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Brain-derived neurotrophic factor (BDNF) is a trophic factor regulating cell survival and synaptic plasticity. Recent findings indicate that BDNF could be a potential regulatory factor for cognitive functioning in normal and/or neuropathological conditions. With regard to neurological disorders, recent data suggest that individuals with Parkinson's disease (PD) may be affected by cognitive deficits and that they have altered BDNF production. Therefore, the hypothesis can be advanced that BDNF levels are associated with the cognitive state of these patients. With this in mind, the present study was aimed at exploring the relationship between BDNF serum levels and cognitive functioning in PD patients with mild cognitive impairment (MCI). Thirteen PD patients with MCI were included in the study. They were administered an extensive neuropsychological test battery that investigated executive, episodic memory, attention, visual-spatial and language domains. A single score was obtained for each cognitive domain by averaging z-scores on tests belonging to that specific domain. BDNF serum levels were measured by enzyme-linked immunoassay (ELISA). Pearson's correlation analyses were performed between BDNF serum levels and cognitive performance. Results showed a significant positive correlation between BDNF serum levels and both attention (p < 0.05) and executive (p < 0.05) domains. Moreover, in the executive domain we found a significant correlation between BDNF levels and scores on tests assessing working memory and selfmonitoring/ inhibition. These preliminary data suggest that BDNF serum levels are associated with cognitive state in PD patients with MCI. Given the role of BDNF in regulating synaptic plasticity, the present findings give further support to the hypothesis that this trophic factor may be a potential biomarker for evaluating cognitive changes in PD and other neurological syndromes associated with cognitive decline. [ABSTRACT FROM AUTHOR]

This study investigated the effect of cognitive training aimed at improving shifting ability on Parkinson’s disease (PD) patients’ performance of prospective memory (PM) tasks. Using a double-blind protocol, 17 PD patients were randomly assigned to two experimental arms. In the first arm (n=9) shifting training was administered, and in the second (placebo) arm (n=8), language and respiratory exercises. Both treatments consisted of 12 sessions executed over 4 weeks. PM and shifting measures (i.e., Trail Making Test and Alternate Fluency Test) were administered at T0 (before treatment) and T1 (immediately after treatment). A mixed analysis of variance was applied to the data. To evaluate the effects of treatment, the key effect was the interaction between Group (experimental vs. placebo) and Time of Assessment (T0 vs. T1). This interaction was significant for the accuracy indices of the PM procedure (p<.05) and for the performance parameters of the shifting tasks (p≤.05). Tukey’s HSD tests showed that in all cases passing from T0 to T1 performance significantly improved in the experimental group (in all cases p≤.02) but remained unchanged in the placebo group (all p consistently>.10). The performance change passing from T0 to T1 on the Alternate Fluency test and the PM procedure was significantly correlated (p<.05). Results show that the cognitive training significantly improved PD patients’ event-based PM performance and suggest that their poor PM functioning might be related to reduced shifting abilities. (JINS, 2014, 20, 1–10) [ABSTRACT FROM PUBLISHER]

Background. Previous data suggest that (i) dopamine modulates the ability to implement nonroutine schemata and update operations (flexibility processes) and that (ii) dopamine-related improvement may be related to baseline dopamine levels in target pathways (inverted U-shaped hypothesis). Objective. To investigate above hypotheses in individuals with Parkinson's disease (PD). Methods. Twenty PD patients were administered tasks varying as to flexibility load in two treatment conditions: (i) "off" condition, about 18 hours after dopamine dose and (ii) "on" condition, after dopamine administration. PD patients were separated into two groups: low performers (i.e., performance on Digit Span Backward below the sample mean) and high performers (i.e., performance above the mean). Twenty healthy individuals performed the tasks in two sessions without taking drugs. Results. Passing from the "off" to the "on" state, only low performer PD patients significantly improved their performance on high-flexibility measures (interference condition of the Stroop test; P < 0.05); no significant effect was found on low-flexibility tasks. Conclusions. These findings document that high-flexibility processes are sensitive to dopamine neuromodulation in the early phases of PD. This is in line with the hypothesis that striatal dopamine pathways, affected early by PD, are precociously implicated in the expression of cognitive disorders in these individuals. [ABSTRACT FROM AUTHOR]

Abstract: Between 2005 and 2007, six patients affected by idiopathic Parkinson''s disease (IPD) were submitted to the bilateral implantation (and subsequent deep brain stimulation — DBS) of the pedunculopontine nucleus (PPN) plus the subthalamic nucleus (STN). This review synthesizes the effects of PPN low-frequency stimulation on non-motor functions, focusing on patient sleep quality and cognitive performance. If not associated to STN-DBS, PPN-DBS promoted a modest amelioration of patient motor performance. However, during PPN-DBS, they experienced on the one hand a significant improvement in executive functions and working memory, on the other hand a beneficial change in sleep architecture. Overall, the limited sample hampers definite conclusions. Yet, although the PPN-DBS induced motor effects are quite disappointing (discouraging extended trials based upon the sole PPN implantation), the neuropsychological profile supports the contention by which in selected PD patients, with subtle cognitive deficits or vanished efficacy of previous implanted STN, PPN-DBS might still represent a reliable and compassionate option. [Copyright &y& Elsevier]