Fundamental deficits of auditory perception in wernicke's aphasia

Robson, Holly; Grube, Manon; Griffiths, Timothy D.; Lambon Ralph, Matthew A.; Sage, Karen

Abstract

Objective: This work investigates the nature of the comprehension impairment in Wernicke's aphasia (WA), by examining the relationship between deficits in auditory processing of fundamental, non-verbal acoustic stimuli and auditory comprehension. WA, a condition resulting in severely disrupted auditory comprehension, primarily occurs following a cerebrovascular accident (CVA) to the left temporo-parietal cortex. Whilst damage to posterior superior temporal areas is associated with auditory linguistic comprehension impairments, functional-imaging indicates that these areas may not be specific to speech processing but part of a network for generic auditory analysis. Methods: We examined analysis of basic acoustic stimuli in WA participants (. n=10) using auditory stimuli reflective of theories of cortical auditory processing and of speech cues. Auditory spectral, temporal and spectro-temporal analysis was assessed using pure-tone frequency discrimination, frequency modulation (FM) detection and the detection of dynamic modulation (DM) in "moving ripple" stimuli. All tasks used criterion-free, adaptive measures of threshold to ensure reliable results at the individual level. Results: Participants with WA showed normal frequency discrimination but significant impairments in FM and DM detection, relative to age- and hearing-matched controls at the group level (. n=10). At the individual level, there was considerable variation in performance, and thresholds for both FM and DM detection correlated significantly with auditory comprehension abilities in the WA participants. Conclusion: These results demonstrate the co-occurrence of a deficit in fundamental auditory processing of temporal and spectro-temporal non-verbal stimuli in WA, which may have a causal contribution to the auditory language comprehension impairment. Results are discussed in the context of traditional neuropsychology and current models of cortical auditory processing. © 2012 Elsevier Ltd.

• Journal Article Type: Article
• Publication Date: Jan 1, 2013
• Journal: Cortex
• Print ISSN: 0010-9452
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 49
• Issue: 7
• Pages: 1808-1822
• DOI: https://doi.org/10.1016/j.cortex.2012.11.012
• Keywords: auditory processing, Wernicke's aphasia, comprehension,; frequency, frequency modulation, dynamic modulation
• Public URL: https://uwe-repository.worktribe.com/output/929484
• Publisher URL: http://dx.doi.org/10.1016/j.cortex.2012.11.012