Olfactory testing combined with dopamine transporter imaging as a method to detect prodromal Parkinson's disease

Abstract

Olfactory testing combined with dopamine transporter imaging as a method to detect prodromal Parkinson's disease Ponsen, M.M.; Stoffers, D.; Wolters, E.C.; Booij, J.; Berendse, H.W. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. (PD). Previously, the authors demonstrated that idiopathic olfactory dysfunction in first-degree relatives of PD patients is associated with an increased risk of developing PD within 2 years. The aim of the present study was to determine the value of combined olfactory testing and SPECT scanning in predicting future PD in the same population of relatives over a 5-year period.Methods In a cohort of 361 non-parkinsonian, non-demented first-degree relatives of PD patients, a combination of olfactory processing tasks was used to select groups of hyposmic (n¼40) and normosmic (n¼38) individuals for a 5-year clinical follow-up evaluation and sequential SPECT scanning, using a dopamine transporter ligand to assess nigrostriatal dopaminergic function at baseline and 5 years from baseline. A validated questionnaire, sensitive to the presence of parkinsonism, was used in the follow-up of the remaining 283 relatives.Results Five years from baseline, five out of the 40 hyposmic relatives fulfilled clinical diagnostic criteria for PD. None of the other 349 relatives available for followup developed PD. All hyposmic individuals developing PD had an abnormal baseline SPECT scan. Discussion In conclusion, idiopathic hyposmia in firstdegree relatives of PD patients is associated with an increased risk of developing clinical PD of 12.5% over a 5-year period. The present data suggest that a two-step approach using olfactory testing followed by SPECT scanning in hyposmic individuals has a very high sensitivity and specificity in detecting PD. The usefulness of this twostep approach needs to be confirmed in larger populations.

Optimizing odor identification testing as quick and accurate diagnostic tool for Parkinson's disease

“…Second, a short olfactory test could be useful as a highly sensitive screening tool in population‐based studies seeking to define cohorts at high risk for PD 3, 24. Along these lines, we found a high sensitivity of the SS‐16 and SS‐8 in identifying PD versus HCs in the center A (92% and 94%) and center B (83% and 85%) validation cohorts combined with a good specificity of ≥82%.…”

“…Olfactory deficits affect 75% to 90% of patients with Parkinson's disease (PD), and olfactory testing may also represent a sensitive screening test for individuals at risk of developing PD,1, 2, 3, 4 whereas olfactory function is normal or only mildly impaired in other forms of degenerative parkinsonism or essential tremor (ET) 2, 5. Olfactory testing has recently been incorporated in the newly established International Parkinson and Movement Disorder Society criteria for PD6 and prodromal PD 7…”

Epidemiology and etiology of Parkinson’s disease: a review of the evidence

“…At five years of follow-up, one additional relative with hyposmia had PD [517]. All relatives with hyposmia who developed PD had abnormal dopamine transporter binding at baseline [517].…”

“…At five years of follow-up, one additional relative with hyposmia had PD [517]. All relatives with hyposmia who developed PD had abnormal dopamine transporter binding at baseline [517]. In the Honolulu-Asia Aging study, individuals were tested for olfactory dysfunction at baseline and followed for incident PD [518].…”

Spotlight on olfactory dysfunction in Parkinson's disease

“…The risk at 5 years of developing PD in first-degree relatives of PD with olfactory dysfunction was estimated to be 12.5%. 62 …”