Neurological Disorders: Alien Hand Syndrome

Synonyms:
 Anarchic hand; Diagnostic dyspraxia;  Intermanual conflict; Magnetic apraxia; Unilateral apraxia; La main etrangere. 

Overview
     Alien hand syndrome  is a rare neurological disorder that causes hand movement without the person being aware of what is happening or having control over the action. The afflicted person may sometimes reach for objects and manipulate them without wanting to do so, even to the point of having to use the healthy hand to restrain the alien hand. A new study identified the areas of the brain involved in both voluntary and involuntary movement and found that neural activity was restricted to the primary motor cortex during the unconscious motor activity seen with AHS. The study will be published online in the official journal of the American Neurological Association.

      The alien hand syndrome, as originally defined, was used to describe cases involving anterior corpus callosal lesions producing involuntary movement and a concomitant inability to distinguish the affected hand from an examiner's hand when these were placed in the patient's unaffected hand. In recent years, acceptable usage of the term has broadened considerably, and has been defined as involuntary movement occurring in the context of feelings of estrangement from or personification of the affected limb or its movements. Three varieties of alien hand syndrome have been reported, involving lesions of the corpus callosum alone, the corpus callosum plus dominant medial frontal cortex, and posterior cortical/subcortical areas. A patient with posterior alien hand syndrome of vascular aetiology is reported and the findings are discussed in the light of a conceptualisation of posterior alien hand syndrome as a disorder which may be less associated with specific focal neuropathology than are its callosal and callosal-frontal counterparts.


Clinical case:
     A 71-year-old right-handed woman developed acute left hemiparesis and visual hallucinations. She also complained that her left hand uncontrollably scratched her and pulled at her hair. Past medical history was notable for chronic hypertension and triple coronary artery bypass graft 6 years earlier. Two weeks before the illness, she had felt diffusely weak; another hospital had attributed this weakness to metoprolol toxicity. When her complaints did not subside after 2 days off medication, her husband brought her to the emergency room. Evaluation disclosed full orientation, left lower facial weakness, right gaze bias, left hemibody hypesthesia, and extensor posturing of the left limbs, with the left hand constantly clenched. Cranial CT scan indicated acute right parietal cortical infarct and extensive bilateral subcortical white matter ischemic changes.
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Sources:
http://jnnp.bmj.com/content/68/1/83.full
http://www.jsmf.org/meetings/2008/may/Mark%20VW%202008%20Alien%20hand%20syndrome.pdf
http://www.ncbi.nlm.nih.gov/pubmed/20220444
http://emedicine.medscape.com/article/1136037-overview

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Little Evidence That Diet, Lifestyle Cuts Alzheimer's Risk

Numerous studies have attempted to link specific behaviors and health conditions to the onset of Alzheimer's disease, but scientists still can't say for sure that anything you do or don't do will prevent the brain disorder, according to a new U.S. review of recent research. The U.S. National Institutes of Health convened a conference last spring to analyze 18 studies of potential risk factors, such as poor eating habits, chronic illness, smoking or little exercise, and development of Alzheimer's disease. "Although we are not dismissing the potential or important role that these major risk factors might play in the development of Alzheimer's disease, at this time, with what we have currently, we cannot confirm any risk associations," said study lead author Dr. Martha L. Daviglus, a professor of preventive medicine and medicine at the Northwestern University Feinberg School of Medicine in Chicago.

"So we need to conduct more research, if we want to have the evidence in hand," she added. The study, which summarizes the NIH conference results, is published in the May 9 online edition and September print issue of the Archives of Neurology. For now, older age is the leading known risk factor for Alzheimer's disease, the study noted. A gene variation is also tied to increased risk, it said. An estimated 5.3 million Americans struggle with Alzheimer's, a figure projected to grow as the country's Baby Boomer population ages, the authors said. The disease is responsible for between 60 and 80 percent of dementia cases. "What we're talking about here is something that is going to affect so many Americans in the years to come," said one expert, Catherine Roe, an instructor in neurology at Washington University School of Medicine in St. Louis. "In fact, there's going to be an explosion in the next 50 years, because everyone is living longer in general," she said.

The studies included in the NIH research review were conducted between 1984 and 2009 in English. Participants were at least 50 years old and living in developed countries. Some of the studies looked into dietary influences, such as folic acid intake, Mediterranean diet and nutritional supplements. Others looked for a link between health problems, such as diabetes or high cholesterol, and Alzheimer's. Still others explored levels of physical activity or alcohol consumption and risk of Alzheimer's disease. The NIH team found that, as a whole, the studies were "compromised by methodological limitations" that undercut the ability to draw a firm association between any particular behavioral habit and/or health condition and Alzheimer's.

