REFERENCES Dunton, J., Bruce, C., Newton, C. (2011). Investigating the impact of unfamiliar speaker accent on auditory comprehension in adults with aphasia. International Journal of Language & Communication Disorders, 46 (1), Jesse, A, & McQueen, J. “Positional effects in the lexical retuning of speech perception.” Psychon Bull Rev (2011) 1-8. Print. DOI: /s Kraljic, T, & Samuel, A.G. (2007). Perceptual adjustments to multiple speakers. Journal of Memory and Language, 56, Kraljic, T & Samuel, A.G. (2005). Perceptual learning for speech; Is there a return to normal? Cognitive Psychology, 51, Myers, E, & L. Mesite. (2012). Neural systems underlying lexically-biased perceptual learning in speech.” Paper presented at the Neurobiology of Language Meeting, San Sebastian, Spain. EXPECTED RESULTS METHODS Screening: We expect to run ~32 participants in the study (16 persons with aphasia, 16 unimpaired controls.) Participants will be monolingual English speakers, between the ages of 18-75, with no known hearing impairments. 1.Hearing Screening- all participants (experimental and controls) will go through a standard hearing screening to ensure they are able to hear the stimuli in the experiment. 2.Western Aphasia Battery Test- only the participants with aphasia will go through an Aphasia Test to test the language function in these adults and determine the type of aphasia and level of severity, so we are able to use that information moving forward and examining their results. Tasks: 1.Lexical Decision Task- Participants hear tokens of 50 words (ex. bullying, document, parakeet) and 50 non- words (ex. klogodar, ryligal, wonimtic) in random order and are asked to decide if what they hear is a word or a non-word. 20 of these tokens are considered “critical words” and contain an ambiguous sound (50% /s/, 50% /sh/) word medially. In this training we expect listeners to retune to their talker and adjust previously held phoneme boundaries to accommodate their speaker. 1.Phoneme Identification Task-Participants hear a continuum of tokens in the same voice from training, ranging from 30% /s/, 70% /sh/ to 80% /s/, 20% /sh/. Each token is inserted into “a?i” and is played randomly 10 times in the set. Participants are asked to decide if what they hear sounds more like “asi” or “ashi.” We expect participants to classify more ambiguous tokens based on the type of training they had (Myers, Mesite, 2012). INTRODUCTION In a dynamic world where relating to others is an important aspect of life, being able to speak and understand people is essential for effective communication. However, it is often the case that we have variation in our speech signal. Examples of Speech Signal Variations:  Boston accent ‘r’ dropping ( “car”  “cah”)  Southern accent vowel breaking (“cat”  “cayut”)  Speaker with a lisp (“sing”  “thing”)  Speaking rate (people tend to talk faster on the East Coast) With all of this variation in the speech signal we encounter how is it that we are able to keep a stable perception of incoming speech in order to understand our talker? Kraljic & Samuel (2005) suggested two techniques of how this occurs. Two Theories of Learning New Talkers: 1. One idea is that a listener holds multiple representations of every speaker they encounter. 2. The other idea suggests a change in phonemic boundaries after exposure to an ambiguous phoneme. Previous studies have shown that listeners who are exposed to a new talker adjust their speech sound categories to correspond with the new speaker (Kraljic & Samuel, 2005). While this is easily observed in a non-disordered population, it is unknown whether the same process occurs in a disordered population, like persons with aphasia. What is Aphasia? Aphasia is a loss of language that occurs usually after a left hemisphere brain damage. People who have aphasia can show a variety of symptoms and different rates of recovery depending on the type of aphasia and the severity. Dunton et. al (2011) conducted an experiment where participants with aphasia heard familiar and unfamiliar accented speech and tested sentence comprehension. They found that the individuals with aphasia were lower in accuracy in both unfamiliar and familiar accents than the non-disordered group. This difficulty in retuning in persons with aphasia is examined in the present study. College of Liberal Arts and Sciences Speech and Language Processing Differences Between Impaired and Unimpaired Populations Julia R. Drouin, SURF Award Recipient, Summer 2013, Dr. Emily Myers, PhD, Department of Speech, Language, and Hearing Sciences Dr. Rachel Theodore, PhD, Department of Speech, Language, and Hearing Sciences /s/ group/sh/ group Critical Word Tokens Era?er Coli?eum Epi?ode Ambi?ion Flouri?ing Publi?er Speaker 1 Speaker 2 Speaker 3 Speaker 2 Speaker 3 Speech Sound Category before new talker Speech Sound Category after new talker DISCUSSION Differences between populations: We expect the unimpaired group to adjust their speech sound categories to accommodate their speaker. Figure 1 shows what we typically expect to see in an unimpaired population,: participants will be more likely to categorize ambiguous sounds based on the type of training received. Figure 2 shows hypothesized data in the impaired population; participants in both training groups will not be more likely to define an ambiguous sound as ‘asi’ or ‘ashi’ just based on training. Differences within population: We also expect to differences within our population of language impaired individuals. Persons with aphasia have deficits in language production and comprehension, however they may show more difficulty in one area.  Fluent Aphasia- This group typically has more difficulty with comprehension than production: we expect to see difficulty adapting to a variable speech signal and anticipate results similar to Figure 2. This would predict that fluent aphasics might have particular difficult adapting to non-standard speech or accents.  Non-fluent Aphasia- This group has relatively intact comprehension. If we see results similar to Figure 2 (impaired) this may suggest that persons who experience brain damage may have permanent effects in speech and language processing. However, given that this group has good comprehension, we may see results similar to Figure 1 (unimpaired), suggesting plasticity in the brain and it’s aptitude to reorganize in order to persevere speech and language processing abilities. “rehearsal” “rehearshal” Talker 1Talker 2 Group 1 Female /s/Male /sh/ Group 2 Female /sh/Male /s/ “rehear?al” 30% /s/40% /s/50% /s/60% /s/70% /s/80% /s/ “ashi” “asi” Figure 1 Figure 2