Word-finding difficulties in left hemisphere stroke, multiple sclerosis and Parkinson's disease - differences in symptom occurrence and effects of anomia treatment

Abstract

Word-finding difficulties, or anomia, are a common symptom in various conditions affecting the brain, such as stroke, multiple sclerosis (MS) or Parkinson’s disease (PD). The aim of this thesis is twofold: (i) to increase our knowledge about the similarities and dissimilarities between the word-finding difficulties associated with different kinds of neurological conditions, and (ii) to evaluate treatment effects of anomia treatment using a method called semantic feature analysis (SFA).

Word-finding ability was assessed by means of a comprehensive test battery to describe and compare signs of anomia, in relation to various health aspects within the International Classification of Functioning, Disability and Health (ICF), in 87 participants with left-hemisphere stroke, MS or PD (in Study I), and to evaluate changes in outcome measures after SFA treatment (in Studies II–IV). Three participants with stroke (Study II) and two participants with MS (Study IV) participated in multiple-baseline across-subjects single-case experimental-design studies, and seventeen participants with stroke participated in a randomized controlled trial (Study III). Findings from Study I revealed similarities in terms of reduced fluency, delayed response times and difficulties supplying sufficiently informative content when re-telling cartoon plots. Most participants reported experiencing a negative impact on their communicative participation and quality of life. Participants with anomia after stroke differed from those with MS or PD in that they typically had more extensive anomia, although there were overlaps between the groups. However, the degree of anomia as assessed in formal tests did not always correlate with the degree of self-perceived communicative difficulties in everyday life. Findings from the three intervention studies (Studies II–IV) showed that participants with stroke found the trained items used in SFA treatment significantly easier to retrieve after the treatment, but that these effects were primarily limited to the trained words and that similar treatment effects could be achieved using another type of anomia treatment as well. No treatment effects were apparent in participants with MS who had mild anomia. Moreover, the findings confirmed those from previous studies, namely that generalization effects on untrained items, effects on connected speech and improvements to self-reported communicative participation and quality of life are difficult to achieve; only minor (statistically non-significant) treatment effects on communicative activity and participation were found. In conclusion, anomia of various degrees in stroke, MS and PD may lead to similar consequences for everyday communication and self-perceived communicative participation. Anomia treatment focused solely on improving single-word retrieval may not be sufficient to yield effects on the activity and participation in everyday communicative situations. Keywords: anomia, word-finding difficulties, ICF, assessment, self-reports, naming, everyday communication, semantic feature analysis, SFA, treatment, stroke, multiple sclerosis, Parkinson’s disease