Word-Retrieval Treatment for Aphasia: Semantic Feature Analysis

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.

Aphasia, Language therapy, Rehabilitation of speech and language disorders, Speech-language pathology

SFA entails having the speech-language pathologist (SLP) guide the participant through generation of pertinent semantic features for pictured treatment items (e.g., category membership, physical description, location of item in context, personal associations, action associated with item). For some participants, treatment items were grouped according to typicality of category membership (e.g,, a robin-typical bird and penguin-atypical bird). Training of atypical items may stimulate a broader semantic activation of the category and thus, may promote greater generalization. Treatment was applied sequentially to sets of items in the context of single-subject, multiple baseline designs. In this way, replication of treatment effects could be evaluated within and across participants. Treatment was administered by certified SLPs three times per week until prescribed accuracy levels were met during nontreatment probes or a maximum number of treatment sessions was completed.

Accuracy of naming of pictured treated and untreated items was assessed in probes conducted separate from treatment. Probes were conducted repeatedly throughout the study, from baseline (prior to treatment) to follow-up (6 weeks following treatment). All naming responses were scored using a 0-10 scale reflecting promptness and presence of errors; scores of 8-10 received an "accuate" score and scores of 0-7 received an "inaccurate" score. A percentage accuracy score was calculated for each experimental set of items for every probe session. Baseline probe scores were compared to end of treatment and follow-up probe scores to obtain individual effect sizes for each experimental list of items for each participant (i.e., several effect sizes were calculated for each participant). All effect sizes were utlized to obtain an average effect size for each participant; these averages were then utlized to obtain a group average.

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

Wambaugh JL, Mauszycki S, Cameron R, Wright S, Nessler C. Semantic feature analysis: incorporating typicality treatment and mediating strategy training to promote generalization. Am J Speech Lang Pathol. 2013 May;22(2):S334-69. doi: 10.1044/1058-0360(2013/12-0070).

Wambaugh JL, Mauszycki S, Wright S. Semantic feature analysis: Application to confrontation naming of actions in aphasia. Aphasiology. 2013 Oct 28; 28(1):DOI:10.1080/02687038.2013.845739.