Freezing of gait is a disabling symptom of Parkinson's disease that causes a paroxysmal inability to generate effective stepping. The underlying pathophysiology has recently migrated towards a ...dysfunctional supraspinal locomotor network, but the actual network derangements during ongoing gait freezing are unknown. We investigated the communication between the cortex and the subthalamic nucleus, two main nodes of the locomotor network, in seven freely-moving subjects with Parkinson's disease with a novel deep brain stimulation device, which allows on-demand recording of subthalamic neural activity from the chronically-implanted electrodes months after the surgical procedure. Multisite neurophysiological recordings during (effective) walking and ongoing gait freezing were combined with kinematic measurements and individual molecular brain imaging studies. Patients walked in a supervised environment closely resembling everyday life challenges. We found that during (effective) walking, the cortex and subthalamic nucleus were synchronized in a low frequency band (4-13 Hz). In contrast, gait freezing was characterized in every patient by low frequency cortical-subthalamic decoupling in the hemisphere with less striatal dopaminergic innervation. Of relevance, this decoupling was already evident at the transition from normal (effective) walking into gait freezing, was maintained during the freezing episode, and resolved with recovery of the effective walking pattern. This is the first evidence for a decoding of the networked processing of locomotion in Parkinson's disease and suggests that freezing of gait is a 'circuitopathy' related to a dysfunctional cortical-subcortical communication. A successful therapeutic approach for gait freezing in Parkinson's disease should aim at directly targeting derangements of neural network dynamics.
Objective
The objective of this work was to investigate survival, dementia, and genotype‐phenotype correlations in patients with Parkinson's disease (PD) with and without mutations on the ...glucocerebrosidase gene (GBA).
Methods
We included 2,764 unrelated consecutive PD patients: 123 GBA carriers (67 mild‐p.N370S and 56 severe mainly p.L444P) and 2,641 noncarriers. Brain perfusion and dopamine transporter imaging was analyzed, including dementia with Lewy Bodies (DLB) as an additional control group.
Results
Multivariable analysis adjusted by sex, age at onset, and disease duration attributed to GBA carriers a greater risk for dementia (hazard ratio HR = 3.16; p < 0.001) and death (HR = 1.85; p = 0.002) than noncarriers. When dementia was introduced in the model as a time‐dependent covariate, the mortality risk remained greater in carriers (HR = 1.65; p = 0.016), suggesting that other clinical features are likely to contribute to reduced survival. At last examination, GBA carriers had worse motor symptoms, particularly nondopaminergic features. Carriers of severe mutations had greater risk for dementia compared to mild mutations (p < 0.001), but similar mortality risk. Consistent with clinical data, GBA carriers showed reduced posterior parietal and occipital cortical synaptic activity and nigrostriatal function than PD noncarriers. Neuroimaging features of carriers of mild mutations overlapped with PD noncarriers, whereas carriers of severe mutations were closer to DLB.
Interpretation
Survival is reduced in GBA carriers compared to noncarriers; this seems to be partially independent from the increased risk for early dementia. The risk for dementia is strongly modulated by type of mutation. In the clinical continuum between PD and DLB, patients with GBA mutations seem to localize midway, with carriers of severe mutations closer to DLB than to idiopathic PD. Ann Neurol 2016;80:662–673
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Transplantation of dopaminergic neurons can potentially improve the clinical outcome of Parkinson's disease, a neurological disorder resulting from degeneration of mesencephalic dopaminergic neurons. ...In particular, transplantation of embryonic-stem-cell-derived dopaminergic neurons has been shown to be efficient in restoring motor symptoms in conditions of dopamine deficiency. However, the use of pluripotent-derived cells might lead to the development of tumours if not properly controlled. Here we identified a minimal set of three transcription factors--Mash1 (also known as Ascl1), Nurr1 (also known as Nr4a2) and Lmx1a--that are able to generate directly functional dopaminergic neurons from mouse and human fibroblasts without reverting to a progenitor cell stage. Induced dopaminergic (iDA) cells release dopamine and show spontaneous electrical activity organized in regular spikes consistent with the pacemaker activity featured by brain dopaminergic neurons. The three factors were able to elicit dopaminergic neuronal conversion in prenatal and adult fibroblasts from healthy donors and Parkinson's disease patients. Direct generation of iDA cells from somatic cells might have significant implications for understanding critical processes for neuronal development, in vitro disease modelling and cell replacement therapies.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A cohort of patients with Parkinson's disease treated with either ergot-derived or non–ergot-derived dopamine agonists underwent echocardiographic evaluation. As compared with a group of normal ...control subjects, patients taking pergolide or cabergoline had a higher frequency of clinically important valve regurgitation and more evidence of stiffening and displacement of the mitral leaflet, as measured by the tenting area of the mitral valve.
