OBJECTIVE: To investigate the degree of language dominance in patients with left and right hemisphere seizure foci compared to normal volunteers using a fMRI reading comprehension task. METHODS: Fifty patients with complex partial epilepsy, aged 8 to 56 years and 33 normal volunteers, aged 7 to 34 had fMRI (1.5 T) and neuropsychological testing. Participants silently named an object described by a sentence compared to a visual control. Data were analyzed with region of interest (ROI) analysis based on t maps for inferior frontal gyrus (IFG), midfrontal gyrus (MFG), and Wernicke area (WA). Regional asymmetry indices (AIs) were calculated [(L - R)/(L + R)]; AI > 0.20 was deemed left dominant and AI < 0.20 as atypical language. RESULTS: Left hemisphere focus patients had a higher likelihood of atypical language than right hemisphere focus patients (21% vs 0%, chi2 < 0.002). Left hemisphere focus patients, excluding those with atypical language, had lower regional AI in IFG, MFG, and WA than controls. Right hemisphere focus patients were all left language dominant and had a lower AI than controls in WA and MFG, but not for IFG. AI in MFG and WA were similar between left hemisphere focus/left language patients and right hemisphere focus patients. Patients activated more voxels than healthy volunteers. Lower AIs were attributable to greater activation in right homologous regions. Less activation in the right-side WA correlated with better verbal memory performance in right focus/left hemisphere-dominant patients, whereas less strongly lateralized activation in IFG correlated better with Verbal IQ in left focus/left hemisphere-dominant patients. CONCLUSIONS: Patients had lower asymmetry indices than healthy controls, reflecting increased recruitment of homologous right hemisphere areas for language processing. Greater right hemisphere activation may reflect greater cognitive effort in patient populations, the effect of epilepsy, or its treatment. Regional activation patterns reflect adaptive efforts at recruiting more widespread language processing networks that are differentially affected based on hemisphere of seizure focus.
OBJECTIVE: To investigate the degree of language dominance in patients with left and right hemisphere seizure foci compared to normal volunteers using a fMRI reading comprehension task. METHODS: Fifty patients with complex partial epilepsy, aged 8 to 56 years and 33 normal volunteers, aged 7 to 34 had fMRI (1.5 T) and neuropsychological testing. Participants silently named an object described by a sentence compared to a visual control. Data were analyzed with region of interest (ROI) analysis based on t maps for inferior frontal gyrus (IFG), midfrontal gyrus (MFG), and Wernicke area (WA). Regional asymmetry indices (AIs) were calculated [(L - R)/(L + R)]; AI > 0.20 was deemed left dominant and AI < 0.20 as atypical language. RESULTS: Left hemisphere focus patients had a higher likelihood of atypical language than right hemisphere focus patients (21% vs 0%, chi2 < 0.002). Left hemisphere focus patients, excluding those with atypical language, had lower regional AI in IFG, MFG, and WA than controls. Right hemisphere focus patients were all left language dominant and had a lower AI than controls in WA and MFG, but not for IFG. AI in MFG and WA were similar between left hemisphere focus/left language patients and right hemisphere focus patients. Patients activated more voxels than healthy volunteers. Lower AIs were attributable to greater activation in right homologous regions. Less activation in the right-side WA correlated with better verbal memory performance in right focus/left hemisphere-dominant patients, whereas less strongly lateralized activation in IFG correlated better with Verbal IQ in left focus/left hemisphere-dominant patients. CONCLUSIONS:Patients had lower asymmetry indices than healthy controls, reflecting increased recruitment of homologous right hemisphere areas for language processing. Greater right hemisphere activation may reflect greater cognitive effort in patient populations, the effect of epilepsy, or its treatment. Regional activation patterns reflect adaptive efforts at recruiting more widespread language processing networks that are differentially affected based on hemisphere of seizure focus.
Authors: Leigh N Sepeta; Madison M Berl; Marko Wilke; Xiaozhen You; Meera Mehta; Benjamin Xu; Sara Inati; Irene Dustin; Omar Khan; Alison Austermuehle; William H Theodore; William D Gaillard Journal: Epilepsia Date: 2015-12-23 Impact factor: 5.864
Authors: Xiaozhen You; Malek Adjouadi; Magno R Guillen; Melvin Ayala; Armando Barreto; Naphtali Rishe; Joseph Sullivan; Dennis Dlugos; John Vanmeter; Drew Morris; Elizabeth Donner; Bruce Bjornson; Mary Lou Smith; Byron Bernal; Madison Berl; William D Gaillard Journal: Hum Brain Mapp Date: 2011-05 Impact factor: 5.038
Authors: R Matsumoto; T Okada; N Mikuni; T Mitsueda-Ono; J Taki; N Sawamoto; T Hanakawa; Y Miki; N Hashimoto; H Fukuyama; R Takahashi; A Ikeda Journal: J Neurol Date: 2008-09-25 Impact factor: 4.849
Authors: J Mbwana; M M Berl; E K Ritzl; L Rosenberger; J Mayo; S Weinstein; J A Conry; P L Pearl; S Shamim; E N Moore; S Sato; L G Vezina; W H Theodore; W D Gaillard Journal: Brain Date: 2008-12-05 Impact factor: 13.501
Authors: Cristina Bigras; Paula K Shear; Jennifer Vannest; Jane B Allendorfer; Jerzy P Szaflarski Journal: Epilepsy Behav Date: 2012-11-30 Impact factor: 2.937