Cognitive decline is one of the most frequent and disabling non-motor features of Parkinson´s disease. Around 30% of patients with Parkinson's disease experience mild cognitive impairment, a well-established risk factor for the development of dementia.However, mild cognitive impairment in patients with Parkinson's disease is a heterogeneous entity that involves different types and extents of cognitive deficits. Since it is not currently known which type of mild cognitive impairment confers a higher risk of progression to dementia, it would be useful to define biomarkers that could identify these patients to better study disease progression and possible interventions. In this sense, the identification among patients with Parkinson's disease and mild cognitive impairment of biomarkers associated with dementia would allow the early detection of this process. This review summarizes studies from the last 25 years that have assessed potential biomarkers of dementia and mild cognitive impairment in Parkinson's disease patients. Despite the potential importance, no biomarker has as yet been validated. However, features such as low levels of epidermal and insulin-like growth factors or uric acid in plasma/serum and of Aß in CSF, reduction of cerebral cholinergic innervation and metabolism measured by 3 PET mainly in posterior areas, and hippocampal atrophy in MRI might be indicative of dementia or of subgroups of patients with distinct subtypes of cognitive deficits with a distinct risk of dementia. Therefore, longitudinal studies combining the existing techniques and new approaches will be needed to identify patients at higher risk of dementia.

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The CSF phosphorylated tau/α-synuclein ratio alone, and in combination with tumor necrosis factor α and plasma interleukin-6 levels, might serve as biomarkers to diagnose PD and monitor its severity. © 2017 International Parkinson and Movement Disorder Society.

Freezing of gait is a disabling phenomenon that appears in a substantial number of Parkinson's disease (PD) patients as the disease evolves. It is considered to be one of the most relevant contributing factors to worsening of quality of life. Current pharmacological or surgical treatment options have limited efficacy. Thus, alternative nonpharmacological/nonsurgical approaches have emerged in recent years in an attempt to improve quality of life in PD. This systematic review summarizes studies of such therapies over the past 5 years. Thirty‐five studies were evaluated by use of a qualitative evaluation, while the methodological quality was assessed using validated tools. According to our results, there appear to be two broad categories of nonpharmacological therapies: those that seek a long‐lasting benefit and those that aim to achieve a transient effect to overcome the freezing of gait episode. Among the former, it is possible to differentiate between “passive” therapies, which include transcranial magnetic stimulation or transcranial direct current stimulation, and “active” therapies, which are based on different cognitive or physical training programs. Finally, “transient effect” therapies use different types of cues, such as visual, auditory, or proprioceptive stimuli, to attempt to shift the patient's habitual motor control to a goal‐directed one. In conclusion, a broad spectrum of nonpharmacological/nonsurgical approaches for freezing of gait has emerged in recent years with promising results. © 2019 International Parkinson and Movement Disorder Society

Low-density lipoprotein cholesterol and suicidal behaviour in a large sample of first episode psychosis patients.

Background: Dynamic functional network analysis may add relevant information about the temporal nature of the neurocognitive alterations in PD patients with impulse control disorders (PD-ICD). Our aim was to investigate changes in dynamic functional network connectivity (dFNC) in PD-ICD patients, and topological properties of such networks. Methods: Resting state fMRI was performed on 16 PD PD-ICD patients, 20 PD patients without ICD and 17 healthy controls, whose demographic, clinical and behavioral scores were assessed. We conducted a group spatial independent component analysis, sliding window and graph-theory analyses. Results: PD-ICD patients, in contrast to PD-noICD and HC subjects, were engaged across time in a brain configuration pattern characterized by a lack of between-network connections at the expense of strong withinnetwork connections (State III) in temporal, frontoinsular and cingulate cortices, all key nodes of the salience network. Moreover, this increased maintenance of State III in PD-ICD patients was positively correlated with the severity of impulsivity and novelty seeking as measured by specific scales. While in State III, these patients also exhibited increased local efficiency in all the aforementioned areas. Conclusions: Our findings show for the first time that PD-ICD patients have a dynamic functional engagement of local connectivity involving the limbic circuit, leading to the inefficient modulation in emotional processing and reward-related decision-making. These results provide new insights into the pathophysiology of ICD in PD patients and indicate that the dFC study of fMRI could be a useful biomarker to identify patients at risk to develop ICD.

Herpes simplex encephalitis (HSE) is the most important viral encephalitis due to its high mortality and neurological sequelae. The aim of this study was to contribute to better characterise the HSE. We retrospectively analysed patients with a diagnosis of HSE in our hospital during 2000 and 2010. We included those patients who had a positive result for PCR for herpes simplex virus in cerebrospinal fluid and those with a negative result presenting with a consistent clinical and neuroimage profile. We included 26 patients (10 men, 16 women). Mean age was 58 years. Most frequent symptoms at admission were fever, confusion, aphasia and seizures. Mortality rate was 11 %. 2 patients presented a clinical relapse. In conclusion, the most frequent neurological sequelae were aphasia and amnesia. Disorientation, hyponatremia and abnormalities in initial brain CT were identified as new prognostic factors.