- Title
- The test-retest properties of the olfactory stress test
- Creator
- Grainger, Jon
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2014
- Description
- Masters Research - Master of Clinical Psychology (MCIPsych)
- Description
- Scope and purpose of the work: Alzheimer’s Disease (AD) is the most common form of dementia and is distinguished from other dementias by specific pathology. Recent studies estimate that around 40% of individuals over 65 have Alzheimer Disease pathology without the cognitive changes characteristic of the disease. It could be that the development of these pathological changes signals future cognitive and functional declines characteristic of AD. If this is the case, a screening test for early detection of these individuals is required. This need will increase once disease altering treatments become available. One area of the brain which is known to exhibit early AD pathology is the olfactory bulb (OB). Impaired olfactory function is known as an early symptom of AD and this may be related to these pathological changes. Acetylcholine (ACh) is a neurotransmitter which is important for normal olfactory functioning and is also implicated in the development of AD. Placing additional stress on the pathways releasing ACh within the OB may have exaggerated consequences. Using this principle, Schofield et al (2012) speculated that intranasal administration of an anticholinergic agent might be used to reveal AD pathology in the OB. In their study it was hypothesised that intranasal administration of an anticholinergic agent (atropine) could help to identify individuals who had started to develop AD pathology in the OB. By testing olfactory function before and after the administration of atropine they were able to demonstrate a significant decline in the group who had features of early AD compared to a “low risk of AD” control group. This is the “Olfactory Stress Test” (OST) and the measure of olfactory change after administration of atropine is the “atropine effect” (AE). The present study attempts to establish the test- retest validity of the OST procedure set out in Schofield et al (2012). Methodology: We recruited individuals 65 years and older without severe cognitive impairment. Participants were asked to attend our clinic on two consecutive occasions. On the first occasion participants were asked to complete the OST and this process was repeated on the second occasion. To establish test- retest reliability we examined the level of agreement between AE scores obtained on each of the two sessions using the Intraclass Coefficient (ICC). Results: There was a weak negative correlation between AE scores at both sessions (with time between sessions ranging from 7 to 125 days) ICC (3,2)= -0.161. Secondary analysis showed weak test- retest agreement, ICC (3,4)= 0.465, for the University of Pennsylvania Smell Identification Test (UPSIT) which is the olfactory measure used in the OST. Conclusions and Implications: The main findings of this study were that the test-retest reliability of the OST was poor. Secondary analysis suggested that test- retest reliability of UPSIT was also poor when used in this procedure. Future study of the OST would benefit from a greater number of participants, further data regarding the reliability of the UPSIT over multiple administrations, and methodological changes aimed at reducing unwanted variability between test sessions.
- Subject
- Olfactory Stress Test; Alzheimer; screen
- Identifier
- http://hdl.handle.net/1959.13/1052880
- Identifier
- uon:15491
- Rights
- Copyright 2014 Jon Grainger
- Language
- eng
- Full Text
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