Tag Archives: Cognitive Impairments

Question?: Rett Syndrome Research

Chris asks…

Does anyone know why Rett Syndrome girls start off “normal” & then regress?

Okay I’m aware of what Rett Syndrome is & how it works (for the most part anyway) but what has me confused the most is that most of these girls develope normally for about the first 6-18 minths & then start to regress/lose skills they’ve already learned (i.e. talking, walking, eye contact) . I know this is due to a mutation in the MEPc2 gene but why/how is it they can learn things & then lose them later on. I relize the gene is responsible for turning on/off certian protiens but what is making these girls funtion properly in the beginning then? another gene maybe?

admin answers:

To quote a passage from wikipedia:
“The recent studies demonstrating that neurological deficits resulting from loss of MeCP2 can be reversed upon restoration of gene function are quite exciting because they show that neurons that have suffered the consequences of loss of MeCP2 function are poised to regain functionality once MeCP2 is provided gradually and in the correct spatial distribution. This provides hope for restoring neuronal function in patients with RTT. However, the strategy in humans will require providing the critical factors that function downstream of MeCP2 because of the challenges in delivering the correct MeCP2 dosage only to neurons that lack it, given that the slightest perturbation in MeCP2 level is deleterious. Thus, therapeutic strategies necessitate the identification of the molecular mechanisms underlying individual RTT phenotypes and picking out the candidates that can be therapeutically targeted. The next phase of research needs to assess how complete the recovery is. Clearly, lethality, level of activity, and hippocampal plasticity are rescued, but are the animals free of any other RTT symptoms such as social behavior deficits, anxiety, and cognitive impairments? Since postnatal rescue results in viability, it will be important to evaluate if even the subtler phenotypes of RTT and MECP2 disorders are rescued when protein function is restored postnatally. This is particularly important given emerging data about early neonatal experiences and their long-term effects on behavior in adults.”

What I get from that is that the nerves become damaged by the defective gene, resulting in a loss of abilities that have already been learned.

Sorry if you’ve already read this, but this is just about all I could find as far as the reason for the decline period.
Hope this helps!

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Question?: Autism Symptoms In Adults

Jenny asks…

Why should autistic people not work in business?

I was reading an article about jobs that are recommended for autistic adults and the article mentioned that business should be avoided. I can understand counselling or social work…but business too? Can someone explain this, is there a lot of social interaction involved?

admin answers:

Anyone who experiences some of the range of symptoms that people with autism frequently have is going to have greater challenges than most people would in almost any line of work; that’s just a given.

But the same could be said of anyone with a visual or hearing impairment, issues with fatigue, ADHD, limited use of their upper extremeties, you name it — yet most of us manage to work despite whatever physical or cognitive impairments we might have to contend with. ALS hasn’t stopped Stephen Hawking; blindness hasn’t stopped Stevie Wonder and – I forget the actor’s name – the guy who plays the coroner on CSI hasn’t let the fact that he’s a dual amputee keep him from being on a wildly successful TV show.

I help people with disabilities start their own small businesses. For me, concern #1 is whether the person I’m working with has the basic training and experience necessary to operate the type of business they want to start. Concern #2 is whether or not there’s a legitimate business opportunity to be exploited (if we build it, will they come?). Finally, concern #3 is if and how we can find reasonable accommodations to enable the person to do the job despite any impairments they may have.

Critical skills for business-related work:
1. Effective communication verbally and in writing
2. Planning skills
3. Problem-solving skills
4. Ability to handle bookkeeping, budgeting and record-keeping
5. Ability to be flexible, juggling multiple priorities

As you said, persons with autism may have difficulty with interpersonal interactions, multitasking or working in high-stimulus enviroments, for instance. I’d work with the entrepreneur to see how we could minimize those facets of the job and/or to find alternative means of handling those dimensions. Could more customer interaction be handled via email for instance? If so, would that help? Could the business support the wages of a second employee who could more effectively handle the personal selling aspects of the job if that was an issue? And so on.

Any person with Any disability should be open to considering Any job that interests them. However, that person and anyone who’s assisting them in making a career choice need to be creative, pragmatic and thorough in determining up front if and/or how they might be able to do the job in question given their impairments. There’s not always a “fix” to be done, but you’d be amazed how often there is a creative solution.

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Mice With Dravet Syndrome Mutation Given Low-Dose Sedative Show Improvements In Autism-Like Behavior

Main Category: Autism
Also Included In: Pain / Anesthetics;  Neurology / Neuroscience;  Genetics
Article Date: 24 Aug 2012 – 0:00 PDT Current ratings for:
Mice With Dravet Syndrome Mutation Given Low-Dose Sedative Show Improvements In Autism-Like Behavior
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A low dose of the sedative clonazepam alleviated autistic-like behavior in mice with a mutation that causes Dravet syndrome in humans, University of Washington researchers have shown.

