title: The relationship between neuropsychological functioning and FDG-PET hypometabolism in intractable mesial temporal lobe epilepsy.
abstract: We examined the relationship between baseline neuropsychological functioning and 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in intractable mesial temporal lobe epilepsy (MTLE). We hypothesized relationships between dominant temporal lobe hypometabolism and verbal memory and between nondominant temporal lobe hypometabolism and nonverbal memory in line with the lateralized material-specific model of memory deficits in MTLE. We also hypothesized an association between performance on frontal lobe neuropsychological tests and prefrontal hypometabolism. Thirty-two patients who had undergone temporal lobectomy for treatment of MTLE and who completed both presurgical FDG-PET and comprehensive neuropsychological investigations with widely used standardized measures were included. Age-adjusted composite measures were calculated for verbal memory, nonverbal memory, relative material-specific memory, IQ, executive function, attention/working memory, and psychomotor speed. Fluorodeoxyglucose positron emission tomography was analyzed with statistical parametric mapping (SPM) to identify hypometabolism relative to healthy controls. Pearson's correlation was used to determine the relationship between regions of hypometabolism and neuropsychological functioning. Dominant temporal lobe hypometabolism was associated with relatively inferior verbal memory, while nondominant temporal lobe hypometabolism was associated with inferior nonverbal memory. No relationship was found between performance on any frontal lobe measures and prefrontal hypometabolism. Statistical parametric mapping-quantified lateralized temporal lobe hypometabolism correlates with material-specific episodic memory impairment in MTLE. In contrast, prefrontal hypometabolism is not associated with performance on frontal lobe measures. We suggest that this is because frontal lobe neuropsychology tests may not be good measures of isolated frontal lobe functioning.
authors.affiliation: Department of Psychology, Macquarie University, NSW, Australia; Department of Medical Psychology, Westmead Hospital, NSW, Australia.
authors.forename: Alex A
authors.initials: AA
authors.lastname: Knopman
authors.affiliation: Sydney Medical School, University of Sydney, NSW, Australia; Departments of Neurology, Westmead Hospital and The Children's Hospital at Westmead, NSW, Australia.
authors.forename: Chong H
authors.initials: CH
authors.lastname: Wong
authors.affiliation: Department of Psychology, Macquarie University, NSW, Australia.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Stevenson
authors.affiliation: Department of Psychology, Macquarie University, NSW, Australia.
authors.forename: Judi
authors.initials: J
authors.lastname: Homewood
authors.affiliation: Sydney Medical School, University of Sydney, NSW, Australia; Department of Molecular Imaging, Royal Prince Alfred Hospital, NSW, Australia.
authors.forename: Armin
authors.initials: A
authors.lastname: Mohamed
authors.affiliation: Institute of Neurological Sciences, Prince of Wales Hospital, NSW, Australia; Faculty of Medicine, University of New South Wales, NSW, Australia.
authors.forename: Ernest
authors.initials: E
authors.lastname: Somerville
authors.affiliation: Sydney Medical School, University of Sydney, NSW, Australia; Department of Molecular Imaging, Royal Prince Alfred Hospital, NSW, Australia.
authors.forename: Stefan
authors.initials: S
authors.lastname: Eberl
authors.affiliation: Sydney Medical School, University of Sydney, NSW, Australia; Department of Molecular Imaging, Royal Prince Alfred Hospital, NSW, Australia.
authors.forename: Lingfeng
authors.initials: L
authors.lastname: Wen
authors.affiliation: Sydney Medical School, University of Sydney, NSW, Australia; Department of Molecular Imaging, Royal Prince Alfred Hospital, NSW, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Fulham
authors.affiliation: Sydney Medical School, University of Sydney, NSW, Australia; Departments of Neurology, Westmead Hospital and The Children's Hospital at Westmead, NSW, Australia. Electronic address: andrew.bleasel@sydney.edu.au.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Bleasel
mesh_terms: D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000379:methods; D001288:Attention; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D005625:Frontal Lobe / Q000503:physiopathology; D044882:Glucose Metabolism Disorders / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000175:diagnosis; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography / Q000379:methods*; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Cognitive functioning; Epilepsy surgery; Episodic memory; Focal epilepsy; Frontal lobes; Positron emission tomography