Dichotic memory: paradoxical effect of removing a left frontal gyrus: a case study.
A 27-year-old right-handed woman was operated with resection of an epileptogenic lesion, a nonmalignant tumor, in the left frontal lobe. The surrounding cortical and subcortical tissue in the tumor-containing gyrus was also resected. Care was taken during the operation not to interfere with motor or language related cortical areas. Pre- and postoperatively, she was tested with a dichotic memory test. In the preoperative test, she showed a marked Left Ear Advantage. In the corresponding tests on the second and fourth postoperative days and at follow-up, her performance had changed to a Right Ear Advantage. A possible explanation of this result is that neighboring cortical areas involved in hemispheric specialization for lateralized, verbal cognitive functions are suppressed by a focal epiletogeneic activity caused by the tumor. The subsequent removal of this influence allowed these cortical areas to function normally.
Wester
K
K
Dept. of Neurosurgery, University of Bergen Medical School, Haukeland Hospital, Norway.
Lundervold
A J
AJ
Hugdahl
K
K
Taksdal
I
I
D000328:Adult; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery; D004007:Dichotic Listening Tests; D004827:Epilepsy / Q000209:etiology / Q000473:pathology / Q000601:surgery; D005260:Female; D005625:Frontal Lobe / Q000502:physiology* / Q000601:surgery; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008568:Memory / Q000502:physiology*