Reporting standards for studies of diagnostic test accuracy in dementia

Objective: To provide guidance on standards for reporting studies of diagnostic test accuracy for dementia disorders.

Methods: An international consensus process on reporting standards in dementia and cognitive impairment (STARDdem) was established, focusing on studies presenting data from which sensitivity and specificity were reported or could be derived. A working group led the initiative through 4 rounds of consensus work, using a modified Delphi process and culminating in a face-to-face consensus meeting in October 2012. The aim of this process was to agree on how best to supplement the generic standards of the STARD statement to enhance their utility and encourage their use in dementia research.

Results: More than 200 comments were received during the wider consultation rounds. The areas at most risk of inadequate reporting were identified and a set of dementia-specific recommendations to supplement the STARD guidance were developed, including better reporting of patient selection, the reference standard used, avoidance of circularity, and reporting of test-retest reliability.

Conclusion: STARDdem is an implementation of the STARD statement in which the original checklist is elaborated and supplemented with guidance pertinent to studies of cognitive disorders. Its adoption is expected to increase transparency, enable more effective evaluation of diagnostic tests in Alzheimer disease and dementia, contribute to greater adherence to methodologic standards, and advance the development of Alzheimer biomarkers.

Neurology 2014

Long-term effectiveness of dopamine agonists and monoamine oxidase B inhibitors compared with levodopa as initial treatment for Parkinson's disease (PD MED): a large, open-label, pragmatic randomised trial

Summary

Background

Whether initial treatment for Parkinson's disease should consist of levodopa, dopamine agonists, or monoamine oxidase type B inhibitors (MAOBI) is uncertain. We aimed to establish which of these three classes of drug, as initial treatment, provides the most effective long-term control of symptoms and best quality of life for people with early Parkinson's disease.

Methods

In this pragmatic, open-label randomised trial, patients newly diagnosed with Parkinson's disease were randomly assigned (by telephone call to a central office; 1:1:1) between levodopa-sparing therapy (dopamine agonists or MAOBI) and levodopa alone. Patients and investigators were not masked to group assignment. Primary outcomes were the mobility dimension on the 39-item patient-rated Parkinson's disease questionnaire (PDQ-39) quality-of-life scale (range 0—100 with six points defined as the minimally important difference) and cost-effectiveness. Analysis was intention to treat. This trial is registered, number ISRCTN69812316.

Findings

Between Nov 9, 2000, and Dec 22, 2009, 1620 patients were assigned to study groups (528 to levodopa, 632 to dopamine agonist, 460 to MAOBI). With 3-year median follow-up, PDQ-39 mobility scores averaged 1·8 points (95% CI 0·5—3·0, p=0·005) better in patients randomly assigned to levodopa than those assigned to levodopa-sparing therapy, with no increase or attrition of benefit during 7 years' observation. PDQ-39 mobility scores were 1·4 points (95% CI 0·0—2·9, p=0·05) better in patients allocated MAOBI than in those allocated dopamine agonists. EQ-5D utility scores averaged 0·03 (95% CI 0·01—0·05; p=0·0002) better with levodopa than with levodopa-sparing therapy; rates of dementia (hazard ratio [HR] 0·81, 95% CI 0·61—1·08, p=0·14), admissions to institutions (0·86, 0·63—1·18; p=0·4), and death (0·85, 0·69—1·06, p=0·17) were not significantly different, but the upper CIs precluded any substantial increase with levodopa compared with levodopa-sparing therapy. 179 (28%) of 632 patients allocated dopamine agonists and 104 (23%) of 460 patients allocated MAOBI discontinued allocated treatment because of side-effects compared with 11 (2%) of 528 patients allocated levodopa (p<0·0001).

Interpretation

Very small but persistent benefits are shown for patient-rated mobility scores when treatment is initiated with levodopa compared with levodopa-sparing therapy. MAOBI as initial levodopa-sparing therapy was at least as effective as dopamine agonists.

The Lancet 2014

Large scale screening of neural signatures of consciousness in patients in a vegetative or minimally conscious state

In recent years, numerous electrophysiological signatures of consciousness have been proposed. Here, we perform a systematic analysis of these electroencephalography markers by quantifying their efficiency in differentiating patients in a vegetative state from those in a minimally conscious or conscious state. Capitalizing on a review of previous experiments and current theories, we identify a series of measures that can be organized into four dimensions: (i) event-related potentials versus ongoing electroencephalography activity; (ii) local dynamics versus inter-electrode information exchange; (iii) spectral patterns versus information complexity; and (iv) average versus fluctuations over the recording session. We analysed a large set of 181 high-density electroencephalography recordings acquired in a 30 minutes protocol. We show that low-frequency power, electroencephalography complexity, and information exchange constitute the most reliable signatures of the conscious state. When combined, these measures synergize to allow.

