Ariane Krakovitch, who I supervised. These were the years of the Covid lockdowns - dark and stressful at least for me - and working with these two smart and fun students was one of the few bright spots during that time.

Finally, the project itself went remarkably smoothly. Our predictions came naturally from previous observations and the data supported them strongly. Some confused head-scratching is fairly typical when one first looks at results, but not here. The data tell a very clear story. And this is the story:

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Speech pauses in speakers with and without aphasia: A usage-based approach.

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Bello-Lepe, S., Mahmood, S., Varley, R., Zimmerer, V. (2024). Speech pauses in speakers with and without aphasia: A usage-based approach. Cortex, 178, 287-298. https://doi.org/10.1016/j.cortex.2024.06.012

When we speak, we can make pauses to emphasize, to give the listener time to reflect, or for other pragmatic/conversational reasons. But most pauses in speech, whether filled (“um …”) or silent, are disruptions. We may struggle with finding a word, or with planning a sentence. We may even struggle to put together a thought. Most pauses happen when our cognition can’t keep pace with our speech rate.

For that reason, we investigate speech pauses to learn more about language as ias we produce it. The presence and duration of pauses reveal when we face additional processing demands, and can inform us about which properties of language matter. For example, we are more likely to make a pause before a complex sentence, or before a verb rather than a noun. Pauses also provide insights into language impairment, for example following stroke. This paper identifies a new relevant variable for understanding pauses in people with aphasia (a language disorder following brain damage) and healthy controls.

This is work carried out by Sebastián Bello-Lepe under my supervision. Putting the final touches on it after he died was extremely difficult for me. It also made me think more about the “bus factor”, about which I am going to talk later in this post.

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Interview for Dementia Action Week.

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University College London (my employer) sent me some interview questions for a profile posted as part of Dementia Action Week. If you want to read the interview, which focuses on my dementia-related research and teaching, click here. Click here to learn what UCL is doing to face the global challenge of dementia.

Thanks to my friend Magnus Long for taking the picture during a stroll through Highgate Wood.

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Automated profiling of spontaneous speech in primary progressive aphasia and behavioral-variant frontotemporal dementia: An approach based on usage-frequency.

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Zimmerer, V.C., Hardy, C.J.D., Eastman, J., Dutta, S., Varnet, L., Bond, R.L., Russell, L., Rohrer, J.D., Warren, J.D., Varley, R.A. (2020). Automated profiling of spontaneous speech in primary progressive aphasia and behavioral-variant frontotemporal dementia: An approach based on usage-frequency. Cortex, 133, 103-119. https://doi.org/10.1016/j.cortex.2020.08.027

This one took ages to publish. Not only because we kept adding (post-hoc) analyses, but also because I thought the work should appeal to journals to which it ultimately did not.

We looked at language in rare dementias: Primary progressive aphasia, which mostly affects an individual’s ability to use language (we include the three major types, logopenic variant, semantic variant, and non-fluent variant), and behavioral-variant frontotemporal dementia, which primarily causes behaviour and mood change. Data were provided by colleagues at UCL’s Dementia Research Centre.

The fascinating thing about dementia is that, ultimately, each kind has been associated with some language symptoms.

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#TrumpIsNotWell vs. Sleepy Joe: On the weaponization of dementia in politics, and its bleak future.

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When Ronald Reagan, who died of Alzheimer’s disease in 2004, ran for president at age 69 and a second time at 73, senility was part of the public debate. The Democratic Party used it in their campaign. After a presidential debate, a senior Democrat told the press: “Reagan showed his age”.

When dementia is mentioned today, the discourse is much more aggressive. The basic mental capacity of both candidates is under scrutiny.

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For people with a language or cognitive impairment, the difference between "know" and "think" can be the difference between understanding and not understanding a sentence.

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Zimmerer, V.C., Varley, R.A., Deamer, F., Hinzen, W. (2019). Factive and counterfactive interpretation of embedded clauses in aphasia and its relationship with lexical syntactic and general cognitive capacities. Journal of Neurolinguistics, 49, 29-44.