Dravet syndrome is an infant seizure disorder accompanied by developmental delays and behavioral symptoms that include autistic features. It usually originates spontaneously from a gene mutation in an affected child not found in either parent.

Studies of mice with a similar gene mutation are revealing the overly excited brain circuits behind the autistic traits and cognitive impairments common in this condition. The research report appears in Nature. Dr William Catterall, professor and chair of pharmacology at the UW, is the senior author.

Dravet syndrome mutations cause loss-of-function of the human gene called SCN1A. People or mice with two copies of the mutation do not survive infancy; one copy results in major disability and sometimes early death. The mutation causes malformation in one type of sodium ion channels, the tiny pores in nerve cells that produce electrical signals by gating the flow of sodium ions.

The Catteralll lab is studying these defective ion channels and their repercussion on cell-to-cell signaling in the brain. They also are documenting the behavior of mice with this mutation, compared to their unaffected peers. Their findings may help explain how the sporadic gene mutations that cause Dravet syndrome lead to its symptoms of cognitive deficit and autistic behaviors.

The sodium ion channels in question malfunction in specific nerve cells, called inhibitory neurons, whose job is to send messages to hush the electrical signaling of neighboring cells. If only transmissions that excite nearby cells get through, the balance of cell signals that excite or inhibit the brain is seriously tilted toward excessive excitability.

“Imagine New York City traffic without any red lights, just green lights,” said Catterall. This kind of electrical traffic jam might explain the heightened brain state of children with the Dravet mutation. These children suffer from frequent electrical storms, called epileptic seizures, in their brains. They are hyperactive, anxious and have difficulty sleeping. Their problems in learning, remembering and reasoning often follow a downhill course through childhood. The children also show several symptoms of an autistic spectrum disorder, including withdrawing from social interactions, repeated movements, and restricted, intense interests. The brain mechanisms behind this disorder have been poorly understood, Catterall said.

In observing the behavior of mice with the same genetic variation, Catterall and his team saw that they did not display many normal social interactions of mice. Mice are naturally curious about a mouse they haven’t met before, and will approach and sniff it. Sometimes they will attack, wrestle and playfully bite the stranger. Usually mice are more interested in mice they haven’t met before than those they already know. Mice with the Dravet syndrome were not interested in meeting strangers or acknowledging acquaintances, and did not approach them either aggressively or with mild manners. In fact, they froze when confronted with new mice, the scent of male mouse urine, or new food smells like banana oil, which usually attracts mice unfamiliar with the scent.

These altered behaviors suggested that the Dravet mice were unable to have normal social interactions with recently introduced mice and were repelled by new experiences, even new food odors. The Dravet mice also had problems in spatial learning and memory. They were unable to learn and remember the location where fearful events occurred or to learn and remember how to escape a brightly lighted area. In an open field test and maze running comparisons with mice without the mutation, the Dravet mice traveled more, spend less time in the center, and walked in circles. They also groomed themselves and wiped their whiskers excessively.

“Like many children with autism, the mice seemed overwhelmed by changes in their environment and unable to interact socially with other mice,” Catterall said. “They also showed stereotypic movements and repetitive behaviors common in autism.”

His team went on to explore the cellular and biochemical underpinnings of the autism-related traits and spatial learning deficits in the Dravet mutation mice. They tested the hypothesis that the condition arises from decreased activity of particular sodium ion channels in the brain cells that relay inhibitory information to other nerve cells in the forebrain.

They found that the deep layer of the prefrontal cortex of the brain was the most affected by the mutation. Among the core components linking thinking and emotion circuits of the brain are the interneurons. These cells release a neurotransmitter called GABA, a brain chemical signal that inhibits neighboring cells. On the other hand, excitatory nerve cells release a different neurotransmitter that activates neighboring nerve cells. Normally, these excitatory and inhibitory nerve cells balance each other.

The researchers found that the Dravet mutation mice had the normal number of the GABAergic interneurons, the cells that fire a “turn it down” signal to their neighbors. However, a significant percentage of these cells lacked a specific type (type-1 or Nav1.1) of gated sodium channel. This deficit kept these cells from firing enough electrical signals. As a consequence, excitatory signals dominated circuits in critical areas of the brain.

“We reasoned that the decreased in sodium channel activity in these GABAergic interneurons could be rescued by increasing the strength of the GABAergic transmissions,” Catterall said.

His team decided to treat both the normal and the Dravet mutation mice with the benzodiazepine clonazepam. This drug is often given to people suffer from moderate, debilitating anxiety, such as fear of flying. Benzodiazepines also control some forms of epileptic seizures. The researchers lowered the dose to make sure they were not sedating the mice or removing their anxious state.

