Prevalence of Convergence Insufficiency-Type Symptomatology in Parkinson’s Disease

This article has been published in a revised form in Canadian Journal of Neurological Sciences https://doi.org/10.1017/cjn.2017.39 This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © The Canadian Journal of Neurological SciencesBackground: Individuals with Parkinson’s disease (PD) often present with visual symptoms (e.g., difficulty in reading, double vision) that can also be found in convergence insufficiency (CI). Our objective was to estimate the prevalence of CI-type visual symptomatology in individuals with PD, in comparison with controls. Methods: Participants ≥50 years with (n=300) and without (n=300) PD were recruited. They were administered the Convergence Insufficiency Symptom Survey (CISS–15) over the phone. A score of ≥21 on the CISS–15, considered positive for CI-type symptomatology, served as the cutoff. Data from individuals (n=87 with, n=94 without PD) who were approached but who reported having a known oculovisual condition were analysed separately. Student’s t test and chi-square at the 0.05 level were employed for statistical significance. Results: A total of 29.3% of participants with versus 7.3% without PD presented with a score of ≥21 on the CISS–15 (p=0.001). Of the participants having a known oculovisual condition, 39.1% with versus 19.1% without PD presented with a score of ≥21 on the CISS–15 (p=0.01). Conclusions: The prevalence of CI-type visual symptoms is higher in individuals with versus without PD whether or not they have a coexisting oculovisual condition. These results suggest that PD per se places individuals with the disease at greater risk of visual symptomatology. These results further underline the importance of providing regular eye exams for individuals with PD.This work was supported by the Comité aviseur pour la recherche clinique (CAREC) at the Institut universitaire de gériatrie de Montréal (IUGM), the Canadian Institutes of Health Research (CIHR: MOP-123462) and the Canadian Optometric Education Trust Fund (COETF)

Portrait of blood-derived extracellular vesicles in patients with Parkinson's disease.

The production of extracellular vesicles (EV) is a ubiquitous feature of eukaryotic cells but pathological events can affect their formation and constituents. We sought to characterize the nature, profile and protein signature of EV in the plasma of Parkinson's disease (PD) patients and how they correlate to clinical measures of the disease. EV were initially collected from cohorts of PD (n = 60; Controls, n = 37) and Huntington's disease (HD) patients (Pre-manifest, n = 11; manifest, n = 52; Controls, n = 55) - for comparative purposes in individuals with another chronic neurodegenerative condition - and exhaustively analyzed using flow cytometry, electron microscopy and proteomics. We then collected 42 samples from an additional independent cohort of PD patients to confirm our initial results. Through a series of iterative steps, we optimized an approach for defining the EV signature in PD. We found that the number of EV derived specifically from erythrocytes segregated with UPDRS scores corresponding to different disease stages. Proteomic analysis further revealed that there is a specific signature of proteins that could reliably differentiate control subjects from mild and moderate PD patients. Taken together, we have developed/identified an EV blood-based assay that has the potential to be used as a biomarker for PD

LINGO1 Variants in the French-Canadian Population

Essential tremor (ET) is a complex genetic disorder for which no causative gene has been found. Recently, a genome-wide association study reported that two variants in the LINGO1 locus were associated to this disease. The aim of the present study was to test if this specific association could be replicated using a French-Canadian cohort of 259 ET patients and 479 ethnically matched controls. Our genotyping results lead us to conclude that no association exists between the key variant rs9652490 and ET (Pcorr = 1.00)

Articles Increased Prevalence of Non-motor Symptoms in Essential Tremor

Background: Cases with essential tremor (ET) have been described with Lewy body inclusions, the hallmark of Parkinson disease (PD). Patients with PD may suffer from anosmia, depression, constipation, and rapid eye movement sleep behavior disorder (RBD), sometimes years before the appearance of their motor syndrome. The objective of this study was to evaluate the prevalence of these non-motor Parkinson’s associated symptoms in patients with ET. Methods: Fifty ET subjects were contacted by phone and given questionnaires evaluating the presence or absence of anosmia, depression, constipation, and RBD. Frequencies of these symptoms were compared with their published prevalence in the general population. Results: Of the patients with ET, 4.5 % reported having anosmia or hyposmia and 21.7 % reported being constipated, similar to what is observed in the general population. Using a screening questionnaire for RBD, 43.5 % of ET patients are possibly suffering from RBD, whereas in the general population prevalence is estimated to be 0.5%. Finally, depression was detected in 21.7 % of ET patients; in the general population, prevalence is 5%. Discussion: Patients with ET seem to have more RBD and more depression than found in the general population. Prospective studies with normal control group

