Olfactory function combined with morphology distinguishes Parkinson's disease

Interesting to see that this battery can differentiate PD from atypical Parkinson's which can be very tricky. What about PD versus controls does MRI of the bulbs and tracts differentiate these two groups??

Parkinsonism Relat Disord. 2015 May 11. pii: S1353-8020(15)00197-2. doi: 10.1016/j.parkreldis.2015.05.001. [Epub ahead of print]

http://www.prd-journal.com/article/S1353-8020(15)00197-2/abstract

Sengoku R, Matsushima S, Bono K, Sakuta K, Yamazaki M, Miyagawa S, Komatsu T, Mitsumura H, Kono Y, Kamiyama T, Ito K, Mochio S, Iguchi Y.

OBJECTIVE:

This study aimed to examine whether the volume of the olfactory bulbs and tracts (OB & T) on magnetic resonance imaging (MRI) is useful for differentiating Parkinson's disease (PD) from PD-related disorders.

METHODS:

The study group comprised 13 patients with PD, 11 with multiple system atrophy (MSA), five with progressive supranuclear palsy, and five with corticobasal degeneration (PSP/CBD). All patients were evaluated using the odor stick identification test for Japanese (OSIT-J), 123I-meta-iodobenzylguanidine (MIBG) scintigraphy, and brain MRI. OB & T areas on 1-mm-thick coronal images were measured and summed for volumes. We examined relationships between olfactory function and volume, and cardiovascular dysautonomia. We defined the cut-off values for OSIT-J score or MIBG uptake and OB & T volume to discriminate PD from PD-related disorders and calculated the proportional rate of PD in four categorized groups.

RESULTS:

OB & T volume was smaller in PD than in MSA or PSP/CBD (p < 0.05 each). The cut-off for detecting PD patients was OSIT-J score <8, heart/mediastinum ratio <1.6, and OB & T volume <270 mm3. In the group with OSIT-J score <8 and OB & T volume <270 mm3, the proportion of PD patients among all patients with PD-related disorders was 91%. The rate of probable PD gradually increased as OSIT-J score and OB & T volume decreased (p < 0.001).

CONCLUSIONS:

Although preliminary, these data obtained from a combined morphological and functional evaluation of OB or cardiovascular dysautonomia could be useful for further differential of PD and other PD-related disorders.