Anosmia is very common in the Lewy body variant of Alzheimer's disease

John M Olichney, C. Murphy, C. R. Hofstetter, K. Foster, L. A. Hansen, L. J. Thal, R. Katzman

Research output: Contribution to journalArticle

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Abstract

Background: Olfactory abnormalities are reported in Alzheimer's disease and Parkinson's disease. Anosmia appears to be common in dementia with Lewy bodies but not in pure Alzheimer's disease. Objective: to determine whether anosmia improves discrimination between the Lewy body variant (LBV) of Alzheimer's disease and "pure" Alzheimer's disease. Methods: 106 cases of necropsy confirmed pure Alzheimer's disease (n = 89) or LBV (n = 17) were reviewed. All had received butanol odour threshold testing. Anosmia was defined as a score ≤ 1.0 on a 0-9 point scale. Logistic regression analysis was used to model potential predictors (for example, parkinsonism, smoking, hallucinations) of neuropathological diagnosis and anosmia. Results: LBV cases had an increased prevalence of anosmia (65%) compared with Alzheimer's disease (23%; odds ratio (OR) = 6.3, p = 0.00045), or normal elderly people (6.7%). Within the dementia cases, the negative predictive value (92%) and specificity (78%) of anosmia were both good; sensitivity for detecting LBV was 65%, but the positive predictive value (PPV) was only 35%. Logistic regression models showed anosmia (OR = 5.4, p = 0.005) and visual hallucinations (OR = 7.3, p = 0.007) were strong independent predictors of Lewy body pathology. When anosmia was added as a core feature to consensus diagnostic criteria for probable Lewy body dementia, five additional cases of LBV were detected (29% increased sensitivity), but with four additional false positives (1% increased discrimination, 4% decreased specificity, 33% decreased PPV). Conclusions: Anosmia is very common in LBV. Adding anosmia as a core feature improved sensitivity for detecting LBV, but did not improve discrimination between Alzheimer's disease and LBV owing to a concomitant increase in false positives.

Original languageEnglish (US)
Pages (from-to)1342-1347
Number of pages6
JournalJournal of Neurology, Neurosurgery and Psychiatry
Volume76
Issue number10
DOIs
StatePublished - Oct 2005

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Olfaction Disorders
Lewy Bodies
Alzheimer Disease
Lewy Body Disease
Logistic Models
Hallucinations
Odds Ratio
Lewy Body Variant of Alzheimer Disease
Butanols
Parkinsonian Disorders
Parkinson Disease
Dementia
Consensus
Smoking
Regression Analysis

ASJC Scopus subject areas

  • Neuropsychology and Physiological Psychology
  • Neuroscience(all)
  • Psychiatry and Mental health

Cite this

Olichney, J. M., Murphy, C., Hofstetter, C. R., Foster, K., Hansen, L. A., Thal, L. J., & Katzman, R. (2005). Anosmia is very common in the Lewy body variant of Alzheimer's disease. Journal of Neurology, Neurosurgery and Psychiatry, 76(10), 1342-1347. https://doi.org/10.1136/jnnp.2003.032003

Anosmia is very common in the Lewy body variant of Alzheimer's disease. / Olichney, John M; Murphy, C.; Hofstetter, C. R.; Foster, K.; Hansen, L. A.; Thal, L. J.; Katzman, R.

In: Journal of Neurology, Neurosurgery and Psychiatry, Vol. 76, No. 10, 10.2005, p. 1342-1347.

Research output: Contribution to journalArticle

Olichney, JM, Murphy, C, Hofstetter, CR, Foster, K, Hansen, LA, Thal, LJ & Katzman, R 2005, 'Anosmia is very common in the Lewy body variant of Alzheimer's disease', Journal of Neurology, Neurosurgery and Psychiatry, vol. 76, no. 10, pp. 1342-1347. https://doi.org/10.1136/jnnp.2003.032003
Olichney, John M ; Murphy, C. ; Hofstetter, C. R. ; Foster, K. ; Hansen, L. A. ; Thal, L. J. ; Katzman, R. / Anosmia is very common in the Lewy body variant of Alzheimer's disease. In: Journal of Neurology, Neurosurgery and Psychiatry. 2005 ; Vol. 76, No. 10. pp. 1342-1347.
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abstract = "Background: Olfactory abnormalities are reported in Alzheimer's disease and Parkinson's disease. Anosmia appears to be common in dementia with Lewy bodies but not in pure Alzheimer's disease. Objective: to determine whether anosmia improves discrimination between the Lewy body variant (LBV) of Alzheimer's disease and {"}pure{"} Alzheimer's disease. Methods: 106 cases of necropsy confirmed pure Alzheimer's disease (n = 89) or LBV (n = 17) were reviewed. All had received butanol odour threshold testing. Anosmia was defined as a score ≤ 1.0 on a 0-9 point scale. Logistic regression analysis was used to model potential predictors (for example, parkinsonism, smoking, hallucinations) of neuropathological diagnosis and anosmia. Results: LBV cases had an increased prevalence of anosmia (65{\%}) compared with Alzheimer's disease (23{\%}; odds ratio (OR) = 6.3, p = 0.00045), or normal elderly people (6.7{\%}). Within the dementia cases, the negative predictive value (92{\%}) and specificity (78{\%}) of anosmia were both good; sensitivity for detecting LBV was 65{\%}, but the positive predictive value (PPV) was only 35{\%}. Logistic regression models showed anosmia (OR = 5.4, p = 0.005) and visual hallucinations (OR = 7.3, p = 0.007) were strong independent predictors of Lewy body pathology. When anosmia was added as a core feature to consensus diagnostic criteria for probable Lewy body dementia, five additional cases of LBV were detected (29{\%} increased sensitivity), but with four additional false positives (1{\%} increased discrimination, 4{\%} decreased specificity, 33{\%} decreased PPV). Conclusions: Anosmia is very common in LBV. Adding anosmia as a core feature improved sensitivity for detecting LBV, but did not improve discrimination between Alzheimer's disease and LBV owing to a concomitant increase in false positives.",
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T1 - Anosmia is very common in the Lewy body variant of Alzheimer's disease

