Olfaction in patients with mild cognitive impairment and Alzheimer's disease

Djordjevic, Jelena; Jones-Gotman, Marilyn; De Sousa, Kathy; Chertkow, Howard

doi:10.1016/j.neurobiolaging.2006.11.014

« Previous Next »Neurobiology of Aging
Volume 29, Issue 5 , Pages 693-706, May 2008

Olfaction in patients with mild cognitive impairment and Alzheimer's disease

Jelena Djordjevic
- Montreal Neurological Institute, 3801 University Street, Department of Neurology and Neurosurgery, McGill University, Montreal, H3A 2B4, Québec, Canada
- Corresponding author. Tel.: +1 514 398 6644x00248; fax: +1 514 398 1338.
Marilyn Jones-Gotman
- Montreal Neurological Institute, 3801 University Street, Department of Neurology and Neurosurgery, McGill University, Montreal, H3A 2B4, Québec, Canada
Kathy De Sousa
- Bloomfield Centre for Research in Aging, Lady Davis Institute, Department of Clinical Neurosciences, Sir Mortimer B. Davis - Jewish General Hospital, Department of Neurology and Neurosurgery, McGill University, Montreal, H3T 1E2, Canada
Howard Chertkow
- Bloomfield Centre for Research in Aging, Lady Davis Institute, Department of Clinical Neurosciences, Sir Mortimer B. Davis - Jewish General Hospital, Department of Neurology and Neurosurgery, McGill University, Montreal, H3T 1E2, Canada

Received 31 July 2006; received in revised form 10 November 2006; accepted 19 November 2006. published online 08 January 2007.

Abstract

Understanding of olfactory dysfunction in Alzheimer's disease (AD) remains limited. In particular, it is not known how early in the course of the disease olfactory deficits occur, and whether they are restricted to identification or involve other aspects of olfaction. We studied olfactory (odor detection thresholds, quality discrimination, and identification) and cognitive (attention, reasoning, memory, naming and fluency) functioning in patients with AD, with mild cognitive impairment (MCI), and in normal elderly control (NEC) participants. MCI patients were impaired in olfactory sensitivity and identification, while a discrimination deficit was accounted for by abnormal thresholds. AD patients were impaired in all three domains, and were worse than the MCI group. Odor discrimination (OD) and identification performance correlated more prominently than detection thresholds with performance on neuropsychological tests. We concluded that deficits in olfactory detection thresholds and identification occur early in AD, before clinical symptoms are fully developed, and decline further over the course of the disease. High detection thresholds, together with impaired identification, may be useful as an early indicator of AD.

Keywords: Olfaction, Olfactory dysfunction, Mild cognitive impairment, Alzheimer's disease