Drawing in Alzheimer-type dementia

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Axonal damage and loss of connectivity in nigrostriatal and mesolimbic dopamine pathways in early Parkinson's disease

A progressive loss of dopamine neurons in the substantia nigra (SN) is considered the main feature of idiopathic Parkinson's disease (PD). Recent neuropathological evidence however suggests that the axons of the nigrostriatal dopaminergic system are the earliest target of α-synuclein accumulation in PD, thus the principal site for vulnerability. Whether this applies toin vivoPD, and also to the mesolimbic system has not been investigated yet. We used [11C]FeCIT PET to measure presynaptic dopamine transporter (DAT) activity in both nigrostriatal and mesolimbic systems, in 36 early PD patients (mean disease duration in months ± SD 21.8 ± 10.7) and 14 healthy controls similar for age. We also performed anatomically-driven partial correlation analysis to evaluate possible changes in the connectivity within both the dopamine networks at an early clinical phase. In the nigrostriatal system, we found a severe DAT reduction in the afferents to the dorsal putamen (DPU) (η2 = 0.84), whereas the SN was the less affected region (η2 = 0.31). DAT activity in the ventral tegmental area (VTA) and the ventral striatum (VST) were also reduced in the patient group, but to a lesser degree (VST η2 = 0.71 and VTA η2 = 0.31). In the PD patients compared to the controls, there was a marked decrease in dopamine network connectivity between SN and DPU nodes, supporting the significant derangement in the nigrostriatal pathway. These results suggest that neurodegeneration in the dopamine pathways is initially more prominent in the afferent axons and more severe in the nigrostriatal system. Considering PD as a disconnection syndrome starting from the axons, it would justify neuroprotective interventions even if patients have already manifested clinical symptoms

Which patients discontinue? Issues on Levodopa/carbidopa intestinal gel treatment: Italian multicentre survey of 905 patients with long-term follow-up

Objectives To report the results of a national survey aimed at quantifying the current level of diffusion of Levodopa/carbidopa intestinal gel (LCIG) in Italy. Methods Sixty Parkinson's Disease (PD) specialists in Italy were invited to complete a survey covering issues on clinical and practical aspects of LCIG therapy. Results Clinical features of 905 patients were collected retrospectively. The majority of centres reported the use of a multidisciplinary team, biochemistry testing, neurophysiological and neuropsychological tests before and after treatment, in addition to caregivers’ training and patient's follow as outpatients. Most centres (60%) used internal guidelines for patient selection. The overall rate of adverse events was 55.1%. Weight loss, chronic polyneuropathy and stoma infection were the most frequently reported. 40% of centres used replacement therapy with Vitamin B12 and Folic acid from the start of LCIG and continued this for the duration of treatment. The rate of discontinuation was of 25.7% overall, with 9.5% of cases occurring in the first year. The main causes of withdrawal were device-related complications, disease progression (comorbidity, severe dementia) and caregiver and/or patient dissatisfaction. Conclusions In Italy LCIG infusion is managed in a uniform manner at a clinical, practical and organizational level even though the selection criteria are not standardized through the country. The high percentage of patients remaining on treatment in the short- and long-term follow-up confirms effectiveness of treatment, careful follow-up, and appropriate patient and caregivers training