Neurology 2014

Effect of 1 Night of Total Sleep Deprivation on Cerebrospinal Fluid β-Amyloid 42 in Healthy Middle-Aged Men A Randomized Clinical Trial

Importance  Increasing evidence suggests a relationship between poor sleep and the risk of developing Alzheimer disease. A previous study found an effect of sleep on β-amyloid (Aβ), which is a key protein in Alzheimer disease pathology.

Objective  To determine the effect of 1 night of total sleep deprivation on cerebrospinal fluid Aβ42 protein levels in healthy middle-aged men.

Design, Setting, and Participants  The Alzheimer, Wakefulness, and Amyloid Kinetics (AWAKE) study at the Radboud Alzheimer Center, a randomized clinical trial that took place between June 1, 2012, and October 1, 2012. Participants were cognitively normal middle-aged men (40-60 years of age) with normal sleep (n = 26) recruited from the local population.

Interventions  Participants were randomized to 1 night with unrestricted sleep (n = 13) or 1 night of total sleep deprivation (24 hours of wakefulness) (n = 13).

Main Outcomes and Measures  Sleep was monitored using continuous polysomnographic recording from 3 pm until 10 am. Cerebrospinal fluid samples were collected using an intrathecal catheter at defined times to compare cerebral Aβ42 concentrations between evening and morning.

Results  A night of unrestricted sleep led to a 6% decrease in Aβ42 levels of 25.3 pg/mL (95% CI [0.94, 49.6], P = .04), whereas sleep deprivation counteracted this decrease. When accounting for the individual trajectories of Aβ42 over time, a difference of 75.8 pg/mL of Aβ42 was shown between the unrestricted sleep and sleep deprivation group (95% CI [3.4, 148.4], P = .04). The individual trajectories of evening and morning Aβ42 concentrations differed between the unrestricted sleep and sleep deprivation groups (P = .04) in contrast to stable Aβ40, tau, and total protein levels.

Conclusions and Relevance  Sleep deprivation, or prolonged wakefulness, interferes with a physiological morning decrease in Aβ42. We hypothesize that chronic sleep deprivation increases cerebral Aβ42 levels, which elevates the risk of Alzheimer disease.

JAMA Neurology 2014

The Preclinical Alzheimer Cognitive Composite Measuring Amyloid-Related Decline

Importance  As Alzheimer disease (AD) research moves to intervene in presymptomatic phases of the disease, we must develop outcome measures sensitive to the earliest disease-related changes.

Objective  To demonstrate the feasibility of a cognitive composite outcome for clinically normal elderly participants with evidence of AD pathology using the ADCS Preclinical Alzheimer Cognitive Composite (ADCS-PACC). The ADCS-PACC combines tests that assess episodic memory, timed executive function, and global cognition. The ADCS-PACC is the primary outcome measure for the first clinical trial in preclinical AD (ie, the Anti-Amyloid Treatment in Asymptomatic Alzheimer’s study).

Design, Setting, and Participants  With the ADCS-PACC, we derive pilot estimates of amyloid-related decline using data from 2 observational studies conducted in North America and another conducted in Australia. The participants analyzed had normal cognition and mean ages of 75.81, 71.37, and 79.42 years across the 3 studies.

Main Outcomes and Measures  For the 2 studies that collected data on Aβ levels (ADNI and AIBL), we estimate decline in a preclinical AD “Aβ-positive” placebo group and compare them with an “Aβ-negative” group. For the study that did not include data on Aβ levels (the ADCS Prevention Instrument [ADCS-PI] study), we grouped participants by the presence of APOE-ε4 and by clinical progression.

Results  In ADNI, Aβ-positive participants showed more decline than did Aβ-negative participants with regard to the ADCS-PACC score at 24 months (mean [SE] difference, −1.239 [0.522] [95% CI, −2.263 to −0.215]; P = .02). In AIBL, the mean (SE) difference is significant at both 18 months (−1.009 [0.406] [95% CI, −1.805 to −0.213]; P = .01) and 36 months (−1.404 [0.452] [95% CI, −2.290 to −0.519]; P = .002). In the ADCS-PI study, APOE-ε4 allele carriers performed significantly worse on the ADCS-PACC at 24 months (mean [SE] score, −0.742 [0.294] [95% CI, −1.318 to −0.165]; P = .01) and 36 months (−1.531 [0.469] [95% CI, −2.450 to −0.612]; P = .001). In the ADCS-PI study, cognitively normal participants who progress from a global Clinical Dementia Rating score of 0 are significantly worse on the ADCS-PACC than cognitively normal participants who are stable with a global Clinical Dementia Rating score of 0 at months 12, 24, and 36 (mean [SE] ADCS-PACC score, −4.471 [0.702] [95% CI, −5.848 to −3.094]; P < .001). Using pilot estimates of variance and assuming 500 participants per group with 30% attrition and a 5% α level, we project 80% power to detect effects in the range of Δ = 0.467 to 0.733 on the ADCS-PACC.

