Cerebrospinal fluid biomarkers of neurodegeneration in patients with juvenile and classic myotonic dystrophy type 1.

BACKGROUND AND PURPOSE: The aim of the present study was to analyze cerebrospinal fluid (CSF) levels of total tau (T-tau), phosphorylated tau (P-tau) and the 42-amino-acid form of ß-amyloid (Aß42 ) in patients with myotonic dystrophy type 1 (DM1), and their possible correlations with cognitive and behavioral manifestations in these patients. METHODS: Lumbar puncture was performed in 74 patients with DM1 [27 with the childhood/juvenile form (jDM1) and 47 with the adult form (aDM1) of the disease] and 26 control subjects who were subjected to orthopedic surgery. Sandwich ELISA was used for measuring the levels of T-tau, P-tau and Aß42. RESULTS: The CSF level of Aß42 was at its lowest in patients with jDM1 and at its highest in controls (P < 0.05). A tendency of T-tau and P-tau to increase was greater in aDM1 patients than in jDM1 patients and controls (P > 0.05). In both jDM1 and aDM1 patients, significant correlations were found between Aß42 and T-tau (rho = 0.81 and rho = 0.67, respectively, P < 0.01), as well as between Aß42 and P-tau (rho = 0.87 and rho = 0.67, respectively, P < 0.01). The Aß42/P-tau ratio decreased with age in aDM1 patients (rho = -0.30, P < 0.05). Only the level of Aß42 in the CSF of jDM1 patients was correlated with the size of the CTG expansion (rho = -0.53, P < 0.05). Only a few correlations were observed between levels of biomarkers and neuropsychological testing. CONCLUSION: The CSF level of Aß42 was decreased in patients with jDM1, whilst the Aß42/P-tau ratio was decreased in aDM1 patients. Positive correlations between Aß42 , T-tau and P-tau were observed in both forms of disease. Further studies with larger cohorts of DM1 patients are necessary.

Diabetes mellitus and cognitive functioning in a Serbian sample.

INTRODUCTION: Diabetes is associated with cognitive impairments, particularly in executive functioning and memory. AIM: The aim was to describe cognitive functioning in Type 1 (T1DM) and Type 2 (T2DM) diabetes compared to healthy controls in a Serbian sample. METHOD: We studied 15 patients with adult onset T1DM (age range 19-60 years), 37 patients with T2DM (age range 50-77 years), and 32 healthy controls (28-78 years). All participants underwent comprehensive neuropsychological assessment. RESULTS: T2DM subjects exhibited poorer performance than healthy controls in global cognitive performance, as well as verbal learning and memory. After correcting for multiple comparisons, follow-up examination of individual tests showed significantly poorer performance only on Trail Making Test Part B (TMT-B). Effect sizes for T2DM versus healthy controls ranged from medium to large for several cognitive variables, while comparisons between T1DM and the other two groups tended to yield much smaller effects. CONCLUSION: T2DM is associated with poorer cognition, particularly in executive functions, learning/memory, and global cognition. Lack of group differences may be due to use of an adult onset T1DM sample, relatively young age of our T2DM sample, or characteristics of healthy control subjects in our Serbian sample.