Reviews & Analysis

Dementia is commonly encountered in advanced stages of Parkinson disease (PD), but evidence is accumulating that cognitive decline can manifest much earlier in the disease course. Aarsland and colleagues review current knowledge regarding cognitive impairment in patients with PD, focusing on cerebrospinal fluid and imaging biomarkers as potential predictors of cognitive decline in this population.

Patients with drug-resistant focal epilepsy who lack structural abnormalities on MRI constitute a challenge in presurgical work-up. A longitudinal single-centre study of long-term seizure outcomes in patients with nonlesional epilepsy showed that 59% of the cohort was free from disabling seizures 10 years after resective epilepsy surgery. These results are encouraging and valuable for patient counselling.

Two studies have shown no added benefit of intravenous thrombolysis in patients with acute stroke who are treated with mechanical thrombectomy. We review the importance and interpretation of these findings, compare them to the current guidelines on stroke thrombectomy, and discuss how these studies can change our daily clinical practice.

Altered brain network connectivity might underlie the deficits in social cognition that characterize autism spectrum disorders (ASD). Here, Modi and Sahin discuss the use of event-related potentials (ERPs) evoked by sensory and social stimuli to assess network connectivity in humans with ASD and in animal models, and consider the potential for ERPs to provide a translational biomarker of social dysfunction.

Stroke is associated with an increased risk of dementia, but efforts to develop treatments that prevent dementia in survivors of stroke have thus far been unsuccessful. Here, Mok and colleagues review the mechanisms underlying early-onset and delayed-onset poststroke dementia, and highlight promising future strategies for the development of preventive treatments.

Neuroinflammation can cause acute secondary injury after traumatic brain injury (TBI), and has been linked to chronic neurodegenerative diseases; however, anti-inflammatory agents have failed to improve TBI outcomes in clinical trials. In this Review, the authors propose a new framework for targeted immunomodulation after TBI.

A European working group has provided a new set of recommendations for the use of cerebrospinal fluid (CSF) biomarkers in the diagnostic evaluation of Alzheimer disease and mild cognitive impairment. These recommendations represent an important step towards the implementation of CSF biomarker tests in the clinic, but several challenges remain.

Research into the mechanisms of diabetic neuropathy have focused on neurons, but evidence is accumulating that Schwann cells have a central role. In this Review, the authors consider how Schwann cell dysfunction and the interactions of these cells with neurons and microvessels contribute to the pathogenesis of neuropathy in diabetes.

Brain tumours encompass a heterogeneous collection of neoplasms, traditionally classified by histopathological criteria. In 2016, the WHO published an updated classification that, for the first time, defines brain tumour types according to integrated histological and molecular parameters. Furthermore, clinical trial results were reported that inform therapeutic decision-making in diffuse gliomas.

In 2016, new highly active treatment options for relapsing–remitting multiple sclerosis (MS) emerged. At the same time, large clinical trials in progressive MS highlighted the limitations of immune-directed therapies, and called for new strategies to treat disease progression in MS.

The past 2 years have seen major breakthroughs in endovascular treatment for acute ischaemic stroke. As highlighted in 2016, we now need to refine the logistics for delivery of this treatment, including patient selection. We should not forget, however, that it is better to prevent strokes in the first place.

The publication of a consensus definition of Parkinson disease (PD) psychosis in 2007 led to a rapid expansion of literature focusing on clinical aspects, mechanisms and treatment. The authors review this literature and discuss the evolving view of PD psychosis, from distinct classes of symptoms to a continuum progressing over the course of PD.

In 2016, the literature on neurological infections was, understandably, dominated by Zika virus. However, we should not overlook important publications on the treatment of cryptococcal and bacterial meningitis.

In the field of movement disorders, areas that have seen important advances in 2016 include the pathogenesis of Parkinson disease involving extra-CNS α-synuclein pathology, treatment of hyperkinetic disorders with novel dopamine-depleting drugs, and MRI-guided ultrasound surgery for the treatment of essential tremor.

Investigational treatments to impede the progression of Alzheimer disease (AD) are being evaluated in clinical trials, and biomarkers to detect and track the disease are being developed and deployed. Recent findings underscore the importance of ongoing clinical trials and biomarker developments in the understanding, treatment and prevention of AD.

Real-world observational studies have the potential to answer questions about multiple sclerosis (MS) treatment that randomized controlled trials cannot. Trojano and colleagues discuss the pitfalls and necessary safeguards in observational studies, and the insights that such studies have provided into treatment decisions for patients with MS.