Phonemic Verbal Fluency and Midbrain Atrophy in Progressive Supranuclear Palsy.

BACKGROUND

The neuropsychological profile of progressive supranuclear palsy (PSP) patients is mainly characterized by executive dysfunction, but the relationship between the latter and midbrain atrophy is still unclear.

OBJECTIVE

The aims of the study were to investigate which test evaluating executive functioning is more frequently impaired in PSP patients and to evaluate the relationship between midbrain-based MRI morphometric measures and executive dysfunction.

METHODS

PSP patients who had undergone a neuropsychological battery assessing executive functioning with the Frontal Assessment Battery (FAB), the phonemic verbal fluency F-A-S, the Raven's Progressive Colored Matrix, and the Stroop word colors test (time and errors) were enrolled in the study. A group of Parkinson's disease (PD) patients matched by age, sex, education, and global cognitive status was selected. All the enrolled patients also underwent a volumetric T1-3D brain MRI.

RESULTS

Thirty-five PSP patients and 35 PD patients were enrolled. Patients with PSP as compared to patients with PD showed a significant greater impairment in verbal fluency (16.0±7.9 and 23.4±8.7 words/180 s; p < 0.001) and a significant lower score at the FAB total score (11.5±3.8 and 13.7±3.4; p = 0.013). Midbrain area was significantly smaller in PSP patients than in PD patients (83.9±20.1 and 134.5±19.9 mm2; p < 0.001). In PSP patients, a significant positive correlation between verbal fluency and the midbrain area (r = 0.421; p = 0.028) was observed.

CONCLUSION

Our findings suggest that the phonemic verbal fluency is among the most frequently impaired executive functions in PSP patients and is strongly correlated to midbrain atrophy.