Neurology September 2012 Volume 79 Issue 10

Objective: To study the accuracy of the ABCD2 score in predicting early stroke risk following TIA and to model post-test probability of stroke for varying cutoff scores and baseline stroke risk.Methods: Medline, PubMed, Embase, conference proceedings, and manuscript references up to October 2010 were searched for studies reporting ABCD2 score and stroke outcome after TIA. Additional data were requested from authors. Meta-analysis, meta-regression, and post-test probability modeling were undertaken to assess prediction of stroke at 2, 7, and 90 days.Results: Of 44 eligible studies, data were available for 33 (16,070 patients): 26/33 reported stroke at 2 days (533 strokes), 32/33 at 7 days (781 strokes), and 28/33 at 90 days (1,028 strokes) after TIA. Using scores 0-3 ("low risk") and 4-7 ("high risk") for stroke at 7 days, pooled measures were sensitivity 0.89 (0.87-0.91), specificity 0.34 (0.33-0.35), positive predictive value 0.08 (0.07-0.09), negative predictive value 0.98 (0.98-0.98), positive likelihood ratio (PLR) 1.43 (1.33-1.54), negative likelihood ratio (NLR) 0.40 (0.33-0.50), and area under the curve (AUC) 0.70 (0.62-0.78). Results were similar at days 2 and 90. There was moderate heterogeneity while pooling PLR (p < 0.01, I2 >50%), with stroke specialist TIA diagnosis associated with slightly higher PLR. At 5% baseline stroke risk, ABCD2 >3 indicated an absolute increase in 7-day stroke risk of only 2.0% while a score <=3 indicated a 2.9% decrease in risk. Changes in risk were very small when baseline stroke risk was lower.Conclusions: The ABCD2 score leads to only small revisions of baseline stroke risk particularly in settings of very low baseline risk and when used by nonspecialists.GLOSSARY: .AUC: area under the curveIQR: interquartile rangeNLR: negative likelihood ratioNPV: negative predictive valuePLR: positive likelihood ratioPPV: positive predictive value(C)2012 American Academy of Neurology

Objective: To study the effect of a neurohospitalist service on length of stay, cost, patient satisfaction, and education at an academic medical center.Methods: This was a retrospective cohort study using administrative data, educational surveys, and standardized patient satisfaction surveys to compare outcomes in the 21 months before (n = 343) and 27 months after (n = 436) the introduction of a neurohospitalist service in October 2006 at a single tertiary care academic medical center.Results: The most common diagnoses treated in both periods were demyelinating disease, neuromuscular disease, seizure, CNS infection, and cerebrovascular disease. Mean length of stay was reduced during the neurohospitalist period compared with that during the preneurohospitalist period (4.6 days vs 6.3 days; p < 0.001), but there was no difference in median cost ($6,758 vs $7,241; p = 0.25) or in-hospital mortality (1.6 vs 1.2%; p = 0.61). After adjustment for diagnosis, admission source, and severity of illness, both length of stay (coefficient -1.85, 95% confidence interval [CI] -2.47 to -1.24) and cost (coefficient -1,558, 95% CI -2,645 to -470) were reduced during the neurohospitalist period. Thirty-day readmission rates were not different between the 2 periods in adjusted analysis. There were no differences in patient satisfaction or resident trainee satisfaction between the 2 periods, but medical student satisfaction was higher on standard educator evaluations after the neurohospitalist program was introduced.Conclusions: The introduction of a neurohospitalist service at an academic medical center coincided with a reduction in length of stay and cost and a nonsignificant trend toward improvement in medical student satisfaction without affecting mortality, readmission rates, or patient satisfaction.GLOSSARY: ICU: intensive care unitIQR: interquartile range.(C)2012 American Academy of Neurology

