Two items relevant to long COVID

One of the tricky issues in studying in long COVID is: how widely do researchers cast their net? Initial reports acknowledged that people who were hospitalized and in intensive care may take a while to get back on their feet. But the number of people who had SARS-CoV-2 infections and were NOT hospitalized, yet experienced lingering symptoms, may be greater. A recent report from the United Kingdom, published in PLOS Medicine, studied more than Read more

All your environmental chemicals belong in the exposome

Emory team wanted to develop a standard low-volume approach that would avoid multiple processing steps, which can lead to loss of material, variable recovery, and the potential for Read more

Signature of success for an HIV vaccine?

Efforts to produce a vaccine against HIV/AIDS have been sustained for more than a decade by a single, modest success: the RV144 clinical trial in Thailand, whose results were reported in 2009. Now Emory, Harvard and Case Western Reserve scientists have identified a gene activity signature that may explain why the vaccine regimen in the RV144 study was protective in some individuals, while other HIV vaccine studies were not successful. The researchers think that this signature, Read more

hypocretin

Deep brain stimulation for narcolepsy: proof of concept in mouse model

Emory neurosurgeon Jon Willie and colleagues recently published a paper on deep brain stimulation in a mouse model of narcolepsy with cataplexy. Nobody has ever tried treating narcolepsy in humans with deep brain stimulation (DBS), and the approach is still at the “proof of concept” stage, Willie says.

People with the “classic” type 1 form of narcolepsy have persistent daytime sleepiness and disrupted nighttime sleep, along with cataplexy (a loss of muscle tone in response to emotions), sleep paralysis and vivid dream-hallucinations that bleed into waking time. If untreated, narcolepsy can profoundly interfere with someone’s life. However, the symptoms can often be effectively, if incompletely, managed with medications. That’s why one question has to be: would DBS, implemented through brain surgery, be appropriate?

The room where it happens. Sandwiched between the thalamus and the pituitary, the hypothalamus is home to several distinct bundles of neurons that regulate appetite, heart rate, blood pressure and sweating, as well as sleep and wake. It’s as if in your house or apartment, the thermostat, alarm clock and fuse box were next to each other.

Emory audiences may be familiar with DBS as a treatment for conditions such as depression or Parkinson’s disease, because of the pioneering roles played by investigators such as Helen Mayberg and Mahlon DeLong. Depression and Parkinson’s can also often be treated with medication – but the effectiveness can wane, and DBS is reserved for the most severe cases. For difficult cases of narcolepsy, investigators have been willing to consider brain tissue transplants or immunotherapies in an effort to mitigate or interrupt neurological damage, and similar cost-benefit-risk analyses would have to take place for DBS.

Willie’s paper is also remarkable because it reflects how much is now known about how narcolepsy develops. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Measuring sleepiness: alternatives to five naps

In a 2015 episode of The Simpsons, Homer is diagnosed with narcolepsy. Overwhelming sleepiness at the nuclear power plant lands him in the hospital. Sampling his spinal fluid (ouch!), Homer’s chuckling, deep-voiced doctor quickly performs a test for hypocretin, a brain chemical important for staying awake and regulating REM sleep.

Reality check: testing for hypocretin takes time, and is not currently available in the United States. Let’s talk about how sleep disorders such as narcolepsy and idiopathic hypersomnia are actually diagnosed: operationally, rather than biologically. The less flashy, but standard, way to assess patients is to ask them to take a series of five naps and see how fast they doze off, and how fast they go into REM sleep (the rapid eye movement dreaming phase).

This process, known as the Multiple Sleep Latency Test or MSLT, works pretty well for narcolepsy type 1, the more distinctive form of narcolepsy that includes cataplexy. And it’s hard to fake being sleepy enough to zonk out within a few minutes. But it has a bunch of problems, and dissatisfaction with the MSLT has been developing among sleep specialists for the last several years.

Lynn Marie Trotti, MD

At Emory, neurologists Lynn Marie Trotti and David Rye published an analysis of what I will call the “flip flop problem” in 2013, with others in the field following up more recently. The flip flop problem is: someone who takes the MSLT one day will frequently get another result if they take it again on a different day. Read more

Posted on by Quinn Eastman in Neuro 1 Comment