Çokal, D., Zimmerer, V., Varley, R., Watson, S., Hinzen W. (2019). Comprehension of embedded clauses in schizophrenia with and without formal thought disorder. The Journal of Nervous and Mental Disease, 207(5), 384-392.

You and your friend get ready for a day trip to the coast. You see your friend pack light clothing and sunscreen. “I know that it is sunny over there,” she says. You check the weather forecast. It is all clouds and rain. “No,” you say. “You just think that it is sunny.”

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Automated analysis of language production in aphasia and right hemisphere damage: Frequency and collocation strength.

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Zimmerer, V.C., Newman, L., Thomson, R., Coleman, M., & Varley, R.A. (2018). Automated analysis of language production in aphasia and right hemisphere damage: Frequency and collocation strength. Aphasiology, 32(11), 1267-1283. DOI: 10.1080/02687038.2018.1497138

People with aphasia rely on more common words, and more strongly collocated word combinations, in spontaneous language production.

In aphasia, the effects that make a word or sentence easier or harder to process become intensified. Words that take milliseconds longer for a healthy speaker may become out of reach after brain damage. Sentences that are a bit more taxing for grammatical systems may become uninterpretable.

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Artificial grammar learning in Williams syndrome and in typical development: The role of rules, familiarity, and prosodic cues.

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Stojanovik, V., Zimmerer, V., Setter, J., Hudson, K., Poyraz-Bilgin, I., & Saddy, D. (2017). Artificial grammar learning in Williams syndrome and in typical development: The role of rules, familiarity, and prosodic cues. Applied Psycholinguistics, 1-27.

I heard about Williams syndrome (WS) for the first time when I was a linguistics student in Düsseldorf. The genetic disorder was interesting for one perceived dissociation: People with WS, so the view, had typical language capacities, but impairments of general cognitive abilities, demonstrating that the language system was independent, modular in the sense of (early) Chomsky and Jerry Fodor. Today we know this to be wrong. The language in WS may appear typical at a quick glance, but there are production as well as comprehension deficits, especially at a grammatical level. This study, led by Vesna Stojanovik at the University of Reading, aimed to understand what underlies the language profile in WS.

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Deictic and propositional meaning – new perspectives on language in schizophrenia.

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Zimmerer, V.C., Watson, S., Turkington, D., Ferrier, I.N., & Hinzen, W. (2017). Deictic and propositional meaning – new perspectives on language in schizophrenia. Frontiers in Psychiatry, 8, 1-5.

While schizophrenia is generally considered a thought disorder, its symptoms are to a large degree observable through language. We learn via language about a person's thought disorder and delusions, and most hallucinations in schizophrenia concern hearing voices. Negative symptoms (for example lethargy, aphathy) as well go with changes in communication.

One question that may turn out to be important for understanding schizophrenia, and possibly clinical practice, is whether people with schizophrenia only differ in what they say (for example, if they claim that the Queen is their aunt), but whether they also differ in how they say it.

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Language formulas - for your convenience.

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Let's say you know about 30,000 words in your language, which, according to some studies, makes you slightly above average. Some of these entries are everyday words, such as "you", "door", or "go". Others are more rare, like "aghast" and "triptychon". Some of these words are easy to access, usually those that we use often and have a more concrete ("dog") than abstract ("democracy") meaning. There is also an effect of "age of acquisition" in that words that we learned earlier in life seem cognitively more anchored. It is difficult to tell this effect apart from frequency of use, since children tend to learn everyday words first.

If your language system works like the majority of language models suggest, it is based on "words and rules". All words, or at least their roots, are stored in a mental lexicon, and when you utter a sentence your system retrieves each needed word and applies combinatorial ("grammatical") principles to generate the utterance. This needs to happen within fractions of a second. Our system must work like this at least to some degree since we can use our word and combinatorial knowledge to generate a virtually infinite number of sentences.

But how often do we need this procedure?

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Formulaic language in people with probable Alzheimer's disease: a frequency-based approach.

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Zimmerer, V.C., Wibrow, M., & Varley, R.A. (2016). Formulaic language in people with probable Alzheimer's Disease: a frequency-based approach. Journal of Alzheimer's Disease, 53, 1145-1160.

