Volume 10 Issue 8, August 2014

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.

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.

Correct diagnosis of chronic neuropathies is paramount, because acquired neuropathies are frequently immune-mediated and, thus, amenable to treatment. Distinction between different types of neuropathies, however, is not trivial. In this Review, Norman Latov discusses clinical presentation, differential diagnosis and treatment of chronic acquired demyelinating neuropathies, and suggests a diagnostic pathway for clinical practice.

Optic neuritis is an inflammatory optic neuropathy that is frequently—but not always—associated with multiple sclerosis (MS). Despite recent developments in laboratory, imaging and electrophysiological techniques, no consensus guidelines have yet been formulated for the diagnostic work-up in patients presenting with optic neuritis. In this Review, Petzold and colleagues contribute to the development of such a consensus by proposing an investigation protocol for optic neuritis.

Brain imaging and histopathological studies have suggested that iron plays a crucial part in the pathophysiology of multiple sclerosis (MS). In this Review, Yong and colleagues discuss the growing evidence of widespread dysregulation of iron metabolism associated with MS, from focal iron deposits around grey matter lesions to iron deficits in white matter that might interfere with remyelination and other cellular repair processes. The authors then outline several potential mechanisms for treating iron dysregulation that balance the trophic and toxic properties of this molecule.

Guillain–Barré syndrome (GBS) is a postinfectious disease characterized by rapidly progressive, symmetrical weakness of the extremities, and can lead to life-threatening complications such as respiratory insufficiency and autonomic dysfunction. Here, van den Berg et al. describe the immune pathogenesis and clinical characteristics of GBS and its subtypes, and highlight the importance of careful diagnostic assessment of patients and the possible additional diagnostic value of cerebrospinal fluid examinations and nerve conduction tests. The authors review treatment options and prognosis, including novel predictive models, for patients with GBS.