Successful syllable detection in aphasia despite processing impairments as revealed by event-related potentials.

Full Abstract

BACKGROUND:
The role of impaired sound and speech sound processing for auditory language comprehension deficits in aphasia is unclear. No electrophysiological studies of attended speech sound processing in aphasia have been performed for stimuli that are discriminable even for patients with severe auditory comprehension deficits.

METHODS:
Event-related brain potentials (ERPs) were used to study speech sound processing in a syllable detection task in aphasia. In an oddball paradigm, the participants had to detect the infrequent target syllable /ta:/ amongst the frequent standard syllable /ba:/. 10 subjects with moderate and 10 subjects with severe auditory comprehension impairment were compared to 11 healthy controls.

RESULTS:
N1 amplitude was reduced indicating impaired primary stimulus analysis; N1 reduction was a predictor for auditory comprehension impairment. N2 attenuation suggests reduced attended stimulus classification and discrimination. However, all aphasic patients were able to discriminate the stimuli almost without errors, and processes related to the target identification (P3) were not significantly reduced. The aphasic subjects might have discriminated the stimuli by purely auditory differences, while the ERP results reveal a reduction of language-related processing which however did not prevent performing the task. Topographic differences between aphasic subgroups and controls indicate compensatory changes in activation.

CONCLUSION:
Stimulus processing in early time windows (N1, N2) is altered in aphasics with adverse consequences for auditory comprehension of complex language material, while allowing performance of simpler tasks (syllable detection). Compensational patterns of speech sound processing may be activated in syllable detection, but may not be functional in more complex tasks. The degree to which compensational processes can be activated probably varies depending on factors as lesion site, time after injury, and language task.

Learn Faster Today Improve your study skills

Author information

Author/s: Becker, Frank (F); Reinvang, Ivar (I);

Affiliation: Sunnaas Rehabilitation Hospital, Faculty Division Ullevål University Hospital, University of Oslo, 0318 Oslo, Norway. frank.becker(-atsign-)sunnaas.no

Journal and publication information

Publication Type: Journal Article

Journal: Behavioral and brain functions : BBF (Behav Brain Funct), published in England. (Language: eng)

Reference: 2007-; vol 3 (issue ) : pp 6

Dates: Created 2007/02/27; Completed 2007/07/25; Revised 2008/11/20;

PMID: 17239239, status: PubMed-not-MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

No MeSH Headings found.

The article may not be MeSH Indexed as yet.

This article has not been indexed for related articles as yet, however you can still use the live related article search links below.

See 100+ related articles.

See a large map of 100+ related articles.