Aphasia is an acquired impairment of language and communication typically caused by stroke, which affects about one million people in the US. Anomia, the inability to name, is very common in aphasia. Anecdotally, people with aphasia often report being able to retrieve a word correctly, even when they have difficulty saying it out loud. They say that the word sounds right in my head, as if they could say it internally. This description represents a subjective experience called inner speech, and is very difficult to verify. Remarkably, although the sense of inner speech is nearly universal for people with aphasia, only one prior study published in 1976 directly investigated whether the insights of people with aphasia regarding their inner speech are meaningful. This project will use modern brain imaging techniques and tests of language to understand the relationship between the subjective experience of inner speech and word finding in people with aphasia. The main hypothesis is that the sense of successful inner speech in people with aphasia reflects true access to the phonological code (sound) of the word. Further, we expect that activity in brain areas involved in phonological access should reflect the report of successful inner speech, regardless of whether the word is said correctly out loud. We will use inner speech and out loud naming tasks, tests of phonological access, and fMRI scans during inner speech to test whether the sense of successful inner speech predicts out loud speech, access to phonological information (like number and type of syllables), and brain activity during use of inner speech. Analyses will be performed primarily at the single subject level, because we ultimately hope to use these approaches to guide individualized treatments for anomia, and the meaning of subjective reports of inner speech may depend critically on the specific language and cognitive deficits of the person. Pilot data from two volunteers suggest that the experimental design is feasible and will yield valid results. It also suggests that self- report of inner speech in aphasi is meaningful and does reflect phonological access, even when the word cannot be said out loud. Moreover, these pilot data suggest that self-report of successful inner speech is predictive of word-by-word success in subsequent anomia treatment. This research project will provide new information relevant to the study of language and language deficits, and could fundamentally change the way that we understand the experience of aphasia.
Aphasia, an acquired impairment in language and communication frequently resulting from stroke, affects about one million people in the US, causing significant suffering and long-term disability. People with aphasia almost always have difficulties saying some words out loud but often say that 'it sounds right in my head.' This study uses language tests and neuroimaging to investigate what the report of 'inner speech' tells us about word-finding failure in people with aphasia, so that this information can be used to predict treatment outcomes and improve recovery of language after stroke for individuals on a word-by-word basis.
| Fama, Mackenzie E; Hayward, William; Snider, Sarah F et al. (2017) Subjective experience of inner speech in aphasia: Preliminary behavioral relationships and neural correlates. Brain Lang 164:32-42 |
| Hayward, William; Snider, Sarah F; Luta, George et al. (2016) Objective support for subjective reports of successful inner speech in two people with aphasia. Cogn Neuropsychol 33:299-314 |
