title: Effects of Alphabet-Supplemented Speech on Brain Activity of Listeners: An fMRI Study.
abstract: OBJECTIVE
  The purpose of this article was to examine the neural mechanisms associated with increases in speech intelligibility brought about through alphabet supplementation.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.forename: Kelene
authors.initials: K
authors.lastname: Fercho
authors.forename: Lee A
authors.initials: LA
authors.lastname: Baugh
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Hanson
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D004401:Dysarthria / Q000503:physiopathology; D005260:Female; D006309:Hearing / Q000502:physiology; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D013060:Speech / Q000502:physiology*; D013065:Speech Intelligibility / Q000502:physiology; D013067:Speech Perception / Q000502:physiology; D055815:Young Adult