title: Using multivariate data reduction to predict postsurgery memory decline in patients with mesial temporal lobe epilepsy.
abstract: Predicting postsurgery memory decline is crucial to clinical decision-making for individuals with mesial temporal lobe epilepsy (mTLE) who are candidates for temporal lobe excisions. Extensive neuropsychological testing is critical to assess risk, but the numerous test scores it produces can make deriving a formal prediction of cognitive change quite complex. In order to benefit from the information contained in comprehensive memory assessment, we used principal component analysis (PCA) to simplify neuropsychological test scores (presurgical and pre- to postsurgical change) obtained from a cohort of 56 patients with mTLE into a few easily interpretable latent components. We next performed discriminant analyses using presurgery latent components to categorize seizure laterality and then regression analyses to assess how well presurgery latent components could predict postsurgery memory decline. Finally, we validated the predictive power of these regression models in an independent sample of 18 patients with mTLE. Principal component analysis identified three significant latent components that reflected IQ, verbal memory, and visuospatial memory, respectively. Together, the presurgery verbal and visuospatial memory components classified 80% of patients with mTLE correctly according to their seizure laterality. Furthermore, the presurgery verbal memory component predicted postsurgery verbal memory decline, while the presurgery visuospatial memory component predicted visuospatial memory decline. These regression models also predicted postsurgery memory decline successfully in the independent cohort of patients with mTLE. Our results demonstrate the value of data reduction techniques in identifying cognitive metrics that can characterize laterality of damage and risk of postoperative decline.
authors.affiliation: Rotman Research Institute at Baycrest, Toronto, Ontario, Canada; Department of Psychology, University of Toronto, Toronto, Ontario, Canada; Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Marie
authors.initials: M
authors.lastname: St-Laurent
authors.affiliation: Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Cornelia
authors.initials: C
authors.lastname: McCormick
authors.affiliation: Department of Psychology, University of Toronto, Toronto, Ontario, Canada; Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Cohn
authors.affiliation: Rotman Research Institute at Baycrest, Toronto, Ontario, Canada; Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bratislav
authors.initials: B
authors.lastname: Mišić
authors.affiliation: Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Irene
authors.initials: I
authors.lastname: Giannoylis
authors.affiliation: Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Psychology, University of Toronto, Toronto, Ontario, Canada; Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada. Electronic address: marypat.mcandrews@uhn.ca.
authors.forename: Mary Pat
authors.initials: MP
authors.lastname: McAndrews
mesh_terms: D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology; D004833:Epilepsy, Temporal Lobe / Q000601:surgery; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis* / Q000209:etiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures / Q000009:adverse effects; D011183:Postoperative Complications / Q000503:physiopathology*; D011237:Predictive Value of Tests; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Bootstrapping; Cross-validation; Neuropsychology; Principal component analysis; Surgical cognitive outcome; Temporal lobe excision