A novel diagnostic marker for progressive supranuclear palsy targeting atrophy of the subthalamic nucleus

Despite great progress in radiological diagnostic tools for neurodegenerative disorders, their diagnostic accuracy has been unsatisfactory. One of the pathological hallmarks of progressive supranuclear palsy (PSP) is atrophy of the subthalamic nucleus, which has not attracted much attention for imaging analysis.

The clinical data of patients with PSP, multiple system atrophy (MSA), Parkinson's disease (PD), and corticobasal syndrome (CBS) who underwent brain magnetic resonance imaging at our department between June 2019 and March 2020 were retrospectively reviewed. The volumes of the subthalamic nucleus and of the whole cerebrum were then analyzed and compared among the disorders.

Fourteen PSP-Richardson syndrome (RS), 14 MSA, 14 PD, and 8 CBS patients were assessed. The mean volume of the bilateral subthalamic nuclei was smaller in PSP patients (0.148 ± 0.012 cm³) than in MSA (0.183 ± 0.026 cm³; p < 0.001), PD (0.209 ± 0.031 cm³; p < 0.001), and CBS (0.180 ± 0.056 cm³; p < 0.001) patients. The volume of the whole cerebrum was not significantly different among the disorders. Using an STN volume cut-off of 0.01925, the sensitivity and specificity for differential diagnosis between PSP and the other disorders were 0.846 and 0.972, respectively.

Subthalamic nucleus volume may be a useful diagnostic marker for PSP; it may easily differentiate it from other neurodegenerative parkinsonian disorders.