Increased Prevalence of Non-Motor Symptoms in Essential Tremor

Background: Cases with essential tremor (ET) have been described with Lewy body inclusions, the hallmark of Parkinson disease (PD). Patients with PD may suffer from anosmia, depression, constipation, and rapid eye movement sleep behavior disorder (RBD), sometimes years before the appearance of their motor syndrome. The objective of this study was to evaluate the prevalence of these non‐motor Parkinson's associated symptoms in patients with ET.Methods: Fifty ET subjects were contacted by phone and given questionnaires evaluating the presence or absence of anosmia, depression, constipation, and RBD. Frequencies of these symptoms were compared with their published prevalence in the general population.Results: Of the patients with ET, 4.5% reported having anosmia or hyposmia and 21.7% reported being constipated, similar to what is observed in the general population. Using a screening questionnaire for RBD, 43.5% of ET patients are possibly suffering from RBD, whereas in the general population prevalence is estimated to be 0.5%. Finally, depression was detected in 21.7% of ET patients; in the general population, prevalence is 5%.Discussion: Patients with ET seem to have more RBD and more depression than found in the general population. Prospective studies with normal control groups are needed to confirm these findings.</p

Eligibility Criteria for Deep Brain Stimulation in Parkinson's Disease, Tremor, and Dystonia

In this review, the available evidence to guide clinicians regarding eligibility for deep brain stimulation (DBS) in the main conditions in which these forms of therapy are generally indicated - Parkinson's disease (PD), tremor, and dystonia - is presented. In general, the literature shows that DBS is effective for PD, essential tremor, and idiopathic dystonia. In these cases, key points in patient selection must include the level of disability and inability to manage symptoms using the best available medical therapy. Results are, however, still not optimal when dealing with other aetiologies, such as secondary tremors and symptomatic dystonia. Also, in PD, issues such as age and neuropsychiatric profile are still debatable parameters. Overall, currently available literature is able to guide physicians on basic aspects of patient selection and indications for DBS; however, a few points are still debatable and controversial. These issues should be refined and clarified in future studies

Mood stability during acute stimulator challenge in Parkinson's disease patients under long-term treatment with subthalamic deep brain stimulation

Acute and chronic behavioral effects of subthalamic stimulation (STN-DBS) for Parkinson's disease (PD) are reported in the literature. As the technique is relatively new, few systematic studies on the behavioral effects in long-term treated patients are available. To further study the putative effects of STN-DBS on mood and emotional processing, 15 consecutive PD patients under STN-DBS for at least 1 year, were tested ON and OFF stimulation while on or off medication, with instruments sensitive to short-term changes in mood and in emotional discrimination. After acute changes in experimental conditions, mood core dimensions (depression, elation, anxiety) and emotion discrimination processing remained remarkably stable, in the face of significant motor changes. Acute stimulator challenge in long-term STN-DBS-treated PD patients does not appear to provoke clinically relevant mood effects. © 2007 Movement Disorder Societ

Deep Brain Stimulation Target Selection for Parkinson's Disease

During the DBS Canada Day symposium held in Toronto July 4-5, 2014, the scientific committee invited experts to discuss three main questions on target selection for deep brain stimulation (DBS) of patients with Parkinson's disease (PD). First, is the subthalamic nucleus (STN) or the globus pallidus internus (GPi) the ideal target? In summary, both targets are equally effective in improving the motor symptoms of PD. STN allows a greater medications reduction, while GPi exerts a direct antidyskinetic effect. Second, are there further potential targets? Ventral intermediate nucleus DBS has significant long-term benefit for tremor control but insufficiently addresses other motor features of PD. DBS in the posterior subthalamic area also reduces tremor. The pedunculopontine nucleus remains an investigational target. Third, should DBS for PD be performed unilaterally, bilaterally or staged? Unilateral STN DBS can be proposed to asymmetric patients. There is no evidence that a staged bilateral approach reduces the incidence of DBS-related adverse events