“The treatment with a single low dose of clonazepam completely alleviated the impaired social interactions of the Dravet mice. It also removed the freezing reaction to novel situations. They were willing to approach mice that were strangers to them and to explore new odors. They behaved just like their peers,” Catterall observed. “This dose of the drug had no effect on the behavior of their normal peers.” The effects of the drug wore off after it cleared completely from the body, which takes a few days in mice.

“The results showed that a single low dose of clonazepam can reversibly rescue core autistic traits and cognitive deficits in mice with the Dravet mutation,” Catterall said. Additional measurements of cell firing in brain tissues from affected mice showed that the behavioral effects were likely based on decreased strength of the inhibitory signals, which caused an overall increase in brain electrical signaling by releasing the restraint on excitatory neurons. Their research also suggested that the cognitive and behavioral impairments in Dravet syndrome are not the result of damage from epileptic seizures, but are due to an innate shortage of a certain type of sodium ion channel and the resulting failure of inhibitory electrical signaling.

Catterall added that the research indicates that low-dose benzodiazepine treatment could be a potential drug intervention for cognitive deficits and autistic symptoms in Dravet syndrome patients, if clinical trials show they are effective in humans, and perhaps more broadly in certain other types of autism spectrum disorders.

“Interestingly, mutations in many other autism spectrum disorders also cause an imbalance of excitatory over inhibitory electrical activity in the brain,” the research team noted. Perhaps autistic traits in some other conditions within the realm of autism spectrum disorders might also be caused by a reduction in GABAergic signaling between brain cells.

Dravet syndrome is not the only genetic disorder that has autistic traits accompanying other physical and developmental disabilities. Rett, fragile X, and Timothy syndromes also have autistic features.

Article adapted by Medical News Today from original press release. Click ‘references’ tab above for source.
Visit our autism section for the latest news on this subject. The study was supported by grants from the National Institutes of Health R01NS25704, R01MH075016, and R37MHO49428 and from the McKnight Foundation. This research was part of the doctoral research of Dr. Sung Han, now a postdoctoral fellow at UW, and involved scientists at the University of California at San Francisco and Seoul National University in Korea.
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Asperger’s vs Autism

There has been a lot of debate about the nature of Asperger’s syndrome and where it fits within the Autism spectrum. The one thing that is known for sure is that Asperger’s IS a type of autism, but without many of the debilitating symptoms. There are many differences between what most people think of when they imagine an autistic child and one that suffers from Asperger’s syndrome. Let’s take a look at some of the basic differences.

1. A child who is typically autistic will show severe lapses in the development of language. A high percentage of autistic children may never develop language skills at all. With a child or an adolescent who has Asperger’s syndrome, language skills are usually not affected at all and in fact can be above average. A child with Asperger’s syndrome can show impaired social development that may lead to a lack of language usage, but the actual development of the language itself is on par with other children of the same age.

2. A second way to differentiate Asperger’s disease from classic autism is the cognitive abilities of Asperger’s children. Most kids that have Asperger’s show normal or even above average cognitive ability in classroom settings and on I.Q. tests. This extends into the later years of development too. However, children with classic autism show cognitive impairments that usually do not improve with age.

3. A third and major difference between kids with autism and Asperger’s is the way the two interact socially. In most cases, although there are variances since each child with autism and each child with Asperger’s reacts differently, a child who is autistic can sometimes come across as being cocky or not really caring about children around them. However children with Asperger’s syndrome in most cases want to be social but are just very, very awkward. They tend to be too formal in social situations, and they are thought to not show empathy to other children. They may also appear to have no knowledge of social rules and proper mannerisms. They can also show almost complete lack of eye contact, which many regard as a lack of interest in being social, but it is more out of awkwardness than a lack of wanting to be social.

4. A final way that you can tell if a child has Asperger’s syndrome and not traditional autism is the way an Asperger’s syndrome child becomes obsessed with things. The subject of the obsession can range something like sports statistics to obscure things like names of Russian czars or any other bizarre thing you can think of. This obsessive behavior also has an impact on the child’s socialization. They tend to only want to talk about whatever their current obsession is with other people, including kids their own age. This can add to the awkward social interaction that is common for those with Asperger’s syndrome.

For more information about symptoms and the various treatments for Asperger’s Syndrome sign up for the free newsletter below.

When talking about Asperger’s vs Autism, children with Asperger’s are sometimes referred to as having ‘high functioning autism’. This is a subjective term and has no medical definition. However it is often used to refer to children with typical Asperger’s symptoms or mild autism symptoms.
for more information visit http://www.autism.scotnetwork.com .

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