Patients with Parkinson's disease taking pergolide or cabergoline had a higher frequency of clinically important valve regurgitation and more evidence of stiffening and displacement of the mitral leaflet than controls.
Several studies and case reports strongly support a causal relationship between the occurrence of drug-induced “restrictive” valvular heart disease and treatment with pergolide, an ergot-derived dopamine receptor agonist mainly used to treat Parkinson's disease.
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More specifically, pergolide may induce fibrotic changes in valve leaflets and in the mitral subvalvular apparatus, causing thickening, retraction, and stiffening of valves and resulting in incomplete leaflet coaptation and valve regurgitation.
Valvular heart damage has also been reported with the ergot-derived dopamine agonists bromocriptine and cabergoline.
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This is important, since cabergoline is widely prescribed in many countries for Parkinson's disease and, at low . . .
The natural pattern of progression of Parkinson's disease is largely unknown because patients are conventionally followed on treatment. As Parkinson's disease progresses, the true magnitude of the ...long-duration response to levodopa remains unknown, because it can only be estimated indirectly in treated patients. We aimed to describe the natural course of motor symptoms by assessing the natural OFF in consecutive Parkinson's disease patients never exposed to treatment (drug-naïve), and to investigate the effects of daily levodopa on the progression of motor disability in the OFF medication state over a 2-year period. In this prospective naturalistic study in sub-Saharan Africa, 30 Parkinson's disease patients (age at onset 58 ± 14 years, disease duration 7 ± 4 years) began levodopa monotherapy and were prospectively assessed using the Unified Parkinson's disease Rating Scale (UPDRS). Data were collected at baseline, at 1-year and 2-years follow-up. First-ever levodopa intake induced a significant improvement in motor symptoms (natural OFF versus ON state UPDRS-III 41.9 ± 15.9 versus 26.8 ± 15.1, respectively; P < 0.001). At 1-year follow-up, OFF state UPDRS-III score after overnight withdrawal of levodopa was considerably lower than natural OFF (26.5 ± 14.9; P < 0 .001). This effect was not modified by disease duration. At the 2-year follow-up, motor signs after overnight OFF (30.2 ± 14.2) were still 30% milder than natural OFF (P = 0.001). The ON state UPDRS-III at the first-ever levodopa challenge was similar to the overnight OFF score at 1-year follow-up and the two conditions were correlated (r = 0.72, P < 0.001). Compared to the natural progression of motor disability, levodopa treatment resulted in a 31% lower annual decline in UPDRS-III scores in the OFF state (3.33 versus 2.30 points/year) with a lower model's variance explained by disease duration (67% versus 36%). Using the equation regressed on pretreatment data, we predicted the natural OFF at 1-year and 2-year follow-up visits and estimated that the magnitude of the long-duration response to levodopa ranged between 60% and 65% of total motor benefit provided by levodopa, independently of disease duration (P = 0.13). Although levodopa therapy was associated with motor fluctuations, overnight OFF disability during levodopa was invariably less severe than the natural course of the disease, independently of disease duration. The same applies to the yearly decline in UPDRS-III scores in the OFF state. Further research is needed to clarify the mechanisms underlying the long-duration response to levodopa in Parkinson's disease. Understanding the natural course of Parkinson's disease and the long-duration response to levodopa may help to develop therapeutic strategies increasing its magnitude to improve patient quality of life and to better interpret the outcome of randomized clinical trials on disease-modifying therapies that still rely on the overnight OFF to define Parkinson's disease progression.