AU - Olichney, John M

AU - Murphy, C.

AU - Hofstetter, C. R.

AU - Foster, K.

AU - Hansen, L. A.

AU - Thal, L. J.

AU - Katzman, R.

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N2 - Background: Olfactory abnormalities are reported in Alzheimer's disease and Parkinson's disease. Anosmia appears to be common in dementia with Lewy bodies but not in pure Alzheimer's disease. Objective: to determine whether anosmia improves discrimination between the Lewy body variant (LBV) of Alzheimer's disease and "pure" Alzheimer's disease. Methods: 106 cases of necropsy confirmed pure Alzheimer's disease (n = 89) or LBV (n = 17) were reviewed. All had received butanol odour threshold testing. Anosmia was defined as a score ≤ 1.0 on a 0-9 point scale. Logistic regression analysis was used to model potential predictors (for example, parkinsonism, smoking, hallucinations) of neuropathological diagnosis and anosmia. Results: LBV cases had an increased prevalence of anosmia (65%) compared with Alzheimer's disease (23%; odds ratio (OR) = 6.3, p = 0.00045), or normal elderly people (6.7%). Within the dementia cases, the negative predictive value (92%) and specificity (78%) of anosmia were both good; sensitivity for detecting LBV was 65%, but the positive predictive value (PPV) was only 35%. Logistic regression models showed anosmia (OR = 5.4, p = 0.005) and visual hallucinations (OR = 7.3, p = 0.007) were strong independent predictors of Lewy body pathology. When anosmia was added as a core feature to consensus diagnostic criteria for probable Lewy body dementia, five additional cases of LBV were detected (29% increased sensitivity), but with four additional false positives (1% increased discrimination, 4% decreased specificity, 33% decreased PPV). Conclusions: Anosmia is very common in LBV. Adding anosmia as a core feature improved sensitivity for detecting LBV, but did not improve discrimination between Alzheimer's disease and LBV owing to a concomitant increase in false positives.

AB - Background: Olfactory abnormalities are reported in Alzheimer's disease and Parkinson's disease. Anosmia appears to be common in dementia with Lewy bodies but not in pure Alzheimer's disease. Objective: to determine whether anosmia improves discrimination between the Lewy body variant (LBV) of Alzheimer's disease and "pure" Alzheimer's disease. Methods: 106 cases of necropsy confirmed pure Alzheimer's disease (n = 89) or LBV (n = 17) were reviewed. All had received butanol odour threshold testing. Anosmia was defined as a score ≤ 1.0 on a 0-9 point scale. Logistic regression analysis was used to model potential predictors (for example, parkinsonism, smoking, hallucinations) of neuropathological diagnosis and anosmia. Results: LBV cases had an increased prevalence of anosmia (65%) compared with Alzheimer's disease (23%; odds ratio (OR) = 6.3, p = 0.00045), or normal elderly people (6.7%). Within the dementia cases, the negative predictive value (92%) and specificity (78%) of anosmia were both good; sensitivity for detecting LBV was 65%, but the positive predictive value (PPV) was only 35%. Logistic regression models showed anosmia (OR = 5.4, p = 0.005) and visual hallucinations (OR = 7.3, p = 0.007) were strong independent predictors of Lewy body pathology. When anosmia was added as a core feature to consensus diagnostic criteria for probable Lewy body dementia, five additional cases of LBV were detected (29% increased sensitivity), but with four additional false positives (1% increased discrimination, 4% decreased specificity, 33% decreased PPV). Conclusions: Anosmia is very common in LBV. Adding anosmia as a core feature improved sensitivity for detecting LBV, but did not improve discrimination between Alzheimer's disease and LBV owing to a concomitant increase in false positives.

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