Exploring the Sensitivity of Episodic and Spatial Memory Tests to Healthy and Pathological Cognitive Ageing

Gina Michallat-Bragg¹Megan Bennett¹Bethany Iona Flewitt¹Sayed Kazmi²Sarah Jane Smith³Christine Wells⁴Annabel Hollins¹Sarah Thwaites⁵Wendy Neil⁶David Howett⁷Sarah Dexter-Smith⁸Dennis Chan⁹James Dachtler¹Steven Poulter¹Stephen Evans^1,10Colin Lever^1,11*

• ¹Department of Psychology, University of Durham, Durham, United Kingdom
• ²Ascentys Limited, Bradford, United Kingdom
• ³Centre for Dementia Research, Leeds Beckett University, Leeds, United Kingdom
• ⁴Leeds Trinity University, Leeds, United Kingdom
• ⁵School of Psychology, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, England, United Kingdom
• ⁶Leeds and York Partnership NHS Foundation Trust, Leeds, United Kingdom
• ⁷School of Experimental Psychology, Faculty of Life Sciences, University of Bristol, Bristol, England, United Kingdom
• ⁸Tees, Esk and Wear Valleys NHS Foundation Trust, Darlington, United Kingdom
• ⁹Institute of Cognitive Neuroscience, Faculty of Brain Sciences, University College London, London, England, United Kingdom
• ¹⁰The department of Psychological Medicine, Bootham Park, York Hospital, York, United Kingdom
• ¹¹Durham University, Durham, United Kingdom

In an increasingly ageing society, testing hippocampal-dependent cognition in a quick and lowresource manner will be crucial in assessing the potential benefits of lifestyle choices and interventions affecting cognitive ageing (such as those involving exercise, diet, and sleep). Over 300 participants aged 18-89 completed three cognitive tests, namely the Addenbrooke's Cognitive Examination-III (ACE-III), The Four Mountains Task (4MT), and a new task introduced here, the Spaces and Sequences Episodic Video Task (SSEVT). Hippocampal tissue is particularly vulnerable to ageing, and the 4MT and SSEVT were designed to be hippocampal-dependent. Accordingly, we tested the hypothesis that 4MT and SSEVT performance would be significantly compromised by ageing. Supporting this idea, 4MT and SSEVT scores showed appreciably stronger age-related declines than ACE-III scores. The middle-aged group (mean: ~51 years) were significantly worse than the young group (mean: ~21 years) on the 4MT (Cohen's d = 0.724) and the SSEVT (Cohen's d = 0.443); and the older group (mean: ~71 years) were significantly worse than the middle-aged group on the SSEVT (Cohen's d = 0.724). Neither pattern was seen for ACE-III. We conclude that the 4MT and SSEVT may be suitable for assessing lifestyle choices and interventions affecting cognitive ageing.Finally, as an initial proof-of-concept exploration of these tests' ability to detect pathological ageing, such as in Alzheimer's disease where hippocampal degeneration occurs relatively early on, we compared 10 patients with Mild Cognitive Impairment (MCI) with matched subsamples of the older group (Healthy ageing, HA). Suggestively, the MCI patients performed worse than the matched HA group on the 4MT (consistent with previous work) and on our novel SSEVT, but not on the ACE-III.