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Can Hormone Therapy or the Pill Prevent Brain Aneurysms?

Taking birth control pills or hormone replacement therapy could protect women against brain aneurysms later in life, a new study suggests, although one neurologist questioned the quality of the research. Cerebral aneurysms occur when a blood vessel in the brain weakens and balloons out, potentially leading to a hemorrhagic (or bleeding) stroke if the vessel bursts. These types of aneurysms are more common in women than men, possibly because lower levels of female hormones after menopause play a role in their development, the study authors noted.

Brain aneurysms are more common after the age of 40 and are most likely to burst when people are in their 50s. In the study, Dr. Michael Chen, of Rush University Medical Center, and colleagues interviewed 60 women who had experienced brain aneurysms and asked about their use of birth control pills and hormone replacement therapy, and compared their answers to those from a group of almost 4,700 other women in the general U.S. public. The women who had brain aneurysms were significantly less likely to have taken birth control pills or received hormone replacement therapy, and were also more likely to have entered menopause earlier, according to the report published online May 4 in the Journal of NeuroInterventional Surgery.

Previous research has suggested that taking birth control pills lowers the risk of hemorrhagic (bleeding) stroke in later life. However, women who either begin menstruating at an early age, don't have children, or both, face a higher risk. Because estrogen is important for the repair and maintenance of blood vessel walls, a drop in the levels of the female hormone is believed to be the reason for the increased risk to the structure of these vessels, the study authors noted in background information about the research. However, commenting on the study, neurologist Dr. Cathy Sila said the research is flawed and its conclusions overstated.

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Stroke Hospitalizations Up in Teens, Young Adults

Older Americans are suffering fewer strokes, but new government research shows that stroke hospitalizations are sharply rising among children and younger adults, especially for men under 35. Although the study doesn't explore the reasons for the trend, experts point to the obesity epidemic, increasing rates of diabetes and high blood pressure as likely culprits. Recreational drugs may play a role as well, they added. "Young people should see their doctor for regular checkups," said Dr. Brett Kissela, a professor of neurology at the University of Cincinnati Neuroscience Institute, who has conducted previous research on strokes but was not involved with this study.

Routine check-ups can help control risk factors for stroke, such as high blood pressure, he explained. Dr. Mary George, a researcher with the U.S. Centers for Disease Control and Prevention, is scheduled to report the findings Wednesday at the International Stroke Conference in Los Angeles. Experts note that research presented at meetings typically has not been subjected to the same scrutiny as studies published in peer-reviewed medical journals. For the study, CDC researchers examined hospitalization data for the period from 1994 to 2007 from the Nationwide Inpatient Sample, identifying patients with a primary diagnosis of ischemic stroke.

Ischemic stroke, which occurs when a blood clot or clogged artery blocks the blood supply to the brain, is more common than hemorrhagic stroke, the result of a ruptured blood vessel. The increases and decreases in stroke rates varied by gender and age group, the researchers found. Among males aged 15 to 34, the rate surged by nearly 53 percent. Among females in that age group, it increased 17 percent. Strokes soared 36 percent in boys aged 5 to 14 and 31 percent in girls of the same age. Men between 35 and 44 years old had a 47 percent increase in stroke incidence. For women in that age range, stroke incidence rose 36 percent.

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Electrical Stimulation of the Brain May Spark Insight

Electrical stimulation of the brain can bring a flash of insight that can help people solve new, difficult problems, research suggests. Investigators in Australia found that volunteers who received electrical stimulation of the brain's anterior temporal lobes were three times more likely to be able to figure out a challenging, unfamiliar problem than participants in a control group.

Many people have difficulty achieving creative leaps needed to solve new problems because they tend to stick to strategies and insights that have been successful before, study authors Richard Chi and Allan Snyder, from the Center for the Mind at the University of Sydney, explained in a news release from the Public Library of Science.The use of "transcranial direct current stimulation" temporarily increases or decreases the activity of populations of brain cells, the study authors said.

This safe, noninvasive technique can be used to manipulate the competition between the left and right hemispheres of the brain by inhibiting and/or activating certain networks, they explained. According to Chi and Snyder, the right anterior temporal lobe is associated with insight or finding new meaning, and the inhibition of activity in the left anterior temporal lobe can lead to thinking that is less likely to be influenced by preconceptions. However, the authors noted that more research is needed.

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Brisk Walks May Boost Memory in Older Adults

Older adults who took a brisk walk three times a week did better on memory tests and increased the size of their hippocampus, a portion of the brain involved with memory formation, researchers report. The findings suggest that loss of brain volume in old age can be delayed, and may even be reversible. Brain shrinkage is associated with memory impairment in the elderly. "We can change the brain in older adults," said lead study author Kirk Erickson, an assistant professor of psychology at the University of Pittsburgh.

