Do neuropsychiatric fluctuations temporally match motor fluctuations in Parkinson’s disease?

Neurological Sciences - In Parkinson’s disease (PD), non-motor fluctuations (NMFs), especially neuropsychiatric fluctuations, often coexist with motor fluctuations (MFs) but are often...     

A novel spinocerebellar ataxia type 15 family with involuntary movements and cognitive decline

Background and purpose: SCA15 is a recently identified spinocerebellar ataxia with pure cerebellar involvement. Here, we report a novel SCA15 Italian family with atypical clinical features. Methods: Three affected members from a three‐generation family segregating an autosomal dominant cerebellar ataxia underwent clinical examination and genetic tests for hereditary ataxia. Results: All affected members present with cognitive impairment and two of them with mild intermittent involuntary movements in association with the clinical hallmarks of SCA15 (gait ataxia, balance impairment, and dysarthria). Genetic tests detected a large deletion spanning ITPR1 and SUMF1 genes in affected members. Conclusion: Our findings help enlarging the clinical spectrum of SCA15.     

Hyperdopaminergic behavioral spectrum in Parkinson's disease: A review

Impulse control disorders (ICDs) and other related behaviors, such as punding and dopamine dysregulation syndrome, are frequent yet underrecognized non-motor complications of dopamine replacement therapy (DRT) in Parkinson's disease (PD); they can also have a major negative impact on quality of life. They result from complex interactions between a given individual's predispositions, non-physiological dopaminergic stimulation and PD pathology. Also, sensitization of the mesocorticolimbic pathway, reflected by the psychotropic effects of dopaminergic treatment, plays a crucial role in the emergence of these addictive behaviors. While early detection of changes in behavior, less use of dopamine agonists (DA) that have a relative selectivity for mesocorticolimbic dopamine receptors, and fractionation of levodopa dosages to avoid non-physiological pulsatile stimulation of dopamine receptors are key strategies in the management of this hyperdopaminergic behavioral spectrum, other complementary approaches are also addressed in this review.     

Battery longevity of neurostimulators in Parkinson disease: A historic cohort study

BackgroundDeep brain stimulation (DBS) of the subthalamic nucleus (STN) is a well-established treatment for motor complications in Parkinson disease (PD). Since 2012, the nonrechargeable dual-channel neurostimulator available in France seems to have shorter battery longevity compared to the same manufacturer's previous model.ObjectiveThe aim of this study was to evaluate the battery longevity of older and more recent neurostimulators from the same manufacturer and to explore factors associated with battery life variations.Materials and methodsWe retrospectively studied our cohort of PD patients who underwent STN DBS between 1987 and 2017. We collected data concerning neurostimulator replacements and parameters. We compared the survival of the first device available, Kinetra® and the current one, Activa-PC® (Medtronic Inc.) and estimated the factors that had an impact on battery longevity through a Cox logistic regression.ResultsThree hundred sixty-four PD patients received a total of 654 DBS STN neurostimulators: 317 Kinetra® and 337 Activa-PC®. The survival analysis, using the Kaplan-Meier estimator, showed a difference between the curves of the two devices (log-rank test; p < 0.001). The median survival of an Activa-PC® neurostimulator was 1666 days, while it was 2379 days for a Kinetra®.After adjustment, according to the multivariate analysis, the main factors associated with battery lifetime were: the neurostimulator type; the number of subsequent neurostimulator implantations; the total electrical energy delivered (TEED); and sex.ConclusionThe Kinetra® neurostimulator lifetime is 2.5 years longer than the Activa-PC®. The type of the device, the high TEED and the number of subsequent neurostimulator implantations influence battery longevity most. These results have medical-economic implications since the survival of PD patients with DBS increases over years.     

Anesthesia reduces discharge rates in the human pallidum without changing the discharge rate ratio between pallidal segments

Classical rate models of basal ganglia circuitry associate discharge rate of the globus pallidus external and internal segments (GPe, GPi respectively) solely with dopaminergic state and predict an inverse ratio between the discharge rates of the two pallidal segments. In contrast, the effects of other rate modulators such as general anesthesia (GA) on this ratio have been ignored. To respond to this need, we recorded the neuronal activity in the GPe and GPi in awake and anesthetized human patients with dystonia (57 and 53 trajectories respectively) and in awake patients with Parkinson's disease (PD, 16 trajectories) undergoing deep brain stimulation procedures. This triad enabled us to dissociate pallidal discharge ratio from general discharge modulation. An automatic offline spike detection and isolation quality system was used to select 1560 highly isolated units for analysis. The mean discharge rate in the GPi of awake PD patients was dramatically higher than in awake dystonia patients although the firing rate in the GPe was similar. Firing rates in dystonic patients under anesthesia were lower in both nuclei. Surprisingly, in all three groups, GPe firing rates were correlated with firing rates in the ipsilateral GPi. Thus, the firing rate ratio of ipsilateral GPi/GPe pairs was similar in awake and anesthetized patients with dystonia and significantly higher in PD. We suggest that pallidal activity is modulated by at least two independent processes: dopaminergic state which changes the GPi/GPe firing rate ratio, and anesthesia which modulates firing rates in both pallidal nuclei without changing the ratio between their firing rates.