Structural Brain MRI Abnormalities in Kennedy's Disease (P5.015)

Objective. We investigated cortical and white matter (WM) alterations in a large sample of Kennedy’s disease (KD) patients compared to healthy subjects and amyotrophic lateral sclerosis (ALS) patients. Background. Diagnosis of KD might be challenging. Subtle MRI alterations have been reported in KD, but the extent of central nervous system (CNS) involvement relative to ALS still needs to be investigated. Methods. 19 patients with genetically confirmed KD were compared with 21 healthy subjects and 17 sporadic ALS patients matched for demographics and ALSFRS-r score. All patients underwent clinical assessment and Magnetic Resonance Imaging (MRI). Tract-based spatial statistics was applied to investigate WM damage and cortical thickness analysis to identify cortical atrophy. Results. KD patients were characterized by pronounced behavioral symptoms and only subtle cognitive deficits. Relative to controls, KD patients showed pronounced damage of the pontine crossing fibers, right frontotemporal and fronto-occipital tracts, and right cingulum. They also showed subtle cortical thinning of the inferior frontal gyrus bilaterally, left premotor regions, middle temporal gyrus, and right precuneus. ALS patients, compared to controls, showed the classic pattern of damage of the corticospinal tracts (CST) and corona radiata bilaterally with an additional involvement of the left superior longitudinal (SLF), frontotemporal and fronto-occipital tracts, and cortical thinning of precentral gyrus, frontal cortex, lateral temporal and parietal regions, and precuneus bilaterally. The involvement of the CST, corpus callosum, external capsule bilaterally, and left SLF was greater in ALS compared with KD. Conclusions. We found subtle cortical abnormalities and the involvement of long-range frontal and limbic connections in patients with KD, likely related to their behavioral abnormalities. The pattern of WM damage is similar in KD and ALS, while DT MRI measures of the CST and corpus callosum represent powerful tools to differentiate ALS from mimic syndromes, including KD. Funding: Italian Ministry of Health (#RF-2010-2313220).