Neurotoxic snakes of the Americas.

Snake envenomation is a global problem and often a matter of life or death. Emergency treatment is not always readily available or effective. There are numerous neurotoxic snakes in the Americas, chiefly elapids; some crotalids have also evolved neurotoxic venom. The variability of neurotoxins found in snake venom within the same species makes development and choice of proper antivenom a major challenge that has not been completely addressed. This article reviews the epidemiology, clinical effects, and current treatment of neurotoxic snake envenomation in the Americas.

Neurology and altitude illness.

Problems at altitude are most often thought of in trained athletes summiting extremes of elevation. A more common group that needs consideration is the average person with obstructive sleep apnea who must travel to high altitudes for business or pleasure. While the altitudes involved are not likely to be as extreme as for those athletes climbing peaks like Mt. Everest, the increases in elevation may present difficulties for patients, especially if overnight stay is expected. The pathophysiology of altitude-related CNS, respiratory, and sleep disorders is discussed along with treatment options.

Traumatic brain injury ? What do we know?

Traumatic brain injury (TBI) is a significant problem in both the civilian and military worlds. Although much is understood about the effects of TBI, relatively few diagnostic or therapeutic modalities are available. Currently, TBI treatment is in a primitive phase and other than acute lifesaving interventions, is largely relegated to rehabilitation efforts. This article discusses known aspects of neuronal injury related to blast TBI, as well as a review of the current state of diagnostic and therapeutic interventions.

Visual working memory deficits in patients with Parkinson's disease are due to both reduced storage capacity and impaired ability to filter out irrelevant information.

Given that Parkinson's disease broadly affects frontostriatal circuitry, it is not surprising that the disorder is associated with a reduction of working memory. We tested whether this reduction is due to diminished storage capacity or impaired ability to exclude task-irrelevant items. Twenty-one medication-withdrawn patients and 28 age-matched control subjects performed a visuospatial memory task while their electroencephalograms were recorded. The task required them to remember the orientations of red rectangles within the half of the screen that was cued while ignoring all green rectangles. Behavioural and electroencephalogram measures indicated that patients with Parkinson's disease were impaired at filtering out distracters, and that they were able to hold fewer items in memory than control subjects. The results support recent suggestions that the basal ganglia help control access to working memory.

Sleep and Parkinson's disease.

Movement disorders encompass a wide variety of neurological problems, and each has its own constellation of cognitive, motor and sleep problems. Those problems may be secondary to the disease process, the treatments for the disease or both. One of the most commonly seen of these disorders is Parkinson's disease. This article will discuss the sleep issues commonly associated with that disorder, and will present suggestions for treatment.