Beta-amyloid and phosphorylated tau metabolism changes in narcolepsy over time.

PURPOSE: The aim od this study is to test whether metabolism of beta-amyloid and tau proteins changes in narcolepsy along with the disease course. METHODS: We analyzed a population of narcoleptic drug-naïve patients compared to a sample of healthy controls. Patients and controls underwent lumbar puncture for assessment of cerebrospinal fluid (CSF) beta-amyloid1-42 (Aß42), total tau (t-tau), and phosphorylated tau (p-tau) levels. Moreover, based on the median disease duration of the whole narcolepsy group, the patients were divided into two subgroups: patients with a short disease duration (SdN, <5 years) and patients with a long disease duration (LdN, >5 years). RESULTS: We found significantly lower CSF Aß42 levels in the whole narcolepsy group with respect to controls. Taking into account the patient subgroups, we documented reduced CSF Aß42 levels in SdN compared to both LdN and controls. Even LdN patients showed lower CSF Aß42 levels with respect to controls. Moreover, we documented higher CSF p-tau levels in LdN patients compared to both SdN and controls. Finally, a significant positive correlation between CSF Aß42 levels and disease duration was evident. CONCLUSIONS: We hypothesize that beta-amyloid metabolism and cascade may be impaired in narcolepsy not only at the onset but also along with the disease course, although they show a compensatory profile over time. Concurrently, also CSF biomarkers indicative of neural structure (p-tau) appear to be altered in narcolepsy patients with a long disease duration. However, the mechanism underlying beta-amyloid and tau metabolism impairment in narcolepsy remains still unclear and deserves to be better elucidated.

Paucisymptomatic Marchiafava-Bignami disease with relevant diffusion-weighted MRI lesions.

Marchiafava-Bignami disease (MBD) is a rare alcohol-associated disorder characterized by demyelization and necrosis of the corpus callosum. Diffusion-weighted (DW) MRI may reveal the lesions in patients showing serious clinical manifestations, high mortality rate and severe cognitive sequelae, though some cases with good outcome have been reported. We describe a case of a man with a history of chronic alcohol abuse associated with malabsorption; the man presented mild clinical signs on the first neurological exam, despite the presence of DW-MRI lesions, bilaterally involving entire corpus callosum, that are compatible with MBD diagnosis.