Kliniczne zastosowanie prób fluencji słownej w chorobie Huntingtona

Abstract

Introduction. Verbal fluency (VF) tests are widely used in the neuropsychological assessment mainly because of their sensitivity to various cognitive impairments and their brevity. VF deficits are well documented in Huntington’s disease (HD). Aim. The paper aims at presenting the clinical utility of VF tests in HD in the context of differential diagnosis, cognitive screening and longitudinal observation.Discussion. VF deficits are observed in various degenerative disorders and may be attributed to distinct neuropsychological deficits. Both, phonemic and semantic fluency deficits are observed in HD. Deficient VF in HD is an indicator of impaired executive function, psychomotor slowing and generalized cognitive decline. It is unclear whether language impairment significantly contributes to deficient VF performance. Progressive reduction in switching observed in HD documents the executive aspect of failure on VF tasks. The literature lacks in data on action and alternating fluency in HD. As they seem to be sensitive to frontostriatal dysfunction in Parkinson’s disease and are more demanding than traditional fluency tasks, their utility in HD may be limited to preclinical and early clinical stages. Conclusions. VF tasks are useful at the preclinical and clinical stages of HD unless severe dysarthria occurs in HD course. Semantic fluency tasks can document the progression of cognitive deficits when floor effect is observed on phonemic fluency tasks. Alternating and action fluency in HD requires further study.