1 Department of Psychology, Concordia University, Montréal, QC, Canada; Centre for Research in Human Development, Montréal, QC, Canada.
2 Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada.
3 Department of Psychology, Concordia University, Montréal, QC, Canada; Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada; Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada.
4 Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.
5 Department of Psychology, Concordia University, Montréal, QC, Canada; Centre for Research in Human Development, Montréal, QC, Canada; Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada; Centre for Research on Brain, Language, and Music, Montréal, QC, Canada. Electronic address: natalie.phillips@concordia.ca.

Two independent lines of research provide evidence that speaking more than one language may 1) contribute to increased grey matter in healthy younger and older adults and 2) delay cognitive symptoms in mild cognitive impairment (MCI) or Alzheimer disease (AD). We examined cortical thickness and tissue density in monolingual and multilingual MCI and AD patients matched (within Diagnosis Groups) on demographic and cognitive variables. In medial temporal disease-related (DR) areas, we found higher...