Physiatry Practice Management Resources

Studies Yield Insight Into The Numerical Brain

Two studies in the January 18, 2007, issue of the journal Neuron, published by Cell Press, shed significant light on how the brain processes numerical information--both abstract quantities and their concrete representations as symbols. The researches said their findings will contribute to understanding how the brain processes quantitative information as well as lead to studies of how numerical representation in the brain develops in children. Such studies could aid in rehabilitating people who suffer from dyscalculia--an inability to understand, remember, and manipulate numbers. The researchers also said their findings offer insight into the mystery of how the brain learns to associate abstract symbols precisely with quantities.

Both studies reveal in unprecedented detail how structures in the parietal cortex--the region of higher cognitive processing just above the forehead--activates during perception of both abstract quantities and numerical symbols.

In one paper, Manuela Piazza and colleagues showed that regions of the parietal lobe activate in response to numbers, either when they are presented as patterns of dots or as Arabic numerals.

In their experiments, the researchers asked human volunteers to pay attention to the quantities conveyed by groups of dots or numeric digits presented to them. During the process, the subjects' brains were scanned using functional magnetic resonance imaging (fMRI), in which harmless magnetic fields and radio waves are used to measure blood flow in brain regions, which reflects activity.

The researchers found that the initial presentation of the numeric stimuli activated the parietal region of the subjects' brains, which subsided as they adapted to the stimulus. However, the activation rebounded when the subjects were presented with an abrupt change in the quantity, whether it was represented in the same (dots versus dots) or different (dots versus Arabic numerals) notation as the original. This rebound indicated that the region was processing numerical information.

However, to unambiguously establish that the subjects' brains were really reacting to numerical quantity, the researcher occasionally injected a "deviant stimulus" into the second presentation of a quantity as the brain was adapting to it. This deviant stimulus consisted of a different number that was either close to, or far from, the number being presented. The researchers found that this deviant quantity interrupted adaptation more if it was distant from the adaptation quantity than if it was closer--conclusive evidence that the subjects were processing numerical quantities.

The researchers concluded that their findings "indicate an important role for parietal cortex in the coding of symbolic and nonsymbolic quantities."

They also concluded that "crucially, we observed crossnotation adaptation and recovery, particularly in the right parietal cortex, supporting the idea that shared neural populations encode nonsymbolic quantities and symbolic stimuli." Piazza and colleagues also concluded that their findings shed light on how the brain learns to associate symbols with numbers.

"Our results show that, at least in the adult brain, numerical symbols and nonnumerical numerosities converge onto shared neural representations," they wrote. "Perhaps we attach meaning to symbols by physically linking populations of neurons sensitive to symbol shapes to preexisting neural populations holding a nonsymbolic representation of the corresponding preverbal domain (e.g., numerosity)."

In the other paper in Neuron, Roi Cohen Kadosh and colleagues conducted experiments demonstrating that the two hemispheres of the parietal lobe function differently in processing numbers. While the left lobe harbors abstract numerical representations, the right shows a dependence on the notation used for a number, they found. The researchers concluded that "results challenge the commonly held belief that numbers are represented solely in an abstract way in the human brain." The authors also concluded that their results "advocate the existence of distinct neuronal populations for numbers, which are notation dependent in the right parietal lobe."

In their experiments, the researchers also used the adaptation phenomenon, that the brain adapts to stimuli by reducing its initial activity--and that repeating the same quantity leads to reduced activation compared to changing the quantity. They asked subjects whose brains were being scanned using fMRI to view consecutive numbers presented on a screen that represented either the same or different quantities. Crucially, the numbers were also presented either as two words (e.g., two or eight), two digits (e.g., 2 or 8), or a mixed notation (two and 8).

They hypothesized "that if the assumption of an abstract representation of numbers in the [parietal cortex] held true, the adaptation effect would be observed within and across notations. In contrast, in the case of nonabstract numerical representation, we expected that the adaptation effect would be modulated by the notation type. This result would suggest that distinct neuronal populations for notation exist." This meant that if the brain region was purely representing an abstraction of a number (e.g., 8) then any notational representation of this number (e.g., 8 or eight) would cause an adaptation effect. Alternatively, if a brain region processed a specific nonabstract number (e.g., 8) then adaptation would only be seen for the same notation (e.g., 8 but not eight).

Their analysis revealed an effect of notation in the right parietal lobe, showing that this region appears to harbor neurons that process nonabstract numerical representations, in addition to neurons that code for abstract representations of numeric quantities.