Parkinson's disease (PD) is a progressive neurodegenerative disorder in which the major pathologic substrate is a loss of dopaminergic neurons from the substantia nigra. Our main objective was to ...determine the correspondence between changes in the substantia nigra, evident in neuromelanin and iron sensitive magnetic resonance imaging (MRI), and dopaminergic striatal innervation loss in patients with PD. Eighteen patients and 18 healthy control subjects were included in the study. Using neuromelanin-MRI, we measured the volume of the substantia nigra and the contrast-to-noise-ratio between substantia nigra and a background region. The apparent transverse relaxation rate and magnetic susceptibility of the substantia nigra were calculated from dual-echo MRI. Striatal dopaminergic innervation was measured as density of dopamine transporter (DAT) by means of single-photon emission computed tomography and (123)I N-ω-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl) tropane. Patients showed a reduced volume of the substantia nigra and contrast-to-noise-ratio and both positively correlated with the corresponding striatal DAT density. The apparent transverse relaxation rate and magnetic susceptibility values of the substantia nigra did not differ between patients and healthy controls. The best predictor of DAT reduction was the volume of the substantia nigra. Clinical and imaging correlations were also investigated for the locus coeruleus. Our results suggest that neuromelanin-MRI can be used for quantifying substantia nigra pathology in PD where it closely correlates with dopaminergic striatal innervation loss. Longitudinal studies should further explore the role of Neuromelanin-MRI as an imaging biomarker of PD, especially for subjects at risk of developing the disease.
Speech impairment is commonly reported in Parkinson's disease and is not consistently improved by available therapies – including deep brain stimulation of the subthalamic nucleus (STN-DBS), which ...can worsen communication performance in some patients. Improving the outcome of STN-DBS on speech is difficult due to our incomplete understanding of the contribution of the STN to fluent speaking.
To assess the relationship between subthalamic neural activity and speech production and intelligibility.
We investigated bilateral STN local field potentials (LFPs) in nine parkinsonian patients chronically implanted with DBS during overt reading. LFP spectral features were correlated with clinical scores and measures of speech intelligibility.
Overt reading was associated with increased beta-low (1220) Hz) power in the left STN, whereas speech intelligibility correlated positively with beta-high (2030) Hz) power in the right STN.
We identified separate contributions from frequency and brain lateralization of the STN in the execution of an overt reading motor task and its intelligibility. This subcortical organization could be exploited for new adaptive stimulation strategies capable of identifying the occurrence of speaking behavior and facilitating its functional execution.
•Speech impairment is common in Parkinson's disease (PD)•Deep brain stimulation of the subthalamic nucleus (STN) can worsen speech in PD•Left STN low-beta activity is increased during overt reading•Right STN high-beta power positively relates with speech intelligibility•Speech intelligibility can be measured with semi-automatized algorithms
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
to date, there are no medical or surgical treatments for progressive supranuclear palsy (PSP). It is possible to speculate that patients with PSP could benefit from rehabilitative treatments designed ...for Parkinson's disease, including the use of robot-assisted walking training.
to evaluate whether the use of the robotic device Lokomat® is superior in PSP patients to the use of treadmill with visual cues and auditory feedbacks (treadmill-plus) in the context of an aerobic, multidisciplinary, intensive, motor-cognitive and goal-based rehabilitation treatment (MIRT) conceived for Parkinsonian patients.
we enrolled twenty-four PSP patients. Twelve subjects underwent a 4-week MIRT exploiting the use of the treadmill-plus (MIRT group). Twelve subjects underwent the same treatment, but replacing the treadmill-plus with Lokomat® (MIRT-Lokomat group). Subjects were evaluated with clinical and functional scales at admission and discharge. The primary outcomes were the total PSP Rating Scale (PSPRS) score and its "limb" and "gait" sub-scores. Secondary outcomes were Berg Balance Scale (BBS), Six Minutes Walking test (6MWT) and the number of falls.
total PSPRS, PSPRS-gait sub-score, BBS, 6MWT and number of falls improved significantly in both groups (p ≤ 0.003 all, except 6MWT, p = 0.032 and p = 0.018 in MIRT-Lokomat and MIRT group respectively). The PSPRS-limb sub-score improved significantly only in the MIRT group (p = 0.002). A significant difference between groups was observed only for total PSPRS, indicating a slightly better improvement for patients in the MIRT group (p = 0.047). No differences between groups were revealed for the other outcomes, indicating that the effect of rehabilitation was similar in both groups.
Lokomat® training, in comparison with treadmill-plus training, does not provide further benefits in PSP patients undergoing MIRT. Our findings suggest the usefulness of an aerobic, multidisciplinary, intensive, motor-cognitive and goal-based approach for the rehabilitation of patients suffering from such a complex disease as PSP.
This trial was registered on ClinicalTrials.gov, NCT02109393.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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