Saturday, 30 April 2011

Intraventricular hemorrhage

Intraventricular hemorrhage (IVH) is bleeding into the ventricles of the brain. One characteristic of the immature brain is a weakness of the blood vessels next to the ventricles. The ventricles are cavities that store cerebrospinal fluid (CSF) which nourishes the brain. Of particular concern is a collection of tiny and fragile blood vessels in the germinal matrix, which is the area of brain adjacent to the floor of the ventricles. This is a part of the brain that is active during fetal development but that disappears at about the 35th week of pregnancy. These blood vessels are thin and vulnerable to fluctuations in blood flow through them, which can cause them to rupture and bleed. The younger and smaller the baby, the higher the risk these blood vessels may be ruptured, usually in the first few days of life. A rupture causes blood to flow into a ventricle or ventricles of the brain.

IVH is categorized into grades of severity: grade I is considered mild, grade II moderate, and grade III & IV severe. About 50% of extremely premature babies will sustain an IVH, whereas only about 15% of older premature babies, many of whose germinal matrix has already disappeared, will have an IVH.

If the IVH is classified as grade I or II, the chance that there will be long-term damage is small because the blood remains contained within the ventricles and the additional fluid does not cause excessive pressure.

In grade III and IV, the bleeding is substantial enough to cause a swelling or obstruction of the narrow channels feeding into and out of the ventricles. This may interfere with the normal replenishment and flushing of the CSF. The result can be hydrocephalus, which is a build up of CSF in the ventricles, which puts pressure on surrounding brain tissues. This can then result in injury to that area of brain under pressure. If the bleeding is more severe, blood that has flowed into and filled the ventricles will permanently block CSF flow and lead to hydrocephalus with enlargement of the head, excessive pressure within the skull, and the need for a surgical intervention to relieve the pressure. A small tube or catheter called a ventriculoperitoneal shunt (VP shunt) is inserted to drain off the spinal fluid.

A grade IV IVH results from congestion to the brain tissue around the ventricles when a large IVH has occurred. This results in bleeding into the brain tissue itself with destruction of that area of brain. Lasting brain damage is almost always the result, the severity of which is determined by the extent and location of the bleeding.

Because premature babies have fragile blood vessels, an IVH can occur simply as a result of changes to blood pressure and flow that occurs with birth. Although blood pressure changes occur in most people without bleeding, in the premature baby, the walls of the vessels are vulnerable during these changes. Blood pressure fluctuations can occur as a result of many different conditions, and are often a result of difficulties at the time of birth or lung and breathing complications.

Mechanical ventilation, which is often needed immediately after the birth of a premature baby, can also lead to fluctuations in blood flow. This is particularly likely when the baby is breathing out of sync with the ventilator, which creates additional pressures within the lung and blood vessels in the brain. Much work has been done over the years in an attempt to reduce this particular risk factor and improve a baby’s assisted breathing in general.

The bleeding of IVH occurs typically within the first 48 hours following birth, and it is very unlikely to occur again at a later date.

There are two main ways in which IVH can potentially cause damage. First, IVH may affect the flow of CSF in the ventricles and second, IVH may cause damage to brain tissue adjacent to the ventricles. Once damage has occurred to brain tissue, it cannot be reversed. However, physical damage to brain tissue does not necessarily mean damage to brain function. The areas of the brain that are often affected by an IVH, those adjacent to the ventricles, are those responsible for motor functions. Commonly, problems with vision and hearing, and other higher cognitive functions are associated. The extent of any long-term effect will often depend on the severity of the bleeding: babies with severe IVH are likely to develop some kind of neurological disability. There is however, a wide range of disability, those with hemiplegia are affected on one side of body only and children with milder forms of diplegia, affecting only the legs, are usually able to walk with minimal supports.

Luckily, many babies who have a mild IVH go on to develop normally or with only minimal disabilities associated with learning.

Saturday, 16 April 2011

Cerebral Palsy. - A Short Guide.

My new book, 'Cerebral Palsy. - A Short Guide.'  £5.99  follow the link

Cerebral Palsy. - A Short Guide

This guide is designed for parents whose children have received a diagnosis of cerebral palsy. It aims to fill a void. - The void of information and support, which should be provided by the healthcare professions,but is not. A void which leaves parents without knowledge or support, afraid, confused, and not knowing where to turn or what to do. This guide provides a clear explanation of what CP is, the effects it can have on a child and what can be done to treat it.

Tuesday, 12 April 2011

The Role of Music in Human Evolution.

This is why exposure to music forms a vital part of all Snowdrop rehabilitation programmes for children with developmental disabilities like cerebral palsy and autism.
With thanks to The Scavenger.

