Language disorders as indicators of the diagnosis and progression of Huntington’s disease

Summary: Study reports it may be possible to detect the onset and progression of Huntington’s disease through linguistic changes in patients. Linguistic impairments often begin before the onset of other Huntington’s symptoms.

Source: UPF Barcelona

Huntington’s disease is a hereditary neurodegenerative disorder caused by a gene of chromosome 4 that affects a very important area of the brain, the striatum. People are born with the defective gene but symptoms do not appear until the age of 30 or 40.

This disease, in addition to motor impairments, cognitive and affective problems, also involves changes in language. A study shows that the first symptoms of the disease are revealed through linguistic changes in spontaneous speech.

So reveals a study published in Journal of Communication Disorders by Antonia Tovar as first author, led by Wolfram Hinzen, ICREA research professor, both researchers with the Department of Translation and Language Sciences at UPF, involving researchers from the universities of Paris-Saclay (Orsay, France), the UAB, the UB, together with the Hospital Mare de Déu de la Mercè in Barcelona and FIDMAG Sisters Hospitallers Research Foundation (Barcelona).

“Linguistic impairments in Huntington’s disease arise before the onset of motor impairment and even when neuropsychological tests prove normal. This suggests that language may be a biomarker for the progression of Hungtinton’s”, Tovar and Hinzen explain.

Specific language patterns of Huntington’s disease

In addition to showing that linguistic impairments in Huntington’s disease arise before the onset of motor impairment, the authors have sought to characterize the nature of these specific changes in Huntington’s disease. Thus “language needs to be assessed as a multi-dimensional construct organized at multiple levels (phonology, morphology, syntax, semantics, discourse), which are re-fitted together into an integrated functional whole”, the authors point out.

The few existing linguistic studies on spontaneous speech in Huntington’s disease have reported language shortcomings. For example patterns of reduced syntactic complexity, with fewer words and syntactic structures formed in short, simple sentence constructions, more paraphasic and grammatical errors, etc. These language deficits may form a distinctive signature profile of Huntington’s as compared with Parkinson’s disease or people with cerebral lesions.

To study the language profiles of Huntington’s disease, the authors designed an experiment with 20 HD gene-carriers, all native Spanish speakers; 10 in the early stages of the disease and another 10 with pre-manifest Huntington’s disease, and their respective neurotypical controls not carrying the gene, and compared them regarding the structure and function of language in spontaneous speech. The researchers also studied the relationship between language and non-linguistic cognitive impairment.

“This disease is generally accepted to begin with the onset of motor symptoms, but we have found differences in the language profile of subjects without motor symptoms”, says Tovar, first author of the article.

This shows a man and a speech bubble

In addition to showing that linguistic impairments in Huntington’s disease arise before the onset of motor impairment, the authors have sought to characterize the nature of these specific changes in Huntington’s disease. Image is in the public domain.

In addition to proving that in Huntington’s disease linguistic changes precede other cognitive and motor impairments, it has been shown that language impairments are in the areas of basic grammar organization and cannot be detected with standard neurocognitive tests. This study is important because it has managed to capture subtle changes in the patient’s linguistic profile that could not be detected using the tests generally conducted in this population.

A more detailed and differentiated profile of the linguistic phenotype of this disease

The results showed that while the patients mentioned have “pauses” in their speech, at the beginning of Huntington’s disease they tend to be filled through prolongations and repetitions. Therefore, the study provides further support for the disintegration of language in Huntington’s disease and contributes to a more detailed and differentiated profile of the linguistic phenotype of the disease.

Since language skills mainly have an impact on communication skills, the authors conclude that special attention must be paid to the early detection of Huntington’s disease by means of clinical linguistic tests and the sensitivity and specificity of language as a marker for the progression of the disease must continue to be systematically investigated.

About this neurology research article

Source:
UPF Barcelona
Media Contacts:
UPF – UPF Barcelona
Image Source:
The image is in the public domain.

Original Research: Open access
“Language disintegration in spontaneous speech in Huntington’s disease: a more fine-grained analysis”. Antonia Tovar, Aina Garí Soler, Jesús Ruíz-Idiago, Celia Mareca Viladrich, Edith Pomarol-Clotet, Joana Rosselló, Wolfram Hinzen.
Journal of Communications Disorders doi:10.1016/j.jcomdis.2019.105970.

Abstract

Language disintegration in spontaneous speech in Huntington’s disease: a more fine-grained analysis

Huntington’s disease (HD) is a neurodegenerative disease causing motor symptoms along with cognitive and affective problems. Recent evidence suggests that HD also affects language across core levels of linguistic organization, including at stages of the disease when standardized neuropsychological test profiles are still normal and motor symptoms do not yet reach clinical thresholds (‘pre-manifest HD’). The present study aimed to subject spontaneous speech to a more fine-grained linguistic analysis in a sample of 20 identified HD gene-carriers, 10 with pre-manifest and 10 with early manifest HD. We further explored how language performance related to non-linguistic cognitive impairment, using standardized neuropsychological measures. A distinctive pattern of linguistic impairments marked off participants with both pre-manifest and manifest HD from healthy controls and each other. Fluency patterns in premanifest HD were marked by prolongations, filled pauses, and repetitions, which shifted to a pattern marked by empty (unfilled) pauses, re-phrasings, and truncations in manifest HD. Both HD groups also significantly differed from controls and each other in how they grammatically connected clauses and used noun phrases referentially. Functional deficits in language occurred in pre-manifest HD in the absence of any non-linguistic neuropsychological impairment and did largely not correlate with standardized neuropsychological measures in manifest HD. These results further corroborate that language can act as a fine-grained clinical marker in HD, which can track disease progression from the pre-manifest stage, define critical remediation targets, and inform the role of the basal ganglia in language processing.

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