Cognition and gray and white matter characteristics of presymptomatic C9orf72 repeat expansion

ABSTRACT

Objective: To investigate cognitive function, gray matter volume, and white matter integrity in the presymptomatic stage of chromosome 9 open reading frame 72 repeat expansion (C9orf72RE).

Methods: Presymptomatic C9orf72RE carriers (n = 18) and first-degree family members without a pathogenic expansion (healthy controls [HC], n = 15) underwent a standardized protocol of neuropsychological tests, T1-weighted MRI, and diffusion tensor imaging within our cohort study of autosomal dominant frontotemporal dementia (FTD). We investigated group differences in cognitive function, gray matter volume through voxel-based morphometry, and white matter integrity by means of tract-based spatial statistics. We correlated cognitive change with underlying gray or white matter.

Results: Our data demonstrate lower scores on letter fluency, Stroop card I, and Stroop card III, accompanied by white matter integrity loss in tracts connecting the frontal lobe, the thalamic radiation, and tracts associated with motor functioning in presymptomatic C9orf72RE compared with HC. In a subgroup of C9orf72RE carriers above 40 years of age, we found gray matter volume loss in the thalamus, cerebellum, and parietal and temporal cortex. We found no significant relationship between subtle cognitive decline and underlying gray or white matter.

Conclusions: This study demonstrates that a decline in cognitive functioning, white matter integrity, and gray matter volumes are present in presymptomatic C9orf72RE carriers. These findings suggest that neuropsychological assessment, T1-weighted MRI, and diffusion tensor imaging might be useful to identify early biomarkers in the presymptomatic stage of FTD or amyotrophic lateral sclerosis.

Neurology 2017

Amyloid-PET in sporadic cerebral amyloid angiopathy A diagnostic accuracy meta-analysis

ABSTRACT

Objective: To perform a meta-analysis synthesizing evidence of the value and accuracy of amyloid-PET in diagnosing patients with sporadic cerebral amyloid angiopathy (CAA).

Methods: In a PubMed systematic literature search, we identified all case-control studies with extractable data relevant for the sensitivity and specificity of amyloid-PET positivity in symptomatic patients with CAA (cases) vs healthy participants or patients with spontaneous deep intracerebral hemorrhage (ICH) (control groups). Using a hierarchical (multilevel) logistic regression model, we calculated pooled diagnostic test accuracy.

Results: Seven studies, including 106 patients with CAA (>90% with probable CAA) and 151 controls, were eligible and included in the meta-analysis. The studies were of moderate to high quality and varied in several methodological aspects, including definition of PET-positive and PET-negative cases and relevant cutoffs. The sensitivity of amyloid-PET for CAA diagnosis ranged from 60% to 91% and the specificity from 56% to 90%. The overall pooled sensitivity was 79% (95% confidence interval [CI] 62–89) and specificity was 78% (95% CI 67–86) for CAA diagnosis. A predefined subgroup analysis of studies restricted to symptomatic patients presenting with lobar ICH CAA (n = 58 vs 86 controls) resulted in 79% sensitivity (95% CI 61–90%) and 84% specificity (95% CI 65–93%). In prespecified bivariate diagnostic accuracy meta-analysis of 2 studies using ¹⁸F-florbetapir-PET, the sensitivity for CAA-ICH diagnosis was 90% (95% CI 76–100%) and specificity was 88% (95% CI 74–100%).

Conclusions: Amyloid-PET appears to have moderate to good diagnostic accuracy in differentiating patients with probable CAA from cognitively normal healthy controls or patients with deep ICH. Given that amyloid-PET labels both cerebrovascular and parenchymal amyloid, a negative scan might be useful to rule out CAA in the appropriate clinical setting.

Neurology 2017

Association of intracranial aneurysm rupture with smoking duration, intensity, and cessation

ABSTRACT

Objective: Although smoking is a known risk factor for intracranial aneurysm (IA) rupture, the exact relationship between IA rupture and smoking intensity and duration, as well as duration of smoking cessation, remains unknown.

Methods: In this case-control study, we analyzed 4,701 patients with 6,411 IAs diagnosed at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016. We divided individuals into patients with ruptured aneurysms and controls with unruptured aneurysms. We performed univariable and multivariable logistic regression analyses to determine the association between smoking status and ruptured IAs at presentation. In a subgroup analysis among former and current smokers, we assessed the association between ruptured aneurysms and number of packs per day, duration of smoking, and duration since smoking cessation.

Results: In multivariable analysis, current (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.89–2.59) and former smoking status (OR 1.56, 95% CI 1.31–1.86) were associated with rupture status at presentation compared with never smokers. In a subgroup analysis among current and former smokers, years smoked (OR 1.02, 95% CI 1.01–1.03) and packs per day (OR 1.46, 95% CI 1.25–1.70) were significantly associated with ruptured aneurysms at presentation, whereas duration since cessation among former smokers was not significant (OR 1.00, 95% CI 0.99–1.02).

Conclusions: Current cigarette smoking, smoking intensity, and smoking duration are significantly associated with ruptured IAs at presentation. However, the significantly increased risk persists after smoking cessation, and smoking cessation does not confer a reduced risk of aneurysmal subarachnoid hemorrhage beyond that of reducing the cumulative dose.