The researchers said that exploring how the processing of numerical symbols develops could have clinical implications. "Developmental studies should focus on tracing the emergence of numerical representation in the brain, investigating in particular at which stage such a representational divergence appears. Such findings could contribute significantly both to the field of numerical cognition research and rehabilitation of people suffering from developmental dyscalculia," they wrote.

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Cohen Kadosh et al.

The researchers include Roi Cohen Kadosh of Ben-Gurion University of the Negev in Beer-Sheva, Israel and University College London in London, UK; Kathrin Cohen Kadosh of Ben-Gurion University of the Negev in Beer-Sheva, Israel and Birkbeck College in London, UK; Amanda Kaas of Maastricht University in Maastricht, The Netherlands and Max Planck Institute for Brain Research in Frankfurt am Main, Germany; Avishai Henik of Ben-Gurion University of the Negev in Beer-Sheva, Israel; Rainer Goebel of Maastricht University in Maastricht, The Netherlands.

This work was supported by grants to R.C.K. from the Boehringer Ingelheim Fonds, the Zlotowski Center for Neuroscience, and the Kreitman Foundation.

Piazza et al.

The researchers include Manuela Piazza, Philippe Pinel of INSERM, Service Hospitalier Frédéric Joliot, CEA, DRM, DSV, and IFR49 in Orsay, France; Denis LeBihan of Service Hospitalier Frédéric Joliot, CEA, DRM, DSV and IFR49 in Orsay, France; Stanislas Dehaene of INSERM, Service Hospitalier Frédéric Joliot, CEA, DRM, DSV and IFR49 in Orsay, France and Collège de France in Paris, France.

This work was supported by INSERM, CEA, a Marie Curie fellowship of the European Community QLK6-CT-2002-51635 (M.P.), and a McDonnell Foundation centennial fellowship (S.D.).

Cohen Kadosh et al.: "Notation-Dependent and -Independent Representations of Numbers in the Parietal Lobes." Publishing in Neuron 53, 307-314, January 18, 2007. DOI 10.1016/j.neuron.2006.12.025. http://www.neuron.org/

Piazza et al.: "A Magnitude Code Common to Numerosities and Number Symbols in Human Intraparietal Cortex." Publishing in Neuron 53, 293-305, January 18, 2007. DOI 10.1016/j.neuron.2006.11.022. http://www.neuron.org/

Related preview by Ansari et al.: "Does the Parietal Cortex Distinguish Between "10", "Ten", and Ten Dots?"

Contact: Erin Doonan
Cell Press

The Fitting Of A Power Knee For First Time Ever On The First VA Patient To Receive One

What:

Veterans with diabetes comprise over half of all hospitalizations for lower-extremity ulceration, and two-thirds of all hospitalizations for amputation. In fact, diabetes affects nearly one in five veterans who receive care in the VA healthcare system. The VA is taking steps to improve the functional outcome of these amputee patients by empowering their caregivers with the knowledge of advanced bionic prosthetic technologies and gait training.

Who:

Ossur (http://www.ossur.com/) the developer and maker of the most scientifically advanced prosthetic innovations in the world, is working hand-in-hand with the VA to help bring about a seamless transition for soldiers moving from the Department of Defense's care to that of the Department of Veterans Affairs. Between January 16 and 19, Ossur instructed and certified the VA's prosthetists and physical therapists on the selection, fitting and use of the 21st century's hottest technological products - bionics - to improve the quality of life for amputees.

Observe:

Brian Frasure, a relentless winner of numerous gold, silver and bronze medals at three Paralympic Games (so far), demonstrated all of the things he can do today thanks to his PROPRIO FOOT by Ossur, the world's first motor-powered and artificially intelligent prosthesis for below-the knee amputees. Brian is also a Board Certified Prosthetist.

Discuss

Retired Special Forces SGM Brad Halling lost his leg in Somalia (when his Black Hawk went down). He compared his experience as an amputee veteran in those days with that of today's war vet. He also told you what he thinks of his intelligent POWER KNEE by Ossur. Have him show you how he can climb up stairs foot-over-foot. Brad is a prosthetist himself and can explain, in lay terms, the functional benefits about this new and ground-breaking device that replaces lost muscle function.

Meet:

He lost his leg while leading international teams in the clearing of landmines in Afghanistan, but SFC Mike McNaughton has never stopped moving forward, taking one sure step after another on his RHEO KNEE by Ossur. Mike has become quite the celebrity recently, running alongside President Bush at the White House and inspiring millions as he portrays the story of a soldier who has lost his leg in the war, in Lonestar's music video and smash hit "Mountains."