Objective: To describe the phenotype of patients with C9FTD/ALS (C9ORF72) hexanucleotide repeat expansion.Methods: A total of 648 patients with frontotemporal dementia (FTD)-related clinical diagnoses and Alzheimer disease (AD) dementia were tested for C9ORF72 expansion and 31 carried expanded repeats (C9+). Clinical and neuroimaging data were compared between C9+ (15 behavioral variant FTD [bvFTD], 11 FTD-motor neuron disease [MND], 5 amyotrophic lateral sclerosis [ALS]) and sporadic noncarriers (48 bvFTD, 19 FTD-MND, 6 ALS).Results: All C9+ patients displayed clinical syndromes of bvFTD, ALS, or FTD-MND. At first evaluation, C9+ bvFTD patients had more delusions and greater impairment of working memory, but milder eating dysregulation compared to bvFTD noncarriers. C9+FTD-MND patients had a trend for longer survival and had an earlier age at onset than FTD-MND noncarriers. Voxel-based morphometry demonstrated more thalamic atrophy in FTD and FTD-MND carriers than in noncarriers.Conclusions: Patients with the C9ORF72 hexanucleotide repeat expansion develop bvFTD, ALS, or FTD-MND with similar clinical and imaging features to sporadic cases. Other FTD spectrum diagnoses and AD dementia appear rare or absent among C9+ individuals. Longer survival in C9+ FTD-MND suggests slower disease progression and thalamic atrophy represents a novel and unexpected feature.GLOSSARY: AD: Alzheimer diseaseALS: amyotrophic lateral sclerosisbvFTD: behavioral variant frontotemporal dementiaCBS: corticobasal syndromeCDR-SB: Clinical Dementia Rating Scale sum of boxesFTD: frontotemporal dementiaFWE: familywise errorglm: generalized linear modellvPPA: logopenic variant primary progressive aphasiaMND: motor neuron diseasenfvPPA: nonfluent variant primary progressive aphasiaNPI: Neuropsychiatric InventoryPSP: progressive supranuclear palsysvPPA: semantic variant primary progressive aphasiaUCSF: University of California, San FranciscoVBM: voxel-based morphometry(C)2012 American Academy of Neurology

Objectives: Substantial evidence showing an association between type 2 diabetes (T2D) and cerebral atrophy, cognitive impairment, and dementia is accumulating. However, relatively little is known about the subclinical effects of high plasma glucose levels within the normal range. The aim of this study was to investigate the association between plasma glucose levels and hippocampal and amygdalar atrophy in a sample of 266 cognitively healthy individuals free of T2D, aged 60-64 years, taking part in a longitudinal study of aging.Methods: Fasting plasma glucose was assessed at wave 1. Hippocampal and amygdalar volumes were manually traced on 1.5 T MRI scans collected at wave 1 and at wave 2 4 years later. General linear model analyses were used to assess the relationship between plasma glucose and incident medial temporal lobe atrophy after controlling for a range of sociodemographic and health variables.Results: Plasma glucose levels were found to be significantly associated with hippocampal and amygdalar atrophy and accounted for 6%-10% in volume change after controlling for age, sex, body mass index, hypertension, alcohol, and smoking.Conclusions: High plasma glucose levels within the normal range (<6.1 mmol/L) were associated with greater atrophy of structures relevant to aging and neurodegenerative processes, the hippocampus and amygdala. These findings suggest that even in the subclinical range and in the absence of diabetes, monitoring and management of plasma glucose levels could have an impact on cerebral health. If replicated, this finding may contribute to a reevaluation of the concept of normal blood glucose levels and the definition of diabetes.GLOSSARY: BMI: body mass indexCRP: C-reactive proteinFOV: field of viewGLM: general linear modelHPA: hypothalamic-pituitary-adrenalICV: intracranial volumeIGT: impaired glucose toleranceMetS: metabolic syndromeROI: region of interestT2D: type 2 diabetesTE: echo timeTR: repetition time(C)2012 American Academy of Neurology

