The association between olfactory bulb volume, cognitive dysfunction, physical disability and depression in multiple sclerosis

Ö Yaldizli; I-K Penner; T Yonekawa; Y Naegelin; J Kuhle; M Pardini; D T Chard; C Stippich; J-I Kira; K Bendfeldt; M Amann; E-W Radue; L Kappos; T Sprenger

doi:10.1111/ene.12891

The association between olfactory bulb volume, cognitive dysfunction, physical disability and depression in multiple sclerosis

Eur J Neurol. 2016 Mar;23(3):510-9. doi: 10.1111/ene.12891. Epub 2015 Nov 19.

Authors

Ö Yaldizli^{1

2}, I-K Penner³, T Yonekawa⁴, Y Naegelin¹, J Kuhle¹, M Pardini^{2

5}, D T Chard^{2

6}, C Stippich⁷, J-I Kira⁴, K Bendfeldt⁸, M Amann^{1

7

8}, E-W Radue⁸, L Kappos¹, T Sprenger^{1

9}

Affiliations

¹ Department of Neurology, University Hospital Basel, Basel, Switzerland.
² Department of Neuroinflammation, Queen Square MS Centre, NMR Research Unit, UCL Institute of Neurology, London, UK.
³ Department of Cognitive Psychology and Methodology, University of Basel, Basel, Switzerland.
⁴ Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
⁵ Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.
⁶ National Institute for Health Research University College London Hospitals Biomedical Research Centre, London, UK.
⁷ Department of Radiology, Division of Neuroradiology, University Hospital Basel, Basel, Switzerland.
⁸ Medical Image Analysis Center, Basel, Switzerland.
⁹ Department of Neurology, DKD Helios Klinik Wiesbaden, Wiesbaden, Germany.

PMID: 26699999
DOI: 10.1111/ene.12891

Abstract

Background and purpose: Olfactory bulb atrophy is associated with cognitive dysfunction in Parkinson's and Alzheimer's disease, and with major depression. It has been suggested that olfactory bulb atrophy or dysfunction is therefore a marker of neurodegeneration. Multiple sclerosis (MS) is now also recognized as having a significant neurodegenerative component. Thus, the aim of this study was to investigate associations between physical and cognitive disability, depression and olfactory bulb volume in MS.

Methods: In total, 146 patients with MS (mean age 49.0 ± 10.9 years, disease duration 21.2 ± 9.3 years, median Expanded Disability Status Scale (EDSS) score 3.0 (range 0-7.5), 103 relapsing-remitting, 35 secondary progressive and eight primary progressive MS) underwent a standardized neurological examination, comprehensive neuropsychological testing and magnetic resonance imaging (MRI); data of 27 healthy people served as age- and gender-matched control subjects. The olfactory bulb was semi-automatically segmented on high-resolution three-dimensional T1-weighted MRI.

Results: Mean olfactory bulb volume was lower in MS patients than healthy controls (183.9 ± 40.1 vs. 209.2 ± 59.3 μl; P = 0.018 adjusted to intracranial volume). Olfactory bulb volume was similar across clinical disease subtypes and did not correlate with cognitive performance, EDSS scores or total proton density/T2 white matter lesion volume. However, in progressive MS, the mean olfactory bulb volume correlated with depression scores (Spearman's rho = -0.38, P < 0.05) confirmed using a multivariate linear regression analysis including cognitive fatigue scores. This association was not observed in relapsing-remitting MS.

Conclusion: Olfactory bulb volume was lower in MS than in healthy controls. Olfactory bulb volume does not seem to mirror cognitive impairment in MS; however, it is associated with higher depression scores in progressive MS.

Keywords: cognitive impairment; depression; fatigue; magnetic resonance imaging; multiple sclerosis; olfactory bulb volume.

MeSH terms

Adult
Atrophy / pathology
Cognitive Dysfunction / etiology
Cognitive Dysfunction / physiopathology*
Depression / etiology
Depression / physiopathology*
Female
Humans
Male
Middle Aged
Multiple Sclerosis / complications
Multiple Sclerosis / pathology*
Multiple Sclerosis / physiopathology*
Multiple Sclerosis, Relapsing-Remitting / complications
Multiple Sclerosis, Relapsing-Remitting / pathology
Multiple Sclerosis, Relapsing-Remitting / physiopathology
Olfactory Bulb / pathology*