Impaired Verb-Related Morphosyntactic Production in Multiple Sclerosis: Evidence From Greek.

Valantis Fyndanis,Lambros Messinis,Maria Pitopoulou,Efthimios Dardiotis,Maria Martzoukou,Sonia Malefaki,Aikaterini Ntoskou,Grigorios Nasios

doi:10.3389/fpsyg.2020.02051

Abstract

BackgroundA recent systematic review found that language deficits are not very common in individuals with multiple sclerosis (MS). However, there are significant gaps in our knowledge about language abilities in MS. For instance, morphosyntactic production has not been explored adequately thus far. This study investigated verb-related morphosyntactic production in MS focusing on Greek, a morphologically rich language.MethodsA sentence completion task tapping into the production of subject–verb agreement, time reference/tense, and grammatical aspect was administered to 39 Greek-speaking individuals with MS [25 individuals with relapsing-remitting MS (RRMS group) and 14 individuals with secondary progressive MS (SPMS group)]. The task included only regular verbs. Generalized linear mixed-effects models were used to investigate the ability of individuals with MS to produce the above-mentioned morphosyntactic categories.ResultsOverall, the RRMS and SPMS groups performed significantly worse than their matched control groups. Moreover, all four groups performed significantly worse on grammatical aspect than on subject–verb agreement and time reference. The difference between subject–verb agreement and time reference was not significant in any of the four groups. The overall performances of the RRMS and SPMS groups did not differ significantly.ConclusionIndividuals with MS are impaired in verb-related morphosyntactic production. Moreover, the pattern of performance of individuals with MS is identical to that exhibited by neurologically healthy individuals. Thus, the production performance of individuals with MS on verb inflection differs from that of healthy controls quantitatively but not qualitatively.

Highlights

Multiple sclerosis (MS) is an autoimmune, inflammatory, and neurodegenerative disease of the central nervous system that predominantly affects sensorimotor and physical abilities
While the aphasic and Alzheimer’s disease (AD) individuals reported in the studies above were severely impaired in the production of aspect, the individuals with MS who participated in the current study presented a mild-to-moderate impairment in the production of grammatical aspect, as the relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS) groups fared 81 and 68% correctly, respectively
The main finding of this study is that verb-related morphosyntactic production can be impaired in MS, and this impairment can be observed in both RRMS and SPMS

Summary

Introduction

Multiple sclerosis (MS) is an autoimmune, inflammatory, and neurodegenerative disease of the central nervous system that predominantly affects sensorimotor and physical abilities. Brandstadter et al (2019) found that word-finding difficulties attested in MS are linked to left parietal cortical thinning It should be noted, that there are still gaps in our knowledge regarding both the neural substrate of language impairment in MS and the aspects of language affected by MS. This study investigates verbrelated morphosyntactic abilities in MS focusing on Greek, a Abbreviations: AD, Alzheimer’s disease; BICAMS, Brief International Cognitive Assessment for MS; BMVT-R, Brief Visuospatial Memory Test-Revised; EDSS, Expanded Disability Status Scale; GVLT, Greek Verbal Learning Test; IFIH, Interpretable Features’ Impairment Hypothesis; MMSE, Mini Mental State Examination; MS, multiple sclerosis; PWA, persons with aphasia; RRMS, relapsing-remitting multiple sclerosis; SDMT, Symbol Digit Modalities Test; SPMS, secondary progressive multiple sclerosis; SS, source sentence; STM, shortterm memory; TPH, tree pruning hypothesis; TS, target sentence; TUH, tense underspecification hypothesis; WM, working memory. In many languages, including Greek, the person and the number of the grammatical subject of a sentence are morphologically marked on the verb (subject–verb agreement). Present tense in Italian (e.g., mangio “eat”) refers to the present (e.g., Adesso mangio pasta “ I eat-PRESENT.1st.SG pasta”), but it may be used to refer to the future in the presence of a time adverbial referring to the future (e.g., Domani mangio pasta “Tomorrow eat-PRESENT.1st.SG pasta”)

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