Ep. 210: Parkinson’s Disease: Exploring the Interaction between Motor and Language Impairments

00:00:00: Welcome to EA Uncast, your weekly source for education research and updates from the European Academy of Neurology.

00:00:37: This month's topic is the interaction between language and motor system.

00:00:42: And todays episode we will talk about Parkinson disease with special focus on the interaction of motor-and-language impairments.

00:00:51: My guest today, Dr Maura Panozzo-Chiomento She is a postdoctoral researcher at the University of Erfurt working in the field of linguistics.

00:01:05: Her research focuses on language processing and cognition in neurotypical populations, particularly individuals with Parkinson's disease.

00:01:17: In recent years a growing number of studies have reported language deficits in Parkinson's diseases.

00:01:25: however this field still requires further clarification because pitch disorders are a common manifestation of PD and may confound the assessment of language abilities.

00:01:41: Given this complexity, it is important to review current evidence regarding language impairment including its underlying mechanisms clinical characteristics an implication for diagnosis management.

00:01:59: Could you summarize the present state of knowledge on this topic?

00:02:04: Yes, thank-you.

00:02:06: I would divide linguistic difficulties in Parkinson's disease into two main categories.

00:02:12: The first category is motor related linguistic symptoms and these symptoms affect how people produce.

00:02:20: speech also includes this type of language symptoms.

00:02:31: And it evaluates how understandable speech is, whether interlocutors ask people with Parkinson's to repeat during conversations... ...whether they lose voice volume and whether they loose prosodic modulation that is the ability to vary pitch loudness and rhythm while speaking Together, these symptoms form a disorder which is called hypokinetic dysartia and which is a speech disorder that affects about ninety percent of people with Parkinson's disease.

00:03:08: And then moving on to the second type of language difficulties, Parkinson's Disease also causes non-motor language symptoms... ...and this symptom affect how brain processes languages.

00:03:22: The unified Parkinson's disease rating scale does not yet include these non-motor language symptoms because researchers have studied them less, even if they are a promising area of research.

00:03:36: These no motor language difficulties span several linguistic domains including phonology morphology syntax semantics pragmatics.

00:03:48: And to delve deeper into this topic, we also carried out a systematic review entitled Language Competence in Parkinson's Disease – A Systematic Review of Twenty Years Of Research which included forty-five studies.

00:04:03: In other words, Parkinson's disease is more than a movement disorder.

00:04:08: it causes both motor and non-motor symptoms.

00:04:16: the disease affects both speech, which is a motor component and language ,which is the cognitive non-motor component.

00:04:25: Could the language deficits observed in Parkinson's disease be explained within the framework of the embodied cognition theory?

00:04:35: We would greatly appreciate discussion on current evidence supporting this hypothesis.

00:04:44: Furthermore Please describe the tests and assessment batteries that are commonly used, and considered appropriate for evaluation of language deficits in patients with Parkinson's disease.

00:05:01: So this is a fascinating and challenging question!

00:05:05: We know that Embedded Cognition is a framework that says cognition including language depends on sensory motor mechanisms and on bodily experience.

00:05:16: So we understand meaning partially through the body, and through actual systems in the brain And findings of Parkinson's disease —and particularly on semantics— are very interesting.

00:05:29: In this context I will take an example from a study by Boka Negra & Colleagues'.

00:05:38: in this study participants saw pictures representing verbs.

00:05:42: Some verbs had high action-relatedness, for example to dance and some verbs had low action relatedness.

00:05:51: For example to smile which involves less movement And the task was to name the pictures and produce the corresponding words.

00:06:02: So non-demented people with Parkinson's disease performed worse than healthy controls but only for verbs With High Action Relatedness while the two groups performed similarly for low-action relatedness items.

00:06:19: In other words, it seems that a disorder affecting movement also affects words that describe movement and this is done in fine grained way because verbs seem to rely on motor circuits but these also depends how much action is encoded whether these semantic deficits come from a degraded representation of concepts in the brain or difficulties accessing those concepts on behalf of language systems.

00:06:57: My view so far is that Semantic Deficits in Parkinson's disease depend upon an interface-level vulnerability, meaning there might be problems with processes connecting concepts to languages.

00:07:13: it is not necessarily a problem in the concepts themselves, but in the system-to-system mapping between conceptual knowledge and linguistic processing.

00:07:24: And this also consists with an interface level embodiment view where the problem isn't in the embodied concept itself... ...but in processes that make those concepts legible to the linguistic systems.

00:07:40: I will now move on to the second part of your question.

00:07:43: How can we assess language impairments in clinical practice?

00:07:48: So, at present there is no standardized battery and single comprehensive test that gives a full-language profile for Parkinson's disease.

00:07:59: And i think In this clinical condition where still at stage where it is important to raise awareness about language impairment because these impairments are often overlooked.

00:08:12: And, because this deficits are so multifaceted – It's not fully appropriate directly employ tools coming from other conditions such as aphasia – Parkinson's disease is different and the language profile is different.

