A dual task priming investigation of right hemisphere inhibition for people with left hemisphere lesions

Smith-Conway, Erin R., Chenery, Helen J., Angwin, Anthony J. and Copland, David A. (2012) A dual task priming investigation of right hemisphere inhibition for people with left hemisphere lesions. Behavioral and Brain Functions, 8 14.1-14.17. doi:10.1186/1744-9081-8-14

Author Smith-Conway, Erin R.
Chenery, Helen J.
Angwin, Anthony J.
Copland, David A.
Title A dual task priming investigation of right hemisphere inhibition for people with left hemisphere lesions
Journal name Behavioral and Brain Functions   Check publisher's open access policy
ISSN 1744-9081
Publication date 2012-03-21
Sub-type Article (original research)
DOI 10.1186/1744-9081-8-14
Open Access Status DOI
Volume 8
Start page 14.1
End page 14.17
Total pages 17
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2013
Language eng
Formatted abstract
Background: During normal semantic processing, the left hemisphere (LH) is suggested to restrict right hemisphere (RH) performance via interhemispheric suppression. However, a lesion in the LH or the use of concurrent tasks to overload the LH's attentional resource balance has been reported to result in RH disinhibition with subsequent improvements in RH performance. The current study examines variations in RH semantic processing in the context of unilateral LH lesions and the manipulation of the interhemispheric processing resource balance, in order to explore the relevance of RH disinhibition to hemispheric contributions to semantic processing following a unilateral LH lesion.
Methods: RH disinhibition was examined for nine participants with a single LH lesion and 13 matched controls using the dual task paradigm. Hemispheric performance on a divided visual field lexical decision semantic priming task was compared over three verbal memory load conditions, of zero-, two- and six-words. Related stimuli consisted of categorically related, associatively related, and categorically and associatively related prime-target pairs. Response time and accuracy data were recorded and analyzed using linear mixed model analysis, and planned contrasts were performed to compare priming effects in both visual fields, for each of the memory load conditions.
Results: Control participants exhibited significant bilateral visual field priming for all related conditions (p < .05), and a LH advantage over all three memory load conditions. Participants with LH lesions exhibited an improvement in RH priming performance as memory load increased, with priming for the categorically related condition occurring only in the 2- and 6-word memory conditions. RH disinhibition was also reflected for the LH damage (LHD) group by the removal of the LH performance advantage following the introduction of the memory load conditions.
Conclusions: The results from the control group are consistent with suggestions of an age related hemispheric asymmetry reduction and indicate that in healthy aging compensatory bilateral activation may reduce the impact of inhibition. In comparison, the results for the LHD group indicate that following a LH lesion RH semantic processing can be manipulated and enhanced by the introduction of a verbal memory task designed to engage LH resources and allow disinhibition of RH processing.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article # 14

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Created: Fri, 20 Jul 2012, 10:28:25 EST by Roheen Gill on behalf of UQ Centre for Clinical Research