Structural and physiological neurovascular changes in idiopathic Parkinson's disease and its clinical phenotypes

Neurovascular changes are likely to interact importantly with the neurodegenerative process in idiopathic Parkinson's disease (IPD). Markers of neurovascular status (NVS) include white matter lesion (WML) burden and arterial spin labelling (ASL) measurements of cerebral blood flow (CBF) and arterial arrival time (AAT). We investigated NVS in IPD, including an analysis of IPD clinical phenotypes, by comparison with two control groups, one with a history of clinical cerebrovascular disease (CVD) (control positive, CP) and one without CVD (control negative, CN). Fifty-one patients with IPD (mean age 69.0 ± 7.7 years) (21 tremor dominant (TD), 24 postural instability and gait disorder (PIGD) and six intermediates), 18 CP (mean age 70.1 ± 8.0 years) and 34 CN subjects (mean age 67.4 ± 7.6 years) completed a 3T MRI scan protocol including T2-weighted fluid-attenuated inversion recovery (FLAIR) and ASL. IPD patients showed diffuse regions of significantly prolonged AAT, small regions of lower CBF and greater WML burden by comparison with CN subjects. TD patients showed lower WML volume by comparison with PIGD patients. These imaging data thus show altered NVS in IPD, with some evidence for IPD phenotype-specific differences

Gabapentin add-on treatment for drug-resistant focal epilepsy

BackgroundThis is an updated version of the Cochrane Review previously published in 2018. Epilepsy is a common neurological disorder characterised by recurrent seizures. Most people with epilepsy have a good prognosis and their seizures are well controlled by a single antiepileptic drug, but up to 30% develop drug-resistant epilepsy, especially people with focal seizures. In this review, we summarised the evidence from randomised controlled trials (RCTs) of gabapentin, when used as an add-on treatment for drug-resistant focal epilepsy.ObjectivesTo evaluate the efficacy and tolerability of gabapentin when used as an add-on treatment for people with drug-resistant focal epilepsy.Search methodsFor the latest update, we searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid) on 11 August 2020. CRS Web includes randomised or quasi-randomised, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialised Registers of Cochrane Review Groups including Epilepsy. We imposed no language restrictions.Selection criteriaRandomised, placebo-controlled, double-blind, add-on trials of gabapentin in people with drug-resistant focal epilepsy. We also included trials using an active drug control group or comparing different doses of gabapentin.Data collection and analysisTwo review authors independently selected trials for inclusion and extracted the relevant data. We assessed the following outcomes: seizure frequency, seizure freedom, treatment withdrawal (any reason) and adverse effects. Primary analyses were intention-to-treat. We also undertook sensitivity best-case and worst-case analyses. We estimated summary risk ratios (RR) for each outcome and evaluated dose-response in regression models.Main resultsWe identified no new studies for this update, therefore, the results and conclusions are unchanged. In the previous update of this review, we combined data from six trials in meta-analyses of 1206 randomised participants. The overall risk ratio (RR) for reduction in seizure frequency of 50% or more compared to placebo was 1.89 (95% confidence interval (CI) 1.40 to 2.55; 6 studies, 1206 participants; moderate-certainty evidence). Dose regression analysis (for trials in adults) showed increasing efficacy with increasing dose, with 25.3% (95% CI 19.3 to 32.3) of people responding to gabapentin 1800 mg compared to 9.7% on placebo, a 15.5% increase in response rate (95% CI 8.5 to 22.5). The RR for treatment withdrawal compared to placebo was 1.05 (95% CI 0.74 to 1.49; 6 trials, 1206 participants; moderate-certainty evidence). Adverse effects were significantly associated with gabapentin compared to placebo. RRs were as follows: ataxia 2.01 (99% CI 0.98 to 4.11; 3 studies, 787 participants; low-certainty evidence), dizziness 2.43 (99% CI 1.44 to 4.12; 6 studies, 1206 participants; moderate-certainty evidence), fatigue 1.95 (99% CI 0.99 to 3.82; 5 studies, 1161 participants; low-certainty evidence) and somnolence 1.93 (99% CI 1.22 to 3.06; 6 studies, 1206 participants; moderate-certainty evidence). There was no evidence of a difference for the adverse effects of headache (RR 0.79, 99% CI 0.46 to 1.35; 6 studies, 1206 participants; moderate-certainty evidence) or nausea (RR 0.95, 99% CI 0.52 to 1.73; 4 trials, 1034 participants; moderate-certainty evidence). Overall, the studies were at low to unclear risk of bias due to information on each risk of bias domain not being available. We judged the overall certainty of the evidence (using the GRADE approach) as low to moderate due to potential attrition bias resulting from missing outcome data and imprecise results with wide CIs.Authors' conclusionsGabapentin has efficacy as an add-on treatment in people with drug-resistant focal epilepsy, and seems to be fairly well-tolerated. However, the trials reviewed were of relatively short duration and provide no evidence for the long-term efficacy of gabapentin beyond a three-month period. The results cannot be extrapolated to monotherapy or to people with other epilepsy types. Further trials are needed to assess the long-term effects of gabapentin, and to compare gabapentin with other add-on drugs

