Affiliations: [a]
Neuroscience Research Australia, Randwick, Sydney, Australia
| [b] School of Psychology, the University of New South Wales, Sydney, Australia
| [c]
Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, Australia
| [d] School of Medical Sciences, The University of New South Wales, Sydney, Australia
| [e] Department of Clinical Neurosciences, The University of Cambridge, Cambridge, UK
Correspondence:
[*]
Correspondence to: Dr. Muireann Irish, Neuroscience Research Australia, P.O. Box 1165, Randwick, Sydney, NSW 2031,Australia. Tel.: +61 2 9399 1602; Fax: +61 2 9399 1047; E-mail: m.irish@neura.edu.au.
Abstract: Background:Prospective memory (PM) refers to a future-oriented form of memory in which the individual must remember to execute an intended action either at a future point in time (Time-based) or in response to a specific event (Event-based). Lapses in PM are commonly exhibited in neurodegenerative disorders including Alzheimer’s disease (AD) and frontotemporal dementia (FTD), however, the neurocognitive mechanisms driving these deficits remain unknown. Objective:To investigate the clinical and neural correlates of Time- and Event-based PM disruption in AD and the behavioral-variant FTD (bvFTD). Methods:Twelve AD, 12 bvFTD, and 12 healthy older Control participants completed a modified version of the Cambridge Prospective Memory test, which examines Time- and Event-based aspects of PM. All participants completed a standard neuropsychological assessment and underwent whole-brain structural MRI. Results:AD and bvFTD patients displayed striking impairments across Time- and Event-based PM relative to Controls, however, Time-based PM was disproportionately affected in the AD group. Episodic memory dysfunction and hippocampal atrophy were found to correlate strongly with PM integrity in both patient groups, however, dissociable neural substrates were also evident for PM performance across dementia syndromes. Conclusion:Our study reveals the multifaceted nature of PM dysfunction in neurodegenerative disorders, and suggests common and dissociable neurocognitive mechanisms, which subtend these deficits in each patient group. Future studies of PM disturbance in dementia syndromes will be crucial for the development of successful interventions to improve functional independence in the patient’s daily life.
