Phonemic restoration in Alzheimer's disease and semantic dementia: A preliminary investigation

Jessica Jiang, Jeremy C.S. Johnson, Mai Carmen Requena-Komuro, Elia Benhamou, Harri Sivasathiaseelan, Damion L. Sheppard, Anna Volkmer, Sebastian J. Crutch, Chris J.D. Hardy, Jason D. Warren

Research output: Contribution to journalArticlepeer-review


Phonemic restoration - perceiving speech sounds that are actually missing - is a fundamental perceptual process that 'repairs' interrupted spoken messages during noisy everyday listening. As a dynamic, integrative process, phonemic restoration is potentially affected by neurodegenerative pathologies, but this has not been clarified. Here, we studied this phenomenon in 5 patients with typical Alzheimer's disease and 4 patients with semantic dementia, relative to 22 age-matched healthy controls. Participants heard isolated sounds, spoken real words and pseudowords in which noise bursts either overlaid a consonant or replaced it; a tendency to hear replaced (missing) speech sounds as present signified phonemic restoration. All groups perceived isolated noises normally and showed phonemic restoration of real words, most marked in Alzheimer's patients. For pseudowords, healthy controls showed no phonemic restoration, while Alzheimer's patients showed marked suppression of phonemic restoration and patients with semantic dementia contrastingly showed phonemic restoration comparable to real words. Our findings provide the first evidence that phonemic restoration is preserved or even enhanced in neurodegenerative diseases, with distinct syndromic profiles that may reflect the relative integrity of bottom-up phonological representation and top-down lexical disambiguation mechanisms in different diseases. This work has theoretical implications for predictive coding models of language and neurodegenerative disease and for understanding cognitive 'repair' processes in dementia. Future research should expand on these preliminary observations with larger cohorts.

Original languageEnglish (US)
Article numberfcac118
JournalBrain Communications
Issue number3
StatePublished - 2022
Externally publishedYes


  • Alzheimer's disease
  • auditory processing
  • phonemic restoration
  • semantic dementia
  • speech perception

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry
  • Cellular and Molecular Neuroscience
  • Neurology


Dive into the research topics of 'Phonemic restoration in Alzheimer's disease and semantic dementia: A preliminary investigation'. Together they form a unique fingerprint.

Cite this