Blood-brain barrier leakage is increased in Parkinson’s disease

Background: Blood-brain barrier disruption has been noted in animal models of Parkinson’s disease (PD) and forms the basis of the vascular hypothesis of neurodegeneration, yet clinical studies are lacking. Objective: To determine alterations in blood-brain barrier integrity in PD, with comparison to cerebrovascular disease. Methods: Dynamic contrast enhanced magnetic resonance images were collected from 49 PD patients, 15 control subjects with cerebrovascular disease (control positive CP) and 31 healthy control subjects (control negative CN), with all groups matched for age. Quantitative maps of the contrast-agent transfer coefficient across the blood-brain barrier (Ktrans) and plasma volume (vp) were produced using Patlak analysis. Differences in Ktrans and vp were assessed with voxel-based analysis as well as in regions associated with PD pathophysiology. In addition, the volume of white matter lesions (WML) was obtained from T2-weighted fluid attenuation inversion recovery (FLAIR) images. Results: Higher Ktrans, reflecting higher blood-brain barrier leakage, was found in the PD group than in the CN group using voxel-based analysis; differences were most prominent in the posterior white matter regions. Region of interest analysis confirmed Ktrans to be significantly higher in PD than in CN, predominantly driven by differences in the substantia nigra, normal-appearing white matter, WML and the posterior cortex. WML volume was significantly higher in PD compared to CN. Ktrans values and white matter lesion volume were similar in PD and CP, suggesting a similar burden of cerebrovascular disease despite lower cardiovascular risk factors. Conclusion: These results show blood-brain barrier disruption in PD

Gabapentin add-on for drug-resistant partial epilepsy

BACKGROUND: The majority of people with epilepsy have a good prognosis and their seizures are well controlled by a single antiepileptic drug, but up to 30% develop drug-resistant epilepsy, especially those with partial seizures. In this review we summarise the current evidence regarding the antiepileptic drug gabapentin, when used as an add-on treatment for drug-resistant partial epilepsy. OBJECTIVES: To evaluate the efficacy and tolerability of gabapentin when used as an add-on treatment for people with drug-resistant partial epilepsy. SEARCH METHODS: This is an updated version of the original Cochrane review published in The Cochrane Library 2009, Issue 4. We searched the Cochrane Epilepsy Group's Specialised Register (14 May 2013), the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 4, The Cochrane Library) (April 2013) and MEDLINE (1946 to 14 May 2013). We imposed no language restrictions. SELECTION CRITERIA: Randomised, placebo-controlled, double-blind, add-on trials of gabapentin in people with drug-resistant partial epilepsy. Trials using an active drug control group or which compared doses of gabapentin were also included in the review. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion and extracted the relevant data. We assessed the following outcomes: (a) seizure frequency and seizure freedom; (b) treatment withdrawal (any reason); (c) adverse effects. Primary analyses were intention-to-treat. We also undertook sensitivity best and worst-case analyses. We estimated summary risk ratios for each outcome and evaluated dose-response in regression models. MAIN RESULTS: Eleven trials were included representing 2125 randomised participants. We combined data from six trials in meta-analyses of 1206 randomised participants. The overall risk ratio (RR) for 50% or greater reduction in seizure frequency compared to placebo was 1.89 (95% confidence interval (CI) 1.40 to 2.55). Dose regression analysis (for trials in adults) shows increasing efficacy with increasing dose, with 25.3% (19.3 to 32.3) of people responding to 1800 mg of gabapentin compared to 9.7% on placebo, a 15.5% increase in response rate (8.5 to 22.5). The RR for treatment withdrawal compared to placebo was 1.05 (95% CI 0.74 to 1.49). Adverse effects were significantly associated with gabapentin compared to placebo. Risk ratios were as follows: ataxia 2.01 (99% CI 0.98 to 4.11), dizziness 2.43 (99% CI 1.44 to 4.12), fatigue 1.95 (99% CI 0.99 to 3.82) and somnolence 1.93 (99% CI 1.22 to 3.06). No significant differences were found for the adverse effects of headache (RR 0.79, 99% CI 0.46 to 1.35) or nausea (RR 0.95, 99% CI 0.52 to 1.73). Overall the studies together are rated as low/unclear risk of bias due to information on each risk of bias domain not being available. AUTHORS' CONCLUSIONS: Gabapentin has efficacy as an add-on treatment in people with drug-resistant partial epilepsy. However, the trials reviewed were of relatively short duration and provide no evidence for the long-term efficacy of gabapentin beyond a three-month period. The results cannot be extrapolated to monotherapy or to people with other epilepsy types

