Background: Despite being long neglected, olfaction has recently become a focus of intense research in neuroscience, as smell impairment has been consistently documented in both neurodegenerative and neuroinflammatory diseases. Considering the close anatomo-functional correlations between the limbic system and the central olfactory structures, we investigated olfaction in a population of patients with autoimmune encephalitis (AE). Methods: Nineteen adult subjects (14 males, median age 64 years) diagnosed with definite (14/19) or possible (5/19) AE and followed for ≥ 6 months were enrolled. The Brief Smell Identification Test (B-SIT), a 12-item, forced-choice, scratch-and-sniff measure, was used to assess the patients’ olfactory function in comparison with a group of sex- and age-matched healthy controls (HC). According to the B-SIT score, subjects were classified as anosmic (< 6), hyposmic (6–8) and normal (≥ 9). Electro-clinical, laboratory and neuroimaging findings were reviewed. Results: Smell impairment was revealed in 15/19 patients (9 hyposmic, 6 anosmic), compared with 5/19 HC (p = 0.0029). Age, gender and smoking habits did not affect the participants’ performance at B-SIT. Olfactory dysfunction appeared more common among patients with definite AE (p = 0.0374), regardless of autoantibody status. Subjects with higher modified Rankin Scale (mRS) scores at AE onset more likely presented hyposmia/anosmia (p = 0.033), and so did those with bilateral ictal/interictal EEG abnormalities (p = 0.006). Conclusions: We found olfaction to be impaired in a significantly large proportion of AE cases. Smell deficits appeared more common in subjects with severe AE (as indicated by both definite diagnosis and higher mRS score), and might represent an additional feature of immune-mediated encephalitis.

Olfactory impairment in autoimmune encephalitis: another piece of the puzzle / Morano, A.; Cerulli Irelli, E.; Fanella, M.; Orlando, B.; Salamone, E. M.; Tinelli, E.; Ruffolo, G.; Zuliani, L.; Fattouch, J.; Manfredi, M.; Giallonardo, A. T.; Di Bonaventura, C.. - In: JOURNAL OF NEUROLOGY. - ISSN 0340-5354. - (2022). [10.1007/s00415-022-10959-6]

Olfactory impairment in autoimmune encephalitis: another piece of the puzzle

Morano A.;Cerulli Irelli E.;Orlando B.;Salamone E. M.;Tinelli E.;Ruffolo G.;Fattouch J.;Manfredi M.;Giallonardo A. T.;Di Bonaventura C.
2022

Abstract

Background: Despite being long neglected, olfaction has recently become a focus of intense research in neuroscience, as smell impairment has been consistently documented in both neurodegenerative and neuroinflammatory diseases. Considering the close anatomo-functional correlations between the limbic system and the central olfactory structures, we investigated olfaction in a population of patients with autoimmune encephalitis (AE). Methods: Nineteen adult subjects (14 males, median age 64 years) diagnosed with definite (14/19) or possible (5/19) AE and followed for ≥ 6 months were enrolled. The Brief Smell Identification Test (B-SIT), a 12-item, forced-choice, scratch-and-sniff measure, was used to assess the patients’ olfactory function in comparison with a group of sex- and age-matched healthy controls (HC). According to the B-SIT score, subjects were classified as anosmic (< 6), hyposmic (6–8) and normal (≥ 9). Electro-clinical, laboratory and neuroimaging findings were reviewed. Results: Smell impairment was revealed in 15/19 patients (9 hyposmic, 6 anosmic), compared with 5/19 HC (p = 0.0029). Age, gender and smoking habits did not affect the participants’ performance at B-SIT. Olfactory dysfunction appeared more common among patients with definite AE (p = 0.0374), regardless of autoantibody status. Subjects with higher modified Rankin Scale (mRS) scores at AE onset more likely presented hyposmia/anosmia (p = 0.033), and so did those with bilateral ictal/interictal EEG abnormalities (p = 0.006). Conclusions: We found olfaction to be impaired in a significantly large proportion of AE cases. Smell deficits appeared more common in subjects with severe AE (as indicated by both definite diagnosis and higher mRS score), and might represent an additional feature of immune-mediated encephalitis.
2022
Anosmia; Autoimmune encephalitis; Limbic system; Neuroinflammation; Smell impairment
01 Pubblicazione su rivista::01a Articolo in rivista
Olfactory impairment in autoimmune encephalitis: another piece of the puzzle / Morano, A.; Cerulli Irelli, E.; Fanella, M.; Orlando, B.; Salamone, E. M.; Tinelli, E.; Ruffolo, G.; Zuliani, L.; Fattouch, J.; Manfredi, M.; Giallonardo, A. T.; Di Bonaventura, C.. - In: JOURNAL OF NEUROLOGY. - ISSN 0340-5354. - (2022). [10.1007/s00415-022-10959-6]
File allegati a questo prodotto
File Dimensione Formato  
Morano_Olfactory impairment_2022.pdf

accesso aperto

Tipologia: Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 726.6 kB
Formato Adobe PDF
726.6 kB Adobe PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1607443
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 2
social impact