Objective: To electrophysiologically characterize the Nav1.4 mutant N440K found in a Korean family with a syndrome combining symptoms of paramyotonia congenita, hyperkalemic periodic paralysis, and potassium-aggravated myotonia.Methods: We characterized transiently expressed wild-type and mutant Nav1.4 using whole-cell voltage-clamp analysis.Results: N440K produced a significant depolarizing shift in the voltage dependence of fast inactivation and increased persistent current and acceleration in fast inactivation recovery, which gave rise to a 2-fold elevation in the dynamic availability of the mutant channels. In addition, the mutant channels required substantially longer and stronger depolarization to enter the slow-inactivated state.Conclusions: N440K causes a gain of function consistent with skeletal muscle hyperexcitability as observed in individuals with the mutation. How the same mutation results in distinct phenotypes in the 2 kindreds remains to be determined.GLOSSARY: ADM: abductor digiti minimiCMAP: compound muscle action potentialLET: long exercise testPEMP: postexercise myotonic potentialPMC: paramyotonia congenitaSET: short exercise test(C)2012 American Academy of Neurology

Objective: Administrative health data are frequently used for large population-based studies. However, the validity of these data for identifying neurologic conditions is uncertain.Methods: This article systematically reviews the literature to assess the validity of administrative data for identifying patients with neurologic conditions. Two reviewers independently assessed for eligibility all abstracts and full-text articles identified through a systematic search of Medline and Embase. Study data were abstracted on a standardized abstraction form to identify ICD code-based case definitions and corresponding sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs).Results: Thirty full-text articles met the eligibility criteria. These included 8 studies for Alzheimer disease/dementia (sensitivity: 8-86.5, specificity: 56.3-100, PPV: 60-97.9, NPV: 68.0-98.9), 2 for brain tumor (sensitivity: 54.0-100, specificity: 97.0-99.0, PPV: 91.0-98.0), 4 for epilepsy (sensitivity: 98.8, specificity: 69.6, PPV: 62.0-100, NPV: 89.5-99.1), 4 for motor neuron disease (sensitivity: 78.9-93.0, specificity: 99.0-99.9, PPV: 38.0-90.0, NPV: 99), 2 for multiple sclerosis (sensitivity: 85-92.4, specificity: 55.9-92.6, PPV: 74.5-92.7, NPV: 70.8-91.9), 4 for Parkinson disease/parkinsonism (sensitivity: 18.7-100, specificity: 0-99.9, PPV: 38.6-81.0, NPV: 46.0), 3 for spinal cord injury (sensitivity: 0.9-90.6, specificity: 31.9-100, PPV: 27.3-100), and 3 for traumatic brain injury (sensitivity: 45.9-78.0 specificity: 97.8, PPV: 23.7-98.0, NPV: 99.2). No studies met eligibility criteria for cerebral palsy, dystonia, Huntington disease, hydrocephalus, muscular dystrophy, spina bifida, or Tourette syndrome.Conclusions: To ensure the accurate interpretation of population-based studies with use of administrative health data, the accuracy of case definitions for neurologic conditions needs to be taken into consideration.GLOSSARY: AD: Alzheimer diseaseICD: International Classification of DiseasesNPV: negative predictive valuePD: Parkinson diseasePPV: positive predictive value(C)2012 American Academy of Neurology

Objectives: As residency programs adjust to new duty hour restrictions, the use of cross-coverage systems requiring handoffs will rise. Handoffs are vulnerable to communication failures when unstructured. Accordingly, we implemented a standardized sign-out process on our inpatient neurology services and assessed its effect on completeness and perceived accuracy of handoffs.Methods: Residents spent the first half of their rotations utilizing unstructured sign-out. They transitioned to a structured sign-out system (using the situation-background-assessment-recommendation format) during the second half of their rotations. We analyzed survey responses before and after implementation to evaluate for an effect.Results: Residents utilizing structured sign-out were significantly more likely to share test results with patients/families prior to shift changes (p = 0.037), update our electronic service list (p = 0.045), and feel all important data were being transmitted (p = 0.041). Overall satisfaction (scale 1-10) increased from 6.2 +/- 1.6 to 7.4 +/- 1.3 (p = 0.002).Conclusions: Our findings demonstrate that standardized sign-out improves the completeness and perceived accuracy of handoffs. Such improvement has the potential to improve patient safety and quality of care.GLOSSARY: PGY: postgraduate year(C)2012 American Academy of Neurology