Reviews & Analysis

Autism is arguably the quintessential neurodevelopmental disorder. However, despite an explosion of research over the past decade, we know relatively little about the development of autism itself. Recent longitudinal research has provided important new insights—and has raised new questions—concerning the complexities of the disorder.

Dopaminergic brain imaging might aid early diagnosis of Parkinson disease (PD), but some patients with mild symptoms show no evidence of dopaminergic dysfunction at baseline, and apparently do not progress. Although some of these patients may have been misdiagnosed, others continue to fulfil PD diagnostic criteria despite normal follow-up brain scans.

Discovery of the endogenous cannabinoid signalling system unleashed substantial new research into several neurological conditions. A recent systematic review suggests that medical marijuana can improve a number of symptoms—particularly spasticity—in multiple sclerosis, but cannabinoids can have adverse psychological effects and their comparative effectiveness is unknown.

Differential diagnosis in the vegetative and minimally conscious states is notoriously difficult. A new report compares the diagnostic accuracy of two neuroimaging methods, using bedside behavioural assessment as a reference. The results highlight the many theoretical and methodological challenges in studying this patient group.

Sex differences are increasingly recognized in many areas of medicine, and stroke is no exception. Women tend to be more adversely affected by stroke than are men and, as a new study illustrates, this discrepancy cannot be attributed solely to sex-related differences in acute stroke care.

Aggressive, refractory multiple sclerosis warrants unconventional therapy. A retrospective multicentre study assessed the effects of ablating the immune system, then reconstituting it using bone marrow derived stem cells. Though this particular regimen improved disability in some patients, others continued to relapse, perhaps indicating the treatment did not go far enough.

Medication overuse headache (MOH) is a widespread problem, and no global consensus has yet been reached regarding its management. In an attempt to address this issue, six headache centres have collaborated to evaluate a detoxification protocol in a large cohort of patients with MOH from Europe and South America.

A recent multicentre study has assessed the risk of relapse in patients with multiple sclerosis who switched from natalizumab to fingolimod treatment. Despite such efforts, no effective exit strategy from natalizumab treatment has yet been demonstrated for these patients.

Dominant mesial temporal lobe resection for pharmacoresistant epilepsy is frequently associated with verbal memory impairment. More-extensive lesioning improves seizure outcome, but further compromises memory. A better understanding of ipsilateral neural structures and networks for verbal memory could improve selectivity of surgical ablation, thereby holding promise for seizure-freedom without memory impairment.

Responsive neurostimulation (RNS) is an exciting new approach to treating refractory epilepsy. A recent 2 year follow-up study indicates that long-term RNS treatment is safe, and that efficacy improves with time. Although several issues remain to be resolved, RNS is a welcome new arrival in the armamentarium of epilepsy treatments.

A new consensus statement, written by an international panel of experts, seeks to standardize the use of neurosurgery for psychiatric disorders and to enhance patient safety. Although the approach is noble, some recommendations are overly conservative, whereas others might be more appropriate for regulatory authorities.

The effective assessment and treatment of pain in individuals with dementia carries substantial challenges. A recent study evaluating the presence and treatment of pain in individuals with or without dementia reveals valuable insights into analgesic prescribing practices and highlights critical factors to be addressed in dementia treatment.

Gene therapy offers the potential to deliver therapeutic proteins to a target region, and is a promising treatment for Parkinson disease. A new open-label study testing ProSavin^®, which encodes three rate-limiting enzymes required for dopamine biosynthesis, showed favourable safety and efficacy results, but its therapeutic potential awaits confirmation in double-blind trials.

Results of the TOWER phase III trial confirm the efficacy of teriflunomide in relapsing–remitting multiple sclerosis (RRMS). With seven substances now approved for RRMS, individualized treatment for the inflammatory aspect of the disease is within reach, although many questions remain unanswered, particularly concerning the neurodegenerative aspect RRMS.

Amyloid-β (Aβ) is suggested to have a pivotal role in the pathogenesis of Alzheimer disease (AD) and is a major therapeutic target. Recent phase III trials of the anti-Aβ monoclonal antibodies bapineuzumab and solanezumab, which failed to improve cognitive function in patients, provide valuable insights for the future development of immunotherapies.

A large claims-based study has identified several comorbidity clusters in individuals with dementia, corroborating the notion that comorbid conditions are an important contributor to health outcomes. The complexity of comorbidities calls for a patient-centred approach for care. Importantly, good management of comorbidities can improve quality of life in progressive dementia.

The first randomized, placebo-controlled trial of intrajejunal levodopa provides support for the benefits of continuous dopaminergic drug delivery. Motor fluctuations in patients with advanced Parkinson disease were markedly improved. In clinical practice, the symptomatic benefits of this treatment need to be weighed carefully against its adverse effect profile.

Mild cognitive impairment is widely viewed as an early stage of dementia but, as a new study highlights, some people never progress, and might even revert to normal cognition. Poor predictive validity of prodromal conditions has clear implications for the principle of 'do no harm', as overtreatment becomes a possibility.

Early trials that supported short-term opioid treatment in the management of chronic non-cancer pain excluded patients at high risk of drug abuse, and might have overestimated the efficacy of this approach. The recent IMMPACT recommendations suggest inclusion of high-risk groups in future clinical trials of potentially addictive drugs. Is the risk worth taking?

Assessing the burden of stroke is essential to improve stroke care. Two recent systematic reviews provide a picture of the worldwide stroke burden. However, poor-quality data sources in low-income and middle-income countries make this a blurred photograph, and set a challenge to expand stroke registries.