"It's amazing that a one-year period of moderate exercise isn't just slowing down the atrophy, it's actually reversing it." For their the study, researchers from the University of Pittsburgh, University of Illinois, Rice University and Ohio State University divided 120 sedentary adults in their mid to late 60s, on average, into two groups: one group walked around a track for 40 minutes of aerobic exercise, three days a week, while the other group did stretching. Both groups performed better on a test of spatial memory. Spatial memory helps us to remember things like driving directions or where we left our keys.

But the groups differed in one important way. MRI brain scans showed that after a year on the exercise program, the aerobic exercise group's hippocampus was about 2 percent bigger than it was when they started, the equivalent to a reversal in age-related brain shrinkage of about one to two years, the researchers said. Those in the stretching group had a decrease of hippocampal volume of about 1.4 percent, the investigators found. Those who showed the greatest improvements in memory also showed the greatest increases in hippocampal volume, according to the study, published online Jan. 31 in the Proceedings of the National Academy of Sciences.

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Odds of Quitting Smoking May Be Clear on Scans

Brain scans can predict a smoker's chances of being able to quit, according to a new study. It included 28 heavy smokers recruited from a smoking cessation program. Functional MRI was used to monitor the participants' brain activity as they watched television ads meant to help people quit smoking. The researchers contacted the participants one month later and found that they were smoking an average of five cigarettes a day, compared with an average of 21 a day at the start of the study.

But there was considerable variation in how successful individual participants were in reducing their smoking. The researchers found that a reaction in an area of the brain, called the medial prefrontal cortex, while watching the quit-smoking ads was linked to reductions in smoking during the month after the brain scan. Previous research by the same team suggested that activity in the prefrontal cortex is predictive of behavior change.

In the new study, published in the current issue of Health Psychology, "we targeted smokers who were already taking action to quit, and we found that neural activity can predict behavior change, above and beyond people's own assessment of how likely they are to succeed," study author Emily Falk, director of the Communication Neuroscience Laboratory at the University of Michigan Institute for Social Research and Department of Communication Studies, said in a university news release.

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Epilepsy Found to Be More Common in U.S. Than Thought

A new study suggests that one of every 26 people in the United States will develop epilepsy at some point in their life. That's a higher rate than previously believed and, experts say, highlights the need for more funding and attention to the condition. "This study is an important analysis of the potential number of patients of epilepsy in the United States," said Dr. Joseph I. Sirven, the chairman-elect of the Epilepsy Foundation's professional advisory board and a professor and chairman of neurology at the Mayo Clinic in Scottsdale, Ariz.

Sirven, who was not involved in the study, noted that it makes two important points:

* Older adults are more at risk for developing epilepsy.

* A greater number of people will develop epilepsy during their lifetime than thought.

"The study suggests up to 12 million Americans will develop epilepsy, which is a greater number than expected," Sirven said. "Moreover, this is a conservative estimate and not the worst case scenario as the lifetime risk would be higher in more urban areas. Clearly, more attention needs to be paid to this condition." The findings are published in the Jan. 4 issue of Neurology. For the study, Dale C. Hesdorffer, an associate professor of clinical epidemiology at Sergievsky Center at Columbia University Medical Center in New York City, and her research colleagues looked for the likelihood of developing epilepsy among residents of Rochester, Minn., between 1960 and 1979.

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Gene Research Brings Insight Into Deadly Childhood Brain Tumor

U.S. scientists have unraveled the genetic code for the most common type of brain cancer in children. Gene sequencing reveals that this tumor, medulloblastoma, or MB, possesses far fewer genetic abnormalities than comparable adult tumors. The discovery that MB has five to 10 times fewer mutations than solid adult tumors could further attempts to understand what triggers the cancer and which treatment is most effective.

"The good news here is that for the first time now we've identified the broken genetic pieces in a pediatric cancer, and found that with MD there are only a few broken parts," said lead author Dr. Victor E. Velculescu, associate professor with the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University in Baltimore. "And that means it's potentially easier to intervene and to stop it," he said, likening the cancer to a train that's speeding out of control.

Velculescu and his colleagues, who report their findings in the Dec. 16 online issue of Science, say this is the first time genetic decoding has been applied to a non-adult cancer. Each year this cancer strikes about 1 in every 200,000 children younger than 15 years old. Before migrating through the patient's central nervous system, MBs begin in the cerebellum portion of the brain that is responsible for controlling balance and complicated motor function.

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