Effects of alphabet-supplemented speech on brain activity of listeners: An fMRI study

Kelene Fercho, Lee A. Baugh, Elizabeth K. Hanson

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Purpose: The purpose of this article was to examine the neural mechanisms associated with increases in speech intelligibility brought about through alphabet supplementation. Method: Neurotypical participants listened to dysarthric speech while watching an accompanying video of a hand pointing to the 1st letter spoken of each word on an alphabet display (treatment condition) or a scrambled display (control condition). Their hemodynamic response was measured with functional magnetic resonance imaging, using a sparse sampling event-related paradigm. Speech intelligibility was assessed via a forced-choice auditory identification task throughout the scanning session. Results: Alphabet supplementation was associated with significant increases in speech intelligibility. Further, alphabet supplementation increased activation in brain regions known to be involved in both auditory speech and visual letter perception above that seen with the scrambled display. Significant increases in functional activity were observed within the posterior to mid superior temporal sulcus/superior temporal gyrus during alphabet supplementation, regions known to be involved in speech processing and audiovisual integration. Conclusion: Alphabet supplementation is an effective tool for increasing the intelligibility of degraded speech and is associated with changes in activity within audiovisual integration sites. Changes in activity within the superior temporal sulcus/superior temporal gyrus may be related to the behavioral increases in intelligibility brought about by this augmented communication method.

Original languageEnglish (US)
Pages (from-to)1452-1463
Number of pages12
JournalJournal of Speech, Language, and Hearing Research
Issue number5
StatePublished - Oct 1 2015
Externally publishedYes

ASJC Scopus subject areas

  • Language and Linguistics
  • Linguistics and Language
  • Speech and Hearing


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