Archives for April 2020

Preventing Shingles, The Best Way to Decrease Your Risk of Shingles Related Stroke

Apr 23, 2020 by United Brain Association Leave a Comment

Getting vaccinated against the shingles virus could lower your risk of stroke, according to new research presented at the American Stroke Association’s International Stroke Conference. However, a separate study has concluded that treating shingles with the same vaccine after the infection appears has no apparent effect on stroke risk.

Shingles and Stroke

Shingles is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. The virus lies dormant in the body after a chickenpox outbreak, and it can reactivate years later and manifest as shingles, a painful rash that typically appears on the torso.

Scientists have long recognized a connection between shingles and an increased risk for both stroke and heart attacks. The connection seems to lie in the inflammation caused by the infection. Inflamed blood vessels may be prone to tearing, and the tear creates a blood clot that can block blood flow to the brain or the heart.

When the brain’s blood supply is cut off in this way, the result is a type of stroke called an ischemic stroke. One study found that the risk of stroke increased by 41% in the first year after a shingles outbreak, and the risk was highest among people under the age of 40.

Vaccines and Stroke Risk

A vaccine for the shingles virus, Zostavax, has been available since 2006, and it has been proven to reduce the risk of developing shingles by 51%. Although it could be assumed that lowering the risk of shingles should also lower the associated risk of stroke, a new study conducted by the Centers for Disease Control and Prevention aimed to back up that assumption with data.

The study looked at the health histories of more than a million Medicare recipients over the age of 66, both those who had received the shingles vaccine and those who hadn’t, to compare their risk of stroke. The study found that the vaccine lowered overall stroke risk by approximately 16%. The effect was greatest among people ages 66 to 79. The risk for people 80 and older decreased by about 10%.

But does the vaccine only decrease stroke risk by preventing the shingles infection? Can the vaccine or other antiviral therapies to treat the infection after it occurs also lower stroke risk? Another study also conducted by the CDC looked into that possibility and found that treating shingles after an outbreak did nothing to decrease the risk of a stroke in the year following the infection.

A Case for Prevention

The authors of both studies emphasize that preventing shingles is the best strategy for decreasing shingles-related stroke risk, and getting vaccinated is the best way to prevent the infection. That’s especially good news now that Zostavax has been largely replaced by a new vaccine, Shingrix, that is up to 90% effective at preventing shingles. Both CDC studies examined the effects of the older vaccine, and there is reason to believe that the more effective vaccine might have yielded even more promising results.

Sources
American Heart Association, Shingles vaccine may also reduce stroke risk

American Heart Association, Treating shingles after it appears doesn’t reduce increased stroke risk

American College of Cardiology, Shingles Increases Risk of Heart Attack, Stroke

Deep Brain Stimulation Fails to Get a Foothold in OCD Treatment

Apr 9, 2020 by United Brain Association Leave a Comment

Most cases of obsessive-compulsive disorder (OCD) respond well to medication or psychotherapy, but as many as 20% of cases remain resistant to these forms of treatment. Doctors have been looking for effective ways to treat these resistant cases of OCD for decades, and one promising approach involves a surgical technique called deep brain stimulation (DBS). A recent survey of DBS studies suggests that the technique could provide long-term relief for the majority of treatment-resistant OCD sufferers.

Searching for the Heart of OCD in the Brain

Deep brain stimulation (DBS) uses electrodes to deliver electrical pulses directly to the brain. The electrodes are connected to a device that’s implanted under the skin of the chest, and the device controls the pattern of the pulses in much the same way that a pacemaker delivers electrical pulses to the heart. The technique has been used successfully to treat movement disorders such as Parkinson’s disease, and it’s more recently been used to treat depression that doesn’t respond to traditional treatments.

The challenge in using DBS to treat OCD is in finding the correct part of the brain to target. Early studies targeted a part of the brain called the anterior limb of the internal capsule. Imaging studies had indicated that this part of the brain was associated with OCD symptoms, and another surgical procedure called an anterior capsulotomy had produced positive results as a treatment for the disorder.

