P2-077: Smell identification test as a progression marker in Alzheimer's disease

IntroductionFactors influencing or predicting progression in Alzheimer's disease (AD) is not well understood. Olfactory dysfunction, impaired smell identification in particular, is known to occur in AD. Mesial temporal lobe, important for memory function is also critical for the processing of olfactory information. In view of the common anatomical substrate, we hypothesized that olfaction dysfunction worsens faster in people with AD with rapid cognitive decline compared to those with slower cognitive decline.AimsTo test whether smell identification test can be used as a predictor for illness progression in AD patients.MethodsForty one participants with late onset mild to moderate AD were recruited from mental health services for older adults. Subjects were classified as ‘Rapid Progressors’ defined on ‘a-priori’ with a loss of 2 or more points in Mini-Mental State Examination (MMSE) within six months. Assessments included MMSE, Neuropsychiatric Inventory, Bristol Activities of Daily Living, and the University of Pennsylvania Smell Identification Test (UPSIT), at baseline and after 3 months.ResultsTwenty subjects were ‘Rapid Progressors’, and had lower UPSIT scores compared to ‘Non-Rapid Progressors’ both at the baseline (p = 0.02) and at follow up after 3 months (p = 0.05). Baseline UPSIT correlated with follow up UPSIT (r = 0.5, p < 0.01) and MMSE (r = 0.4, p = 0.04). Also it was the baseline UPSIT score that best predicted (p < 0.05) the follow up smell and cognitive function on linear regression analysis.ConclusionsSmell identification function could be useful as a clinical measure to assess and predict progression in AD.

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Smell identification function as a severity and progression marker in Alzheimer's disease

International Psychogeriatrics ◽

10.1017/s1041610213000446 ◽

2013 ◽

Vol 25 (7) ◽

pp. 1157-1166 ◽

Cited By ~ 37

Author(s):

Latha Velayudhan ◽

Megan Pritchard ◽

John F. Powell ◽

Petroula Proitsi ◽

Simon Lovestone

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Late Onset ◽

Functional Dependence ◽

A Priori ◽

University Of Pennsylvania ◽

Progression Marker ◽

Median Split ◽

Identification Function ◽

Smell Identification

ABSTRACTBackground: Olfactory dysfunction, impaired smell identification in particular, is known as a diagnostic and a marker of conversion in Alzheimer's disease (AD). We aimed to evaluate the associations of olfactory identification impairments with cognition, illness severity, and progression in AD patients.Methods: Fifty-seven outpatients with late onset mild to moderate AD and 24 elderly non-demented controls (NDC) were assessed, at baseline and after three months, for Mini-Mental State Examination (MMSE), University of Pennsylvania Smell Identification Test (UPSIT), and Bristol Activities of Daily Living and Neuropsychiatry Inventory. AD participants were classified as Rapid Cognitive Decliners (RCD) defined on a priori with a loss of ≥2 points in MMSE within the previous six months.Results: AD participants had lower olfactory scores than NDC. RCD had lower olfaction scores compared with Non-Rapid Cognitive Decliners (NRCD). Although the baseline UPSIT scores were associated with baseline MMSE scores, it did not interact significantly with change in MMSE over the follow-up period. Using a median split for olfactory scores, the AD participants were classified as Rapid Olfactory Progressors (ROP) (UPSIT ≤ 15) and Slow Olfactory Progressors correlating significantly with RCD/NRCD groups. The ROP group with higher olfactory impairment indicated more symptomatic illness or severity, i.e. lower cognition, higher functional dependence, and presence of behavioral symptoms.Conclusions: Our study supports association of smell identification function with cognition and its utility as an adjunct clinical measure to assess severity in AD. Further work, including larger longitudinal studies, is needed to explore its value in predicting AD progression.

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