News & Views in 2014

Traumatic brain injury (TBI) is increasingly recognized as a risk factor for dementia. New data provide further support for this association and demonstrate the influence of age at injury and injury severity on dementia risk after TBI, revealing that even mild TBI increases dementia risk in those aged ≥65 years.

The notion that the classic motor features of Parkinson disease (PD) are preceded by a prodrome has received renewed interest in the past decade. A recent study corroborates previous findings that smell loss and constipation are signifiers of nigral degeneration. But can we really predict who is going to get PD?

The recent TOPIC trial found that teriflunomide could prevent relapses in patients with clinically isolated syndrome (CIS). Many other multiple sclerosis (MS) therapies are effective for CIS, because CIS is the first clinical manifestation of MS for most patients. Questions remain over the utility of future trials like TOPIC.

LDL-lowering drugs are widely recommended for the secondary prevention of vascular events in patients who have experienced a stroke or transient ischaemic attack. As a new study illustrates, however, lipid management among this group remains inadequate, possibly placing patients at unnecessary risk of stroke recurrence.

After decades of near neglect, the importance of exercise for patients with Parkinson disease is being increasingly supported by recent studies in experimental animal models and controlled clinical trials. Now, an inverse relationship between physical activity and disease burden has been demonstrated in a large cohort study.

Neuromyelitis optica spectrum disorders (NMOSD) can mimic multiple sclerosis (MS). Avoiding misdiagnosis is crucial, because some disease-modifying drugs for MS can aggravate NMOSD, causing blindness and paraplegia. A recent study reports that misdiagnosis of NMOSD as MS occasionally occurs, and that a two-step antibody assay could improve differential diagnosis.

Glioblastoma is the most common primary brain tumour in adults, but—unlike many other cancers—no blood-based biomarkers are available for differential diagnosis, estimation of prognosis or monitoring of treatment response in glioblastoma. New research has detected three proteins with potential clinical value in the blood of patients with glioblastoma.

The knowledge of imaging and fluid biomarkers gained from longitudinal observational studies of Alzheimer disease has recently been translated to a cross-sectional study of randomly selected, cognitively unimpaired elderly individuals. This is the first time that a two-feature biomarker classification system has been applied to a population-based cohort.

Clinical exome sequencing (CES) is becoming a standard tool for molecular diagnosis of genetic disorders, with a diagnostic yield of approximately 25%. New studies demonstrate the favourable diagnostic yield of CES for both early-onset and adult-onset neurogenetic disorders. These studies demonstrate the strengths, limitations and potential of CES in neurology practice.

Epidemiological evidence strongly suggests that circulatory levels of 25-hydroxyvitamin D below 50 nmol/l are associated with cognitive impairment and the development of dementia. A number of biochemical mechanisms could explain these effects; however, interventional studies to date have revealed disappointingly little.

Two recent studies highlight the importance of prompt, coordinated intervention after stroke. A meta-analysis confirms that intravenous thrombolysis is effective within 4.5 h of onset, irrespective of age (below or above 80 years) and stroke severity. Another study demonstrates successful reorganization of care through centralization of stroke services in England.

A pandemic influenza vaccine with a specific type of vaccine antigen has been linked to an increased incidence of narcolepsy in children from 2009–2010. However, the recent retraction of an article that reported a putative autoantigen means that the search for the mechanisms behind the vaccine–narcolepsy connection continues.

Finding a peripheral biomarker for early Alzheimer disease (AD) is a major challenge. A recent study has validated a plasma protein signature that is associated with mild cognitive impairment and AD, and could predict conversion; however, longitudinal cohort studies of presymptomatic individuals are needed to confirm the findings.

The risks of seizures and antiepileptic drug (AED) teratogenicity must be balanced when treating pregnant women with epilepsy. Two recent articles address these risks for newer AEDs. Lamotrigine and levetiracetam carried low risks of malformations, and topiramate exhibited a dose-dependent risk. Levetiracetam controlled seizures more effectively than lamotrigine and topiramate.

Preventive strategies for Alzheimer disease (AD) will depend on the identification of modifiable risk factors for this disorder. A new study has quantified the relative contributions of seven major risk factors for AD, and concludes that around one-third of AD cases are likely to be preventable.

Amyotrophic lateral sclerosis (ALS) shows complex inheritance. A new meta-analysis of three data sets has replicated previous estimates of the heritability attributable to common genetic variation, corroborated some previously identified disease-associated genetic loci, and suggested novel loci. Despite such efforts, our understanding of the genetic architecture of ALS remains limited.

Though effective for parkinsonian motor symptoms, deep brain stimulation (DBS) of the subthalamic nucleus has variable effects on speech. A new study focusing on patients' perceptions reported that DBS recipients complain of greater speech disturbance than do non-DBS recipients. Patients should be made more aware of this possible adverse effect of DBS.

Levodopa is the standard therapy for Parkinson disease, but prolonged use promotes the development of adverse motor effects. A new trial compared the effectiveness of levodopa administration early in the disease with therapies that used alternative dopaminergic agents before levodopa. No clinically relevant differences were found between the treatment strategies.

Copy number variants (CNVs; deletions or duplications of chromosomal regions) have emerged as an important cause of human disease. In a recent study, epilepsy could be attributed to a pathogenic CNV in 5% of patients, but understanding the implications of a CNV for an individual patient can be challenging.

Many patients with brain tumours possess inadequate mental capacity to provide informed consent, but this situation often goes undetected because clinicians do not routinely conduct formal cognitive assessments. This oversight should be recognized and rectified to enable optimum ethical and medical care of these vulnerable individuals.