Cerebral and cerebellar white matter tract alterations in patients with Pantothenate Kinase-Associated Neurodegeneration (PKAN)

Abstract

Background: To examine structural connectivity of white matter tracts in patients with Pantothenate Kinase-Associated Neurodegeneration (PKAN) dystonia and identify those ones which correlate negatively to severity of symptoms.

Methods: In a group of 41 patients suffering from PKAN dystonia and an age- and gender-matched control group, white matter tractography was carried out, based on diffusion tensor imaging magnetic resonance data. Postprocessing included assessment of Quantitative Anisotropy (QA) using q-space diffeomorphic reconstruction in order to reduce influence of iron accumulation in globus pallidus of patients.

Results: Whole brain tractography presented significantly reduced QA values in patients (0.282 ± 0.056, as compared to controls (0.325 ± 0.046, p < 0.001). 9 fiber clusters of tracts correlated negatively to the dystonia score of patients: the middle cerebellar peduncle and the tracts of both cerebellar hemispheres as well as corpus callosum, forceps minor, the superior cortico-striate tracts and the superior thalamic radiations of both cerebral hemispheres (False Discovery Rate FDR = 0.041).

Conclusion: The finding of a reduced global structural connectivity within the white matter and of negative correlation of motor system-related tracts, mainly those between the basal ganglia, cortical areas and the cerebellum, fits well to the concept of a general functional disturbance of the motor system in PKAN.

Keywords: Cerebral white matter; Diffusion tensor imaging; Pantothenate kinase-associated neurodegeneration; Tractography.