Rates of age- and amyloid β-associated cortical atrophy in older adults with superior memory performance

Christa Dang; Nawaf Yassi; Karra D Harrington; Ying Xia; Yen Ying Lim; David Ames; Simon M Laws; Martha Hickey; Stephanie Rainey-Smith; Hamid R Sohrabi; James D Doecke; Jurgen Fripp; Olivier Salvado; Peter J Snyder; Michael Weinborn; Victor L Villemagne; Christopher C Rowe; Colin L Masters; Paul Maruff; AIBL Research Group

doi:10.1016/j.dadm.2019.05.005

Rates of age- and amyloid β-associated cortical atrophy in older adults with superior memory performance

Alzheimers Dement (Amst). 2019 Aug 12:11:566-575. doi: 10.1016/j.dadm.2019.05.005. eCollection 2019 Dec.

Authors

Christa Dang^{1

2}, Nawaf Yassi^{2

3}, Karra D Harrington^{2

4}, Ying Xia⁵, Yen Ying Lim², David Ames^{6

7}, Simon M Laws^{4

8

9}, Martha Hickey¹, Stephanie Rainey-Smith^{10

11}, Hamid R Sohrabi^{10

12}, James D Doecke⁵, Jurgen Fripp⁵, Olivier Salvado⁵, Peter J Snyder¹³, Michael Weinborn^{10

11

14}, Victor L Villemagne^{2

15

16}, Christopher C Rowe^{15

16}, Colin L Masters², Paul Maruff^{2

17}; AIBL Research Group

Collaborators

Affiliations

¹ Department of Obstetrics and Gynaecology, Melbourne Medical School, The University of Melbourne, Parkville, Victoria, Australia.
² The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.
³ Department of Medicine and Neurology, Royal Melbourne Hospital, Melbourne, Victoria, Australia.
⁴ Cooperative Research Centre for Mental Health, Parkville, Victoria, Australia.
⁵ CSIRO Health and Biosecurity, the Australian eHealth Research Centre, Brisbane, Queensland, Australia.
⁶ Academic Unit for Psychiatry of Old Age, Department of Psychiatry, The University of Melbourne, Parkville, Victoria, Australia.
⁷ National Ageing Research Institute, Parkville, Victoria, Australia.
⁸ Collaborative Genomics Group, Centre of Excellence for Alzheimer's Disease Research and Care, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia.
⁹ School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia.
¹⁰ Centre of Excellence for Alzheimer's Disease Research and Care, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia.
¹¹ Australian Alzheimer's Disease Research Unit, Hollywood Private Hospital, Perth, Western Australia, Australia.
¹² School of Psychiatry and Clinical Neurosciences, University of Western Australia, Nedlands, Western Australia, Australia.
¹³ George & Anne Ryan Institute for Neuroscience, The University of Rhode Island, Kingston, RI, USA.
¹⁴ School of Psychological Science, University of Western Australia, Crawley, Western Australia, Australia.
¹⁵ Department of Molecular Imaging & Therapy, Austin Health, Melbourne, Victoria, Australia.
¹⁶ Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia.
¹⁷ CogState Ltd., Melbourne, Victoria, Australia.

Abstract

Introduction: Superior cognitive performance in older adults may reflect underlying resistance to age-associated neurodegeneration. While elevated amyloid β (Aβ) deposition (Aβ+) has been associated with increased cortical atrophy, it remains unknown whether "SuperAgers" may be protected from Aβ-associated neurodegeneration.

Methods: Neuropsychologically defined SuperAgers (n = 172) and cognitively normal for age (n = 172) older adults from the Australian Imaging, Biomarkers and Lifestyle study were case matched. Rates of cortical atrophy over 8 years were examined by SuperAger classification and Aβ status.

Results: Of the case-matched SuperAgers and cognitively normal for age older adults, 40.7% and 40.1%, respectively, were Aβ+. Rates of age- and Aβ-associated atrophy did not differ between the groups on any measure. Aβ- individuals displayed the slowest rates of atrophy.

Discussion: Maintenance of superior memory in late life does not reflect resistance to age- or Aβ-associated atrophy. However, those individuals who reached old age without cognitive impairment nor elevated Aβ deposition (i.e. Aβ-) displayed reduced rates of cortical atrophy.

Keywords: Aging; Alzheimer's disease; Memory; Neurodegeneration; β-amyloid.