Interhemispheric differences of spectral power in expressive language: a MEG study with clinical applications

TY - JOUR

T1 - Interhemispheric differences of spectral power in expressive language

T2 - a MEG study with clinical applications

AU - Fisher, Alison E.

AU - Furlong, Paul L.

AU - Seri, Stefano

AU - Adjamian, Peyman

AU - Witton, Caroline

AU - Baldeweg, Torsten

AU - Phillips, Sunny

AU - Walsh, Richard

AU - Houghton, Judith.M

AU - Thai, Ngoc Jade

N1 - NOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Psychophysiology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fisher, Alison E.; Furlong, Paul L.; Seri, Stefano; Adjamian, Peyman; Witton, Caroline; Baldeweg, Torsten; Phillips, Sunny; Walsh, Richard; Houghton, Judith.M and Thai, Ngoc Jade (2008). Interhemispheric differences of spectral power in expressive language: a MEG study with clinical applications. International Journal of Psychophysiology, 68 (2), pp. 111-122. DOI 10.1016/j.ijpsycho.2007.12.005

PY - 2008/5

Y1 - 2008/5

N2 - In the last decade we have seen an exponential growth of functional imaging studies investigating multiple aspects of language processing. These studies have sparked an interest in applying some of the paradigms to various clinically relevant questions, such as the identification of the cortical regions mediating language function in surgical candidates for refractory epilepsy. Here we present data from a group of adult control participants in order to investigate the potential of using frequency specific spectral power changes in MEG activation patterns to establish lateralisation of language function using expressive language tasks. In addition, we report on a paediatric patient whose language function was assessed before and after a left hemisphere amygdalo-hippocampectomy. Our verb generation task produced left hemisphere decreases in beta-band power accompanied by right hemisphere increases in low beta-band power in the majority of the control group, a previously unreported phenomenon. This pattern of spectral power was also found in the patient's post-surgery data, though not her pre-surgery data. Comparison of pre and post-operative results also provided some evidence of reorganisation in language related cortex both inter- and intra-hemispherically following surgery. The differences were not limited to changes in localisation of language specific cortex but also changes in the spectral and temporal profile of frontal brain regions during verb generation. While further investigation is required to establish concordance with invasive measures, our data suggest that the methods described may serve as a reliable lateralisation marker for clinical assessment. Furthermore, our findings highlight the potential utility of MEG for the investigation of cortical language functioning in both healthy development and pathology.

AB - In the last decade we have seen an exponential growth of functional imaging studies investigating multiple aspects of language processing. These studies have sparked an interest in applying some of the paradigms to various clinically relevant questions, such as the identification of the cortical regions mediating language function in surgical candidates for refractory epilepsy. Here we present data from a group of adult control participants in order to investigate the potential of using frequency specific spectral power changes in MEG activation patterns to establish lateralisation of language function using expressive language tasks. In addition, we report on a paediatric patient whose language function was assessed before and after a left hemisphere amygdalo-hippocampectomy. Our verb generation task produced left hemisphere decreases in beta-band power accompanied by right hemisphere increases in low beta-band power in the majority of the control group, a previously unreported phenomenon. This pattern of spectral power was also found in the patient's post-surgery data, though not her pre-surgery data. Comparison of pre and post-operative results also provided some evidence of reorganisation in language related cortex both inter- and intra-hemispherically following surgery. The differences were not limited to changes in localisation of language specific cortex but also changes in the spectral and temporal profile of frontal brain regions during verb generation. While further investigation is required to establish concordance with invasive measures, our data suggest that the methods described may serve as a reliable lateralisation marker for clinical assessment. Furthermore, our findings highlight the potential utility of MEG for the investigation of cortical language functioning in both healthy development and pathology.

KW - language lateralisation

KW - verb generation

KW - MEG

KW - epilepsy

KW - spectral power

UR - http://www.scopus.com/inward/record.url?scp=43049121680&partnerID=8YFLogxK

U2 - 10.1016/j.ijpsycho.2007.12.005

DO - 10.1016/j.ijpsycho.2007.12.005

M3 - Article

C2 - 18316134

VL - 68

SP - 111

EP - 122

JO - International Journal of Psychophysiology

JF - International Journal of Psychophysiology

SN - 0167-8760

IS - 2

ER -