Lytico-Bodig Syndrome, You Might Get it From Eating Bats

Posted by Daniel Rubio, Drexel University College of Medicine Class of 2014

“A man” obsessing over “bats”…

“A man” eating “bats”…

The patients above are displaying symptoms resulting from a disease known as Lytico-Bodig Syndrome (LBS), a neurologic disease resembling amyotrophic lateral sclerosis (ALS/Lou Gehrig’s Disease), Parkinson’s disease, and Alzheimer’s disease.  The country with the greatest number affected is the US territory of Guam.  In fact, between the 1940-1960 it was the leading cause of death among the Chamorro people, a tribe found on the island of Guam.  The afflicted were usually between the ages of 25-40 years of age.

What’s up with the bats?

Although yet to be proven, it is believed that the high incidence of LBS is due to the consumption of fruit bat, a cultural delicacy on the island.  These fruit bats feed on specific fruits containing high concentrations of an altered amino acid called beta-N-methylamino-L-alanine (BMAA). BMAA is a known neurotoxin and is believed to be the cause of LBS.  BMAA is a protein building block that is incorporated into neuronal proteins to produce an abnormal form that creates clumps with neurons resulting in their dysfunction and death.

I don’t eat bat though?

I addition to the high concentrations found in the fruit bats on the island of Guam, multiple sources have been proposed leading to BMAA exposure within the United States.  Certain bacteria in fresh and salt waters produce BMAA; and, fish and crustaceans will concentrate BMAA within their tissues when they consume the bacteria as part of their normal diet.  It is believed that human consumption of fish and crustaceans in at-risk areas might increase the incidence of neurodegenerative diseases, like Alzheimer’s, Parkinson’s, and Lou Gehrig’s.  This association has been seen in many areas within the United States, especially around the gulf regions and around large bodies of water.  Click here for more details about this.

Am I more lytico or bodig?

Presenting symptoms exist along the continuum of lytico-bodig.  Patients on the lytico spectrum present more like ALS/Lou Gehrig’s disease.  These patients have muscle wasting/atrophy and accompanying weakness, paralysis of mouth and tongue, and an inability to swallow resulting in choking to death.  Over time, paralysis involves the breathing muscles requiring mechanical ventilation to help the patient breath and to prevent choking on secretions.  Lytico patients remain aware of their deterioration.  The form of LBS is fatal in all cases.

On the other end of the spectrum, patients with bodig presentations look more like Parkinson’s disease and Alzheimer’s disease patients.  Bodig patients present with “freezing” with progressive immobility with loss of starting purposeful movement and loss of spontaneous movement.  Progressive dementia with loss of speech and irrational behavior, including violence and rapid fluctuations in mood, are common.  Over time, patients are left in stiff and immobile postures with inability to speak and swallow.

How would I know if I had LBS?

Currently Lytico-Bodig syndrome is diagnosed based upon appropriate history and physical exam by a neurologist.  Definite LBS is declared in post-mortem autopsy.  However, there is research being done to develop rapid tests using cerebral spinal fluid analysis.

What can I do if I have LBS?

Treatment is mainly supportive as is based upon symptoms present, whether it’s Parkinson’s, Alzheimer’s, ALS, or a combination of the three spectrums of diseases.   The more the symptoms resemble Lytico, the greater the mortality: in patients with predominantly lytico-type symptoms the disease is practically 100% fatal.

Playing video games improves aging brain function

We know from previous blogs that there is an escalating incidence of dementia.

We know that the strongest risk factor for developing dementia is old age.

However, we also know that dementia is not an inevitable consequence of old age.

Why do some older adults get dementia and others don’t?

Instead of looking for dementia risk factors, some researchers have turned the tables on this question, and looking at things that might be protective, reduce the likelihood of age related dementia.

This could translate into activities or behaviors  anyone could use to lower their dementia risk.

For example, regular exercise and social stimulation have been shown to lower dementia risk.

New research published in Nature looks at the relationship between brain function and video games performance in aging adults.

The investigators designed a game called NeuroRacer in which the player drives a virtual car along a track and must respond to the appearance of specific road signs by pressing a button. The trick is that the player has to attend to one type of sign only, ignore the others, and continue “driving” all the while.  Then, as the participants learned the game and improved their scores, the game gets harder and harder.

The study had 46 participants, aged 60-85, engage in 12 hours of the training over the course of a month. During that time, they vastly improved their performance, and at the end of that study they played just as well as 20-year olds.  Furthermore, these gains in brain function persisted for more than 6-months, and more importantly weren’t limited to gaming – study participants also showed improved attention and working memory.

Click here to find out more.

New cure for dementia?

Probably not.

However, this study does demonstrate that older adults can still re-shape their brain connections, and also re-affirms that the old adage, if you don’t use it you lose it, also includes brain function!

