Word-Retrieval Treatment for Aphasia: Semantic Feature Analysis

Word-Retrieval for Aphasia: Facilitation of Generalization

The purpose of this investigation is to further develop and test a treatment for word-finding problems in aphasia. The treatment is designed to strengthen meaning associations within categories of words (e.g., animals, tools, fruits). The treatment is also designed to be used as a search strategy in instances of word-finding difficulty. The study was devised to evaluate the extent to which treatment increases the ability to recall trained, as well as untrained, words.

The purpose of the proposed research is to examine the effects of a semantically-oriented treatment on word retrieval in persons with aphasia. The planned investigations are designed to further the development of semantic feature training so that it may serve as not only a mechanism for improving disrupted lexical semantic processing, but also as a compensatory strategy during word retrieval failures. The proposed research will also address the issue of exemplar typicality (Kiran & Thompson, 2003) by examining the effects of training typical versus atypical exemplars of various categories with individuals with different types of aphasia. A series of 24 single subject experimental designs will be conducted in the context of a group design to address the following experimental questions:

• Will training atypical examples of living and artifact noun categories using semantic feature training result in a significantly different outcome* than training typical examples of living and artifact noun categories?

• Will training of one category of nouns using semantic feature training result in improved retrieval of untrained categories of nouns?

• Will effects of semantic feature training vary across aphasia types?

• Will semantic feature training result in increased production of content during discourse?

• Will generalization to untrained typical examples vary across generalization lists that are repeatedly exposed and those that are limited in exposure? (i.e., Does repeated exposure appear to contribute to generalization?)

  • Outcome measure will reflect acquisition, response generalization within category, and response generalization across category effects of treatment.

Inclusion Criteria:

• Diagnosis of Wernicke's, Broca's, or Conduction aphasia with significant word-retrieval deficits
• At least 6 months post-onset of single, left-hemisphere stroke
• Minimum of high-school education
• Visual and auditory acuity sufficient for experimental tasks
• Nonverbal intelligence within normal limits

Exclusion Criteria:

• Diagnosed mental illness other than depression
• Neurological condition other than that which resulted in aphasia
• History of alcohol or substance abuse
• Non-native English speaker
• Premorbid history of speech/language disorder