00:08:28: Also, Language Impairment in Parkinson's Disease does not only mean verbal fluency.

00:08:34: Verbal fluency tasks are those in which we ask people to produce as many words But they are simple to administer and still useful because it can show how people explore the mental lexicon, which is our internal storage of words.

00:09:13: And efficiently, they can retrieve words from them.

00:09:18: Language impairment in Parkinson's disease is orthogonal with different linguistic subdomains.

00:09:25: Impairments do not only compromise one single linguistic level!

00:09:30: So to assess language fully, we need create and validate dedicated tools that can complement the existing gold standards by the Movement Disorder Society.

00:09:42: And of course this work requires close collaboration between neurologists & linguists.

00:09:50: Thank you for your insights!

00:09:52: I would like to raise another question regarding the frequent reports of semantic fluency deficits in Parkinson's disease.

00:10:01: Since reduced semantic fluacy is not unique to PD and it commonly founds several neurological conditions, what factors account for its presence in PD?

00:10:15: Furthermore are there specific characteristics of semantic fluency impairment in Parkinson's disease, in comparison to similar deficits seen in other neurodegenerative diseases.

00:10:32: So the short answer is we still don't know and results are quite mixed on this topic also some studies found that phonemic fluency is impaired so it not only semantic fluency but also phonetic fluency vulnerability.

00:10:51: We don't know why that is so, and it's probably something that has to do with the ability of people with Parkinson's disease to efficiently explore the mental lexicon as neuro-typical individuals

00:11:05: do.".

00:11:06: Thank you!

00:11:07: As we move to the final part of our discussion today I would like to address the prognostic significance.

00:11:20: It is generally assumed that the presence of early and prominent language impairment may not be a typical feature for idiopathic Parkinson's disease.

00:11:31: It could either indicate less favorable prognosis or prompt reconsideration of diagnosis, particularly with regard to a typical Parkinsonian syndrome and other neurodegenerative disorders.

00:11:49: Could you comment on the current evidence regarding the prognostic value of fully speech and language deficits in Parkinson's disease?

00:12:00: Furthermore, how should these symptoms influence the diagnostic process.

00:12:06: In addition given their significant impact on communication and quality of life it is important to discuss of non-pharmacological interventions.

00:12:20: Could you provide an overview?

00:12:45: Low voice volume can make communication harder.

00:12:49: And there are possible interventions that target the motor part of speech, so speech therapy can help here focusing on articulation, voice volume and speech clarity.

00:13:01: In non-motor domain however people with Parkinson's disease often report difficulty in finding words.

00:13:09: for example This is called tip of the tongue phenomenon, which means that a person knows their word but they cannot retrieve it at them moment.

00:13:19: And for this non-motor language difficulty we still need more specific type of interventions.

00:13:26: We need approaches that target directly words retrieval and language processing not only speech production.

00:13:35: The question on whether can use Language deficits for diagnosis or monitoring disease progression is still open, as more research is needed to understand the role of language deficits as no-motor markers.

00:13:50: However there are already some promising results In the domain of progression.

00:13:55: The study by Bocanegra and Collex tested picture naming of items with either high action relatedness meaning such as toothbrush or low-actual relatedness meaning, such as cloud.

00:14:11: And the researchers conducted a cross-sectional comparison between A group of people with Parkinson's disease and Mild Cognitive Impairment.

00:14:24: While non-demented individuals showed selective deficits for high actual relatedness verbs, individuals who also had mild cognitive impairment showed more spread semantic deficits.

00:14:39: And so these results and results from other studies suggest that language can help monitor disease progression.

00:14:48: In the domain of early detection, we again distinguish between motor and non-motor aspects.

00:14:56: On the motor side several studies show speech can act as a biomarker and speech measures can differentiate people with Parkinson's and neurotypicals, with a very high accuracy.

00:15:11: On the non-motor side between group differences are also consistently found.

00:15:17: The answer concerning early detection however is more difficult given that most existing studies test People who already have a diagnosis of Parkinson's disease And Also this slow progression of the disease makes it virtually impossible to conduct longitudinal studies on the topic.

00:15:38: However, there is a study by Garcia and colleagues in twenty seventeen who investigated individuals with genetic forms of Parkinson's disease bearing risk mutations.

00:15:52: they found that language measures targeting semantics and syntax showed reduced performance compared to neurotypical controls.

00:16:04: These findings suggest that linguistic tasks may indeed become useful tools in the context of early detection.

00:16:13: Thank you, Maura!

00:16:14: We have a great pleasure to have Maura Panozeb Q-Mento as guest researcher on this webcast.

00:16:25: we can conclude that Parkinson's disease has got problems in language and speech production.

00:16:34: And this is somehow under still on the investigation, as many issues are not crystallized yet.

00:16:43: There's a lot of work to be done indicator of Parkinson's disease progression, but fortunately there are many speech therapy interventions that could help the people with Parkinson's Disease.

00:17:21: This has been EANcast Weekly Neurology.

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