Does Midbrain Atrophy Distinguish Progressive Supranuclear Palsy from Frontotemporal Dementia?

BACKGROUND

The diagnostic value of midbrain atrophy for distinguishing behavioral variant frontotemporal dementia (bvFTD) from progressive supranuclear palsy (PSP) is unclear.

OBJECTIVE

To investigate whether measures of midbrain atrophy differentiate PSP from bvFTD.

METHODS

We included four groups: healthy controls (n = 19), PSP-Richardson syndrome (n = 20), bvFTD (n = 19) and Parkinson's disease (PD; n = 12). The following quantitative and qualitative measures were calculated: Hummingbird sign rating scale [HBS-RS], global midbrain atrophy [GMA], midbrain area, midbrain/pons ratio, the Magnetic Resonance Parkinsonism Index (MRPI), the MRPI 2.0 and brainstem volume.

RESULTS

Compared to controls, PSP and bvFTD had lower values of midbrain area, HBS-RS and GMA, and higher MRPI and MRPI 2.0. HBS-RS, GMA, midbrain/pons ratio, midbrain area, MRPI, MRPI 2.0 and brainstem volume distinguished PSP from bvFTD with 73%, 67%, 75%, 83%, 71%, 69% and 82% accuracies, respectively.

CONCLUSIONS

Both quantitative and qualitative measures of midbrain atrophy provided modest accuracy in distinguishing PSP from bvFTD.