Fluidez verbal fonológica, morfológica y semántica en sujetos con enfermedad de Parkinson

Abstract

Parkinson's disease (PD) is a progressive pathology that implies a degeneration of the nigro-striatal dopaminergic system with dysfunction of frontal projections, which generates alterations in executive functions, specifically in sustained attention, working memory, planning and cognitive flexibility, among others. In fact, this pathology has repercussions on several language components. Particularly, there is evidence indicating that the ability to evoke lexical units and recover them from long-term memory or lexicon is affected. Although these types of tasks seem to be sensitive for the detection of Parkinson's disease, both in patients with mild cognitive impairment and another with dementia, it is still necessary to have evidence to determine which specific subcomponents of the language are affected, since this will allow us to understand with more specificity both the pathology and its linguistic manifestation, at the same time as to design therapies by support teams for this type of patients. In this context, verbal fluency (VF) tests could contribute to obtaining this type of information. VF is defined as an executive function that involves the access and evocation of clusters of linguistic information, and that is related to attention and working memory processes, since it is initiated by the activation of information groups through specific search strategies Moreover, it involves various linguistic functions, such as the naming, and executive functions of planning, working memory and initiation of behavior. Specifically, this type of task consists of requesting the subject under evaluation to nominate the largest number of elements of a lexical category according to a specific rule for a specific time, such as names of countries or word containing the phoneme / f /. From there, it has been observed which associated language areas are activated: ventral-anterior lower frontal gyrus in categorical tasks, dorsal-posterior lower frontal gyrus in phonological tasks and parietal areas of the right hemisphere that are associated with executive functions and attentional processes in tasks of greater complexity. Within this framework, the aim of the present study was to describe the performance in tasks of verbal fluency of a phonological, morph syntactic, semantic type and their combinations in participants diagnosed with Parkinson's disease (PD). For this, a cross-sectional study was conducted with 42 subjects, grouped as healthy older adults (AMS; n = 23) and older adults diagnosed with PD without dementia (EP; n = 19). The subjects of the control group had a mean age of 66 years (SD = 6.9) and 11.5 years of schooling (SD = 3.1); on the other hand, subjects with PD had a mean age of 71 years (SD = 8.03) and 13.2 years of schooling (SD = 3.9). Each subject performed a total of 15 verbal fluency tasks, in which he had to evoke the greatest number of lexical units in 60 seconds, which were also measured in intervals of 15 seconds. The results shown statistically significant differences in the sub-tasks of the phonemic type of excluded phoneme (FVFLE1: p = .012 and FVFLE2: p = .047), morph syntactic adjective categories (FVM2: p = .005), in the synonymy relationships (FVS3: p = .028) and lexical field and phonology (FVSF: p = .004). These data seem to indicate that subjects with Parkinson's disease show significantly lower performance in tasks that require high inhibitory control, since subtasks that combine tongue levels involve evocation and inhibition at the same time. These results are consistent with the pathophysiology of the condition.