Targeting DBS at the anterior limb of the internal capsule reduced symptoms in many OCD patients, but researchers continued to look for other areas of the brain that might also be effective targets. Other studies have targeted the subthalamic nucleus, the nucleus accumbens, the ventral capsule/ventral striatum, and the inferior thalamic peduncle.

Although the results of targeting these five different areas of the brain varied, the improvement in OCD symptoms have been significant overall. About 60% of participants in the studies fully responded to the treatment, meaning they saw more than a 35% decrease in their symptoms as measured by a commonly used assessment scale.

DBS Fails to Get a Foothold in OCD Treatment

Despite the promising results of DBS studies, and despite the fact that 75% of American Psychiatric Association members say they’d recommend DBS for treatment-resistant OCD, the technique is still almost never used to treat the disorder. The procedure is specialized and expensive, and insurers have been unwilling to cover it as an accepted treatment for OCD. Virtually the only way that an OCD patient can receive DBS treatment is by enrolling in a study. Given that most studies are very small, fewer than 300 OCD patients have been treated with DBS.

The best hope for advancing DBS as a treatment for resistant OCD is an investment in more and larger studies. Further research can more precisely evaluate how effective the treatment is, as well as determine which target areas in the brain produce the best treatment results.

Sources
Deep Brain Stimulation Successfully Treats Refractory OCD Although Targets Vary

Deep Brain Stimulation for Highly Treatment-Resistant OCD

Deep brain stimulation sites for OCD target distinct symptoms

Dreams May Help Unlock the Mysteries of Narcolepsy

Apr 7, 2020 by United Brain Association Leave a Comment

A new study of dream patterns in narcolepsy patients may provide new hints at what the sleep disorder is doing to patients’ brains. A better understanding of the way narcolepsy affects a patient’s dreams could lead researchers to a more thorough understanding of the disorder’s neurological mechanisms. That, in turn, could lead to the development of more effective treatments.

REM Sleep, Dreams, and Narcolepsy

When we fall asleep, we normally move through several stages of sleep during which our brain is not very active. After an hour or two, we usually fall into a type of sleep called REM sleep (so-called because our closed eyes tend to move around rapidly during this stage). During REM sleep, our brain is very active. A normal sleep pattern has us cycling between non-REM and REM sleep throughout the night.

The sleep disorder narcolepsy is characterized by extreme daytime sleepiness and the tendency to fall asleep quickly and often even during the daytime. During these brief daytime sleep episodes, patients often fall into REM sleep much more quickly than normal, sometimes within minutes after falling asleep. These unusual periods are called sleep-onset REM periods (SOREMPs).

Normal REM periods are the times when we tend to dream most vividly. During non-REM sleep, we’re more likely to not dream at all or to have the feeling that we’ve dreamed without being able to recall the dream’s details (a phenomenon referred to as a “white dream”).

Scientists have wondered just how closely SOREMPs resemble normal REM sleep periods, and that’s where dream studies hope to provide answers. Do narcolepsy patients dream during SOREMPS, and if so, how vivid are the dreams?

Dream Stories and Narcolepsy

The study conducted at the University of Bologna examined the dream patterns of narcolepsy patients. Thirty participants were put through a standard exam called a Multiple Sleep Latency Test (MSLT). In the MSLT, patients take a series of short naps spaced about two hours apart. Some of the participants were also studied during nighttime sleep.

After their sleep periods, patients were asked for detailed reports about their dream experiences. Researchers then compared the dream experiences between periods of non-REM sleep, SOREMPs, and nighttime REM sleep.

The study found that participants reported vivid dreams with a strong story-like narrative structure during about 75% of their SOREMP naps. They experienced such vivid dreams only about 25% of the time during naps with only non-REM sleep. The SOREMP dreams were relatively long and complex, with recalled details and a structured series of events, a pattern that was similar to dreams during nighttime REM sleep.