Maybe it’s time to start playing chess or BrainAge regularly?

Robots helping dementia patients live independently

We have already blogged about the Alzheimer’s epidemic.

There are already more than 5 million affected patients, and Alzheimer’s is now the 6th leading cause of death in the US.

 Caregivers spend an average of 70 to 100 hours per week providing care to an affected family member.

Alzheimer’s patients cope better in familiar surroundings.   They get worse more quickly when socially isolated.   It is more cost effective to keep affected patients at home for as long as possible, avoiding expensive residential care.

However, many caregivers need to go to work, and cannot be at home with their affected family member 24/7.

New programs using robots to provide social contact and even supervision for Alzheimer’s patients on their own at home may provide a cost effective solution to this problem.

Robot “pets” have already been used to encourage emotional behaviors for socially isolated dementia patients.

Scotland’s National Health Service  is putting robots into the rural homes of some dementia patients in a pilot scheme to help them to continue to live independently.

A relative or carer – potentially hundreds of miles away – can drive the machine around the house to check that everything is all right. The pair can also have a chat through a two-way video call system.

The robots are about 5ft tall, on wheels and have a TV screen instead of a head.

A relative or carer can connect to the robot with a computer from any location. Their face will appear on the screen allowing them to chat to the other person.

The operator can also drive the robot around the house to check that medication is being taken and that food is being eaten.

Find out more about this innovative program.

Ongoing studies are showing that robots can provide affordable personalized cognitive stimulation, motivation and companionship to dementia patients, and potentially keep them living independently longer.

Find out more about caring for Alzheimer’s patients at home.

Memory Loss? Better check that medication list!

Alzheimer’s disease is the commonest cause of memory loss and dementia.   We do not yet fully understand what causes Alzheimer’s.  However, we do know that the neurotransmitter acetylcholine is important in brain processing and memory.  We also know that the acetylcholinesterase inhibitors (drugs like Aricept<donezepil> , Exelon <rivastigmine> and Razadyne <galantamine>), which inhibit the breakdown of acetylcholine, do provide a symptomatic improvement in affected patients.

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It is also known that many drugs can cause and/or exacerbate memory loss in elderly patients:

Anticholinergics block the effects of acetylcholine, causing confusion. They also negate the beneficial effects of aceylcholinesterase inhibitors in Alzheimer’s patients.  These drugs are commonly prescribed for urinary frequency and urgency, and include Ditropan <oxybutynin> and Vesicare <solifenacin>.  The tricyclics, including Elavil <amitriptyline> and Pamelor <nortriptyline>, commonly prescribed for insomnia and headaches, also have anticholinergic properties.

Benzodiazepine drugs like Xanax <alprazolam> Restoril <temazepam> and Klonopin <clonazepam>, most commonly prescribed for anxiety and insomnia, can also cause and/or exacerbate memory loss because of drowsiness and inattention.

A recent study of Alzheimer’s patients living independently in the community showed that as many 17% were taking anticholinergic drug and almost 9% were taking benzodiazepines.

As if that wasn’t bad enough, 16% of patients were taking both an acetycholineresterase (cholinergic) and an anticholinergic drug at the same time!

The bottom line here is that you should always bring a complete and updated list of all your medications with you to doctors appointments!

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Click here for a link to the full article.

New Brain Imaging for Alzheimer’s Disease

Amyloid proteins in normal brains (left) and abnormal ones (right) visualized with GE Healthcare’s PET tracer flutemetamol.

Alzheimer’s disease is the commonest cause of dementia, and as the population is aging, it’s prevalence is increasing.

Alzheimer’s disease presently affects 5 million Americans aged 65 or older.  Without a major medical breakthrough, by 2025 this number is expected to have risen to 7 million, and by 2050 it could reach 14 million

The costs of caring for Alzheimer’s patients is also increasing, estimated at $203 billion in 2013, and $1.2 trillion by 2050,  including a 500% increase in combined Medicare and Medicaid spending.

Clearly, finding that major therapeutic breakthrough is crucial, and had been identified as a priority by the Obama Administration.

The first barrier to starting any clinical trial is accurate case ascertainment – we have to be able to correctly identify early Alzheimer’s patients for new experimental treatments.

So far, the only definitive test for Alzheimer’s disease is examination of brain tissue (usually obtained at autopsy) for identification of the characteristic pathologic changes of Amyloid paque and Neurofibrillary tangles:

Alzheimer’s disease is usually diagnosed based on  clinical criteria, but many patients diagnosed this way are later found to have other causes of dementia when their brains are examined at autopsy, in other words they were misdiagnosed as Alzheimer’s.