Ask:

They are the experts… the doctors who are helping to make all this possible. They were asked why they do it:

* Lieutenant Colonel Paul F. Pasquina, M.D., Medical Director of the Amputee Program and the Chairman of Physical Medicine & Rehabilitation at Walter Reed Army Medical Center is committed to providing comprehensive and holistic care to all injured military service members.

* Bob Gailey, PhD is admired by prosthetists and orthotists the world over for his groundbreaking workshops that teach amputees how to increase their mobility and make the most of their prosthesis

When:

Wednesday, January 17

Where:

Miami VA Medical Center, 1201 NW 16th Street 33125

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Contact:

Tabi King
Ossur Americas

Susan E. Ward (VA)
Public Affairs Officer

Contact: Beverly Millson
Ossur

Watching With Intent To Repeat Ignites Key Learning Area Of Brain

Watch and learn. Experience says it works, but how? University of Oregon researchers have seen the light, by imaging the brain, while test subjects watched films of others building objects with Tinker Toys.

As detailed in the Dec. 20 issue of the Journal of Neuroscience, researchers, using functional magnetic resonance imaging, found that when a person watches someone else perform a task with the intention of later replicating the observed performance, motor areas of the brain are activated in a fashion similar to that with accompanies actual movement.

"We've been looking at the process of motor learning through observation in the context of procedures," said principal investigator Scott H. Frey, professor of psychology and director of the Lewis Center for Neuroimaging at the University of Oregon. Frey's interest is geared toward improvements in rehabilitation for individuals suffering brain or bodily injury.

"Teaching a physical skill often involves someone demonstrating the essential action components after which the learner tries to reproduce what has been observed. This is true for behaviors ranging from learning to eat with utensils, playing an instrument or performing surgery. We wanted to know how the brain takes what is seen and translates it into a motor program for guiding skilled movements," he said.

In the experiment, 19 college-aged, healthy adults watched a series of digital videos of another person putting together or disassembling objects using six toy parts. In one condition, participants simply watched the activity; in another, they observed clips with the intention to be able to reproduce the actions in the correct sequential order minutes later.

Despite lying completely still during these tasks, observing with the intention to learn actions and subsequently reproduce them engages areas of the brain known to contribute to motor learning thorough actual physical practice. In particular, Frey said, the amount of activity occurring in the intraparietal sulcus -- when watching to learn accurately -- predicts how well these actions are reproduced minutes later.

Frey's group and others have previously implicated that this region is involved in organizing goal-directed manual actions. In effect, Frey said, the activity in intraparietal cortex may act as a thermometer that shows how well a person is translating what they are observing into a motor program for later performance.

"What appears vital is the intention of the observer rather than simply the visual stimulus that is being viewed," Frey said. "If the goal is to be able to do what you are seeing, then it appears that activity through your motor system is up-regulated substantially."

Using fMRI, researchers are able to monitor changes in activity throughout the entire brain while people think by taking advantage of differences in the magnetic properties of oxygenated and deoxygenated hemoglobin. These changes closely track underlying neural activity.

The findings "implicate the parieto-frontal mirror system in encoding the spatial components of observed actions and the primary motor cortex in the formation of novel motor memories through observation," wrote Frey and research assistant Valerie E. Gerry in their conclusions.

"This study is the first in a series of several experiments that we plan to do," Frey said. "It tells us something about how our own motor systems can be engaged and stimulated even in the absence of overt movements. This could prove important as a means of facilitating rehabilitation of individuals with movement impairments or paralysis."

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The National Institutes of Health and the James S. McDonnell Foundation funded the research through grants to Frey.

Contact: Jim Barlow

Source: Scott H. Frey, director, Lewis Center for Neuroimaging

Links:

http://lcni.uoregon.edu/index.html

http://freylab.uoregon.edu/

http://psychweb.uoregon.edu/faculty/facultyinfo.htm#Frey

Contact: Jim Barlow
University of Oregon

As lawmakers in Washington, DC, and in statehouses around the United States continue to debate methods to address the malpractice crisis, 2 facts have become indisputable: premium increases have become unsustainable in some specialties, and access to certain types of medical care has become scarce, even nonexistent.

With the rapid-fire advancements in medicine, it's impossible to store existing and new information in your head and recall it at the point of care for each patient you treat. Fortunately, tools such as flow, clinical protocols, and other reminders can reduce the chance that important factors are overlooked. Call in a consultant or specialist if a patient is critically ill or isn't getting better as quickly as expected or wanted, or when there is an expression of dissatisfaction with the care.

