Thursday, March 6, 2014

Journal Club: Comparison of symptomatic and asymptomatic persons with Alzheimer disease neuropathology

Journal Club: Comparison of symptomatic and asymptomatic persons with Alzheimer disease neuropathology
Neurology recent issues

Advances in neuroimaging, biomarkers, and clinical data have led to the hypothesis that the pathologic process of Alzheimer dementia begins decades prior to functional decline and diagnosis.1–3 High-profile clinical trial results have shown that biomarker changes can be made via pharmacologic intervention; however, the timing of this intervention has likely been too late to impact the cascade of neurodegenerative changes.4,5 In "Comparison of symptomatic and asymptomatic persons with Alzheimer disease neuropathology" by Monsell et al.,6 neuropathologic and clinical data were used to determine the risk of developing clinically significant cognitive impairment. This work represents a significant contribution because it examines a large cohort of autopsy data, which includes patients with Alzheimer dementia neuropathology who were clinically normal or diagnosed with mild cognitive impairment and Alzheimer-type dementia. The authors report a 3-fold increase in the risk of cognitive symptoms in association with quantifiable increases in neurofibrillary tangle pathology. Additionally, several other factors including APOE gene status, history of depression, and age impacted the clinical presentation. The ultimate goal of this investigation and similar studies is to facilitate the early and accurate identification of those at risk of developing Alzheimer dementia, such that potentially disease-modifying therapies may be considered.



Original Article: http://www.neurology.org/cgi/content/short/82/9/e76?rss=1

Acute seizures in the acute ischemic stroke setting: A step forward in their description

Acute seizures in the acute ischemic stroke setting: A step forward in their description
Neurology recent issues

Although the incidence of acute seizures after ischemic strokes is small, about 1.2%–4.2%,1,2 they still represent a substantial clinical challenge. There are no clear management guidelines, and the effect on stroke outcome is a matter of debate.3 Moreover, experiencing a seizure at the stroke onset may represent a relative contraindication for thrombolysis.4 Despite all of these clinical pitfalls and multiple published studies, there remains a lack of knowledge regarding acute seizures after acute ischemic strokes. In this issue of Neurology®, Huang et al.5 add information to this field.



Original Article: http://www.neurology.org/cgi/content/short/82/9/740?rss=1

Percutaneous Stereotactic Radiofrequency Lesioning for Trigeminal Neuralgia: Determination of Minimum Clinically Important Difference in Pain Improvement for Patient-Reported Outcomes

Percutaneous Stereotactic Radiofrequency Lesioning for Trigeminal Neuralgia: Determination of Minimum Clinically Important Difference in Pain Improvement for Patient-Reported Outcomes
Neurosurgery - Most Popular Articles

imageBACKGROUND: The Visual Analog Scale (VAS) and the Barrow Neurological Institute Pain Scale (BNI-PS) are 2 patient-reported outcome (PRO) tools frequently used to rate pain from trigeminal neuralgia (TN). Outcomes studies often use these patient-reported outcomes to assess treatment effectiveness, but it is unknown exactly what degree of change in the numerical scores constitutes the minimum clinically important difference (MCID). MCID remains uninvestigated for percutaneous stereotactic radiofrequency lesioning (RFL), a common surgical procedure for TN. OBJECTIVE: To determine MCID values for the VAS and BNI-PS in patients undergoing RFL. METHODS: Forty-three consecutive patients with TN who underwent RFL by a single surgeon were prospectively assessed with the VAS and BNI-PS preoperatively and 3 years postoperatively. Three anchors were used to assign each patient's outcome: satisfaction, willingness to have the surgery again, and Health Transition Index. We then used 3 well-established, anchor-based methods to calculate MCID: average change, minimum detectable change, and change difference. RESULTS: Patients experienced substantial improvement in both VAS (9.81 vs 3.35; P < .001) and BNI-PS (4.95 vs 2.44; P < .001) after RFL. The 3 MCID calculation methods generated a range of MCID values for each of the PROs (VAS, 4.13-8.20; BNI-PS, 1.03-3.30). The area under the receiver-operating characteristic curve was greater for BNI-PS compared with VAS for all 3 anchors, indicating that BNI-PS is probably better suited for calculating MCID. CONCLUSION: RFL-specific MCID is variable on the basis of the calculation technique. With the use of the minimum detectable change calculation method with the Health Transition Index anchor, the minimum clinically important difference is 4.49 for VAS and 1.16 for BNI-PS after RFL for TN. ABBREVIATIONS: AUC, area under the receiver-operating characteristic curve BNI-PS, Barrow Neurological Institute Pain Scale HTI, Health Transition Index MCID, minimum clinically important difference MDC, minimum detectable change PRO, patient-reported outcome RFL, percutaneous stereotactic radiofrequency lesioning TN, trigeminal neuralgia VAS, Visual Analog Scale

