xRead - Olfactory Disorders (September 2023)

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PATEL et al.

TABLE VIII.4 (Continued) Study

Year LOE Study design

Study groups

Clinical end point

Conclusions

Before OFC, PIOD had decreased gray matter volumes in the limbic system and thalamus; after training these volumes were significantly increased Patients with PD and idiopathic smell loss had significantly reduced fractional anisotropy values in the substantia nigra compared with HCs Hyposmics had similar central olfactory processing, but they had higher activation in regions associated with odor memory and motivation Patients with anosmia had a significant decrease in gray matter and corresponding white matter volumes Atrophy increased with disease duration Patients with CA had larger gray matter volumes in the left entorhinal and piriform cortices and thicker OFC bilaterally, and left piriform cortex Parosmia was associated with gray matter volume loss in regions associated with olfactory discrimination and memory Hyposmic patients had gray and white matter volume loss in several olfactory-related brain regions (Continues) Patients with IOD had reduced gray matter volume in primary and secondary olfactory areas

SS-TDI assessed

Gellrich

2018 3

Cohort

30 patients with PIOD 31 normosmic controls

et al 1084

before and after OFC in patients)

Voxel-based

morphometry

Haehner et al 1091

2018 3

Prospective cohort

19 patients with

SS-TDI, diffusion tensor imaging, diffusion characteristics, fractional anisotropy measures

idiopathic smell loss 17 normosmic controls 12 patients with PD 11 hyposmic patients 12 normosmic controls

Pellegrino et al 1078

SS-TDI fMRI: brain activation

2016 3

Prospective cohort

to olfactory stimulation

Yao

2014 3

Prospective cohort

16 patients with IOD 16 normosmic controls

T&T olfactometer Voxel-based morphometry

et al 1029

Peng

OF (T&T

2013 3

Prospective cohort

19 anosmics 20 normosmic controls

et al 1085

olfactometer)

Voxel-based

morphometry

Frasnelli et al 1083

2013 3

Prospective cohort

17 patients with CA 17 normosmic controls

Voxel-based

morphometry

Bitter

Voxel-based

2011 3

Prospective cohort

22 patients with parosmia 22 hyposmic controls without parosmia (matched for OF) 24 hyposmic patients 43 normosmic controls

et al 1088

morphometry

Bitter

2010 3

Prospective cohort

Voxel-based

et al 1086

morphometry