When dictating notes for the patient's chart, be sure to include all of the important details. If an error is made in the chart, do not go back and surreptitiously alter a record. Correcting errors, when they occur, should be done with a single strike-through line that is initialed, dated, timed, and identified as an "error." Extensive or significant errors may require more detailed explanation. Be objective and discreet, as you do not know who will eventually read the chart. A belligerent patient may seem drunk but rather may be suffering a reaction of some sort. Use language that is descriptive, objective, and respectful.

This should go without saying, but make sure your handwriting is legible. Some physicians actually believe that illegible notes are a good way to prevent lawsuits because they hide any evidence of wrongdoing. In reality, illegible notes provide no protection and are viewed by juries as reflecting sloppy writing and, perhaps, sloppy care. Years later, when the case finally gets to the jury, the medical record can be the doctor's best, and often only, friend as memories fade over time.

Legible and logical notes detailing thoughtful care provide the best malpractice defense. Your best bet is an electronic medical record system, as it brings a wealth of information to the point of care; next best is to have notes dictated and transcribed. If notes must be handwritten, make certain they are legible.

As the malpractice crisis continues, ramifications are being felt by everyone. Patients who lose their doctors suffer. Employers and others who pay for healthcare premiums are penalized with higher rates. Doctors are forced to give up or change their careers. Hospitals pay exorbitant premiums for insurance, which would be better used in improving systems for healthcare delivery.

It remains to be seen whether tort reform will be a reality in Congress this session, or if it will be bogged down in the traditional doctor vs trial lawyer political schism. While the steps above will not ensure that you will avoid an unhappy encounter with our legal system, they should help you avoid some of the mistakes, however unintended, that could lead to a costly verdict.

According to data from the American Medical Association,^[1] 18 states are experiencing serious patient access problems due to physicians who have stopped practicing or have stopped performing high-risk procedures. They include states with large metropolitan areas such as Illinois, New Jersey, and New York; rural states such as Arkansas and West Virginia, and many in between.

A 2003 survey conducted by Blue Cross Blue Shield Association plans in these "crisis states" states found that more than half (56%) of their doctors are either retiring, leaving the state, or refusing to perform high-risk procedures, such as delivering babies. More and more, physicians are resorting to practicing "defensive medicine," by ordering extra tests that may be unnecessary but could provide protection from a potential lawsuit.

With the rapid-fire advancements in medicine, it's impossible to store existing and new information in your head and recall it at the point of care for each patient you treat. Fortunately, tools such as flow, clinical protocols, and other reminders can reduce the chance that important factors are overlooked. Call in a consultant or specialist if a patient is critically ill or isn't getting better as quickly as expected or wanted, or when there is an expression of dissatisfaction with the care.

When dictating notes for the patient's chart, be sure to include all of the important details. If an error is made in the chart, do not go back and surreptitiously alter a record. Correcting errors, when they occur, should be done with a single strike-through line that is initialed, dated, timed, and identified as an "error." Extensive or significant errors may require more detailed explanation. Be objective and discreet, as you do not know who will eventually read the chart. A belligerent patient may seem drunk but rather may be suffering a reaction of some sort. Use language that is descriptive, objective, and respectful.

This should go without saying, but make sure your handwriting is legible. Some physicians actually believe that illegible notes are a good way to prevent lawsuits because they hide any evidence of wrongdoing. In reality, illegible notes provide no protection and are viewed by juries as reflecting sloppy writing and, perhaps, sloppy care. Years later, when the case finally gets to the jury, the medical record can be the doctor's best, and often only, friend as memories fade over time.

Legible and logical notes detailing thoughtful care provide the best malpractice defense. Your best bet is an electronic medical record system, as it brings a wealth of information to the point of care; next best is to have notes dictated and transcribed. If notes must be handwritten, make certain they are legible.

As the malpractice crisis continues, ramifications are being felt by everyone. Patients who lose their doctors suffer. Employers and others who pay for healthcare premiums are penalized with higher rates. Doctors are forced to give up or change their careers. Hospitals pay exorbitant premiums for insurance, which would be better used in improving systems for healthcare delivery.

It remains to be seen whether tort reform will be a reality in Congress this session, or if it will be bogged down in the traditional doctor vs trial lawyer political schism. While the steps above will not ensure that you will avoid an unhappy encounter with our legal system, they should help you avoid some of the mistakes, however unintended, that could lead to a costly verdict.