Evidence suggests that music remains just as essential to the human race now as it did 70,000-80,000 years ago, writes Alan Harvey.
10 April 2011
All human cultures and social groups that we know of respond to music and dance. The type of music may vary but the underlying, fundamental principles of making music are the same.
Our recognition of, and emotional responses to, pleasant and unpleasant music seems to be universal, expressed even in very young infants and seemingly independent of our cultural upbringing.
So what exactly is music for? Why is it a universal that can profoundly affect people, why is it such an essential part of our lives?
Music is a form of communication which is different from language. In humans, music stimulates emotions and elicits autonomic and physiological responses. It entrains neural activity and is inextricably linked to movement and dance.
Music facilitates interactions within groups and can create common arousal states. It helps to provide cohesion and organisation to our social architecture.
Throughout recorded history, leaders – whether of nations, political parties or religious denominations – have understood the power of music to influence populations.
In recent times, researchers have shown that music structures time and provides mnemonic frameworks that aid learning and memory, help organise knowledge. Many of us can remember the lyrics of songs for example, but may not remember much, if any prose.
Attaching words to music somehow makes the words easier to memorise. Yet despite all of this, the impact of music remains mysterious: it does not seem to do anything, it does not transmit data and information in the same way as language/speech.
For many, the evolution of language in Homo sapiens is a unique event that is linked to the evolution of the cognitively modern mind. What then is the relationship between music and language, and to what extent are they dependent or independent of each other?
Our brains are known to be wired to process both forms of communication, but from an evolutionary point of view did music come before language, or vice versa, or was there a common precursor that somehow separated into two systems when Homo sapiens evolved, with both types of communication retained?
Was music an important element that contributed to the early well-being of our species? What, if any, advantages did music give to Homo sapiens from an evolutionary perspective as our founders migrated out of east Africa to colonise the planet?
Why does music continue to exist alongside language and remain important to all human cultures, thousands of generations after the founders of our species evolved?
Modern neuroscience research, especially using new imaging techniques such as positron emission tomography (PET) and functional Magnetic Resonance Imaging (fMRI) confirms that the processing of music has a consistent structural foundation in the human brain.
It has been known for some time that, in right-handed individuals, language is mostly processed in the left cerebral hemisphere while many aspects of music involve right hemisphere activity.
But new imaging data have revealed even more complex circuitries involved in music and language processing. Numerous regions of the brain are integrated into networks that subserve music or language processing and analysis, but the neuroimaging data also show that separation of these processing streams is by no means complete.
For example, there is overlap in brain areas that process the emotional (prosodic) aspects of music and speech, and studies have shown that musical training results in a shift towards processing in the left cerebral hemisphere.
As research continues, more is learned about how music-related circuits differ from, or overlap with, other pathways involved in cognitive and emotional processing. For example, brain areas associated with positive responses to music overlap with networks associated with reward behaviours, subjective experiences and acts of social cooperation.
In close association with the evolution of the modern mind, I believe music was of critical importance to our early ancestors; increased fitness and reproductive advantage of a group is gained not only by an individual’s success but also if co-operative behaviours benefit other members of the group, and importantly for our ancestors these benefits extended to others who were not necessarily genetically related.
For most people, music therapy remains a branch of “alternative” medicine, something outside the mainstream. But recent research suggests that it is time that this attitude was changed.
For example, training in music has measurable effects on brain plasticity and can influence learning ability during development. Music also seems to have mnemonic powers, activating circuits in the brain that are linked to aspects of memory processing.
There are also structural changes in developing brains associated with early musical training, and exposure to music seems to have beneficial effects on children suffering from developmental disorders such as autism and Williams syndrome.
In adults, many studies have shown that music used with physical therapy improves motor control and coordination, with benefits for rehabilitation after injury or in degenerative conditions such as Parkinson’s disease.
Music therapy may also improve memory recall and social awareness in Alzheimer’s patients and recent studies on stroke patients have shown that controlled exposure to music improves cognitive function, increases motivation and awareness, and enhances positive mood states.
Taken together, the evidence suggests that music remains just as essential to Homo sapiens now as it was 70,000-80,000 years ago. It continues to be important for development of our children, for our health and for our overall sense of mental well-being.
Above all, music is perhaps the primary medium which enables individual members of the species Homo sapiens to forget their mortal vulnerability and come together as a collective group to share and enjoy common physiological and emotional experiences.

Monday, 11 April 2011

Does another piece of the autism puzzle fit into place?

Neuroscientists have pinpointed the brain structure regulating our sense of personal space, possibly opening the way to a better understanding of autism and other disorders. 

The structure, the amygdala - a pair of almond-shaped regions located in the brain - was previously known to process strong negative emotions such as anger and fear and is considered the seat of emotion in the brain.  However, it had never been linked rigorously to real-life human social interaction.