The study results suggest that patients’ brains are cognitively active during SOREMPs. They are experiencing an ordered thought process, and they are recording memories of their dreams that they can recall later. This pattern more closely resembles REM sleep than it does non-REM sleep, during which the brain is much less active and its memory centers are less likely to process a dream experience.

Identifying similarities in dream structure between SOREMPs and REM sleep periods is only a small piece of narcolepsy neurophysiology puzzle. Every new piece discovered, however, could move researchers toward new therapies and treatments for the disorder.

Sources
SLEEP, Structural Organization of Dream Experience During Daytime Soremp Sleep of Patients with Narcolepsy Type 1

Harvard Medicine, Natural Patterns of Sleep

Drug Makers Push Ahead with Alzheimer’s Treatments Despite Setbacks

Apr 2, 2020 by United Brain Association Leave a Comment

The past year has been a difficult one for the developers of potential new treatments for Alzheimer’s disease. First, the trial of a promising new drug was suddenly halted because it was not showing the hoped-for results, but then the drug’s developer announced that the results weren’t so bad after all and that they would continue to seek FDA approval for its use.

Then, two more similar drugs were found by a study to have no apparent effect on the disease’s symptoms. Despite these disappointing developments in Alzheimer’s research, the scientists involved have remained hopeful, and their work toward finding an effective treatment for the disease continues.

Pursuing the Mysteries of Amyloid

All of the drugs in question target amyloid, a protein at the root of Alzheimer’s symptoms. In the brains of Alzheimer’s patients, amyloid forms hard plaques that interfere with the function of brain cells and eventually cause irreversible cell damage and cell death. The drugs are designed to remove amyloid and, in theory, slow or even prevent the degeneration of brain tissue seen in Alzheimer’s patients.

To test the drugs’ effects, long-term studies recruited people with a rare genetic mutation that virtually guaranteed that they would develop Alzheimer’s disease. This allowed researchers to give the drugs to people who did not yet have full-blown symptoms of the disease but who would if left untreated, almost certainly show symptoms in time. If the drugs worked, they should be able to prevent symptoms from developing.

In March 2019, pharmaceutical company Biogen announced that it was halting trials on its amyloid-targeting drug aducanumab because the drug was unlikely to show positive results. In October, however, Biogen reversed course and said that after re-evaluating the results of aducanumab studies, they’d be pushing ahead to seek FDA approval for the drug.

In February 2020, the results of a study involving two more amyloid-targeting drugs, solanezumab, and gantenerumab, were released, and the news wasn’t good. Neither drug appeared to prevent declines in memory or cognitive function in the study’s participants. It wasn’t the first failure for gantenerumab, which had already had a failed trial in 2015.

Pharmaceutical Companies Stay On Course

Despite the disappointing study results, drug developers remain confident that they’re on the right track in the pursuit of amyloid. Other studies of solanezumab are underway, and Biogen intends to press for approval of aducanumab as soon as possible, maybe even before the end of 2020. In addition, Biogen is moving forward with another new drug, BAN2401, which also targets amyloid.

Skeptics are less optimistic. Some scientists point to the multiple failed trials of amyloid-targeting drugs as evidence that simply removing the protein may not be the key to effective Alzheimer’s treatments. Perhaps the mechanism of the disease in the brain is more complex than has been assumed, they say, and resources might be put to better use in the pursuit of new, different types of treatments. For now, however, the focus of drug makers remains on amyloid.

Sources
Associated Press, Drugs fail to slow decline in inherited Alzheimer’s disease

New York Times, An Alzheimer’s Treatment Fails: ‘We Don’t Have Anything Now’

Being Patient, New Alzheimer’s Trial Aims to Defeat Amyloid Before Symptoms Develop

Being Patient, Biogen Ends Late-Stage Alzheimer’s Trials, Crushing Hopes and Calling Amyloid Into Question

USC, Alzheimer’s study aims to see if the drug can block brain plaques linked to disease

BioPharma-Reporter, Biogen prepares to step up manufacturing to support Alzheimer’s launch

Endpoints, Roche is bringing back gantenerumab from the dead, taking another stab at Alzheimer’s PhIII