The claim that "language is a window into the mind" has been made in so many contexts. We all use language to show what's in our minds. Steven Pinker and others argue that language shows how the human mind is structured. I focus much on the clinical side: We look at language to see if the mind of an individual is working as it should. Brain lesions, psychosis, intellectual disabilities, dementia - all are likely to have an effect on how we produce and understand language.

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Grammatical impairment, historical accidents and silver bullets.

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In 1973, the neurologist Eric Lenneberg made two statements about the nature of language: 1) The rule systems described by Noam Chomsky cannot possibly reflect neurological reality. At best, they serve as metaphors for what the biological language system may do. 2) What is called "Broca's aphasia", the language impairment which results from damage to the frontal lobe of the brain and is characterised by very impoverished and non-fluent speech output, is not a disorder of language per se, but of speaking. It seemed obvious that people with Broca's aphasia could understand language, so Lenneberg believed in the consensus at that time that people with Broca's aphasia found it so difficult to produce speech sounds that they would limit their expressions to the bare minimum.

Lenneberg died two years later, too early to see both statements refuted in the mainstream.

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The language profile of behavioral variant frontotemporal dementia.

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Hardy, C.J., Buckley, A.H., Downey, L.E., Lehmann, M., Zimmerer, V.C., Varley, R.A., Crutch, S.J., Rohrer, J.D., Warrington, E.K., & Warren, J.D. (2015). The language profile of behavioral variant frontotemporal dementia. Journal of Alzheimer's Disease, 50(2).

Dementia is still a new area for me. I approach it from a language perspective. While dementias, such as Alzheimer's or, in this case, behavioral variant frontotemporal dementia (bvFTD) are not primarily language impairments, they can be associated with particular language profiles. I am certain that with further research these profiles will end up looking unique to the respective pathology. Investigating language in dementias is not just a way to learn more about the pathologies or about how language is anchored in the brain. Linguistic behaviour, in particular naming, memorization and fluency, are substantial in diagnosis.

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When passives are easier than actives.

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I met WR when I helped set up a recording session in a clinic in Sheffield. I was a PhD student at that time. WR had been diagnosed with primary progressive aphasia, which is a type of dementia that first manifests as a language impairment. WR was a friendly, gentle person who looked young for being 62. His language production was poor. When he spoke, he had the tendency to connect words with "is a" in an ungrammatical manner ("Mary is a holiday is a Turkey"). He preferred using pen and paper, and while his written language was also poor, communication was better through it. There was no sign that WR had problems beyond language. His non-verbal IQ was above average and as far as I can tell he was leading a very active life. At the time we carried out our research, WR's brain showed relatively small signs of degeneration. When Rosemary Varley and I discussed MRI scans with a radiologist at Royal Hallamshire Hospital, he said that if WR had come in with different problems, such as chronic migraine, it may have gone undetected at first glance. But it was there. Scans showed grey matter reduction in frontotemporal areas both left and right.

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Language and Mental Health

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The project website is not ready at the time I publish this, so I would like to talk a bit about the big project for which Rosemary Varley and I at UCL are currently recruiting aphasic and non-aphasic participants in the London area.

Broadly, there are two questions that drive all research on language: first, how does this complex and powerful apparatus work, and second, how does it interact with, or form the basis of, human thought? These questions are inherently related. Whether we are investigating how children learn language or how language changes in dementia, whether we are looking at language in the brain or trying to get computers to make use of it, whether we are interested in how a language changes over time or search for properties of language that never change, all work makes assumptions about the relationship between our ability to use language and our ability to think.

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Artificial grammar learning in individuals with severe aphasia

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Zimmerer, V.C., Cowell, P.E., & Varley, R.A. (2014). Artificial grammar learning in individuals with severe aphasia. Neuropsychologia, 53, 25-38.

"Syntactic disorder" can be defined as an impairment of sentence processing, in comprehension as well as production, in spoken language as well as written, despite relatively intact processing of individual words. It is a terrible disorder. Our communication is mostly about who did what to whom, and when. If we lose this ability the complexity of what we can say and understand suffers a lot. People with aphasia can have a complex mental life and above average intelligence, but can find themselves unable to share any of that.

This paper is based on my PhD project.

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