Progressive Olfactory Impairment and Cardiac Sympathetic Denervation in REM Sleep Behavior Disorder

Annette Janzen, David Vadasz, Jan Booij, Markus Luster, Damiano Librizzi, Martin T. Henrich, Lars Timmermann, Mahboubeh Habibi, Elisabeth Sittig, Geert Mayer, Fanni Geibl, Wolfgang Oertel

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Scopus)

Abstract

BACKGROUND: Isolated rapid eye movement sleep behavior disorder (iRBD) is prodromal for Parkinson's disease (PD) and dementia with Lewy bodies (DLB). OBJECTIVE: We investigated the use of cardiac [123I]meta-iodo-benzyl-guanidine scintigraphy ([123I]MIBG) and olfactory testing- in comparison to [123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane single photon emission computed tomography ([123I]FP-CIT-SPECT)- for identifying iRBD patients as prodromal phenotype of PD/DLB. METHODS: 37 RBD subjects underwent cardiac [123I]MIBG and brain [123I]FP-CIT-SPECT at baseline. Olfactory (Sniffin' Sticks), cognitive and motor functions were tested annually for ∼4 years. RESULTS: 29/37 (78.4%) subjects had a pathological [123I]MIBG, of whom 86.2% (25/29) presented at least a moderate hyposmia at baseline (threshold/discrimination/identification-(TDI-)score ≤25). 20/37 (54.1%) subjects had a pathological [123I]FP-CIT-SPECT, always combined with a pathological [123I]MIBG. In subjects with pathological [123I]MIBG, olfactory function worsened (mainly due to threshold and discrimination subscores) from baseline to follow-up (p = 0.005). Olfaction was more impaired in subjects with pathological [123I]MIBG compared to those with normal [123I]MIBG at baseline (p = 0.001) and follow-up (p < 0.001). UPDRS-III scores increased in subjects with both pathological [123I]MIBG and [123I]FP-CIT-SPECT. In this group, seven subjects phenoconverted to PD, all- except for one- presented with at least moderate hyposmia at baseline. CONCLUSION: A combination of the biomarkers "pathological [123I]MIBG" and "hyposmia" likely identifies iRBD patients in an early prodromal stage of PD/DLB, i.e., before nigrostriatal degeneration is visualized. One-third of the subjects with pathological [123I]MIBG had a normal [123I]FP-CIT-SPECT. Noteworthy, in iRBD subjects with pathological [123I]MIBG, olfactory impairment is progressive independent of the [123I]FP-CIT-SPECT status.

Original languageEnglish
Pages (from-to)1921-1935
Number of pages15
JournalJournal of Parkinson s disease
Volume12
Issue number6
DOIs
Publication statusPublished - 2022

Keywords

  • Biomarker
  • [ I]FP-CIT-SPECT
  • cardiac [ I]MIBG scintigraphy
  • hyposmia
  • isolated rapid eye movement sleep behavior disorder
  • prodromal progression marker

Cite this