PSP as distinguished from CBD, MSA-P and PD by clinical and imaging differences at an early stage

Objective Because it is often difficult to precisely diagnose and distinguish progressive supranuclear palsy (PSP) from corticobasal degeneration (CBD), multiple system atrophy-parkinsonism (MSA-P) and Parkinson's disease (PD) at the onset of the disease, we compared the patients and clarified the features of these diseases. Methods We compared 77 PSP, 26 CBD, 26 MSA-P and 166 PD patients from clinical and imaging points of view including cerebral blood flow (CBF) in the frontal eye field. Results The clinical characteristics of PSP were supranuclear gaze disturbance, optokinetic nystagmus (OKN) impairment and falls at the first visit. On head MRI, midbrain tegmentum atrophy was much more frequently detected in PSP than in all of the other groups. Heart-to-mediastinum average count ratio (H/M) in iodine-123 meta-iodobenzyl guanidine ( ¹²³I-MIBG) myocardial scintigraphy was not decreased in PSP, CBD, MSA-P and PD-Yahr 1 (-1), but patients of PD-2, 3, 4 and 5 showed a significant decrease compared with the PSP group. The CBF in the left frontal eye field of PD-3 group and that in right frontal eye field of PD-3 and PD-4 groups were lower than that of PSP group, although other groups showed a tendency without a significant decrease compared with PSP group. Conclusion PSP is distinguishable from CBD, MSA-P and PD even at the early stage with extra-ocular movement (EOM) disturbance, falls, atrophy of the midbrain tegmentum, and H/M in ¹²³I-MIBG myocardial scintigraphy, and the reduction of CBF in area 8 could serve as a supplemental diagnostic method for distinguishing PSP from PD-3 or PD-4.