title: Delayed auditory feedback simulates features of nonfluent primary progressive aphasia.
abstract: The pathophysiology of nonfluent primary progressive aphasia (nfvPPA) remains poorly understood. Here, we compared quantitatively speech parameters in patients with nfvPPA versus healthy older individuals under altered auditory feedback, which has been shown to modulate normal speech output. Patients (n=15) and healthy volunteers (n=17) were recorded while reading aloud under delayed auditory feedback [DAF] with latency 0, 50 or 200 ms and under DAF at 200 ms plus 0.5 octave upward pitch shift. DAF in healthy older individuals was associated with reduced speech rate and emergence of speech sound errors, particularly at latency 200 ms. Up to a third of the healthy older group under DAF showed speech slowing and frequency of speech sound errors within the range of the nfvPPA cohort. Our findings suggest that (in addition to any anterior, primary language output disorder) these key features of nfvPPA may reflect distorted speech input signal processing, as simulated by DAF. DAF may constitute a novel candidate pathophysiological model of posterior dorsal cortical language pathway dysfunction in nfvPPA.
authors.affiliation: Institute of Molecular Medicine and Faculty of Medicine, University of Lisbon, Portugal; Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Carolina
authors.initials: C
authors.lastname: Maruta
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Sonya
authors.initials: S
authors.lastname: Makhmood
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Downey
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Hannah L
authors.initials: HL
authors.lastname: Golden
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Fletcher
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Pirada
authors.initials: P
authors.lastname: Witoonpanich
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Rohrer
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom. Electronic address: jason.warren@ucl.ac.uk.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Warren
mesh_terms: D000368:Aged; D018888:Aphasia, Primary Progressive / Q000503:physiopathology*; D001307:Auditory Perception; D056228:Feedback, Sensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time; D013060:Speech
keywords: Altered auditory feedback; Delayed auditory feedback; Dementia; Dorsal pathway; Language; Progressive aphasia