1. Standardized Assessment of Phonology in Aphasia (PI: Kendall)

In order to prescribe an appropriate treatment program for individuals with aphasia, the type and severity of aphasia must be determined through the use of a valid assessment. While there are existing assessments for aphasia that evaluate components of language such as syntax, lexical retrieval and semantics, there is essentially no measure for phonology. Phonology is a sub-field of linguistics concerned with patterning of sounds in language and is a medium by which sound information is mapped onto higher levels of language such as words. There are theoretical notions supporting phonology in normal language (Nadeau, 2000; Blumstein, 1998). Impaired phonologic processes in adult aphasia have been linked to reading (de Partz, 1986; Kendall et al, 1998; Conway et al, 1998; Adair et al, 2000; Kendall et al, 2003), language comprehension (Blumstein, 1998; Milberg et al, 1988; Heilman et al, 1996), speech production (Nadeau, 2000; Kendall et al, 2003; Browman and Goldstein, 1992) and working memory (Baddley and Hitch, 1974; Friedman et al, 2000) dysfunction. The purpose of this line of research is to develop a valid and reliable measure of phonologic function in aphasia that is sensitive in detecting clinical change and will differentiate between patterns of phonologic dysfunction.

2. Psycholinguistic Analysis of the Boston Naming Test (PI: Choules)
 
The Boston Naming Test (BNT; Kaplan, Goodglass, & Weintraub, 1983) is the most commonly used assessment for individuals with aphasia. The single most common feature of aphasia, and one of the most debilitating aspects of aphasia in most patients, is impairment in ability to name, whether it involves naming seen objects, or producing nouns, verbs and other words conveying meaning in spontaneous language. The BNT assesses the ability to name object based on 60 black and white line drawings ranging in lexical frequency based on the occurrence of the corresponding word in print. Items are presented in order from easiest (high lexical frequency) to hardest (low lexical frequency). Recent analysis of the BNT has found weaknesses in the proposed hierarchy based on lexical frequency. Understanding the factors affecting production of the test items is critical to developing a unidimensional measure which will allow clinicians to accurately assess a person’s ability level. Thus, the focus of this project is to create a hierarchy of the psycholinguistic variables (phonotactic probability, syllable length, cluster effect, and neighborhood density) of the BNT items. The purpose of this analysis will be to determine if the BNT is strictly a test of lexical/semantic frequency.

3. Repetition subtest SAPA (PI: del Toro)

Assessment tools are usually created using classical test theory (CTT) which employs traditional standardization methods which are performed on the test as a whole rather than on the individual items, without attention to the difficulty level of items. An alternative to CTT is Item Response Theory (IRT) that measures responses at an item level. Rasch analysis the one-parameter model of IRT, claims the probability of a person’s response to an item is the combined function of that person’s ability and the difficulty level of the item (Bond & Fox, 2001). We are using Rasch analysis to create a standardized assessment of phonology in aphasia (SAPA). This measure of phonologic function is based on a parallel distributed processing model of phonology in aphasia (Nadeau, 2000). The model describes distributed phonologic representations across various domains (e.g. articulatory, semantic, graphemic, perception). The specific aims of this study are to develop test items for the perceptual to articulatory pathway (repetition) of processing (Nadeau, 2000).

4. High Level Anomia (PI: Hunting Pompon)

Anomia is a common residual symptom of aphasia. People with a mild form of anomia report difficulty finding the right words during conversation, though their scores on traditional standardized assessments of aphasia (such as the Western Aphasia Battery and Boston Naming Test) are often within normal limits. For this reason, people with mild anomia are understudied and underserved. In this retrospective study, we examine data from 25 people with high level anomia and 25 normal controls to determine if there is a relationship between attentional deficits – a concomitant feature of aphasia (Murray, 1999; McNeil, 1991) – and mild anomia. In particular, we examine selective attention and automatic vs. controlled processing of stimuli. This retrospective data analysis seeks to answer the question: Is there a relationship between high level anomia and attentional deficits?

5. Audibility (PI: MacKinnon)

Thousands of seniors are diagnosed with aphasia every year. This population is also prone to age-related and high frequency hearing loss, which often goes undiagnosed and unmanaged. Because some tests of aphasia use auditory stimuli, people with unmanaged hearing loss may miss important high frequency information within the test. Their scores may be reduced due to an inability to hear the sounds presented rather than the severity of their language disorder. When administering the Standard Assessment of Phonology in Aphasia (SAPA), clinicians screen hearing up to 4000 Hz. If the patient passes the hearing screening, the test is administered. This line of research will evaluate the effects of high frequency hearing loss on scores of the SAPA, determine if there are error patterns in test administration and results, and spot scores that are reduced due to hearing loss rather than due to the severity of aphasia. Any error patterns found may help instruct clinicians on when to refer patients for audiologic management of their hearing loss, and ultimately improve test administration to accurately reflect the severity of aphasia.

6. Phonomotor treatment for AOS (PI: Oelke)

Individuals with non-fluent aphasia often exhibit apraxia of speech (AOS). AOS is a motor level disorder in which the retrieval and sequencing of previously learned motor patterns is disrupted. Articulation, rate and prosody are commonly affected. People with AOS often exhibit sound and syllable repetitions, phonemic errors such as substitutions and distortions, and trial-and-error groping (Duffy, 1995). In this retrospective study we examine data from two individuals with aphasia and apraxia of speech to determine the effects of phono-motor treatment on sound production in the rehabilitation of AOS. Phono-motor treatment is an impairment level treatment of phonologic awareness, modified from the Lindamood Phoneme Sequencing Program (LiPS) (Lindamood & Lindamood, 1998).

7. Cognitive Inventory in Stroke (PI: Ouimet-Waters)
  
Anomia, or word finding difficulties, is an established feature across all types of aphasia and has been the subject of extensive research and is commonly targeted for treatment by clinical speech language pathologists (Drew and Thompson, 1999). This specific deficit, however, may not be the most likely to be displayed by individuals with CVAs. While the literature provides evidence that other types of linguistic and neurocognitive impairments do occur, a study relating the most common deficits to result from stroke has not yet been conducted. This study presents a cognitive inventory analysis of linguistic and neuropsychological data from 425 individuals delineating ten of the most common deficits from stroke in an effort to better guide assessment and treatment practices. The ten areas of impairment evaluated in this study include: anomia, aphasia, agraphia, alexia, agrammatism, aprosodia, attention, memory, psychomotor, and executive function.

8. Implicit Priming in Aphasia (PI: Silkes)
 
Current models of spoken language production suggest that the language processing system is composed of a network of lexical and semantic nodes that automatically spread activation to each other as part of language processing. This automatic spread of activation is implicit, in that it occurs outside of conscious awareness or control. Intact implicit processing is thought to underlie the automatic, fluent, rapid use of language in typical adults. Implicit processing is also a component of learning and, therefore, a component of any language rehabilitation that may be undertaken to remediate language deficits following stroke (i.e., aphasia). Previous research has raised the question of whether automatic activation of the linguistic system is preserved or impaired in aphasia. If there is a deficit in the spread of automatic activation in individuals with aphasia, this may underlie their language deficits, and/or may influence their response to treatment. This research study is focused on understanding the status of implicit processing in people with aphasia, with plans for future research applying these findings to developing effective treatment methods for the word-retrieval problems that are so common in aphasia.