With more research trials and potential new effective therapies on the horizon, it is going to become more important to establish a diagnosis of Alzheimer’s more accurately and earlier, perhaps even pre-symptomatically (i.e. mild cognitive impairment or MCI), so that treatment to reverse the build up of plaque and tangles is more likely to be effective.

New positron emission tomography (PET) technology can actually quantify the amount of amyloid in affected patients’ brains.  A recently published small study showed a very high correlation between amyloid identified on PET scans and amyloid plaque demonstrated in brain biopsy specimens taken from demented patients.

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These tests are going to be very important for research studies.

However, don’t rush to your private doctor’s office asking to have one done just yet!

Although approved by the FDA, these test are not yet covered by Medicare or other insurance covering, and cost between $1500 and $3000.

Furthermore, these are new tests, and their role in clinical neurology practice in still unclear.

Some of these issues were recently clarified in a report by the Amyloid Imaging Taskforce convened by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging:

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This taskforce concluded that a Amyloid PET scan is indicated for:

Progressive memory impairment or dementia with atypical features, where a positive PET would indicate definite Alzheimer’s, and a negative scan would rule it out and lead to further testing for other possible causes.

Younger patients (aged 50-65) with suspected Alzheimer’s, in whom making a definitive diagnosis is crucial for log term planning and future medical decision making.

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The taskforce concluded that a Amyloid PET scan is unnecessary and/or unhelpful for:

Patients with typical Alzheimer’s disease,

Determining the severity of dementia,

Asymptomatic patients with a family history of dementia or positive apolipoprotein E4 status,

Patients who complain of memory loss but have no objective findings,

Testing purely for medico-legal, disability, insurance or employment related issues.

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Find out more:

Click here to find out more about Memory loss, Mild Cognitive Impairment and Alzheimer’s.

Click here to find out more about diagnosing Alzheimer’s.

Links to the Alzheimer’s Association, Alzheimer’s Foundation of America and CDC Healthy Brain Initiative

Prions: Could these zombie-like proteins be responsible for causing the most common form of Dementia?

Post courtesy of Dr Michael Chan, PGY2 Medicine Resident, Monmouth Medical Center.

As far as infectious diseases go, prions are a relatively new discovery. While humanity has known about parasites since ancient times, bacteria since the 1660s, and viruses since 1898, the first prion protein was only isolated in 1984. Since then, we’ve gotten to know a little more about these proteins, and we’ve found that its novelty is by no means the most interesting thing about it.
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So what are prions?

Prions are basically the misfolded version of a normal protein, PRP or Protease resistant protein. In the vast majority of instances, the body has mechanisms that adequately deal with misshapen proteins. These get tagged for destruction by antibodies or intracellularly by specific molecular signals and lysosomes. However, prions are not your run of the mill abnormal protein. They are resistant to degradation and exhibit the unique characteristic of causing other normal PRP proteins to misfold, which in turn causes even more misfolding. In this sense, prions behave like protein zombies.

And like zombies, they don’t begin their existence as malevolent molecules either. Indeed this is one of the characteristics which differentiate prions from most other infectious agents such as bacteria or viruses, majority of which are inherently disease causing. Studies have shown that normal PRP has functions in sleep, memory, neural development, and possibly the maintenance of the myelin sheath that surrounds neurons. Indeed, a mutation of PRP causes a very rare disease (only 8 cases have been diagnosed as of 2005) called Familial Fatal Insomnia which leads to progressively worse insomnia leading to dementia, hallucinations, and eventually death.

Yes, complete inability to sleep kills.

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The connection to Alzheimer’s

Until recently, the most notable examples of prion diseases in humans are Creutzfeldt-Jakob disease and Kuru. Although spontaneous CJD does rarely occur, both these diseases are usually caused by ingestion of infected material, ie, eating infected meat (beef) for CJD and cannibalism for Kuru. Both exhibit progressive dementia, memory problems, gait and movement disturbances, and other unusual symptoms like uncontrolled laughter, hallucinations, and personality changes. Pathologically, the disease causes patients’ brains to develop tiny holes, much like a sponge. Thus the name for the disease in cows, Bovine Spongiform Encephalopathy, literally translates “cow spongy brain disease”.

Brain of a CJD patient with multiple “holes”

However, over the past 5 years, research has shown that at least one major protein known to accumulate in Alzheimers disease, amyloid beta, behaves much like prions. Research conducted at UCSF showed that when mice brains are seeded with amyloid beta, after 300 days, the amyloid plaque is found all over the brain, not just the area seeded. A Yale university study in 2009 also showed that prion proteins of CJD interact with amyloid beta in some way to cause the dysfunction in neurons which lead to Alzheimer’s. Although there is no evidence that AD is contagious, it may open up new therapeutic avenues to think of its pathology as like that of prion diseases.