Clinical and electrophysiological characteristics of 103 patients with sensory neuronopathy

Sensory Neuronopathy (SN) represents a distinct peripheral nervous system disorder associated with degeneration of the Dorsal Root Ganglia. We present our retrospective review of 103 patients with an electro-clinical diagnosis of SN. Average age of onset was 54 yr. Aetiologies included Sjogrens (21%), Probable Inflammatory (16%), Idiopathic (29%), Inherited (20%), Toxic (5%) and paraneoplastic (9%). Of those with inherited SN (n=21); CANVAS syndrome 2/21, mitochrondrial cytopathy 9/21 with 4 confirmed POLG1 mutations, 3/21 presumed HSANIIb, Frederich's Ataxia 1/21 and 6/21 unidentified phenotypes. Clinically, acquired causes commonly presented with pain (62%), asymmetrical/non-length dependent sensory disturbance (91%) as compared to the inherited group who are more likely to present with gait disturbance without prominent sensory symptoms (52%). Of the cohort with presumed inflammatory disease, 29 patients were immunosuppressed with 12 patients responding to a combination of steroids and Mycophenolate. IVIG was not found to be beneficial with no sustained benefit in 7 patients. Paraneoplastic causes (n=9) included Breast (n=2), Neuroendocrine tumours (n=2), Carcinoid (n=2), Bowel (n=1), SCLC (n=1) and unknown primary (n=1) with only 4 Hu positive Conclusions Sensory neuronopathy is clinically and aetiologically pleomorphic. In cases with a suspected inflammatory cause it is worthwhile considering a trial of immunomodulatory treatment

Similarities in arterial arrival time prolongation and posterior hypoperfusion in patients with idiopathic parkinson's disease and stroke

The relevance of impaired neurovascular function in idiopathic Parkinson's disease (IPD) is unknown. Furthermore, it is unknown whether any such changes might contribute to, or be the effect of, neurodegeneration, or potentially reflect comorbid cerebrovascular disease (CVD). MRI arterial spin labelling (ASL) is a suitable, non-invasive tool for quantifying cerebral haemodynamics including measurements of cerebral blood flow (CBF) and arterial arrival time (AAT). Prolonged AAT has been attributed to increased collateral circulation, chronic vasodilatation and/or increased tortuosity of vessels. 12 subjects with CVD (mean age 68.9±7.8), 19 tremor dominant (TD) IPD subjects (mean age 67.2±0.6), 17 postural instability and gait dominant (PIGD) IPD subjects (mean age 70.7±6.6) and 23 control subjects (mean age 65.1±5.7) completed a 3T MRI scanning protocol, including ASL. CVD subjects had significantly more cerebrovascular risk factors than the other groups. A significant widespread increase in baseline AAT was seen in IPD (both TD and PIGD) and CVD groups when compared to controls. Voxel-based analysis of CBF revealed significant focal hypoperfusion (predominantly posteriorly) in the TD, PIGD and the CVD groups when compared to controls. These novel findings suggesting similar alterations in cerebral haemodynamics in IPD and CVD groups merit further study

Relapsing cerebral amyloid angiopathy-related inflammation:the wax and the wane

Cerebral amyloid angiopathy-related inflammation (CAA-I) is a rare variant of cerebral amyloid angiopathy (CAA). Its precise pathophysiology remains uncertain and we currently have limited evidence on which immunosuppressive agents are the most effective in its treatment. The disease course of CAA-I disorders can vary from an isolated clinical event to recurrent episodes. We present a case of biopsy-confirmed CAA-I that gives insight into its potential relapsing nature and the challenges of its long-term management