Neurology 2017

High frequency of gastrointestinal manifestations in myotonic dystrophy type 1 and type 2

ABSTRACT

Objective: To analyze gastrointestinal (GI) manifestations, their progression over time, and medications being used to treat GI symptoms in a large cohort of patients with myotonic dystrophy types 1 (DM1) and 2 (DM2).

Methods: We analyzed patient-reported data and medical records in a national registry cohort at baseline and 5 years.

Results: At baseline, the majority of patients reported trouble swallowing in DM1 (55%; n = 499 of 913) and constipation in DM2 (53%; n = 96 of 180). Cholecystectomy occurred in 16.5% of patients with DM1 and 12.8% of patients with DM2, on average before 45 years of age. The use of medications indicated for gastroesophageal reflux disease was reported by 22.5% of DM1 and 18.9% of patients with DM2. Greater risk of a GI manifestation was associated with higher body mass index and longer disease duration in DM1 and female sex in DM2. At the 5-year follow-up, the most common new manifestations were trouble swallowing in patients with DM1 and constipation in patients with DM2.

Conclusions: GI manifestations were common in both DM1 and DM2, with a relatively high frequency of gallbladder removal in DM1 and DM2 occurring at a younger age compared to normative data in the literature. Studies are needed to determine the pathomechanism of how sex, weight gain, and duration of disease contribute to GI manifestations and how these manifestations affect quality of life and clinical care for patients with DM1 and DM2.

Neurology 2017

A predictive model to identify Parkinson disease from administrative claims data

ABSTRACT

Objective: To use administrative medical claims data to identify patients with incident Parkinson disease (PD) prior to diagnosis.

Methods: Using a population-based case-control study of incident PD in 2009 among Medicare beneficiaries aged 66–90 years (89,790 cases, 118,095 controls) and the elastic net algorithm, we developed a cross-validated model for predicting PD using only demographic data and 2004–2009 Medicare claims data. We then compared this model to more basic models containing only demographic data and diagnosis codes for constipation, taste/smell disturbance, and REM sleep behavior disorder, using each model's receiver operator characteristic area under the curve (AUC).

Results: We observed all established associations between PD and age, sex, race/ethnicity, tobacco smoking, and the above medical conditions. A model with those predictors had an AUC of only 0.670 (95% confidence interval [CI] 0.668–0.673). In contrast, the AUC for a predictive model with 536 diagnosis and procedure codes was 0.857 (95% CI 0.855–0.859). At the optimal cut point, sensitivity was 73.5% and specificity was 83.2%.

Conclusions: Using only demographic data and selected diagnosis and procedure codes readily available in administrative claims data, it is possible to identify individuals with a high probability of eventually being diagnosed with PD.

Neurology 2017

Causal inference methods to study gastric tube use in amyotrophic lateral sclerosis

ABSTRACT

Objective: To estimate effects of gastric tube (G-tube) on survival and quality of life (QOL) in people with amyotrophic lateral sclerosis (ALS) correcting for confounding by indication inherent in nonrandomized observational data.

Methods: To complement a recent causal inference analysis, which concluded that G-tube placement increases the hazard of death, permanent assisted ventilation, or tracheostomy by 28%, we fit causal inference models on a different sample of 481 patients with ALS enrolled in a recent clinical trial of ceftriaxone. Forward selection identified predictors of G-tube placement. Effects of G-tube on survival and QOL were estimated using structural nested models and marginal structural models, accounting for predictors of G-tube treatment.

Results: Forced vital capacity and the total score and bulbar subscale of the revised ALS Functional Rating Scale best predicted G-tube placement. Correcting for these confounders, G-tube placement decreased survival time by 46% (p < 0.001) and had no effect on QOL (p = 0.078). Sensitivity survival analyses varied in significance, but none revealed a survival benefit.

Conclusions: In the absence of randomization, causal inference methods are necessary to correct for time-varying confounding. G-tube placement may have a negative effect on survival with no QOL-related benefit for people with ALS. A randomized controlled trial is warranted to further evaluate the efficacy of this widely used intervention.

Neurology 2017

Neurologic complications of sickle cell disease in Africa A systematic review and meta-analysis

ABSTRACT

Objective: To summarize prevalence data on the neurologic complications of sickle cell disease (SCD) in Africa.

Methods: We searched EMBASE, PubMed, and African Index Medicus to identify all relevant articles published from inception to May 31, 2016. Each study was reviewed for methodologic quality. A random-effects model was used to estimate the prevalence of neurologic complications of SCD across studies.

Results: Thirty-one studies were included. Methodologic quality was high or moderate in 90% of studies. Stroke, conditional and abnormal cerebral blood flow, seizures, and headache were the complications most frequently reported, with overall prevalence rates of 4.2%, 10.6%, 6.1%, 4.4%, and 18.9%, respectively. Some complications, like silent brain infarcts, peripheral neuropathies, neurocognitive deficits, or moyamoya disease, have been rarely or not studied at all in the African setting. Incidence data were scarce and of poor quality.

Conclusions: The burden of neurologic complications of SCD is important in Africa and most likely underestimated. A better evaluation of this burden requires larger prospective studies using standard up-to-date screening methods. Accessibility to diagnostic tools such as neuroimaging, transcranial Doppler, EEG, and neuropsychological evaluation, as well as to preventive and therapeutic interventions and trained health care providers, should be improved in routine clinical practice.

Neurology 2017