Conclusions and Relevance  Analyses of at-risk cognitively normal populations suggest that we can reliably measure the first signs of cognitive decline with the ADCS-PACC. These analyses also suggest the feasibility of secondary prevention trials.

JAMA Neurology 2014

Effectiveness of Antiepileptic Drug Combination Therapy for Partial-Onset Seizures Based on Mechanisms of Action

Importance  To our knowledge, the current study is the first to describe antiepileptic drug (AED) combination therapy patterns according to their mechanism of action (MOA) in a real-world setting and to evaluate the differences in outcomes comparing different-MOA combination therapy with same-MOA combination therapy for patients with partial-onset seizure.

Objective  To compare treatment persistence and health care use with AED combinations categorized by MOA in patients with partial-onset seizures.

Design, Setting, and Participants  Using the Truven Health MarketScan Commercial Claims Database containing 96 million covered lives from July 1, 2004, through March 31, 2011, adults with concomitant use of 2 different AEDs and a recent partial-onset seizure diagnosis were selected. Antiepileptic drugs were categorized by MOA: sodium channel blockers (SC), gamma-aminobutyric acid analogs (G), synaptic vesicle protein 2A binding (SV2), and multiple mechanisms (M). Patients were assigned a combination category based on their concomitant AED use.

Main Outcomes and Measures  Treatment persistence was measured from the start of AED combination therapy until the end of the combination. Health care resource use was measured during the combination treatment duration. Multivariate analyses evaluated AED discontinuation risk and health care use according to MOA combinations.

Results  Distribution of 8615 selected patients by combination was 3.3% for G+G, 7.5% for G+SV2, 8.6% for G+M, 13.9% for SC+SC, 19.0% for G+SC, 21.5% for SC+M, and 26.3% for SC+SV2. The same-MOA (G+G and SC+SC) combinations had the shortest persistence (mean [SD], 344 [345] days and 513 [530] days, respectively) and greater hazard of discontinuation compared with different-MOA combinations. Patients with different-MOA G combinations had a significantly lower risk for inpatient admission (odds ratio, 0.716; 95% CI, 0.539-0.952; P = .02) compared with G+G combinations. Patients with different-MOA SC combinations had significantly lower risks for emergency department visits (odds ratio, 0.853; 95% CI, 0.742-0.980; P = .03) compared with SC+SC combinations.

Conclusions and Relevance  The findings suggest that AED combinations with different MOAs have greater effectiveness as measured by treatment persistence and lower risks for hospitalization and emergency department visits. Further research is needed to more fully understand the role of the MOA in achieving optimal outcomes.

JAMA Neurology 2014

Prevalence of fatigue in Parkinson disease and its clinical correlates

Objective: To assess in a noninterventional setting the prevalence and severity of fatigue in patients with Parkinson disease (PD).

Methods: This was a cross-sectional study conducted in Italian patients with PD. Objectives included the evaluation of the current prevalence and severity of fatigue in patients with PD measured using the 16-item Parkinson Fatigue Scale (PFS-16), distressing fatigue (defined as a PFS-16 mean score ≥3.3), and assessment of its clinical correlates.

Results: A total of 402 patients were enrolled and 394 patients completed the PFS-16 questionnaire with a PFS-16 mean (±SD) score of 2.87 ± 0.99. Of these, 136 patients (33.8%) reported distressing fatigue (PFS-16 mean score ≥3.3). Patients with distressing fatigue were older (p = 0.044) and had a longer duration of PD (p < 0.0001) than those without distressing fatigue. The presence of distressing fatigue was associated with higher total Unified Parkinson's Disease Rating Scale (UPDRS) scores, poorer quality of life (39-item Parkinson's Disease Questionnaire [PDQ-39]), worse social and psychological behaviors, a higher severity of depressive symptoms, and a higher prevalence of sleep disorders (all p < 0.001). Logistic regression analyses revealed that higher total UPDRS scores, female sex, depression, sleep disorders, as well as higher UPDRS activities of daily living scores and PDQ-39 mobility scores increase the likelihood of distressing fatigue in patients with PD.

Conclusions: Approximately one-third of patients with PD have distressing fatigue, which is significantly associated with depression and sleep disorders. The fact that the presence of fatigue worsens patient quality of life supports the need to better diagnose and treat this debilitating symptom.

Neurology 2014