The scientists, led by Ralph Adolphs, psychology and neuroscience professor and post-doctoral scholar Daniel P. Kennedy, at the California Institute of Technology (Caltech), were able to make this link with the help of a unique patient, a 42-year-old woman known as SM, who has extensive damage to the amygdala on both sides of her brain.

"SM is unique, because she is one of only a handful of individuals in the world with such a clear bilateral lesion of the amygdala, which gives us an opportunity to study the role of the amygdala in humans," says Kennedy, who led the study.

SM has difficulty recognising fear in the faces of others, and in judging the trustworthiness of someone, two consequences of amygdala lesions that Adolphs and colleagues published in prior studies.

During his years of studying her, Adolphs also noticed that the very outgoing SM is almost too friendly, to the point of "violating" what others might perceive as their own personal space.

"She is extremely friendly, and she wants to approach people more than normal. It's something that immediately becomes apparent as you interact with her," says Kennedy.

Previous studies of humans never had revealed an association between the amygdala and personal space.

From their knowledge of the literature, however, the researchers knew that monkeys with amygdala lesions preferred to stay closer to other monkeys and humans than did healthy monkeys.  Intrigued by SM's unusual social behaviour, Adolphs, Kennedy, and their colleagues devised a simple experiment to quantify and compare her sense of personal space with that of healthy volunteers.

The experiment used what is known as the stop-distance technique. Among the other subjects, the average preferred distance was .64 metres-roughly two feet.  SM's preferred distance was just .34 meters, or about one foot. Unlike other subjects, who reported feelings of discomfort when the experimenter went closer than their preferred distance, there was no point at which SM became uncomfortable; even nose-to-nose, she was at ease. Furthermore, her preferred distance didn't change based on who the experimenter was and how well she knew them.

"Respecting someone's space is a critical aspect of human social interaction, and something we do automatically and effortlessly," Kennedy says.

The discovery appeared in the Sunday issue of Nature Neuroscience.
What these researchers do not allude to is that just because the amygdala may be wired in a specific way in people who have autism, this does not mean that the situation is unchangeable. We know that the brain possesses a high degree of plasticity and can and does restructure it's functional organisation in response to the environment in which it finds itself. Therefore if we provide the appropriate neuro-developmental environment, we give people who face difficulties on the autistic spectrum every opportunity for their brain to reorganise itself. This is exactly what a Snowdrop programme entails.

Wednesday, 6 April 2011

Periventricular Leukomalacia. (PVL)

What is periventricular leukomalacia (PVL)?

Periventricular leukomalacia (PVL) is damage and softening of the white matter, the inner part of the brain that transmits information between the nerve cells and the spinal cord as well as from one part of the brain to another. "Periventricular" means around or near the ventricles, the spaces in the brain containing the cerebrospinal fluid. "leuko" means white. "malacia" means softening.

Why is periventricular leukomalacia a concern?

With PVL, the area of damaged brain tissue can affect the nerve cells that control motor movements. As the baby grows, the damaged nerve cells cause the muscles to become spastic, or tight, and resistant to movement. Babies with PVL have a higher risk of developing cerebral palsy and may have intellectual or learning difficulties. PVL may occur alone or in addition to intraventricular hemorrhage (bleeding inside the brain). PVL is commonly a cause of cerebral palsy.

What causes periventricular leukomalacia?

It is not clear why PVL occurs. This area of the brain is very susceptible to injury, especially in premature babies, whose brain tissues are fragile. PVL may happen when the brain receives too little oxygen. However, it is not clear when the trigger for PVL occurs - before, during, or after birth. Most babies who develop PVL are premature, especially those born before 30 weeks gestation. Other factors that may be associated with PVL include early rupture of membranes (amniotic sac) and infection inside the uterus.

What are the symptoms of periventricular leukomalacia?

PVL may not be apparent until later months. Each baby may experience symptoms differently. The most common symptom of PVL is spastic diplegia, tight, contracted muscles, especially in the legs. Symptoms of PVL may resemble other conditions or medical problems, so it may not be spotted straight away.

How is periventricular leukomalacia diagnosed?

cranial ultrasound, a painless test that uses sound waves to view the baby's brain through the fontanelles, the soft openings between the skull bones. With PVL, the ultrasound shows cysts or hollow places in the brain tissue.

magnetic resonance imaging (MRI). This test uses a combination of a large magnet, radio frequencies, and a computer to produce detailed images of internal structures. MRI may show some of the early changes in the brain tissue that occur with PVL.

Can PVL be treated?

Yes. Snowdrop treats many children where PVL has gone on to cause cerebral palsy. Many of them make good progress on our programme.