Original Article: http://journals.lww.com/neurosurgery/Fulltext/2014/03000/Percutaneous_Stereotactic_Radiofrequency_Lesioning.4.aspx

Serum Biomarkers of Brain Injury to Classify Outcome After Pediatric Cardiac Arrest*

Serum Biomarkers of Brain Injury to Classify Outcome After Pediatric Cardiac Arrest*
Critical Care Medicine - Most Popular Articles

imageObjectives:Morbidity and mortality in children with cardiac arrest largely result from neurologic injury. Serum biomarkers of brain injury can potentially measure injury to neurons (neuron-specific enolase), astrocytes (S100b), and axons (myelin basic protein). We hypothesized that serum biomarkers can be used to classify outcome from pediatric cardiac arrest. Design:Prospective observational study. Setting:Single tertiary pediatric hospital. Patients:Forty-three children with cardiac arrest. Interventions:None. Measurements and Main Results:We measured serum neuron-specific enolase, S100b, and myelin basic protein on days 1–4 and 7 after cardiac arrest. We recorded demographics, details of the cardiac arrest and resuscitation, and Pediatric Cerebral Performance Category at hospital discharge and 6 months. We analyzed the association of biomarker levels at 24, 48, and 72 hours with favorable (Pediatric Cerebral Performance Category 1–3) or unfavorable (Pediatric Cerebral Performance Category 4–6) outcome and mortality. Forty-three children (49% female; mean age of 5.9 ± 6.3) were enrolled and 17 (40%) died. Serum S100b concentrations peaked earliest, followed by neuron-specific enolase and finally myelin basic protein. Serum neuron-specific enolase and S100b concentrations were increased in the unfavorable versus favorable outcome group and in subjects who died at all time points (all p < 0.05). Serum myelin basic protein at 24 and 72 hours correctly classified survival but not good versus poor outcome. Using best specificity, serum S100b and neuron-specific enolase had optimal positive and negative predictive values at 24 hours to classify both favorable versus unfavorable outcome and survival, whereas serum myelin basic protein's best accuracy occurred at 48 hours. Receiver operator curves for serum S100b and neuron-specific enolase to classify favorable versus unfavorable outcome at 6 months were superior to clinical variables. Conclusions:Preliminary data show that serum S100b, neuron-specific enolase, and myelin basic protein may aid in outcome classification of children surviving cardiac arrest.

Original Article: http://journals.lww.com/ccmjournal/Fulltext/2014/03000/Serum_Biomarkers_of_Brain_Injury_to_Classify.21.aspx

A Review of Percutaneous Treatments for Trigeminal Neuralgia

A Review of Percutaneous Treatments for Trigeminal Neuralgia
Neurosurgery - Most Popular Articles

imageBACKGROUND: Common treatments for trigeminal neuralgia include percutaneous techniques, microvascular decompression, and Gamma Knife radiosurgery. Although microvascular decompression is considered the gold standard for treatment, percutaneous techniques remain an effective option for select patients. OBJECTIVE: To review the historical development, advantages, and limitations of the most common percutaneous procedures for trigeminal neuralgia: balloon compression (BC), glycerol rhizotomy (GR), and radiofrequency thermocoagulation (RF). METHODS: Publications reporting clinical outcomes after BC, GR, and RF were reviewed and included. Operative technique was based on the experience of the primary surgeon and senior author. RESULTS: All 3 percutaneous techniques (BC, GR, and RF) provide effective pain relief but differ in method and specificity of nerve injury. BC selectively injures larger pain fibers while sparing small fibers and does not require an awake, cooperative patient. Pain control rates up to 91% at 6 months and 66% at 3 years have been reported. RF allows somatotopic nerve mapping and selective division lesioning and provides pain relief in up to 97% of patients initially and 58% at 5 years. Multiple treatments improve outcomes but carry significant morbidity risk. GR offers similar pain-free outcomes of 90% at 6 months and 54% at 3 years but with higher complication rates (25% vs 16%) compared with BC. Advantages of percutaneous techniques include shorter procedure duration, minimal anesthesia risk, and in the case of GR and RF, immediate patient feedback. CONCLUSION: Percutaneous treatments for trigeminal neuralgia remain safe, simple, and effective for achieving good pain control while minimizing procedural risk. ABBREVIATIONS: BC, balloon compression GR, glycerol rhizotomy MS, multiple sclerosis MVD, microvascular decompression RF, radiofrequency thermocoagulation TN, trigeminal neuralgia

Original Article: http://journals.lww.com/neurosurgery/Fulltext/2014/03001/A_Review_of_Percutaneous_Treatments_for_Trigeminal.3.aspx