An Analysis of Errors Produced by Individuals with Aphasia, Across Conditions of High and Low Word Frequency

• Other Authors: Martin, Amanda (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Communication; Communicative disorders
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-5019

The ability to use language effectively is a function we rely on every day. Unfortunately for many individuals, language ability can be impaired following damage to the language centers of the brain. Aphasia is the term that applies to individuals who have suffered such language impairment, and while there are six general classifications of aphasia, word retrieval difficulty is a universal component across them. As such, factors that influence word retrieval have been widely studied in individuals with aphasia. One such factor, word fluency, has been the focus of numerous investigations, leading to an understanding of the "word frequency effect". The word frequency effect is the understanding that words which occur with high frequency (i.e. hat, pen) are much easier to produce than words that occur with low frequency (i.e. violin, binoculars). More specifically, words of high frequency are produced more accurately and faster than low frequency words. This frequency effect in word retrieval is well documented. However, to date, there has been no investigation on the errors that are produced on high and low frequency words. Studying the error productions of individuals with aphasia might offer a greater understanding of word retrieval and where the breakdown may occur. The purpose of the current study was to conduct an analysis on the errors produced by individuals with aphasia across two word retrieval conditions (high and low frequency). Seven individuals with aphasia participated in this investigation. All seven were native English speakers, originally right-handed, suffered a single episode, left hemisphere thrombo-embolic CVA, were at least six months post onset, and had no overt sensory or severe motor speech impairments. Each participant completed word retrieval across conditions of high frequency (30 words) and low frequency (30 words). An analysis of the errors produced in the two conditions was completed according to the Foygel and Dell (2000) classification system. After the errors were coded, the expected configuration of errors (fewer errors in the high frequency condition) was obtained by this sample of individuals with aphasia. Specific analysis of error productions indicated several individual patterns of errors, which were similar across the two conditions. With a few exceptions (perseverations and "I don't know" responses), semantic errors were produced with the greatest frequency across both conditions. The remaining breakdown of errors differed slightly across conditions. The unique contribution of this study was the systematic analysis of error productions. These findings offer preliminary evidence that error patterns are similar across the two conditions, as a differential effect was not revealed. These results suggest that the underlying mechanism of word retrieval difficulty operates the same, regardless of word frequency. Finally, the knowledge of error patterns (in this case semantic errors) may have clinical implications for guiding treatment, although additional study is warranted to either support or refute these preliminary findings. === A Thesis submitted to the School of Communication Science and Disorders in partial fulfillment of the requirements for the degree of Master of Science. === Summer Semester, 2012. === July 13, 2012. === aphasia, naming, word frequency === Includes bibliographical references. === Julie A. G. Stierwalt, Professor Directing Thesis; Leonard L. LaPointe, Committee Member; Charles Ouimet, Committee Member.