Amyloid plaques and Neurofibrillary tangles in Alzheimer’s disease

How Alzheimer’s spreads in the brain.

Indeed, last year, a British team accidentally stumbled on a discovery that antibodies designed to treat CJD were found to block Alzheimer’s disease. These antibodies, ICSM-35 and ICSM-18, blocked the interaction between the PRP prion and amyloid beta in mice brains, resulting in decreased hippocampal nerve cell disruption. ICSM-18 and ICSM-35 are presently undergoing human trials for the treatment of CJD. With this finding, it’s likely they will be tested for Alzheimer’s as well, and we, for the first time, might have an effective and specific treatment for this disease which affects roughly 20 million people worldwide.

To see just how significant any form of treatment might be, check out the facts and figures provided by http://www.alz.org below:

References:

Jucker M, Walker LC. Pathogenic protein seeding in Alzheimer disease and other neurodegenerative disorders. 2011:70, 532–540.

Prusiner SB: A unifying role for prions in neurodegenerative diseases. 2012:336, 1511–1513.

Freir DB, Nicoll AJ, Klyubin I et al. Interaction between prion protein and toxic amyloid β assemblies can be therapeutically targeted at multiple sites. Nature Communications, June 7 2011

Diagnostic testing for Alzheimer’s?

The only definitive test for Alzheimer’s disease is examination of brain tissue (usually obtained at autopsy) for identification of the characteristic pathologic changes of Amyloid paque and Neurofibrillary tangles:

Alzheimer’s disease is usually diagnosed based on  clinical criteria, but many patients diagnosed this way are later found to have other causes of dementia when their brains are examined at autopsy, in other words they were misdiagnosed as Alzheimer’s.

With more effective new therapies on the horizon, it is going to become more important to establish a diagnosis of Alzheimer’s more accurately and earlier, perhaps even pre-symptomatically (i.e. mild cognitive impairment or MCI), so that treatment to reverse the build up of plaque and tangles is more likely to be effective.

There has been interest in Apoprotein E (APOE) genotype and Alzheimer’s risk. APOE genes come in 3 types (2-4).  If you have 2 copies of  APOE4 (1-2% of the population)  you are 15 times more likely to develop Alzheimer’s than averages, and if you have one copy of APOE4 you have are 3 times more likely to develop Alzheimer’s than average.   Clearly, there is an association between APOE4 genoytpe and Alzheimer’s.  However, not every patient with APOE4 develops Alzheimer’s, and you can develop Alzheimer’s without APOE4, so APOE genotyping is not recommended as a diagnostic test.

The ratio of cerebrospinal fluid levels of beta-amyloid and tau proteins can be predictive for Alzheimer’s, but this test requires a lumbar puncture, and is inconclusive in many cases.

Magnetic resonance imaging (MRI) of the brain has shown selective atrophy of the hippocampus in patients with early Alzheimer’s (a) vs. normal elderly controls (b), and this technique has been proposed as a diagnostic test for Alzheimer’s, but requires special computerized imaging processing not available at most imaging centers.

Fluorodeoxyglucose posititon emission tomogrpahy (FDG-PET) shows reduced metabolic activity (uptake of sugar) in the temporal and parietal lobes of patients with early Alzheimer’s (these regions are darker) vs. normal elderly controls (these regions are brighter), and this test is FDA approved, covered by Medicare, and widely available at imaging centers around the counrty:

A recent study compared the results of MRI, FDG-PET and analysis of CSF biomarkers  in 97 MCI patients, to see which was best for predicting who would convert to Alzheimer’s first. During a mean follow-up of almost 3-years, 43 patients progressed to AD and 54 did not. Of the 3 tests, an abnormal FDG-PET was most predictive.

Before you all rush out and get your FDG-PET to see if you are high risk for Alzheimer’s, be warned that results may be unreliable when the test is performed at an inexperienced center. Data presented at this year’s American Academy of Neurology meeting showed that up to 2/3 of patients referred to a University dementia program had been misdiagnosed with Alzheimer’s dementia based on misread FDG-PET scans performed at community imaging centers.

The Amyvid™ (Florbetapir F 18) PET scan, which was FDA approved this year, actually quantifies the amount of amyloid plaque in affected patients’ brains (bright), and is probably a more promising new PET technique for predicting Alzheimer’s disease. However, this test is not yet covered by Medicare or other insurance covering, and costs between $1500 and $3000:

In sum, the hope for the future is that with earlier and more accurate diagnosis, future treatments could target Alzheimer’s in its earliest stages, before irreversible brain damage or mental decline has occurred.  However, it is clear that none of the available diagnostic tests are perfect, and although promising, amyloid plaque PET scans are not yet covered by Medicare, so for now we mostly continue to make do with clinical diagnostic criteria.